>our welders were a little sloppy in the beginning with arc strikes

I have to watch my guys when they lay the arc gouging lead down.
...the lead is still hot and they leave the carbon rod in the holder.
...it always ends up hitting against something by accident.

Brent-
    Again great job, I just ran the idea past my boss to educate our welders with the arc strike experiment.  We have recently ran some heavy steel jobs and our welders were a little sloppy in the beginning with arc strikes and not really paying attention to where the lead was in their hands.  I gave him a brief overview of your article and am having one of our shop guys cut plate now.  I really appreciate what all you guys do for this forum.  Not only does it make things easier to understand but make it easier to reiterate to either my students or my welders.  Much like Al's baby oil experiment its a real world experiment that a welder will understand right away. Straight up function at work.  You are giving me much needed ammo for my first semester of teaching this fall. Which brings me to this question:
What else do you guys have for welding experiments???

I would like to think I am inbetween a welder and an inspector, even though I am both, but Visual learning is something that everyone can benifet from.

Ill be sure to write a nice letter to the editor. 
Keep up the good work!

-Jordan

Brent;

I just read your article in Inspection Trends on the subject of arc strikes. All I can say is it is a good article and well written.

The photographs were a nice touch.

You gave John an honorable mention. Excellent!

Keep the articles coming my friend. Don't forget to keep copies to submit to AWS when it is time for your 9 year renewal. Take full credit for each article and by-pass having to take the Part B examination. Just one more way to accrue the 80 PDHs required to be exempt from taking the Part B examination.

Best regards - Al

Great job Brent! It took me a long time to get it downloaded due to remote access, well worth the wait. I remember when I was at your shop you mentioned to me some testing you had done on arc strikes. I will be passing this along to the guys!

Well done Brent....  I very much enjoyed reading your important paper in "Inspection Trends"

In my opinion, Arc Strikes should be placed within the scope of table 6.1

D1.1  only says that arc strikes are "undesirable"   What kind of marshmellow wrote that!?!?!?!

Guess what? I have worked on some rehab projects here in the good old USA and have seen just as bad and even worse in some cases. Mostly stuff put in prior to 1965. It seems that prior to that welding had began to improve but gas and oil companies began to realize that these lines could last a long time. The oldest rehab job I was ever on was a line that was put in in 1942 as a war efforts gas line supplying gas to some factories building various pieces of equipment for WW-II. As poor as the welds were, as poorly as the line was installed, and how the pipe and attachments were made, the line had never had a failure. It did leak a few times but nothing catastrophic. I have seen 24" pipe welds with 100% hi-lo in the line up operating at 850 PSIG, arc strikes all over the pipe and even the welder's initials welded on the surface of the pipe. I've seen them only half finished and some with only a root bead and hot pass in them operating at high pressures.

Most of these pipeline welds operate well with some tremendous defects in them. The stand hoop stress very well but longitudinal stresses, cyclic loading, and stress caused from 3rd party damage are tough obstacles to overcome.

You probably drive over some of these welds in the buried pipelines everyday. Strength is relative. Poor welds are probably stronger than the material they join together. But I, just as you, realize there are limits.

I agree with Al on this John.

It would have been different if he had found some missing welds, arc strikes, and other indications that easily caught the eye and brought up some gross negligence items.  Then I could see reviewing items already on site. 

I do TPI work for CA engineers for jobs being prefabbed in AZ shops.  Occassionally they get a little snippy.  The guys I work with and I stress that we will not go after anything outside of the codes.  We have to really watch because of Demand Critical, Seismic, and other considerations.  But we even stand our ground with inspectors on site who think we are not doing our job as TPI's properly.  Some of these guys go way overboard.  Especially those working directly for engineers.

Sounds like you should have just shipped them.  I don't have all the facts, but I think someone wanted to push his weight around.

Have a Great Day,  Brent

We've got 250 lb.s more of Excalibur to go through.  I thought that it was sticking a bit more than usual. 

I've got a guy that strikes it like a match first, making sure it arcs, then does his regular arc start.  Seems to work well for him.  We haven't had any porosity though.

Yeah, its recent. I had the super on this job convinced to buy a pallet of anything but excaliber, but available stocks put us right in a sinking boat. My day goes from bright and shining, to pure misery by noon. These other welders are young, and waste at least half a box of rods. I'm "sticking" it out.

Thank goodness the inspector passes arc strikes...criminy!

Watch my next post to see the worst welds in the world...

Here are some interesting questions to be answered if I say so myself! Can anybody or shall I say instead; Does anyone want to answer them???

1.)  A 12 mm diameter steel bolt joining two plates, each of 2 cm thickness, is tensioned to one-half of its yield strength of 900 MPa. The depth of the threads is one millimeter.
   What force is holding the two plates together due to tension in the bolt?
   How much has the bolt extended due to this tension?

2.)  Estimate the maximum shear load that can be applied to a riveted joint between two one millimeter thick aluminum sheets. The aluminum sheet has a yield strength of 100 MPa and a tensile strength of 225 MPa. The rivets are 2.5 mm in diameter, on 5 mm centers. Their strength is 175 MPa yield and 250 MPa tensile.
   Assume that the sheets are held together with one row of rivets.
   Assume that a double row of rivets holds the sheets together.

3.)  Two steel plates are to be joined together using either bolting or welding. The joint can be made with either six bolts or with 500 grams of weld metal. No procedure qualification is needed to produce the bolted joint. but the welded joint will require qualification of a test weld at a cost of $I,000. The probability of passing this qualification is 80% on the first attempt, 98% on the second attempt and 100% on the third attempt. The total cost of depositing weld metal is $8.00 per kilogram. The cost of a bolt, the bolt hole and assembly is $6.00 per bolt. How many units of production are needed to make the welded joint less expensive than the bolted joint?
  
4.)  An adhesive with a viscosity of 20 gm/cm/sec is applied between two disks of 2 cm diameter, using a force of 10 newtons. How long does it take to form a joint of 0.01 mm thickness? If the adhesive hardens to a viscosity of 108 gm/cm/sec, how long will the joint last under a tensile load of 500 newtons?
  
5.)  Estimate the force required to quickly separate two Johansson blocks which are 5 cm square, if the joint is 0.005 mm thick. The surface energy of water is 0.080 J/m2 and the viscosity is 1 gm/cm/sec. If the thickness of the lower block is 2 cm, how long will the joint last if the lower block is suspended by attachment to the upper block? The density of steel is 7.8 gm/cm3.
  
6.)  The world's largest diffusion bonding furnace can join plates 2.5 m by 3.5 m with a force of 10,000 metric tons. If the initial area of asperity contact is only ten percent of the apparent area of the plate and the flow strength of the material being bonded is 70 MPa at the bonding temperature. have the asperities deformed plastically at the start of the process?
  
7.)  The initial thickness of a transient liquid phase diffusion bond is 0.1 mm. The diffusivity of the diffusing species in the base metal is 10-10 cm2/sec. Estimate the time necessary to complete the bond. Compare this time with the time required to complete a joint which is initially 0.01 mm thick. [Note that the relationship in Equation 5 for heat diffusivity can be applied to mass diffusivity as well.]
  
