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Need help w/carbon equivalency determination

Need help w/carbon equivalency determination

Need help w/carbon equivalency determination

(OP)
OK here's a dumb question from someone who usually works in the oil patch, not metallurgy.

I need to calculate a carbon equivalent so that I can show that a steel proposed for use in a tank will meet UL 142.  

There are several formulae one can use to calc the carbon equivalent %.  Which is the one to use?  None of my references have this info (Marks dropped the ball on this one... at least I can't find it in there!) and a web search produces at least five different eqns for carbon equiv %.

Thanks for your help guys!  Pete

Thanks!
Pete

RE: Need help w/carbon equivalency determination

The most common CE formulas to evaluate weldability for fabrication depends if the metal is an alloy steel or modern carbon steel. Here are both common CE equations;

for low alloy steel, elements are w% amounts;

Ceq = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15


for modern low carbon steels, elements are expressed in weight percent amounts;

Ceq = C + Si/25 + (Mn+Cr)/16 + (Cr+Ni+Mo)/20 + V/15

RE: Need help w/carbon equivalency determination

(OP)
Thanks for your reply.  The steels in question are are SA36 and SA516-70.  Which category would these steels fall into, in your post?  Thanks!  Pete

Thanks!
Pete

RE: Need help w/carbon equivalency determination

(OP)
Also - the first eqn you presented is the IIW eqn.  What is the name or reference for the second one?  Thanks! ! !

Thanks!
Pete

RE: Need help w/carbon equivalency determination

74ELsinsore;
Use IIW for comparison with SA 36 to SA 516 Grade 70. These are considered C-Mn low alloy steels, and the IIW is used by AWS and ASME B&PV code for base metal weldability comparisons.

The second CE equation was referenced from a Welding Research Council Bulletin.

RE: Need help w/carbon equivalency determination

(OP)
Thanks metengr - you're a stud    Exactly what I needed to know.  Nice timely response.  You get two stars    THanks ! ! !

Thanks!
Pete

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