[zoeper]

I am cutting parts from 316 grade stainless steel instrument tubing that i buy in the annealed condition. Is there any way that i can harden it again without "working" the metal?
Thank you
Pieter

[JWB_Machining]

If you've got a Furnace large enough and the parts are small enough there's no reason you couldn't heat treat them yourself. You can get guidance on temperature, duration and rate of cooling in any Material Science text. If you need more guidance or things aren't going right try contacting a local university's engineering department and talking to whomever teaches Engineering Material Science or Manufacturing processes, my bet is the EMS guy will be able to help you.

[Geof]

316 is low carbon and I don't think it can be hardened by quenching from a high temperature.

[JWB_Machining]

That's true, I don't know what the application for your parts is but you could try and case harden the pieces, this process doens't make the entire piece hard, just the exterior, I forget how deep the hardening goes but not much. You do this by getting your parts up to temperature and then, as fast as you can, coat them in a carbon powder, i think the popular Brand is Called kase-nit or something like that, you can look up case hardening. And Then quench this. This will leave a high carbon layer on the exterior. I don't know if you can do it with Stainless, I haven't case hardened anything in years but if you do a lil research i'm sure you'll find what you want, that's all depending on your application.

[zoeper]

My application does not require a hard surface as such, but i do need the parts to be stiff and resist bending. The difference between 316 as i normally buy it off the shelf and in the annealed condition is quite noticible so the question remains how do they get it hard in the first place?
Machinery's handbook makes absolutely no mention of the hardening of SS.
The only reason i am making it from tube is to avoid a gundrilling operation.(something i do not have the capacity for)
Pieter

[Geof]

... the question remains how do they get it hard in the first place?...Pieter

You more or less answered this yourself in your first post; it is work hardened by the drawing operation.