8.)In wave soldering of printed circuit boards, the board is floated over a bath of flowing solder. All of the heat is supplied to the board by the molten solder. If the speed of soldering is controlled by the wetting time of freshly cleaned copper and the length of the solder bath is 3 cm, what is the maximum velocity at which the boards can be passed over the bath to provide fully soldered joints? If the electronic components on the board must not be heated to a depth greater than 0.5 mm beneath their surface, what is the slowest rate of travel of the board over the molten solder bath? You may assume a thermal diffusivity of the ceramic or plastic component housing of 0.02 cm2/sec.
  
9.)  A laser beam with a source intensity of 106 watts/cm2 strikes a large piece of steel with an absorption efficiency of forty percent.
   Estimate how long it will take to melt the surface of the steel if the heat necessary to raise iron from room temperature to the molten state is 10.2 joules/mm3.
   How long would it take for an arc of 104 watts/cm2 to melt the surface? The thermal diffusivity of steel is 0.1 cm2/sec.
 
10.)  Compare these times with the time to melt an aluminum surface. The thermal diffusivity of aluminum is 0.7 cm2/sec and the heat content from room temperature to the    molten state is 2.87 joules/mm3.
    The time of a resistance spot weld is measured in cycles of 60 Hz electric current. Estimate the depth to which a copper electrode is heated by conduction from the steel sheet in a 12 cycle weld. The thermal diffusivity of copper is 0.9 cm2/sec.The electrode has internal water cooling. The distance from the electrode-sheet interface to the water cooling channel is 7 mm.

12.)  In a robotic welding application, welds of 12 cycle duration are made at a rate of 40 welds per minute. Is the water effective in cooling the end of the electrode during this process?

Respectfully,
Henry

Here are some interesting questions to be answered if I say so myself! Can anybody or shall I say instead; Does anyone want to answer them???

1.)  A 12 mm diameter steel bolt joining two plates, each of 2 cm thickness, is tensioned to one-half of its yield strength of 900 MPa. The depth of the threads is one millimeter.
   What force is holding the two plates together due to tension in the bolt?
   How much has the bolt extended due to this tension?

2.)  Estimate the maximum shear load that can be applied to a riveted joint between two one millimeter thick aluminum sheets. The aluminum sheet has a yield strength of 100 MPa and a tensile strength of 225 MPa. The rivets are 2.5 mm in diameter, on 5 mm centers. Their strength is 175 MPa yield and 250 MPa tensile.
   Assume that the sheets are held together with one row of rivets.
   Assume that a double row of rivets holds the sheets together.

3.)  Two steel plates are to be joined together using either bolting or welding. The joint can be made with either six bolts or with 500 grams of weld metal. No procedure qualification is needed to produce the bolted joint. but the welded joint will require qualification of a test weld at a cost of $I,000. The probability of passing this qualification is 80% on the first attempt, 98% on the second attempt and 100% on the third attempt. The total cost of depositing weld metal is $8.00 per kilogram. The cost of a bolt, the bolt hole and assembly is $6.00 per bolt. How many units of production are needed to make the welded joint less expensive than the bolted joint?
   
4.)  An adhesive with a viscosity of 20 gm/cm/sec is applied between two disks of 2 cm diameter, using a force of 10 newtons. How long does it take to form a joint of 0.01 mm thickness? If the adhesive hardens to a viscosity of 108 gm/cm/sec, how long will the joint last under a tensile load of 500 newtons?
   
5.)  Estimate the force required to quickly separate two Johansson blocks which are 5 cm square, if the joint is 0.005 mm thick. The surface energy of water is 0.080 J/m2 and the viscosity is 1 gm/cm/sec. If the thickness of the lower block is 2 cm, how long will the joint last if the lower block is suspended by attachment to the upper block? The density of steel is 7.8 gm/cm3.
   
6.)  The world's largest diffusion bonding furnace can join plates 2.5 m by 3.5 m with a force of 10,000 metric tons. If the initial area of asperity contact is only ten percent of the apparent area of the plate and the flow strength of the material being bonded is 70 MPa at the bonding temperature. have the asperities deformed plastically at the start of the process?
   
7.)  The initial thickness of a transient liquid phase diffusion bond is 0.1 mm. The diffusivity of the diffusing species in the base metal is 10-10 cm2/sec. Estimate the time necessary to complete the bond. Compare this time with the time required to complete a joint which is initially 0.01 mm thick. [Note that the relationship in Equation 5 for heat diffusivity can be applied to mass diffusivity as well.]
   
8.)In wave soldering of printed circuit boards, the board is floated over a bath of flowing solder. All of the heat is supplied to the board by the molten solder. If the speed of soldering is controlled by the wetting time of freshly cleaned copper and the length of the solder bath is 3 cm, what is the maximum velocity at which the boards can be passed over the bath to provide fully soldered joints? If the electronic components on the board must not be heated to a depth greater than 0.5 mm beneath their surface, what is the slowest rate of travel of the board over the molten solder bath? You may assume a thermal diffusivity of the ceramic or plastic component housing of 0.02 cm2/sec.
   
9.)  A laser beam with a source intensity of 106 watts/cm2 strikes a large piece of steel with an absorption efficiency of forty percent.
   Estimate how long it will take to melt the surface of the steel if the heat necessary to raise iron from room temperature to the molten state is 10.2 joules/mm3.
   How long would it take for an arc of 104 watts/cm2 to melt the surface? The thermal diffusivity of steel is 0.1 cm2/sec.
  
10.)  Compare these times with the time to melt an aluminum surface. The thermal diffusivity of aluminum is 0.7 cm2/sec and the heat content from room temperature to the    molten state is 2.87 joules/mm3.
    The time of a resistance spot weld is measured in cycles of 60 Hz electric current. Estimate the depth to which a copper electrode is heated by conduction from the steel sheet in a 12 cycle weld. The thermal diffusivity of copper is 0.9 cm2/sec.The electrode has internal water cooling. The distance from the electrode-sheet interface to the water cooling channel is 7 mm.

12.)  In a robotic welding application, welds of 12 cycle duration are made at a rate of 40 welds per minute. Is the water effective in cooling the end of the electrode during this process?

Respectfully,
Henry

Chris,

I am currently doing the in shop TPI on a Sideplate job going to CA.  The company I am working with is starting a second one in this Fabricator's shops here in AZ this week.

If you have a chance to go through ALL the engineer's structurals and not just the shop/erection drawings you really need to do so.  A lot of questions will be answered.  You also need to go to a meeting they are supposed to have before beginning that covers all the aspects of their holdbacks, one hole dimension, Z dimension (not related to Z-loss), pre-heat requirements, and other specifics.  They usually do this with a powerpoint. 

Their system takes D1.1 & 1.8 to new heights.  Watch your undercuts, arc strikes, and other criteria very closely.  The CA inspectors (OSPHD) are terribly critical, beyond the scope of the codes.  And yes, they will try to get you to reject things that are not beyond any of the inspection perameters.  We have fought back on several items, but they can make it hard on you if you don't just comply with their demands.

The mock ups and seeing them after testing were awesome.  The stress that this system will take compared to standard moment connections is far and away superior.

I hope you are working with a real good and serious fabricator who has a good detailer and is interested in quality.  There are many aspects of this system that won't work if someone messes up. 

Have a Great Day,  Brent

My thoughts to the original post are that the OP welded out the joint without a written procedure...  End of line

You can point fingers at everybody from the CEO on down to the guy that scrubbs the crapper if you like.

