Cold Worked 204Cu SS vs conventional heat treated SS 4

[slashragnarok]

While researching some high strength steels I came across 204Cu which apparently offers quite high tensile strength values depending on how much cold reduction it's subjected to. What difference would there be between heat treated stainless steels and cold worked 204Cu? I am looking at 150 ksi - 180 ksi UTS. Also it seems that 204Cu is a lot cheaper than other SS.

Thanks

 

[mcguire]

True, much 200 is junk. I have seen alloys which have 11% Cr and lots of Mn and N. I question whether the thermodynamics render this truly stainless, since the activity of Cr is altered by that amount of Mn. It is used for food service items imported from India. It is austenitic so it can easily passed off as 304 to an unwary consumer. This is not a criticism of India by any means. I simply cite unfair marketing over which no US agency has jurisdiction.
In the US the best 201 is 5.0% Ni, 17Cr and less than 0.10% N. This alloy forms exactly like 304, which makes the substitution easy. High N versions have too high a yield strength. You can easily make a 3.0% Ni version but that requires lots of N, which is fine if you want high yield strength.

Michael McGuire

 

[slashragnarok]

Thanks for your response, Michael. Indeed, my main requirement is yield strength. I need only moderate corrosion resistance as I don't live in an overtly humid climate or anywhere near the sea.

 

[mcguire]

If you want to maximize the yield strength, then find the highest nitrogen level. The copper in 204Cu is a substitution for Ni, and it isn't a good value proposition. Get that low Ni, high N material that India is famous for. No nickel, no cry, as Mister Marley might have said.


Michael McGuire