Rosie,
What exact wire are you using? And; on what type of parent material are you welding? Knowing that will give folks here the best chance to answer correctly.
Also, for your own research, here is a link to Hobart, Corex, McKay and Trimark fillers. If you follow the links each manufacture on this link will provide recommended user specifications for the wires they sell.
If you are doing code work you ought to have been provided with a WPS or at least a data sheet available that details the essencials.
Rosie,
Virtually every manufacturer of flux core, both stainless steel and carbon steel, makes a "flat and horizontal" and an "all-position" designation. The "flat and horizontal" designation is just what it says, but the "all position" is actually designed for the vertical up and overhead designations. This is not to say some folks don't use it for "vertical down", but when using it welding down, you compromise two very important attributes. One, is that you lose the penetration by welding downhill as opposed to welding uphill. Another drawback is you lose the deposition rate. Flux core is usually used for it's high deposition rates in thicker material. Welding downhill, one must speed up the downhill progression so the flux can freeze and allow the metal to stay contained. This applies to both stainless and carbon steel flux core. It also takes greater skill to successfully weld flux core downhill. The higher voltage and amperage usually does not allow the flux core to be welded downhill with a lot of success, but again, people use for that.
Chuck
Rosie,
I don't know which code you're bound by, but D1.1 allows vertical down on tubing, provided the welder is qualified in the vertical down direction for tubing. D1.1 also allows any undercut to be repaired in the vertical down position, as long as the preheat requirements are met, but in no case lower than 70 degrees Fahrenheit.
i HAVE USED FLUXCORE FOR YEARS AND WILL TELL YOU THAT THIS IS ABOUT THE EASIEST WELDING TO DO. i USE .052 WHICH IS GREAT FOR HIGH CARBON STEELS. as far as welding down if the material is 1/16 turn your heat down in stead of speeding your travel up.penatration will still be great . if the metal is 1/4 then you will be better off running a vertical up set your wire feed to 250 set your heat to 7.5 and burn away.this has always given me a weld that allows the flux to peel it self away while you are still welding resulting in a weld that is smooth as glass. do not get me wrong it takes playing around with the machine tou are using but yes it is achevable. remember have fun and enjoy what you do.
It depends on the wire (and the application of course).
There are several flux core wires made to run downhill, and quite a few that aren't.
JTMcC.
I would agree that vertical up is definately the most preferred progression when welding vertical with FCAW. However, when fast travel speed on sheet metal is desired, vertical down is a good choice. Other than that, I wouldn't have any use for vertical down. In addition to the drawbacks for vertical down already listed, the concave bead profile that usually comes from vertical down is also sensitive to centerline cracking when welding on things with any restraint.
It's not the prefered progression when the procedure calls for downhill, as it usually does in my world.
Using consumables intended for code quality downhill work, doesn't result in a concave profile, in fact a concave cap is cause for rejection.
JTMcC.
Thank you for your response we are using lincoln electric .45 outershield wire. The materal is 1/4" tubing. They were welding this with fluxcore for years without any breakage. They just hired a guy they made welding inspector and he says that it has to be run up not down. I read in the lincoln website that this wire can be run any possition what is your response to this my boss wants to know.
Rosie,
By 1/4" tubing do you mean HSS shapes 1/4" thick (pipe, square or rectangular)? Or do you mean small, 1/4"diameter tubing?
Given that you mentioned 0.045 Outershield, I assume you are talking about HSS shapes, and that probably AWS D1.1 is the welding code. Small diameter tubes would likely not be welded with 0.045 FCAW.
Based on that, I believe the new inspector is correct to bring up the subject. I think it was GRoberts in an above post who explained that vertical down FCAW welds have thin throats. To build on that, vertical up welding provides a "shelf" of cooler weld metal that helps to hold the more molten metal above it in position long enough for the metal to solidify before gravity overcomes the puddle. That allows for a thicker throat in the weld, and we know that more metal is stronger if all else is equal.
Vertical down welds don't have a shelf to hold the molten metal in place, or not much of one if there is any. The weld is held in place by surface tension which can't support very much molten metal. That results in beads that are thin in proportion to the width. Also, vertical down welds cool more quickly which may not give enough time for shrinkage forces to 'even out'. That can promote cracking.
All this is not to say that vertical down welding is wrong. Like any other subject, there is a time and place where it makes sense. The fact that you have used vertical down welding for years is strong evidence that it is OK for your situation. Whatever your product is, if none of the weldments have failed, then the welds must be strong enough for their purpose.