If a welder with 18 years experience strikes an arc on a coded project without a written welding procedure, he is out of compliance and he has nobody to blame but himself.  

End of line.

Wow!  This thread took off in an unexpected direction!  When I said in my 1st post that sleeves can be put over arc strikes and cracks, I failed to mention that prior to the sleeve being installed, the defect is OFCOURSE totally documented and fully inspected for severity by a 3rd party inspecting contractor.  In the case of a crack (often longitudinal near the long seam of the pipe, atleast in my experience), the inspection contractor will grind out the crack.  This "reduced wall thickness area" gets sleeved.  Same goes for the arc strikes I mentioned.  Shane, and perhaps others, seem to assume that we are out there sleeving over arc strikes and cracks without 1st eliminating them.  This is not the case.  Hope this clears it up.  And Shane, I edited my 1st post which offended you. I apologize for that.

To the OP, has your original question been answered to your satisfaction?

Shane,

I have been asked several times in my career by the City, Municipality, gas company, etc, to sleeve a bad section of pipe (rather gas, jet fuel, water, etc).  Always to the requirements of an engineer.  That is not "HIDING" anything.  It is an authorized repair.  It has been done on new projects as well as in use pipe that developed a leak, was damaged by construction but not yet leaking, or was determined to be corroding and needed extra thickness BEFORE it blew out completely.  Testing was done to determine the extent of the repair.  Maintaining is usually cheaper than emergency repairs or a complete replacement. 

Sometimes while installing the sleeve we find the source of problems such as arc strikes (burns), copper deposits from improper grounding (electrolysis), dents from equipment, etc. 

Back to the OP, I'm trying to picture a sleeve application where you could use backing bars?  Am I missing a "sleeve" application where there is nothing underneath for a space?  Or when doing a T connection and cutting out for flow at the union?  If you totally remove a bad section to replace it, even if only a portion of the circumference is removed not the whole section of pipe, is it still a sleeve?  It would sleeve the good section of pipe and cover the hole created by removing the corrosion affected area I guess.  Then you could install backing around the edge but if your replacement is sleeving the good area the weld would not hit the backing bar.  So it would only apply if the patch part just fit in where the removed part was cut out in order to leave the OD approximately the same as original while replacing a defective section of piping.  Then you would use backing in order to assure CJP while also distributing stresses and eliminating stress risers. 

Other than that I'm not sure why you would use backing.  I guess I'm not sure enough of your application and how you are proceding with the operation.  You didn't give us a code, geographic location, nor complete information as to the job.

Have a Great Day,  Brent

The  anomaly has to be evaluated before a sleeve is installed. It does not make any difference if it is a corrosion pit, dent, arc strike,etc. Until the mid 1970's arc strikes were NOT considered a defect and were left on the pipe. When high grades of pipe began to be used in the 1970's and the effects of notch defects were recognized arc burns became a defect.
Using a sleeve is NOT hiding a defect. When a pipeline operator installs a sleeve the reason and location has to be documented along with the repair sleeve materials, welder qualificaiton and procedures. It is not only legal it is a recognized repair as long as the anomaly has been evaluated. If you will look at 195.226 all it requires is arc burns be REPAIRED not removed. Arc burns requiring replacement is one of those things that that a lot of inspectors know what they know that just aint so.

This is what is LEGALLY required in the United States on regulated pipelines for new construction:
§ 195.226   Welding: Arc burns.
(a) Each arc burn must be repaired.
(b) An arc burn may be repaired by completely removing the notch by grinding, if the grinding does not reduce the remaining wall thickness to less than the minimum thickness required by the tolerances in the specification to which the pipe is manufactured. If a notch is not repairable by grinding, a cylinder of the pipe containing the entire notch must be removed.
(c) A ground may not be welded to the pipe or fitting that is being welded.
http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=6a61777137a9b362a7d9f3a2ea8bf604&rgn=div8&view=text&node=49:3.1.1.1.11.4.21.14&idno=49

The standard for acceptability:
§ 195.228   Welds and welding inspection: Standards of acceptability.
(a) Each weld and welding must be inspected to insure compliance with the requirements of this subpart. Visual inspection must be supplemented by nondestructive testing.
(b) The acceptability of a weld is determined according to the standards in Section 9 of API 1104. However, if a girth weld is unacceptable under those standards for a reason other than a crack, and if Appendix A to API 1104 (incorporated by reference, see § 195.3) applies to the weld, the acceptability of the weld may be determined under that appendix.
http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=6a61777137a9b362a7d9f3a2ea8bf604&rgn=div8&view=text&node=49:3.1.1.1.11.4.21.15&idno=49

And as for cracks. Again here is what is LEGALLY required:
§ 195.230   Welds: Repair or removal of defects.
(a) Each weld that is unacceptable under § 195.228 must be removed or repaired. Except for welds on an offshore pipeline being installed from a pipelay vessel, a weld must be removed if it has a crack that is more than 8 percent of the weld length.
(b) Each weld that is repaired must have the defect removed down to sound metal and the segment to be repaired must be preheated if conditions exist which would adversely affect the quality of the weld repair. After repair, the segment of the weld that was repaired must be inspected to ensure its acceptability.
(c) Repair of a crack, or of any defect in a previously repaired area must be in accordance with written weld repair procedures that have been qualified under § 195.214. Repair procedures must provide that the minimum mechanical properties specified for the welding procedure used to make the original weld are met upon completion of the final weld repair.
http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=6a61777137a9b362a7d9f3a2ea8bf604&rgn=div8&view=text&node=49:3.1.1.1.11.4.21.15&idno=49

You cant umpire baseball without knowing the rule book
http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&tpl=/ecfrbrowse/Title49/49cfr195_main_02.tpl
This is for liquid pipelines.
http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&tpl=/ecfrbrowse/Title49/49cfr192_main_02.tpl
This is for natural gas.

atc250r,
I spent the whole day trying not to respond to your post but finally gave in.
How many sleeves I have installed is totally irrellevant.
Cracks and arc strikes are not allowed by any welding code I know of and yet you are saying it is OK to cover them with a sleeve ?
So what are you doing ? - you are hiding defects !!!!
Have you ever heard of propogation ?
You keep doing what you think is OK but if it is a pipeline please do not do it near any populated areas,
Regards,
Shane

Shane,

What do you think is the point of a sleeve??  Its to "beef up" the pipe where strength has been compromised due to any number of reasons: arc strikes, corrosion/wall loss, dents, cracks, etc.    How much sleeving have you seen and done???

atc250r,
Really hope no pipeline operating companies are reading your post.
Hide pesky little cracks / arc strikes under a sleeve where no one can see them - what a great idea !
Regrds,
Shane

Because in most cases, corrosion has eaten away some/most of the wall thickness., hence the reason for the sleeve. 

Other reasons for sleeves include dents (caused by rocks when backfilling), cracks, arc strikes, etc.

Hey Superflux,

So you're saying that both me and Tommy are uncommon welders???

It doesn't matter if it's a API 1104 job or not... Arc strikes on the material away from the joint is something that always should concern anyone especially from an engineering standpoint and you know that also, and arc strikes are not the same thing as Wulfram inclusions my friend.

