Gap size 6G tig Stainless

GregOrtiz · Tue Jan 14, 2014 12:53 am

Hi I recently finished a 6month combo welding job with many years previous in this line of work! I recently took a test for the same type of welding only on a different material and size! I failed! The test was 6g stainless steel 6" 10 gauge pipe. I have welded thin gauge sanitary and chemical process pipe with 8lmp before, no filler,purged with no gap and no bevel, walking the cup! This test was a lower grade of stainless and seemed to be thicker than other pipe I welded and it also had a bevel. I was asked what the size of gap I wanted, I replied 1/16''. I was confused because I assumed the gap or no gap was their preference according to their weld proceedure! I free handed the root and sealed the pipe and removed the purge cap to see the results. There was lack of fusion in some areas and I was about to walk the cup over the root to get good penetration all around the root,the inspector saw and said stop and that I failed! Was I supposed to have no gap and fuse without filler on the root? What did I do wrong?

Mike · Tue Jan 14, 2014 10:23 am

Welcome to the forum Greg.

GregOrtiz · Tue Jan 14, 2014 1:31 pm

Thank you Mike hope I can get a clear answer so I can retest!

AKweldshop · Tue Jan 14, 2014 1:32 pm

Don't worry Gregg, one of our stainless guys will chime in, once they see your post.
John

GregOrtiz · Tue Jan 14, 2014 1:40 pm

Thanks buddy for the post! I'll be checking regularly for the replies!

Tue Jan 14, 2014 8:18 pm

For sch. 10 stainless (304/304L), I like a knife-edge (no land) to walk a root pass, with little or no gap and 1/16" filler.

If you're used to sanitary pipe, this should work for you. Do it the same, but lay the filler in the bottom of the bevel and walk it in.

We all do it a bit different, so just consider this a suggestion.

Steve S

GregOrtiz · Tue Jan 14, 2014 8:29 pm

Thank you I guess it is solely up to the welder what type of fitt! Since he asked I assumed the smallest was what they wanted! Live and learn!

Tue Jan 14, 2014 8:32 pm

GregOrtiz wrote:Thank you I guess it is solely up to the welder what type of fitt! Since he asked I assumed the smallest was what they wanted! Live and learn!

Many tests will have a WPS (Weld Process Specification). Ask if there is one for your test.

It will tell you the minimum and maximum for EVERYTHING. (Gap, land, weld current, filler size, tungsten size). If there is one, you must follow the limits set. If not, it's entirely up to you.

Steve S

GregOrtiz · Wed Jan 15, 2014 3:27 am

Your name says it all bro! I know I've been called a weld monger myself! Juggling the trade to satisfy the cwi inspector and the superintendants work!! Face it, Its a living and thats it. Politics always get in the way! Some how I can do it though thanks for the reply! Next time that question may straighten out any downplay on the test set up! Live and Learn. Nothing negative on inspectors side since some process pipe is really dangerous! Kudos to you and the inspectors! AWS was great when it was created and still has its validations!

MinnesotaDave · Wed Jan 15, 2014 8:39 am

GregOrtiz wrote:Hi I recently finished a 6month combo welding job with many years previous in this line of work! I recently took a test for the same type of welding only on a different material and size! I failed! The test was 6g stainless steel 6" 10 gauge pipe. I have welded thin gauge sanitary and chemical process pipe with 8lmp before, no filler,purged with no gap and no bevel, walking the cup! This test was a lower grade of stainless and seemed to be thicker than other pipe I welded and it also had a bevel. I was asked what the size of gap I wanted, I replied 1/16''. I was confused because I assumed the gap or no gap was their preference according to their weld proceedure! I free handed the root and sealed the pipe and removed the purge cap to see the results. There was lack of fusion in some areas and I was about to walk the cup over the root to get good penetration all around the root,the inspector saw and said stop and that I failed! Was I supposed to have no gap and fuse without filler on the root? What did I do wrong?

Disclaimer - I'm shootin from the hip since I have not done that type of welding and you have experience that I do not.

If i read you correctly, you had lack of fusion in the the root? Isn't that a cause for him to fail you?

My understanding of all root passes is that it must be fused (fully penetrated) on the initial root pass - no trying to drive it deeper during the hot pass.

GregOrtiz · Wed Jan 15, 2014 2:30 pm

My assumption is that he believed my attempt was final for the root and that I would begin the hot pass! I was going to walk over the root to correct any imperfections without filler! There shouldnt have been a gap and with the tungsten barely out of the cup I could have had perfect penetration! Lack of communication was my error and next time Im going to take my time and think things through quite a bit more!

GregOrtiz · Sun Jan 26, 2014 12:07 am

Well its been a few days since my post and I want to thank all that have viewed and replied. This is a great tool for us that see the trade as much more than meets the eye! My lesson on this one is patience and more patience and a lot more communication goes along way! Never give up and press on forward! Hopefully someone can use this at my expense lol! But true and few 100 dollars worth!

Sun Jan 26, 2014 12:21 am

Greg,

What was the final outcome? Did you re-test?

Steve S

GregOrtiz · Mon Jan 27, 2014 12:03 am

No Otto I didnt it was a job that was really out of my way and dont think I would spend to go back and retest for the job anyway! Also I was told that it was illegal or something to that nature! Sounded like hogwash!!!! Thats why I asked so I can be aware for my next test!

Mon Jan 27, 2014 11:49 am

I've been on jobs where you couldn't retest for some minimum period, like 60 days, so I'm not too surprised. I'm not sure whether that was a code requirement or customer requirement, but either way, I think "illegal" was a strong way for them to word it... unless it was a government contract/subcontract job.

Steve S