Carbon Equivalence and P(subscript)cm 4

[mechmike]

I am try to figure out a specification that has requirements for carbon steel forgings of CE=0.42 and Pcm=0.22 (The cm is a subscript) I got the Carbon Equivanlence figured out but I can't find out what Pcm is or the equation for it?

 

[sayee1]

Typical Pcm Composition parameter as per annexure XI, AWS D1.1
C+ Mo/15+V/10+(Mn+Cu+Cr)/20+Si/30+Ni/60+5B.


Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[UKCats]

What is Pcm??? Is it another way to calculate CE???

 

[GRoberts]

Carbon equivalent is a index used to determine hardenability. It is usefull for welding, but did not always correlate with cracking susceptability, so the Japanese develeoped the Pcm equation to give an index for a materials susceptability to cracking from welding.

 

[CWIC]

Sayee & GR:
I tried to "star" you, but it did not work. So, this is the best I can do.: * *

You guys provide some very good responses and equally interesting questions. Thanks.

 

[sayee1]

CWIC,
Thanks for the star. A site like this would be incomplete without the interaction by people like yourself, GRoberts, TVP, TEV, Metalguy, Kenvlach, Corypad, Mcguire and others. I find it interesting that the seemingly simplest of problems I post here gets the best of replies without any hint of "looking down" on the posts. Knowledge is to be shared and I find that sharing more with an educated forum like this is learning more. Just getting a bit non technical and emotional I guess! thanx once again for boosting my enthusiasm.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[kenvlach]

Here are several Carbon Equivalents, from N.Yurioka

http://member.nifty.ne.jp/yurioka/exp.html

[Thanks to grampi1 for connecting link in thread330-54594]

"Carbon Equivalents

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)}"

Note: Yurioka's is an interactive site on 'Weldability Calculations,' I recommend a visit.

[CWIC, I awarded stars to Sayee & GR]

 

[mtune]

CE given in percentage is indeed for hardenability. This is turn allows for working out the pre heat and interpass temperatures to be applied and maintained, before and during welding. If you look around the Material certificate for the material it normally gives you the equation used to work out CE or Pcm. Normally at the bottom of Chemical or ladle analysis detais page.