Now I'm sure the work was taxing to say the least for Tommy but after all, we're talking about Tommy who always knows how to hustle when he absolutely has to on any job since he's the one making the money or not from each job he's on... In other words, he is the company and he knows that if he don't hustle, then his profit margin not his paycheck will shrink enough to where he can no longer operate at the level he's currently on or expand his operations or handle even bigger jobs.. Not to mention what damage it'll do to his reputation. Go get'em Tommy!!!

Respectfully,
Henry

Yes I had some arc strikes..outside the joint too...pipe was moving a lot and the wind made me break arc in a hurry several times.  A little frustration.  BTW I did a few joints on the ground in 5f and no I did not do them near as quick.  Henry pretty much nailed it, lots of current, big rods, gas etc.  That torch head was getting as soft as licorice in the summer time.   Thanks for the compliments tho.

They threw the maxstar up there for me to knock out some structural stuff (smaw) while they were rigging the next joint...just in case yall thought I was tigging off of that

Hello fellow welding gurus:

I am not sure what you really want to know. I am not sure there is really a question being asked. Here goes nothing.

Preheat (AWS A3.0-2001
preheat. The heat applied to the base metal or substrate to attain and maintain preheat temperature.
preheat temperature, welding. The temperature of the base metal in the volume surrounding the point of welding immediately before welding is started. In a multipass weld, it is also the temperature immediately before the second and subsequent passes are started.

The preheat temperature is the ambient temperature if no supplemental heat is added. However, ambient is not a discrete value and it is not the temperature recorded on the procedure qualification record (PQR) when the welding procedure specification is qualified by testing. The value recorded on the PQR is the actual temperature of the part just before the welder strikes the first arc.

If supplemental heat is used, preheat is still the temperature of the parts just before welding is initiated. The source of heating is not important. If could be the result of preparing the weld joint by grinding (friction), heating the part in an oven or by heating it with a torch or electric resistance heaters. Preheat is still the temperature of the part just before welding commences.

In the case of welding steels, preheating is often used to reduce the cooling rate to mitigate the formation of undesirable phases, i.e., microstructures, which tend to be sensitive to delayed hydrogen cracking or have a propensity to harden.

Welding standards typically include ranges for welding parameters used in production that are based on the parameters used when the test coupon was welded. The lowest preheat temperature is usually limited by the applicable welding standard and is a function of the preheat temperature used when qualifying the WPS.

In the event the individual that witnesses the welding of the test coupon fails to record an actual temperature (a numerical value) of the preheat on the PQR, there is no basis of limiting the lower limit of preheat used for production welds.

Moisture
Many welding standards state that the surfaces must be dry and free of moisture before welding. The concern is free moisture on the surfaces or between components such as lapped members as a result of standing water, snow, ice, etc. The concern is twofold; the moisture can flash off as steam which can result in porosity or it can disassociate into hydrogen and oxygen. The oxygen can combine with carbon to form porosity and the iron to form oxides. The problems associate with oxygen can be mitigated by introducing deoxidizers into the weld pool. Atomic hydrogen, from the disassociation process, easily goes into solution with the molten weld pool. Much of the hydrogen escapes harmlessly as the weld pool solidifies. However some of the hydrogen can potentially cause delay hydrogen cracking under the proper conditions.

Supplemental heat can be used to hasten the evaporation of any snow, ice, or standing water.

As for how preheat is to be addressed in the WPS: Preheat temperatures listed on the WPS is the minimum preheat temperature based on the requirements of the applicable welding standard. The preheat temperature may be determine prescriptively as in the case of a prequalified WPS where the minimum preheat is determined by the thickness and chemistry of the base metal. As an alternative, the preheat temperature may be based on actual preheat temperature of the test coupon when it was welded.

The issue of wet surfaces can require the inspector or contractor making decision based on good engineering judgment. If the dew point is about the same as the ambient conditions, supplemental heat may be required to ensure there is no moisture between lapped members.Other considerations include the chemistry of the base metal and its poropensity to hardening and sensitivity to delayed hydrogen cracking. Increased carbon equivalency and high dew points can easily justify the need to use supplemental heating to ensure the base metal temperature is high enough to ensure the surfaces are free of all moisture even when not stipulated by the fabrication code.

There were many occasions where I used the torch to heat the base metal to evaporate surface moisture entrapped between lapped members. There was no need to “preheat” the steel, it was already above the minimum preheat temperature required by the applicable code. However, failure to completely dry the joint before welding would cause gross porosity. Closely related to this problem was the use of preheating cold steel in the winter. The preheat had to be maintained for a period of time to ensure the condensate from the torch flame had sufficient time to completely evaporate. Failure to evaporate all the moisture would result in porosity.

Moisture from the steel, i.e., subsurface moisture in the steel? I think not. The water molecule is too large to diffuse into or out of the atomic lattice and it cannot survive the high temperatures of the casting, rolling, or extrusion processes associated with making the primary shapes.

Best regards – Al

Okay,

99205, I think I understand where you are coming from, and yes, I also do a lot of that while doing TPI work in shops.  The Customer/engineer has us monitoring Ht#, temps, amps/volts, fitup on CJPs and even continuity plate for fillet welds, in some cases weld mapping, etc.

BUT, these are supposed to verify the Fabricators in house QC and documentation for the job being done and we are also making sure nothing else that is code required gets missed along the way.  Then, before the member goes out the door, we go over the welds and entire member looking for arc strikes, discontinuities in welds, etc. and sign off on the finished product after any required UT, MT, etc.

So, are these people with the CPWI basically filling a spot as an In-House QC?  Many of the shops that I go into have at least some personnel who are not CWI's but do a lot of the "grunt" activities to document all the afore mentioned items so the CWI's can do more detailed work.  And the TPI's/CWI's just verify that all is being handled per Code and Job Specs/Contract Documents. 

But at least they would be someone who had a documented QC experience if they had taken this course.  And one that was particularly involved in the pipeline trade. 

I'm just asking.  Trying to find the positive out of the course and the thread that Hillbilly started.  I don't think any additional training is a negative but there are times when they aren't worth wasting time and money on.  That's why I was asking if they (Hillbilly and a couple of others who had been through the course) thought it was worth it and met expectations.

Have a Great Day,  Brent

T91 is one of those alloys that WILL form martensite with arc strikes. And this WILL embrittle the material. And it WILL form microfissures on the surface. And it WILL become a site susceptible to stress corrosion cracking. Grade 91, of any product form needs to be stress relieved after any kind of welding regime including arc strikes.

>the effects of rapid cooling you can simply prepare a piece of plain A36 in the shape of a bend strap and apply an arc strike

I can help with that....I have a few pics of arc strikes on A36 flatbar, and bent in my coupon bender.

As a control piece, the A36 flatbar bent "without" any arc strikes is to the far left in the picture. The other 4 were laid on a table side by side and a welder took a E7018 and drug it quickly across the four pieces, then ground them down to his satisfaction, the samples were bent in a coupon bender set up for A36/V50 using the correct bend radius and bent. As shown in the pic, every where there was a droplet of weld metal that melted and rapidly cooled....initiated a crack.

[http://img.photobucket.com/albums/v345/jwright650/welding%20pictures/arcstrike2.jpg]

Nitesky,
I think you put it in better perspective for me.  Cumlative effect of 25000 arc strikes =  1 second of exposure time. I can live with that!

