Welding Materials

They become subject to creation of martensite in the HAZ Heat Affected Zone, especially as the increased use of electric furnace steel production methods has allowed the residual elements to increase, thus increasing what we call the "carbon Equivalent:"

CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 ( all weight percent)

if the steel is microalloyed to produce very fine grain size and thus air precipiattion hardening effects, that requires a different formula:

Ceq = C + Si/25 + (Mn+Cr)/16 + (Cr+Ni+Mo)/20 + V/15
the advice that we followed using this was :

above .45 carbon equivalent, depending on section thickness, a post weld heat treatment may be needed.

Be very careful of the advice on this subject on the web that uses 0.14 wt% as a cut off, and 0.14%- 0.45 % as "modest preheats necessary;" and above 0.45 CE being "extreme complications." These advice do not mention need for post weld heat treatment or stress relief; they do not mention the role of section thickness, and they seem to imply that low hydrogen electrodes make the problem go away(they don't, they can help to minimize hydrogen problems, but not all of it, nor eliminate all stress from sectional and cooling differences.

I have not been able to find the original source for the 0.14% cutoff, and the absence of mention of post weld heat treatments is nonfeasance at best; malfeasance likely in the eyes of a jury...

(The Ityo Besseyo formula uses 0.18% not 0.14% !!! )see this article:

http://www.msm.cam.ac.uk/phase-trans/2004/Adams.Bhadeshia.AWJ.2004.pdf

milo

P.S. I would also point out that grade 1144 which is above 0.35 wt % carbon is resulfurized, and as a result should never be welded.