How to work-harden Stainless Steel 1

[gruntguru]

I have designed a beam element to use as a flexure. Needs to be stainless steel for several reasons. Dimensions are 255 x 12 x 8 mm (approx 10" x 1/2" x 5/16"). They will be profile cut from 8mm plate. These are spring elements and need to operate beyond the elastic limit of the as-delivered material. We have 316 or 301 available.

I want to increase the yield strength from the ~200 MPa (as-delivered) to at least 400 MPa. (301 in "1/2 hard" temper has a yield of 760 MPa which would be ideal)

 

[3DDave]

How do you feel about a bit of squashing with rollers?

I expect that pulling might also do the job, but rolling should be more uniform.

I note that annealed has 40% elongation and 1/2Hard is down to 15%, so somewhere between 40% and 15% stretching should get from annealed to 1.2 Hard. One source suggests that it becomes magnetic when cold worked, so that could be used to monitor the process.

Another has this to say:

301 Stainless steel Cold Working:​

Stainless steel grade 301 with low carbon content is commonly used in high strength applications. The cold working of this kind of alloy leads to very high work hardening rates with typical values of 14MPa (2ksi) per 1% reduction in area. As a consequence, cold rolling and roll forming processes can achieve high strength.

This means that you need a part that is oversized in at least one dimension to squash it enough to get the work hardening required; probably need some post-hardening machining to get the exact dimensions you need.

Where's Ed Stainless to figure this out??

 

[IRstuff]

Is this an application for Damascus steel process, which involves hammering thin and folding mulitple iterations. Swords made that way are flexible and hard.

 

[EdStainless]

You do this by buying cold finished bar.
It will either be cold drawn or rolled.
You can't do this yourself.
Product other than sheet does not have definitions for "1/2 hard" and such.

 

[EdStainless]

Since you will buying new material you might just want to get some 17-4PH aged to H1000 or H1050 to use for this.