Paladin,
I've never worn glasses, so have not had UV protection before.  Come to think about it, I haven't had a bad case of arc flash (next morning, eyes glued shut, gritty feeling) since using auto darkening.

I think I will still shut my peeps a split second before striking an arc, and book a visit to the eye doctor.

Tyrone

IMO there is a welder shortage:  a shortage of really good welders.

It should be recognized that some welding jobs don't require or expect much out of the worker.  Some production welding jobs are really just semi-skilled at best.  There is no reason to expect that just because a job requires a guy to run a gun all day on repetitive work with minimal acceptance standards that the job should pay a generous wage.  Many "experienced" guys have backgrounds in these types of lower skilled welding jobs.  As automation and overseas manufacturing limit the demand for this level of worker, and as illegal immigrants are able to slip into some of these remaining jobs here in the US, the wages can become pretty dismal.

You don't have to work in the field too long to realize some full time welders, even some with 20 years of experience, have substantial issues with their professional behavior, skill set, and/or knowledge set.

Think about it.  Honestly, how many really good welders have you ever met?  Guys who can weld, cut, and gouge to a high standard, thoroughly understand machine setup, trouble shoot equipment, read prints, apply math, perform accurate layout, do bend computations, fit, control distortion, leave a fabrication free or arc strikes, hammer marks, grinder gouges, and sharp edges, comply with WPSs and other written directions, show up everyday on time with a good attitude and in a physical condition that is conducive to production, present a professional personal appearance, use language that favorably presents the employer's company, live healthy and fit, work safely, push a broom when that that is what needs to be done, and who can be counted on to behave honorably when no one is looking?

A golden arm is good, but adding at least a bronze brain, a genuine interest in the career field, an admirable work ethic, and good professional judgment and the opportunities to make higher wages are seriously improved.

There are many great jobs in weldng, but these also expect the man to bring a lot of value to them.  They will continue to offer good pay and benefits in order to compete for the welders who can offer what they need.

Due to past experiences with problematic welders, some employers want a guy to prove his worth before shaking loose better pay.  I know a lot of guys who have started at $15 / hour and who worked up quite quickly.  But they wouldn't have had the chance had they turned their nose up at the chance to get a foot in the door.

Do not check arc voltage if you are using GTAW with the high frequency on continuous mode. HF will destroy the voltmeter. Even if the HF is set for"Start" only, the meter will be destroyed as soon as the welder strikes the arc. Turn the HF off before using the voltmeter.

There is no need to set the voltage range to more than 100 volts. The maximum OCV is around 80-84 volts as dictated by the NEMA. The intent is that the maximum OCV should not be high enough to electrocute the welder if he inadvertantly becomes part of the electrical circuit.

Al

I agree with Brent and can “name that tune” in 2 notes …. To answer the OP’s original question:

A: … Shut him down before he even strikes an arc!

Write a non-Compliance Report (NCR) stating that the welder was unwilling follow the ‘pre-wps’.

You will be paid for your efforts and the company can do as they wish with the welder. 

Cheers,
jb

>So what about the cracked ones?

They really need to be removed or really thinned so to be certain that they get remelted completely.

>Also should heavy sections be preheated per clause 3 prior to tack placement if they are incorporated?

My take is on this is no, as long as it is remelted and incorporated.
Although, the reason for the preheat is to prevent cracking because of that huge heat sink that quenches the weld metal creating a hard, brittle spot. I have pictures of an arc strike test that we did and you would be surprised at how it cracked everywhere those little arc strikes were.

>Lastly, should WPS's be written for final welds where tacked using GMAW and welded using FCAW be qualified? or am I thinking too much?

I'm not certain about writing a procedure and having to qualify it because of mixing  processes like that...although, we have used SMAW to tack with and FCAW to weld. I'm thinking that you could have a WPS for tacking with GMAW, and a seperate WPS for the FCAW final weld.

Maybe others will chime in with thier opinions.

Are any of you involved in failure analysis?

I am not now but from 1992-2002 at Weyerhaeuser Paper Company as their QA/QC Representative, I investigated the origins of fractures and helped determine preventative measures for avoiding their subsequent failures in the future.

The following is an informative, basic guide on failure analysis for your perusal.

Weld repair—Analyze the failure before attempting the repair
By Elia Levi

When something breaks, you acknowledge the shock, scratch your head, take stock of the situation, and look for the fastest way to repair the item and put it back into operation. The pressure to repair quickly is understandable, but common sense suggests stopping for a moment and trying to understand what caused the break before attempting the repair.

Failure Analysis
Almost anything can fracture. The science investigating the origins of fractures is called failure analysis, and it is used to establish responsibilities for fractures and to determine preventive measures for avoiding future occurrences. An introductory, interesting book on this subject was written by Donald J. Wulpi and is titled Understanding How Components Fail. 1

Service Failures
This article discusses only in-service weldment breakage, also described as service failures. Weldments are assemblies with parts joined by welding. Failures occurring during or immediately following welding are easier to deal with, because all conditions are known.

So if the item was welded originally, it should be weldable again for repair, right?

Yes, but only if you know the materials and their conditions and whether they still are exactly as they were at fabrication time—no heat treatment or other surface conditioning has been introduced. You also must know the precise process and welding procedure that were used in the first place, which usually isn't the case.

What Caused the Break?
Before attempting any repair, you must determine why the break occurred. If you restore the item exactly to its original condition, chances are another breakage will occur.  While a fully implemented professional investigation by an experienced metallurgist would be the best recourse, this usually is justifiable only in selected cases—for example, for presenting claims to the manufacturer or to the insurance company. It is mandatory, however, if injury to persons or property loss was or could have been involved.

Left to involved people, the human urge to clear oneself and to find fault in someone else's actions or inactions can interfere with an investigation.

The main reasons that weldments fail are:
•Inadequate material or properties.
•Poor design.
•Poor workmanship.
•Excessive unanticipated service conditions.

The Investigation Process
Even if the person in charge is not specifically trained as a failure analyst, a few investigative steps should always be taken:

1.First take care that nothing be moved, manipulated, reassembled, or fixed.
2.Document the condition of the weldment when the breakage was found.
3.Write down all that is known, and question all who were present.
4.Note the ambient temperature at the time of occurrence.
5.Take pictures, both general and close-ups.
6.Protect the place from rain and other environmental disturbing factors
Firmly resist the pressing urge (your own and of those around you) to supply a theory for the breakage, especially before having assembled all the information.

A description of the weld profile as visible under low-power magnification should include such details as dimensions and fit-up as much as they can be determined visually. If possible, these details should be compared with design requirements.

When the structure operates normally at elevated temperature, it is probably under some code legislation that may request an official investigation.

A weld breakage usually is a crack or a fracture. Much information can be drawn from an exact description of the failure. A crack should be characterized by its dimensions, by its orientation (longitudinal, along the weld bead, or transversal), and by its position relative to the weld itself (on the weld bead or on its sides, in the heat-affected zone, or in the base metal).

If the fracture is open, do not reassemble the mating parts. Doing so can obliterate important clues. Inspect the fractured surfaces with a low-power lens or microscope that can show internal defects like gas holes or pores, nonmetallic inclusions, or indications of fatigue failure in the form of concentric beach marks.

The presence of macroscopic deformations and the fibrous or glassy aspect of the surfaces should be assessed to reveal if the failure was ductile (with deformation) or brittle (without deformation).

