Effect of carbon on the 15-5 PH mechanical properties ?

[stanislasdz]

The ASME A702 said that the carbon content in the 15-5 PH steel is 0.07 Max.

My question is what is the effect of the carbon content on the mechanical properties when the carbon move from 0.03 % to 0.07 %

Thanks all

Any links to paper are welcome

 

[mcguire]

The alloy has Nb to combine with the carbon. Thus, the absolute carbon level is less important than the uncombined carbon (i.e. that in excess of 10 x the Nb level). This amount will lower the Ms temperature and produce retained austenite which would reduce the yield strength slightly.

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[stanislasdz]

Thanks mcguire

What about the impact toughness in the cases where the carbon content is 0.30 % and 0.70 %

 

[metengr]

stanislasdz;
Higher carbon content at 0.07% versus 0.03% mass percent means lower impact energy values, and a shift in DBTT toward higher test temperature.

 

[stanislasdz]

Thanks metenger

That is was i have expected.

Can we ajust the tempering temperature of a 0.7 % carbon to get the same value of impact toughness of a sample with 0.3% of carbon ?

 

[arunmrao]

Can we ajust the tempering temperature of a 0.7 % carbon to get the same value of impact toughness of a sample with 0.3% of carbon ?

This is the second time you are referring the carbon content as 0.3 and 0.7%. Hope it is only a typo error .
Carbon is not deliberately added into stainless steels as in low alloy or carbon steels. Hence the role of carbon is quite different. Also it is never desirable to have free carbon in the stainless steels as they can combine with chromium and form carbides,thus reducing stainlessness.

Learn the rules,so you know how to break them properly.
Dalai Lama

_____________________________________

 

[stanislasdz]

Absolutely Arunmrao, it's a typo Error

I mean

Can we ajust the tempering temperature of a 0.07 % carbon to get the same value of impact toughness of a sample with 0.03% of carbon ?

Instead of

Can we ajust the tempering temperature of a 0.7 % carbon to get the same value of impact toughness of a sample with 0.3% of carbon ?

 

[metengr]

stanislasdz;
This PH grade of stainless is not normally tempered, it is aged according to a selected range of aging temperatures and hold times to achieve desired mechanical properties.

If you want increased toughness beyond what the published values are for an H1150 or H1150-M condition for 15-5 PH, the lower carbon content will only improve your margin for increased toughness.

See the bulletin below for 15-5PH and the impact values published for a material specification with a maximum of 0.07% C by mass. Using a heat of lower carbon content will guarantee that you will reach the values or exceed them.

http://www.aksteel.com/pdf/markets_products/stainless/precipitation/15-5 PH PDB0504.pdf

 

[stanislasdz]

Thanks metengr