15-5 stainless

[monstermetal]

Anyone know anything about 15-5 ? Reading what popped up on google it sounds like good stuff. I got a few hundred pounds of the stuff and buy a 1000 lb bar of 4x4 at around a buck per lb

[Swamptroll]

It is like 17-4 ph but of different hardness, it is difficult to machine and probably tough to forge

[Jeff Seelye]

Sounds interesting, I've never worked it either but,it is probably a Martensitic Stainless(as opposed to Austenitic Precipitation Hardening or Ferritic stainless) which should put it in the 400 series probably at the high end (around 430?). It can be heat treated. Looked it up in the ASM book. It says to forge above 2000 degrees to 2200 degrees and never below 1600. If you want more heat treat out of this book I can send more info to you If you have any more info on it maybe I can look up more stuff for you.

[monstermetal]

Sounds interesting, I've never worked it either but,it is probably a Martensitic Stainless(as opposed to Austenitic Precipitation Hardening or Ferritic stainless) which should put it in the 400 series probably at the high end (around 430?). It can be heat treated. Looked it up in the ASM book. It says to forge above 2000 degrees to 2200 degrees and never below 1600. If you want more heat treat out of this book I can send more info to you If you have any more info on it maybe I can look up more stuff for you.

It is magnectic and it is precipitation hardening (its marked 15-5 PH Vac Melt)

Here is the dope sheet15-5


It looks to be air hardening

[patrick]

17-4 and 15-5 are both Martensitic Precipitation hardening stainlesses. The chemistries are very close. In our shop, we usually see 15-5 as a remelted ingot, which typically gives higher cleanness than a single melt material since secondary melting is either done under vacuum or via a process called Electroslag Remelting. In any event, both grades are handled nearly identically from a forge and heat treat point of view. Upper forging temperature will be around 2200 F. Air cool. Solution anneal as soon as possible after the pieces cools to 90F. The grade does develop martensite upon cooling and if not either tempered or taken directly to a solution annealing step, the pieces have a high risk of cracking. To solution anneal, heat to 1900-1950. Fan cool. For larger sections, say 6" and over, a short quench of around 30 second per inch can be used. Cool to 90 F and load back into a furnace for aging. Typically aging temps are between 900 and 1150 F. There are expected hardness and strength values that go with each temperature. Note that with this grade the thermal cycle following the quench is referred to as AGING, not tempering. In the case of tempering, you are taking an as-quenched part and making it SOFTER. With aging, the opposite occurs. You end up with a HARDER part. I would not suggest working with this steel unless you are able to either do all the heat treat yourself or at least get the part tempered after forging to prevent cracking before shipping it to a shop specializing in heat treating.

Patrick Nowak