Specific colors on the surfaces should be remarked; they might be clues about local heating and oxidation. The extent of corrosion, if present, has to be determined and documented.

The presence of arc strikes on the surface, improper starting conditions, or accidental contact may be at the origin of considerable damage.

Hardness testing is a very informative, simple, nondestructive test. However, selecting the proper locations, especially if the weldment must be sectioned for testing, may be beyond what can be expected from a technician not specifically trained for this kind of investigation.

The materials involved should be known and their properties checked for conformance to specifications. No weld repair should be attempted without this essential knowledge. Having this information allows you to select the proper repair procedures and filler metal.

If materials are not known, an effort should be made to provide at least qualitative information. This information can be obtained by X-ray fluorescence, a nondestructive test readily available from many metal-related services.

What Next?
Having assembled and organized all the facts, you now should be able to formulate an educated guess as to the possible causes of the failure.

Was faulty workmanship the culprit? A professional investigation service uses metallographic examinations of weld sections to look for weld defects in the original weldment. Obviously, faulty welds should have been detected by inspection after manufacturing, but nobody is perfect. If the original weld was faulty, a repair weld performed with utmost care should improve the future in-service performance of the repaired item.

A design change is not normally applicable for repair. However, if it is clear a faulty design caused the failure, an improvement might be introduced. But you should be aware that adding stiffness may make the matter worse, by increasing internal stresses and paving the way for the next fatigue fracture.

If the breakdown was sudden but caused by a progressively deteriorating condition of certain components (as in the case of fatigue fractures or corrosion), a corrective action program should be initiated. The plan has to incorporate periodic examination of the parts involved, after the structure is repaired, to detect dangerously spreading cracks before much damage occurs again.

Cracks must be removed completely by careful grinding before rewelding. If the base metal is in acceptable condition, weld repair may be attempted with suitable ductile filler metal or low-hydrogen electrodes.

The process selected should introduce minimum heat and residual stresses, and possibly should be followed by light hammer peening. Preheat and/or postheat, if necessary.

If separation has occurred, then a proper joint has to be designed and prepared, possibly by introducing a transition element to make up for the volume of metal to be discarded.

Experience and common sense always are important, and even more so when dealing with weld repairs.

1Understanding How Components Failby Donald J. Wulpi is available from http://www.asminternational.org/.Click on Bookstore, then on Failure Analysis, and then on Understanding How Components Fail.

Thanks for posting all the info Al.  Very interesting.

I have virtually no metalurgical knowledge... read a few books over the years but without practical application and observation of outcomes I find it quite dificult to retain much of the info and theory.

Anyhow I was curious one day about the this topic as I have seen locals welding out in the rain here in the coastal PacNW.  Where I come from in the SW welding frequenty shuts down until it stops raining.  For fun I heated up a bunch of A36 3/8 x 1 flat bar red hot with a rose bud and quenched it in different ways before attempting to bend it in a press brake. 

After doing this on numerous occassions with A36 over the years, I have found the outcome can vary a fair bit.  With a full immersion and swishing around from red heat I have had bars snap like a candy can with virtually no deformation at all.  Once a piece snapped and shot out of the brake with considerable force, almost hitting a bystander in the head.  On other occaissions the bars have not broken in half but only cracked open on the outside of the bend.  (Different lots of steel, same grade, same bend radius, all bars bent cold)

I have also heated the bars red hot and sprayed with a squirt bottle to simulate rain.  These have always bent the same as bars that weren't heated at all.  Even when slowly pouring the contents of the squirt bottle so that it would run down the bar, like may be the case if rain were running down a column I have not seen any real difference in how the bars bent v. unheated bars.

At the recommendation of a colleague (Allan maybe?) I have done something similar with the bars, arc striking them rather than heating and quenching.  Then bending after having ground the arc strikes smooth.  These samples have always opened cracks on the outside of the bend.  Same with a small tack weld that is ground smooth and bent.

That info may not be usuable in its self, but I think doing activities like this do help one to understand and retain some very basic principles.

Rig Hand,
When you say it doesn't long arc like the older ones, does that mean you can break the arc easier with less likelihood of arc strikes? Does it still keep pushing the root bead even if you crowd it?

Cactus,
Other than less output, how do you think the Pipe Pro 350 falls short of the Vantage? I'm thinking of selling my Pipe Pro 304 and would consider the 350 or Vantage.

I too would like to hear from someone who has welded with a 304, 350, and a Vantage.

Floyd

It isn't a case of the third party inspector saying the weld is 1/64 inch undersized. To do so would be a mistake a novice inspector would make. The inspector determines if the weld is conforming or it is nonconforming. Simply put; it doesn't meet the acceptance criteria of the drawing or the applicable welding standard. It is then left to the Engineer to determine if the undersized weld meets the intended service requirements of the project.

The abbreviation for inspector (other than the Authorized Inspector) is not spelled "GOD." The inspector simply reports his findings to the Engineer or the client. The work meets the requirements of the approved drawings and applicable welding standard or they are simply nonconforming.

It is interesting to note that I rarely encounter welds that are nonconforming for one reason. If the welds are running undersized, there are usually other problems as well. That is why it is important to evaluate all of the attributes and to note all nonconformances. While the undersized weld may meet the service requirements, the fact that there are unfilled craters, missing welds, unauthorized welds, arc strikes, etc. may be more of a detriment than the fact that it is undersized.  

The welding inspector, whether he or she is a CWI or not, serves as the client’s eyes and ears on the project. The completeness and accuracy of the written report is what the Engineer or the client uses to judge the work being inspected. The final decision to accept or to reject work is not left to the contractor. It is the Engineer or the client that makes the final decision to accept or reject the work. That responsibility may be delegated to the inspector by the Engineer or client, but that responsibility shouldn’t be an automatic assumption.

It is all in the “Word Smithing” of the report. If the inspection report is well written, there is little chance the Engineer or the client will allow the nonconforming welds slip through. 

If the concept is difficult to understand, think of it this way; You and I agree that I will pay you $100.00/hour, but when I hand you your check you discover I only paid you $99.00/hour. Somehow, even though you work with a contractor, I don't believe you would be inclined to say, "Close enough." as you skip merrily off to the bank to cash the check.

Best regards - Al

For subsurface defects????
MT is a surface method and is not reliable for subsurface defects.
A trip down memory lane may help with that: Edit: to understand why General dynamics says what it does.

ASME Section V 1974 Edition
T720
Magnetic particle examination provides for the
detection of cracks and other linear discontinuities
and shall be applicable only to ferrormagnetic materials.

Its sensitivity is greatest for surface discontinuities
and diminishes rapidly with depth below the surface.

In T-725 It mentions SE 109 and SE 138. 109 for dry, and 138 for wet.

Historically, any mention of dry was assumed to be prods unless thereafter modified.
Reading 138 shows that there was not a focus on the magnetizing technique for wet inspection.
Section 3 of E138 current of the 74 ASME 5 list all normal methods.

By contrast, E109 specifically calls out prods under section 6.
Under section 7 it states the following:
7.1 Over-all magnetization (as specified in Appendix A1) or the wet method of magnetic
particle inspection may be used if such methods are more practical for certain cases. If
such a method is used it shall be by mutual agreement of the manufacture and the purchaser.

