6G procedures

By heath hanson Date 08-08-2008 20:07

37 degrees on the bevel and thats good to work on while your waiting to test don,t cheat yourself keep in a true 6G position and practice untile you can,t stand it. Then when your real pissed off and never want to see that light again you will know if you want to be a pipe hand. Give yourself a heavy land when your learning to that will help you get a heavy root in there and that makes the thing a lot easier. There are lots of procedures I would say to practice with 6010 root and hot then a low hy cover use 5p and excaliber.

By Cumminsguy71 (*****)

Date 08-08-2008 22:41 Edited 08-08-2008 22:43

Thanks Heath. I've been going with a 1/16th land right now. The one I just did the gap opened up on my third tack weld and caused havoc. I'm playing around with the gap between the two pieces to find the magic spot, seems to remind me of when I was doing the plate tests in mig. Had to find the right gap opening and then it all fell into place. The pipe I got is only 1/4" though and by the time I get the root in there and try and run a hot pass without burning a hole it's pretty much filled in. That is a tricky position, it don't look bad until you strike the arc. When I get the two pieces tacked together I tack the lower piece to a piece of 1/2" solid square that I have in a bench vise on a 45 degree angle. I have a company that is gonna test my 3G and 4G plates and I'm the witness to my own welds and I thought a man could cheat but why? The only person I'll be cheating is myself and when I say one day, "I can weld" I want to back it up with the weld to prove it. Just about got my 3G in the bag though, did one today and my cap had a bit of undercut in it so no good, but I felt confident about my root and intermediate pass. Back to burning more rod.

By Twangfactor (*)

Date 08-09-2008 02:21

For a 6" Sch. 40 6G up-hill test I use a 3/32" landing and a 3/32" gap, use 1/8" 5P+ and set the machine for 90 amps as a starting point. Put your coupons on the bench and gap them with a 3/32" tig rod or a 3/32" 7018 electrode after you have knocked ALL of the flux off and bent it in the middle to look like this < line up the INSIDE of the two coupons. Put in one tack about 1-1/4" long between the open legs of the gapping wire. Take the wire out, close up the opposite side from your 1st tack to make the gap even all the way around and put in another tack about 1-1/4" long. Drive your wedge in to the tight side 90 degrees to the two tacks to even up the gap and put in your third tack opposite of the wedge about 1-1/4" long. AS SOON AS THAT TACK IS IN, flip over your coupon with the wedge pointing towards you. JUST AS SOON AS THAT WEGE GETS LOOSE, put in your last tack about 1-1/4" long.

What you have done is used the first two tacks to adjust your machine, tacked up your coupon in four places with one tack going the opposite direction and have a nice even gap all of the way around. Feather the starts of the tacks down to a knife edge at the root and back about a 1/4", and just "kiss" the stops to shine them up, this gives you the famous "one inch tacks".

Tack your coupon in place at 45 degrees with the key holes at the top of the tacks at 9 and 3 o' clock. Start your root pass by welding the section that will require you to tie into the key hole at the top. Then weld the quarter that is 180 of that. Then weld the other top quarter and finish up with the bottom quarter. I use a combination of "stepping", "Whipping" and "Dragging" as required to make thing happen, WATCH THE SIDES AND THE BACK and do what is required to tie everything together and keep the center of the leading edge of the root pass following the rod up the gap. Point the rod slightly back toward the bottom tack along the bottom and as you advance up you should be pointing straight in along the middle and tip the rod so it starts to point toward the top tack as you get to the top. This angling of the rod will help you keep your root pass an even thickness all of the way around. If you point straight in all the way around your root will be light at the bottom and heavy at the top because of gravity.

