Gentlemen (and Ladies - if there are any viewing this),
I have a question regarding gouges left in the base metal from grinding of welds. My shop recently did a job in which the customer complained of gouges left in the base metal of non-structural sections of the unit. The gouges were due to our welders not being careful enough when grinding the welds flush. Physically, the welds are fine as the gouges do not contact the weld material whatsoever. And since it is not a pressure vessel or structural, there should be no negative impact on the product lifetime (everything gets painted, so corrosion shouldn't be an issue). Anyway, I do agree that certain areas should have been fixed by filling with weld material, but I was wondering if anyone has experience regarding acceptable base metal gouge (defect) depth based on the thickness of the steel. I have looked through D1.1, but it mostly deals with repair of welding defects and determination of acceptable criteria for the welds themselves, not necessarily the base metal. Does anyone have a chart or know where I can find one that shows various thicknesses and the corresponding depth of removed material, or if it is easier, just a percentage of the base metal thickness would work too. Thanks in advance!
Andrew Panariso
Also, D1.1 section 5.15.4.4 states in regards to thermally cut material: Roughness exceeding these values (from 5.15.4.3) and notches or gouges not exceeding 3/16" deep on otherwise satisfactory surfaces shall be removed by machining or grinding. This is, I believe, only the case when dealing with cut surfaces in preparation for a weld joint, not in the case of base material outside the weld zone. This was the only thing I could find in regards to a size limitation of gouges or notches in base material.
Would that I could sir . . . guess I might have to buy that one - it has come up several times as a supplement to ASME and ANSI guidelines to fill in the gray areas. The ASME guidelines are about as detailed on the subject as the AWS are, with no real indication as the acceptable gouge sizes. I understand that any gouging of the base metal is really unacceptable, but you can only control the workforce so much . . . and grinders get away from people. Anyway, thanks for the reply.
Best regards,
Andrew
What type, grade and size of material are you working with?
drewp29,
AWS D1.1 5.26 Repairs
The removal of weld metal or portions of the base metal may be done by machining, grinding, chipping, or gouging. It shall be done in such a manner that the adjacent weld metal or base metal is not nicked or gouged. Oxygen gouging shall not be used in quenched and tempered steel. Unacceptable portions of the weld shall be removed without substantial removal of the base metal. The surfaces shall be cleaned thoroughly before welding. Weld metal shall be deposited to compensate for any deficiancy in size.
You stated that you are working to D1.1. Now I understand that what was being done with the grinder could arguably be called "removal of weld metal by grinding". This SHALL (not yelling, just emphisis on the word as it is an important word,IE should or shall. Should means you should but do not have to. Shall, however means exactly that, you will) be done in such a manner that the adjacent weld metal or base metal is not nicked or gouged, and without substantial removal of the base metal. Then weld metal SHALL be deposited to compensate for ANY deficiancy in size.
Having said that, do I think it will affect anything? I can not honestly comment without seeing the sections, but probably not. Ultimatly EOR should be the one to make that decision, because if your building the structure to AWS D1.1 I would say that the gouges should be repaired, unless EOR will sign off on the gouges. IMO
Yes, I had read that section after my post earlier - and I DO agree with exactly what you said . . . I guess then that any and all gouging caused by overshoot during grinding SHALL be repaired. So, in your opinion, since there is no size qualification on the nicking or gouging (i.e. any gouging is unacceptable), do you feel it would be acceptable to feather smaller gouges by grinding to eliminate sharp transitions in thickness, while deeper gouges would be filled with weld material? Any suggestions on a depth guideline . . . or just leave it to visual inspection to determine whether the nick can be repaired by grinding as opposed to filling? Again, strictly speaking, on non-structural, non-pressure vessel materials.
Normally we do not have this problem, but this was a rush job with little more than 2 weeks to draw up and build something that would normally take at least 1 to 1 1/2 months. And, things as they were we didn't get the chance to inspect the entire job and determine whether these areas were acceptable. Thanks for the input . . . I'm sure my boss won't be pleased (more work in the shop, etc. etc.), but if that's what it takes, then so be it!
Well, I would suggest looking at the material standard before you go doing anything.
hogan and CWI555 both, have made valid points that should be used in the determination of an acceptable depth. D1.1 uses the words " without substantial removal of the base metal" and I think that the material specs would be essential to the determination of acceptable depth. IMO once you have determined the acceptable depth, and if you have gouges not exceeding this depth, then it would be acceptable to feather them. Unless you are working with very thick material, IE 1/2", I would venture to say that the acceptable depth would be very small, IE 1/16" to 1/32". Keep the EOR tightly in the loop, because if this truly is not a structural issue and only cosmetic, EOR may sign off on minor gouges. Keep in mind though, most customers take cosmetics as seriously as structural if it will be visable in the final stage.
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