By default, dry powder 40 years ago assumed prods. This has changed in later years of most codes due to:
1. Propensity of arc strikes from prods
2. The general unreliability for detection of subsurface discontinuities.

There are exceptions to that, but as a general rule of thumb, most people stay away from trying to
detect subsurface flaws with MT. That’s what the volumetric methods are for.

In saying that, and if you absolutely must for some reason I cannot fathom; then the dry prod method
is the most sensitive for subsurface. (reference table 1 SE 709 article 25 ASME V 2010 edition) EDIT:(109 and 138 rolled together)
However, your still going to be stuck with relatively small inspection areas, high risk of arc strikes,
and the need to be able to prove your getting down to where you say you are.

That last bit is a killer.

In all, 'surface' indications by florescent wet method is your most sensitive method for 'surface' indications.
The exception to that rule is Prod dry powder.

As for wet being less permeable, that can be argued as well. They are relatively the same particles with a coating.

BTW, for people who may not know, WABO has two requirements that trip a lot of welders.

First, arc strikes are prohibited.

Second, on plate undercut is limited to 1/32" max depth, and it can not excede 10% of the test weld length.

Arc strikes (for stick and TIG) and the linear limitation on undercut (for stick and FCAW) probably cause more welders dificulty than anything else. 

I had two bust out today for one small arc strike each, and one for very minor undercut that exceded the length allowance using dual shield.

Sweat stings the eyes as we toil all day.
It’s hard to imagine what we do for pay.
We hammer out products that are used worldwide,
Pouring our hearts into the steel with pride.

Welders squeeze triggers on wire fed guns,
Shooting hot bullets as molten blood runs.
Welding arcs flash white in eyes that are red,
Hammers keep playing a chorus in our head.

Blue tongued torches lick at the steel,
After taking a taste, they devour their meal.
Metal screams as grinders’ teeth bite.
Orange sparks shoot up in fireworks of light.

Smoke uncoils and strikes at our eye,
Struggling to resist vents to the sky.
Searing sparks leap, looking for flesh,
While laboring lungs look for air that’s fresh.

Eyes grow weary as skin grows tough.
Calluses reproduce, there’s never enough.
Sometimes the steel has a mind of its own.
When it finally yields, it starts to moan.

The product draws life from the men who create it.
Although it’s our livelihood, at times, we hate it.
The factory is a graveyard of dead dreams and desires,
All killed by the heat of molten steel’s fires.

Retirement is nothing more than a dream.
The hope that it promises fades when it’s seen.
But who among us dare raise his voice?
We are all here by our own choice.

So we continue to work, for work we must,
As we toil and moil in the dust and rust.
The whistle blows.  The next shift has begun.
We emerge like cavemen squinting in the sun.

We pound on the iron for eight hours or ten,
Then come back the next day and do it again.
We trudge ever onward, the work never ends.
Our only reward is what Friday sends.

Ok, now here is something that has bouncing around in my head about the Independent Contractor.  If and Independent Contractor is hired to weld then is that Independent Contractor ultimately responsible for having proper procedures and paperwork squared away before that Independent strikes an arc?   It seems that the lawyers could point at the Independent as the "Contractor" responsible for procedures and testing.  Maybe I'm thinking too deep into this.

There is no code requirement, i.e., AWS D1.1, ASME Section IX, etc., that requires the test be administered by a third party, much less an AWS Accredited Test Facility. Likewise, there is no requirement for the welder performance test record to be notarized. 

The test record is certified by the employer, it is not a sworn statement.

All I can say about the AWS ATF is, "God save us from ourselves!"

People seem to overlook the important fact that the welder qualification test is no different from the driver's test given to the 16-year old. On a particular day of the week, when the stars were aligned, there was no lunar eclipse, and the welder did everything correctly; he passed the required test. It is not a warrantee that the welder will never make a bad weld, it doesn't even profess to say that in all cases, under any circumstance, with any welding machine, the welder can make a sound weld. The welding standards do not even require the welder to "set up" his or her own machine. It is a simple demonstration that the welder could deposit 3 or 6-inches of relatively sound weld metal. It does not even mean the weld was without any discontinuities; only that it was "sound enough" to satisfy the requirements of the applicable welding standard.

All the welder performance test record provides is objective evidence that the welder took and passed a prescribed performance test with a certain welding process, with a certain filler metal, with a certain base metal, blah, blah, blah. Big deal. It gets you on a job site, but it will not keep you there unless you perform and meet the requirements of the applicable welding standard to the satisfaction of the employer. If you screw up enough, it is bye-bye or a new test.

I, for one, always require the welder to pass at least the fillet break test on the job-site using the equipment that will be used on a daily basis. That is, if I am involved in developing the project specifications or if I can legitimately reject the paperwork offered by the welder when I arrive at the site. I really do not care that the welder passed a test under the laboratory conditions many welder performances tests are given. They do not represent what the welder will be dealing with in the field or on the shop floor. I like to see the welder hook up his own welding leads, adjust the welding machines controls, and fit-up the backing bar and extension tabs. Once that has been done, the welder is ready to make sparks. That is not what is required by the welding standards, those are Al's rules when taking an "Al's Test" and if he is going to receive a piece of paper with my name attesting to the fact that the welder knows the fundamentals of depositing a sound weld. 

To be fair to all involved, all the requirements are documented and presented to the welder at the time of the test. Together, the welder(s) and I review the requirements, the "do's and don’ts" of taking the test, and the acceptance criteria that will be used to gauge the completed weld. There are no secrets, I do not change course in the middle of the stream, and the welder knows exactly what is expected before he/she strikes the first arc.

I supply only the test plates that are beveled beforehand. The welder supplies everything else down to the toothpick in his mouth. If he is dumb enough to use   "rehydrated E6010 electrodes,” so be it, he's going to fail. It is his (or his employer's) money and if he wants to throw it away, who am I to protest? The profit is twice as nice the second time around. If the welder believes using a multipass flux cored electrode means he does not have to chip the slag between passes, so be it. Weld class begins after the check has cleared and the test plates fail the bend test. 

The welder performance test record is not sacrosanct. I reject many of them because the forms are not completed properly, there is missing information, a missing signature, the wrong gas, etc.

“Sorry buddy, you have to take another test.”

"What's that? A P.E. signed it and his mother is a CWI! So what, who cares, the idiot cannot even fill in the test record properly. Sorry buddy, you have to take another test."

The rant of the day is done.

Best regards - Al

What you are proposing is one of the worst things you can do to concrete reinforcing bars (rebar), i.e., small welds, that do not actually transmit a load.

What I typically see  are "tack" welds that are made without the use (or consideration) of preheat accompanied by arc strikes everywhere.

Rather than writing a long complicated explanation of the potential problems, simply try this experiment. Cut two pieces of rebar to about 12 to 18 inches in length. Make a small weld (about the size you expect to see in production) on one of the rebars and leave the other rebar in the as received state. Bend each rebar around a mandrel that is 4 times the diameter of the rebar. The bend on the welded rebar should be such that the weld is centered on the outside of the bend radius. Bend the rebars a full 180 degrees to make a "perfect" horseshoe. Compare the results of the welded piece and the unwelded piece.

You can simulate the affects of an arc strike by dragging the welding rod across the rebar to simulate a typical arc strike. Bend this sample the same way as the previous samples and compare the results. (This sounds like J. Wright’s experiment doesn’t it.)

