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Heat treating 17-4 stainless

JimGlass

Stainless
Joined
Jan 15, 2003
Location
Genoa, Illinois
I need to make some parts from 3/16" dia 17-4 stainless. The print calls for 17-4 PH (H1150).

My local steel suppliers are unable to obtain this grade (PH) of stainless in diameters under 1/2".

Can I buy 3/16 dia annealed 17-4 stainless then heat treat after machining. I did some research and sources say it is a precipitation heat treating. Heat the parts to 1150 degrees and hold for 4 hours then quench in still air. My heat treater says it will cost $150 to heat treat 25 pieces 3/16 dia X 5" long.

Can I heat treat these parts in my own heat treat oven. I heat treat tool steels all the time but never any stainless steel.

I'm clueless on this stainless steel.
Thanks
Jim
 
The AMS spec for 17-4PH H1150 should tell you the HT specifics. If you HT yourself, since you likely can't cert to the spec, you better make sure your customer is OK with that
 
Your oven got a printer or any other way to log the time and temperature?

When we did 17-4 at my former workplace, we Rockwell hardness tested each piece before machining, to determine if it was the correct HT condition.

It really was as simple as that, though. Heat it up, hold it there based on thickness, cool, hardness test to confirm.

Sounds like the heat treater wants his minimum charge to turn on an oven.

Cheers
Trev
 
Can I buy 3/16 dia annealed 17-4 stainless then heat treat after machining.

Heat treat, and then machine, from a solution treated/annealed state to an H1150 your machinability will go up about 50%.

In the annealed/solution treated state, its kind of gummy and behaves more like a 300 series stainless. Get that
stuff heat treated, especially an H1150, and it acts like a pre hard 4140, except shinier.

We dabbled in the heat treat crap at my shop, and decided the only thing we will heat treat anymore is PH grades, easiest
heat treat out there. To temp and hold, air cool.

The only thing easier is taking an aluminum at a T0 and bringing it to a T4 (actually got paid for that once, they wanted a cert,
3 days at room temperature).

If you are doing tool steels, 17-4 is a cake walk.

Definitely my favorite stainless.
 
Buy the 17-4 in condition H1150 and then machine. It should only be about 28 Rc (277 Bnh). Like Bob says, it machines nice at that stage. We literally do tons of it. H900 and H1025 are over the 35 Rc. We'll machine and then harden those.
JR
 
Bob!!!!!!! Zip it!!! You are giving away all the secrets!!!! Come on... there has to be at least one mystery metal left...

(all in good fun, mind you)



Heat treat, and then machine, from a solution treated/annealed state to an H1150 your machinability will go up about 50%.

In the annealed/solution treated state, its kind of gummy and behaves more like a 300 series stainless. Get that
stuff heat treated, especially an H1150, and it acts like a pre hard 4140, except shinier.

We dabbled in the heat treat crap at my shop, and decided the only thing we will heat treat anymore is PH grades, easiest
heat treat out there. To temp and hold, air cool.

The only thing easier is taking an aluminum at a T0 and bringing it to a T4 (actually got paid for that once, they wanted a cert,
3 days at room temperature).

If you are doing tool steels, 17-4 is a cake walk.

Definitely my favorite stainless.
 
Come on... there has to be at least one mystery metal left...

Where should I send the Nitronic 50 to?
We usually only get duplex stainless in as castings, so I can't do one of those. Ferralium and Zeron are a PITA.
Then there's my favorites, tantalum and zirconium.

Our engineers are working right now on an updated version of the turbo-encabulator. Ours will be made from hard-faced unobtainium.
JR
 
Where should I send the Nitronic 50 to?
We usually only get duplex stainless in as castings, so I can't do one of those. Ferralium and Zeron are a PITA.
Then there's my favorites, tantalum and zirconium. Our engineers are working right now on an updated version of the turbo-encabulator. Ours will be made from hard-faced unobtainium.
JR

Same experiences, here. Lately, I've been working with NiTinol. Oh my GODS does this stuff suck.
And as for the Hard Faced Unobtanium, you can forget about it... We own the rights... :)
It's the very specific aging of Scrapbinium that will get ya...!
 
I have been looking for info on annealing 17-4. I understand everything i need to do except for one thing, when going back to condition A; Can I toss the parts in to a pre-heated oven at 1900ºF ? I'm assuming I can but looking for a little reassurance.
 
Odds are they'll shrink a few thou but can't imagine that being a problem on hinges like that, and they'll be dark/blue/brownish if done in a plain furnace with no wrap/shielding or such.
 
Odds are they'll shrink a few thou but can't imagine that being a problem on hinges like that, and they'll be dark/blue/brownish if done in a plain furnace with no wrap/shielding or such.

I guarantee that they will not "shrink a few thou". In fact, I will bet you actual, hard money that they will not if treated correctly. And by correctly, I mean simply not mishandled extremely.
 
I guarantee that they will not "shrink a few thou". In fact, I will bet you actual, hard money that they will not if treated correctly. And by correctly, I mean simply not mishandled extremely.

I dug into this a while ago when I was looking at shrink factors for 13-8.. IIRC 17-4 will shrink in at least 2 directions, and will be unpredictable
as to what will happen in the third direction.. Its a few tenths an inch.. Probably half thou at the most...

13-8 on the other hand, well documented and predictable. Customers freak out when you ship them all oversize parts... I've started
attaching an explanation and a chart to the box... When they come back from heat treat, they are right in tolerance.

As for how they will look after heat treat.. If you send them out dirty, they are going to look like shit... If they are really
oily, you might get some black scale over an ugly brown. Slightly dirty, dark purple and brown.. Really clean they will most
likely come back purple and dark blue with maybe a little bit of brown..

As to the hinge, you could probably hang a car off of it as is.... Why bother heat treating 'em at all?
 
John- I know it is pointless to argue with you, I kind of agree about the looks, but they also are not finished.

Short answer to your question, they go in a cabinet (built by someone else, not me) that costs more than your house & car.

They have to be durable with a mechanical automatic actuating system that puts a lot of force on them. The hinges have to clear a lot of non-structural wood with a huge lever arm. The wood pieces in the background are so I can work out the mechanical pieces in my shop. They are not the "real" parts, and are dramatically simplified only to provide dimension and weight to my seat of the pants engineering. :D

But I know you are something of a designer and I'm always open to ideas. :)

Actually, I suggested strap hinges like on a barn door as they would be simple and take all the stress. But it was shot down.

smt
 
custom wood cabinet hinges out of 17-4? Why?

And they don't even look good and aren't engineered well. :crazy:

John, If you've seen pictures of Stephen's work, I think the presumption should be of extreme competence. Making a derogatory comment about work in progress doesn't convince anybody, and only ends up making you look immature and incompetent. I've seen pics of your work, and I know you're not incompetent.
 








 
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