Can I heat treat this 17-4?

M

Mikeeal

Plastic

Joined

Jan 29, 2019

• Feb 20, 2019

• #1

Good day. I get this 17-4 from McMaster currently, attached are the specs that they give. Untouched we get 36rc hardness. Machines nice. I'd like to machine, then harden it further. Can this be done? In my reading it looks like I can, (put in kiln at 925 then air cool) will hopefully get us into the mid 40's. Yeah?

Thanks.

 

M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Feb 20, 2019

• #2

I'm pretty sure you have to anneal it first, then follow the procedure for hardening and tempering to get to whatever new H value you want. The reason is you have to go to an elevated temperature for HT, then temper to get the final hardness. As the material has already been tempered to a higher value, just trying to use the lower number from this point will only reduce the properties of the material.

 

beege

Stainless

Joined

May 18, 2007

Location

Massachusetts

• Feb 20, 2019

• #3

It does say "annealed", which should probably read "solution annealed". You should be able to soak at 900F or 925F to get it to about 44 Rc

 

Bobw

Diamond

Joined

Feb 8, 2005

Location

Hatch, NM Chile capital of the WORLD

• Feb 20, 2019

• #4

Toss her in the oven, and cook her up. 4 hours, unless it's an h900, in which case it would be for only 1 hour for some reason. I'm not sure where an h925 would land time wise.

That's the beauty of 17-4. Quick simple low(relatively) temp heat treat, and fairly stable.

Also don't get to hung up on the hardness #s, they can vary a lot from the same H#, though they tend to be pretty consistent from the same batch of material.

 

M

Mikeeal

Plastic

Joined

Jan 29, 2019

• Feb 20, 2019

• #5

Thanks guys! I appreciate the replies. So what if these parts are small? Like .04 thick? (they're actually tapered from .04 to roughly .09) Still 4 hours? Then just pull out and let sit in the shop till cool?

Mike

 

beege

Stainless

Joined

May 18, 2007

Location

Massachusetts

• Feb 21, 2019

• #6

Used to run 17-4ph almost exclusively. 1 hour at 900°F should do it. No need for 4 hours at 925°F. You'll get 44Rc. If you have to test, make a small slug and heat with your parts.

 

M

Mikeeal

Plastic

Joined

Jan 29, 2019

• Feb 21, 2019

• #7

Thanks, I'll give it a shot!

 

E

eaglemike

Stainless

Joined

Apr 25, 2014

Location

san diego

• Feb 21, 2019

• #8

Does shrink small amount. It make a difference, depending in whether h900 or h1150. H1150 shrinks a bit more. It might not matter to you.
I machine a fair bit of 17-4 every year, heat treat to h900 before machining. Not too bad if you plan for 44rc.
As others above have said, it's an easy-peasy process to heat treat this stuff.

 

M

Mikeeal

Plastic

Joined

Jan 29, 2019

• Feb 22, 2019

• #9

So what I neglected to mention is that after I machine, it then spends an hour in the kiln at 650 degrees, then another hour at 550 degrees, (in a mold to inject two different types of plastic) So with that said, do you guys know what that will do to the hardness?