Cobalt - alloy steel

[vukk]

Hi,
I would like to ask you for your opinion about a low carbon steel (0,2 wt.%.) steel alloyed with cobalt 0,2 – 1 wt.%. The other composition - Ni - 1%, Mo – 0,5%, Cr – 0,5%, Mn – 1,1 %.
I know that cobalt is already used in high speed steel (2 wt. % and more), where cobalt bring higher hardness and temperature resistance.
Do you have any experience with cobalt alloying?
What do you think, does cobalt decrease impact toughness of the steel? Ok, it stands to reason, higher hardness = lower toughness. But I would like to know, if this decrease is also observed in a steel with cobalt 0,2 – 1 wt.%.

Thank You for your idea.

Best regards

 

[EdStainless]

the Co should help keep the toughness up.
Co behaves similar to Ni.
this is an interesting looking chemistry. I don't have my references handy to compare it to existing grades.


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Plymouth Tube

 

[arunmrao]

0.2-1.0% is quite a wide range for Co. I have seen some Russian specs,where cobalt was added 0.2-0.3% .

Agree with ed that the role of Co will be to improve toughness.

 

[metengr]

You might want to review the paper below

http://www.springerlink.com/content/t22624641x7714l6/