Welding of Rebar 8

[LPPE]

Can anyone tell me why welding rebar results in a brittle weld? What does AWS D1.4 say about welding rebar?

 

[lsmfse]

I have a paper published by SEANC on the subject. Its somewhat dated but useful. I can email it to those interested.

 

[dik]

Agreed... I was thinking that the plate assemblies could be shop welded... I'm aware of field problems with MIG and TIG... not knowing the procedure used initially, I made reference to weld being affected by an outside breeze... BTW in this locale, there has been an increase in the use of MIG and TIG in the field over the last few years...

"I respectfully disagree that these welds are suceptable to cracking. Particularly if a qualified WPS and PQR were implemented"

Could be... I don't know... I'm not familiar with E308L-16... my programmer buddy mentioned that E308 should only be used for stainless to stainless welding and not stainless to regular steel... for which he suggested E309 as a better choice... again, I don't know what his source for the statement is. Pylco can check into the suitability of using the original electrodes...

Without knowing that the welds had cracked, however, my programmer buddy asked if they had (out of the blue) and mentioned that it could be because of the dissimilar metals.

 

[dik]

Ismfse:

Be appreciated... my email address is in my user profile (put there on suggestion by another user that addresses not be published in the forum for spam reasons).

thanks

 

[BigH]

One comment - make sure that the welder who is doing the job is a good one!

 

[jdsteel]

From a fabricator erector standpoint, we typically use E309 as the filler metal of choice, but the filler metal does not appear the primary source of your situation.

From what you have said, it sounds as though the problem was in the procedure (or lack thereof). You did not mention the thickness of the materials, but the fact that your getting consistant failure indicates that the rebar was not the A706, and that preheat was not being done. If a welding procedure was submitted and distructive test performed with satisfactory results to gain it's approval, then the procedure was not followed.

Fabricating companies are production driven and welding carbon to stainless is a more sensitive procedure that should be avoided in structurally critical conditions. There are a variety of companies that produce weld studs and derformed bar in stainless steel materials that can be welded with consistantly sound results. The materials are expensive, but not as expensive as the forensic studies and consequencial repairs to carbon/stainless joints.

 

[dik]

jdsteel:
Do you or would you use E308 as the original problem indicated? if not, why? and can you copy a writeup of a procedure or a reference using E309? In your opinion, what is the best stick and procedure to use for welding rebar to stainless (assuming that the rebar is suitable)?

I'm using this thread as a distance learning experience...