Grind your root pass along the sides and just knock off the starts in the center, if you have some lumps knock them off too you want things fairly flat and even before your hot pass. For the hot pass I like to run the machine at about 90 amps and use a combination of "circle weave" "Stepping" and "Whipping". Start off the hot pass by striking off at 6 o" clock at the bottom edge of the root, move the puddle to the top edge of the root, this ties both edges together. Move the rod in a circle away from the puddle across the bottom and back up to the top and SLIGHTLY push in on the puddle. Understand that this happens quickly and the rod tip moves in a circle that is only about a wide as the root face. What you want to do is tie both bevels together with the root pass and burn out any slag or under cut. What you want is all of the edges tied in nice and clean so that you won't trap any slag from your 7018 for your fill pass. To control the heat if things get toasty on the hot pass make the circles oblong and long arc SLIGHTLY away from the puddle then come back into it and push in SLIGHTLY. When you get to the top pause to leave a nice even round spot to tie the hot pass into when you go up the other side.

Twangfactor

By Josh Flynn (**)

Date 08-16-2008 17:39

On the 6g cap weld do you use a weave to cap or a series of stringers. I have not done any pipe welding but would like to try it. I have seen the 2G with stringer passes and the 5G with a single weave. I just didn't know what the 6G called for or what was easier or better to use.

By CLaytonACARTER (*)

Date 08-17-2008 16:37

on 6G it is better to run 3 stringer cap.

By Josh Flynn (**)

Date 08-17-2008 17:01

It should be a 6010 root,6010 hot pass, 7018 fill, and 7018 cap with strings right? How much height can you have on the welds over the base metal?

By swsweld (****)

Date 08-17-2008 19:54

As far as the 6010 hot pass that is up to the WPS. My WPS states that the hot pass can be with 6010 or 7018. Then fill and cap with 7018 and as stated earlier the caps are normally done with 3 stringers on a 6G test. The cap height or reinforcement may vary depending on the code you are working to. API, ASME, D1.1 etc.

ASME B31.1 Table 127.2 states that base metal thickness 1/2" and under the max reinforcement is 1/16" if the temperature is over 750F.
Over 1/2' to 1" the reinforcement is 3/32'
Over 1' to 2' is 1/8'
Over 2' is 5/32"

1/8" to 2"= 3/16"
Over 2"= 1/4" for temperatures less than 350F

It MUST be flush or above as under fill is rejectable.

Shoot for 1/16" to 1/8" above flush and you will be all right in MOST situations.

When capping with stringers it helps to keep them tight. Big "valleys" between beads are bad for several reasons.

By Josh Flynn (**)

Date 08-17-2008 21:16

For the 6" 6G sch 40 uphill test is there a difference between AWS and ASME standards? Does taking one qualify for the other or would you have to take two different test?

By swsweld (****)

Date 08-17-2008 23:41

There is a big difference between AWS and ASME codes. One does not qualify the other unless the owner or owners representative (architect firm, engineer) specifies that it does and that is not often. AWS is a structural code and ASME covers pipe, pressure vessels, boilers, nuclear, flanges, valves, welding and brazing qualifications etc.

If you are a structural welder you will probably test to AWS D1.1.
However it does have pipe and tubular test in it.

If you are a pipe welder you will probably test to Section IX of the ASME Boiler and Pressure Vessel Code. It is an international code for welding and brazing qualifications. It is very widely recognized.

As an independent contractor you should have both of these as a minimum. I (we) are asked for certs for both of them depending on the job we are doing.

The contract documents (specifications) will state which code to test to. Example: I'm currently doing some underground pipe work and the specs state that it is to be installed to ASME B31.1 Power Piping. You then go to B31.1 and refer to 127 Welding then 127.1.1 The welding processes that are to be used under this part of the Code shall meet all the test requirements of Section IX of the ASME Boiler and Pressure Code. You then go to Section IX (a different book) and find the test requirements that will cover you for the work that you are going to do.

If we erect steel on that same job the contract documents will specify AWS D1.1 So all welders will be qualified to AWS D1.1

If you weld in the oil and gas industry you will probably qualify under the API Standard 1104 Welding of Pipelines and Related Facilities (American Petroleum Institute) It is similar to ASME pipe work but IS different. I think that the reinforcement and underfill is limited to 1/16". I don't have that standard with me so I can't specify the paragraph.

It is important to remember that "one size does not fit all".

If you are testing for an employer, they will be responsible for giving you the appropriate test for the work you will be doing.

Hope that was as clear as mud.

By Josh Flynn (**)

Date 08-18-2008 00:30

It did clear some up
Thanks,
Josh