Please let us know what the results of the three experiments are.

You can use lengths of pipe slipped over the ends of the bars to make it easier to wrap the rebar around the mandrel or you can get fancy and rig up a bending die in a hydraulic press. The best method is dependent on the diameter of the rebar.

Best regards - Al

It is good practice to unreel the welding leads. If left on the reel, the coil creates a strong magnetic field, the strength of which can be described as turns times amps, which acts as a choke on the current. The end result is that the machine is working harder than it should have to. The energy is wasted because a good portion of it is utilized by the solenoid and the resultant magnetic field.

It is for the same reason that when the cables are unwrapped from the reel, they should not be coiled neatly on the ground. To do so creates a strong magnetic field and wastes energy.

Just try this little experiment. Coil the welding leads around a piece of steel and hold a wrench near the end of the steel bar while someone else strikes an arc. The strength of the magnetic field is directly proportional to the number of turns in the coil and the amperage. Double the amperage and you will double the strength of the magnetic field. Double the number of turns and you will double the double the strength of the magnetic field. Double the current and the number of turns and the field strength increases by a factor of four. 

Best regards – Al

Joe,
I am really struggling to understand this "visible and audible range" ?
What is the difference between "visible and audible" and being 100 miles away ?
Surely every time a CWI signs off on anything a CAWI has inspected he is in breach of the code of ethics ?
If the CWI has not personally inspected something himself how can he sign off on work that has been inspected by an "unqualified" inspector ?

"Bob" the CWI and "Dave" the CAWI are inspecting structures in a yard (within visual and audible range) and Dave marks up some porosity and points it out to Bob for his report but due to his lack of knowledge/experience he misses a couple of nasty arc strikes.
Bob signs the structures off as acceptable and the structures go into service - one of the arc stikes turns into a crack and a major failure occurs which leads to a full on investigation.
First question from the lawyer - "Bob, did you visually inspect every weld on this structure ?"
Bobs reply "No, Dave and I inspected them"
The Lawyers next question would be "Bob, what qualifications does Dave hold or what tests has he passed to show he is competent to perform these inspections"
Bobs reply - "Well he failed the required test and he holds no qualifications but AWS have deemed it is OK as long as I can see or hear him while he is doing his inspections"

I am not an AWS CWI - I am dual certified to CBIP (New Zealand) and CSWIP (British/European)
If I visually inspect a yard full off structures with another CWI I cannot and will not sign off on items I have not personally inspected (no matter how confident I am in his ability) - it is a clear breach of ethics. I will write my report based on what I inspected and he will do the same and we will both sign and stamp our reports.
How then can AWS deem it acceptable for a CWI to sign off on work visually inspected by a CAWI if the CWI has never personally inspected it ?
Regards,
Shane

all this speaking of the farm code, has any ever made an effort to actually start compiling all this information into one document

off the top of my head

"magic wire trick"
this texan guy as our handy spokesman
using coat hangers, bailing wire, whatever is sitting in the corner for filler
that crazy rant that Welder helper posted awhile back.
rolling bottles of mixed gas to mix them.
hurt feelings report
how to beat xray
how to hide arc strikes
how to get paid more for working less

But lets be clear here, welding current in and of itself does not damage chains or cable chokers. The problem is if the grounding is not sufficient and arc strikes occur which does damage them and renders them unsafe.

If you can find any arc strikes on the inside/outside of any of the chain links, I would permantly remove the chain from service. Arcing through the bearings, cables and whatnot on the crane cannot be good for those parts. And if the welder is getting any grounding through the crane itself, then there is a possiblity of the current finding the path of least resistance through the crane. Not an ideal situation in my eyes.

I thought there was something in OSHA 1910.179 or OSHA 1910.184 that didn't allow this practice, but I glanced through it a minute ago and didn't see anything.

Quality seems suspect if you zoom in. branches look like fillet welds, undercut and arc strikes?

There are two types of jobs; those that are critical that have to meet code requirements and those that are non-critical and meet the Farm Code standards.

For the Farm Code all is fair and there is no reason to waste perfectly good electrode stubs. Low hydrogen electrodes can be stored in an old refrigerator with or without a light bulb for heat. A little porosity; no matter. A small crater crack; no matter. As long as it sticks to gether until you break it and reweld it for the third or fourth time; no matter. Get the job done. No stub is too short.

For jobs that are critical, for those that have to meet very high standards, for those situations where porosity, etc. cannot be tolerated, the cost of the electrode is secondary to the quality of the job. The cost of repairing a poor restart far outweighs the cost of electrodes and it is false economy to try to restart electrodes with limestone-based coverings.

Do not get me wrong, I do not like to see electrodes wasted, but the job requirements come first. I can buy several cans of low hydrogen electrode for the cost of one cut out due to porosity, slag inclusion, or for other flux related causes. Restrikes can cause the flux to break away and that will result in porosity because of insufficient slag coverage as the arc initiates. Cost of cut out includes the welder's time, lost of productivity, and reinspection; be it UT or radiographic examination.

Granted there are methods that can be employed that will allow the welder to restart the arc, but still the opportunity for a defect far outweighs the cost of the electrode.

For welders learning to weld; there is no reason to allow them to waste electrode. They are not meeting stringent inspection requirements and it teaches good work habits. That is why they are in school to learn good working practices as well as a new "skill.” There are many jobs where it is imperative to maximize resource utilization and minimize waste. For typical structural applications where loads are static and porosity is not a concern (other than piping porosity), restriking the electrode is standard practice. For fracture critical work I would not recommend restriking with a partially used electrode.

Electrodes that use a cellulose type coating are a different animal. The flux is friable, thus not as prone to breaking off like the limestone-based coverings. Restriking with electrodes utilizing cellulose coverings does not present the problems associated with low hydrogen type electrodes. Never waste a good stub!

Best regards - Al

I rarely do any welding these days but I vividly recall my days as a fitter/welder in a structural steel fab shop.

All of our tacking was with 7018 and those rods would get burned down almost to the stinger.  Not because we had to; it just seemed to be that way.  Using the stab & scratch light-off method you could get several tacks per rod (and without arc-strikes - most of the time). 

When I had a tack that required more care, a fresh rod was used.

If I was welding, I would try to avoids lots of start/stops - so then I would use a fresh rod instead of using up stubs.  A 3" long weld with a start/stop in it doesn't look as good - acceptable but not as good.

Not all shops are not created equal.

In our shop, a Welder, Mechanic, Machinist or inspector can make slightly under $30 with an almost quarantined 40 hours plus per week with premium pay (1 ½ and 2x time), sick pay, paid holidays and vacation + more paid benefits and they go home to their families every night.

Heck I even buy their top of the line speedglas hoods for them (cant afford any false arc strikes on customers expensive equipment).

Our field people get much higher wages but they pay for it, at least those that would prefer to be home at night. Some do some don’t.

But the works not for every one, sometimes they may have to sit at a automatic SAW machine for 8 to 12 hour days even weeks and never put their hoods or gloves on.

We have shops in Fl, Ca, Canada, and Europe but even they are different from our Houston shop.

If it’s a non union shop the pay scale is just like the Gasoline company’s prices “What the market will bare” If you have the credentials do some bargaining.