What is the difference between CEV and Pcm values in Welding?

Hi Sneha, Well they have in common: - the same purpose: both values were crated to estimate the weld-ability of a carbon steel material - they both measure the propensity of a material to create martensite during cooling ( ability to quench-) - they are both based on the chemical content of several element of you material. these element are known to increase the 'quenchability' of you base material However, they are based on slight different formula and the numerical values cannot be compared from the Cev to the Pcm. For example, the pipes in API 5L X65 (base material grade) we are welding in my job actually have a Ceq of 0,34 ( considering the IIW formula-see below), and the Pcm is 0,14 Be careful, there is different formula for the Ceq, one from the IIW ( international institute of welding) and another one from I-don't-know-where-exactly. Usually the formula used to calculate the Ceq is showed on the base materials certificates. from The Japan Welding Engineering Society the formulas: CE(IIW) = C + Mn/6 + (Cu+Ni)/15 + (Cr+Mo+V)/5 CE(WES) = C + Si/24 + Mn/6 + Ni/40 + Cr/5 + Mo/4 + V/14 Pcm = C + Si/30 + Mn/20 + Cu/20 + Ni/60 + Cr/20 + Mo/15 + V/10 + 5B CEn = C + f(C){Si/24 + Mn/6 + Cu/15 + Ni/20 + (Cr+Mo+Nb+V)/5} where, f(C) = 0.75 + 0.25tanh{20(C - 0.12)} Hope this helps. Click on the thumbs up or mark it as the best, if you found this useful. Wish you Luck!

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