Stainless with Best Balance of Biocompatability, Strength and Corrosion Resistance

Huh? Notably present in the list was perspiration.

Hah!! Guess I skimmed over that! Mea culpa.

SO can we assume that this means contact with skin for long periods of time is fine? Why is 420 never (that I can find) used in jewelry, watches etc. Are there large enough variances in 420 alloys (while still being a 420 alloy) that one supplier's 420 could fail miserably in this application?

In short would 420 stainless be your recommendation or is there another widely available stainless that would be better suited?

I don't think you can get there from here.

420 is iffy, Niobium and Titanium are good for implants but may not be strong/inexpensive enough for tools.

I'd try 316L and see what you get. Do you want jewelry, or tools?

Have you considered Hastelloy C-276? It ain't cheap, for sure.

316L is not strong enough (<35HRC and <100ksi). Niobium, Titanium and C-276 are all too expensive.

Am thinking 431 as it is the most CRES of it's class (martensitic) however because of its high yield strength, this grade is not readily cold worked and is therefore not recommended for use in operations such as cold heading, bending, deep drawing or spinning. We do need to bend a part 180 deg (around a rad of 3-4mm) so that is a concern. It's a strip of metal about 1cm in width and 1mm thick that we bend using a mold on a stamping machine - do you know if that will be a problem?

That's way over my competence level. My experience is in chemical etching equipment, not processing the metals. I think you know more about this than I do.

Milo, our resident metallurgical expert will know.

OK but thx for your input anyway (and I'm sure you're being too modest)

done some reading on C-276, it has 55% Ni which (based on % content alone) puts it waaaay out of the hypoallergenic field

Try looking at the 17 series SS (17-4 low Ni 4.5%.) You can play with the hardening temps to achive a balance of Yield/Tensiel strength to hardness. Corrosion resistance in the hard condition is better that 400 seires comparable to 304

thank you, will do

"I want to make a stainless steel piece of jewelry (constant skin contact) that will double as a hex key or maybe a screwdriver."

I don't know about anyone else, but I sure would like to see some pics of these.

I'm forever misplacing my lug wrench.

Maybe a pendant on a chain would work for me. I don't think my ear lobes (or any other body part) are strong enough.

they're actually for quite a well known client, so while I can't show you the designs for obvious reasons am sure you'll be seeing or hearing of them soon.

I agree with oak50, 17-4PH would be a superior choice is this application. It is readily available (here in the US) in different hardened and annealed conditions.

If you are going to be making hex keys from it you would probably check with a local mill and see if they could provide the hex stock on size, preferably ground, and soft for bending. Once bent and made into parts have them electro polished for maximum corrosion resistance.

Good Luck

Thanks so much