I wouldn't be hard on your new inspector though. He likely has been trained to recognize potential problems and bring them the bosses' attention. Vertical down welding is an automatic alarm bell for inspectors, like a strange noise coming from your car. Not an automatic problem, simply a warning for a closer look.
It would also be wise to review the product history. Have some welds failed but are not routinely reported? Could the customer overload the product and cause weld failure? Would a switch to vertical up welding increase productivity? For that matter, does it make sense to switch to GMAW? It doesn't hurt to take a fresh look and see if improvements can be made.
Chet Guilford
For WPS of GMAW & FCAW, in Table QW-255, paragraph QW-405.3 indicated it is a nonessential variable, quoted change from upward to downward, or form downward to upward, in the progression specified for any pass of a vertical, exect that the cover or wash pass may be made up or down. The root pass may also be run either up or down when the root pass is removed to sound weld metal in the preparation for welding the second side unquoted.
For WPQ of GMAW & FCAW, in Table QW-355, paragraph -405.3, it does indicated that changed of vertical welding from uphill to downhill or downhill to uphill is an essential variable.
Therefore, in the WPS you should addresses the position with uphill or downhill, or both(code required to address all nonessential variables). But the welder must be limited to use the postion(s) that he/she has been qualified for.
Kind regards
H.Chang
Rosie, if you need to prove who is right or wrong, then there is one thing that needs to be done and that is, to do a welding procedure. If the inspector thinks he is right, then have him do a WPS and have one of your welders do a WPQ.
I'm a government welder at Puget Sound Naval Station, and in my admittedly short experience I have never seen a FCAW Vertical pass NDT if it was VISIBLY welded downhill. We are told that the earth will stop turning and the moon will fall if we are caught welding downhill by our bosses and engineers.
There are only a very few limited times when it is permissible for us to weld downhill, and those are only on very thin sheet metals and some piping (piping is all GTAW).
That said, if it's the cover pass and there's undercut on the toes, I've had experienced mechanics tell me to do it and grind it up so no one can tell.
NavSea WP-1688, WP-1689, NDTP-271 and NDTP-278 are the technical publications we have to work to.
Hope that helps,
Chris Ables
Rosie;
You never stated what welding standard you are working with.
Notice that the responses you received were different for the welding standards cited, i.e., AWS D1.1, ASME Section IX, NAVSEA TP278, NAVSEA TP1688, etc. Different welding standards have different requirements and different restrictions.
In any event, all the welding standards I've been involved with require the welder to qualify using the progression to be used in production. That is, if you are welding using upward progression, that is the progression used on the welder performance test. If you are going to weld with downward progression, then that is how you weld the test coupons.
With the exception of ASME Section IX, most welding standards require the contractor to qualify the coupon (for the PQR) using the same position and progression to be used in production especially if downward progression is to be used.
The inspector should review the WPS and the supporting PQR to see what progression is called for. Then review the welder performance test records to see how the welders qualified (and thus certified). I've seen many instances where the welders qualified using vertical upward progression on their tests and then used vertical downward progression in production. A definate "No-No'.
Best regards - Al
Greg is right, the generally preferred progression for FCAW is uphill. But this is not absolute. There are times when downhill may be preferred though its hard to imagine many. You can weld it quite well downhill. And it will produce very good welds. The problem is efficiency. Its just not as efficient or productive as running it uphill.
Stick rods that are recommended downhill have a larger volume % of fast freeze compounds in the flux coating. Wires have them too (some more than others), its just that you can't put as much inside a wire as you can outside an extruded rod, therefore you can't carry as much metal.
As for your inspector, I do wish inspectors would get it through their thick skulls that their responsibility is to verify compliance not engineer welding.
If you have a properly qualified WPS he does not have the authority to enforce something already in compliance. If however you are violating your WPS he does have the authority, or at least should have based upon code and manual.
i have been told that running the flux core wire down hill the throat is shallow and you will actually bridge the pieces together, but there is a gap underneath,causing the weld to crack or break.
i burn 072 232 wire and if its got gap ill run one down to fill then another uphill. im in w.n.c. and welding inspection is a joke here. there is a woman who asked a (cough) carpenter what to look for in weld. the .045 i wont run down hill nor will i run it anymore. too slow
Forum
