SS question

[Will W.]

Hello everyone. 

Recently, I've become employed at an industrial machine shop, and with some persuasion, I could get my hands on the cut offs of steel. 

Now, the steels we work with are 5640 and 5673. I've never forged these alloys, so I'm curious if anybody has any experience with them. Will they make good tools? Perhaps a knife? I know stainless alloy numbers can be weird sometimes, but the 40 and 73 are, I assume, 0.4% C and 0.73% C, respectively. Any info would be much appreciated. 

Thanks in advance. 

[-Quint-]

5640 is 303, which can be forged, but it must be forged very hot, otherwise I think it crumbles. As far as heat treatment, I believe it will work harden, but heating/quenching won't harden it. When I was looking for a good alloy to use to make medical type instruments, I researched the 300 series and wound up going with 304. Quenching 304 optimizes it's corrosion resistance but like 303, it won't harden  

I honestly know nothing about 5673 without looking it up. 

By the way, I just looked in my stainless section of my Forge log and the site I have written down for info is steelforge.com. Tons of info on alloys there.

[Will W.]

Alright, I'll look into it. 

Thanks for the info on the 5640. Funny, everyone at work calls it "hard steel." They've obviously never worked with properly heat treated 440C before! Lol. 

[rhitee93]

300 series and 400 series stainless steels have completely different behaviors.  The 400 series steels can be heat treated to make them harder.  The 300 series stuff cannot.  If fact, the only way to anneal 304 stainless is to heat it up past transition and quench it.  The exact opposite of most steel.