17-4 SS process

[chipman]

We need to make some parts out of some 17-4 SS, it comes in annealed, we need it to end up in condition H1025 around 38rc.

The part is about 12 x 2 x 5/8 has a few areas with some cutouts, lots of critical detail and a handful of tight tolerance holes.

Just trying to get an idea of how some of you process this stuff.

Do you send it out to get it treated and then do ALL machining, or rough some detail out and send it out for h/t then do final machining.

BTW, only 4 parts with aprrox. 40-50 hours of machining going into them.

 

Thanks ahead of time!

[jeff]

Do you send it out to get it treated and then do ALL machining, or rough some detail out and send it out for h/t then do final machining.

BTW, only 4 parts with aprrox. 40-50 hours of machining going into them.

 

Thanks ahead of time!

 

You can do it either way.

I did some 17-4 SS parts that if made out of something like 8620 or 1045 would have been turned into a pretzel.

This stuff is very stable in HT, and won't move very much.

The parts we did were finished before HT.

 

If you're unsure, make up a test piece that has a couple of reamed holes and a thin wall area and send it to HT to see what happens.

[?Mark]

17-4 annealed is one of the worst ss to work with, very gummy which doesn't work well with indexable tooling.

Heat treat it BEFORE finishing.

HTH

[chipman]

17-4 annealed is one of the worst ss to work with,

 

I agree, warps, twists you name it... sadly the only state we have ever machined this stuff is in the annealed state,

just now trying to explore the thought of h/t to reduce instability.

 

Thanks for the help guys!

[?Mark]

sadly the only state we have ever machined this stuff is in the annealed state,

So did I, I had to...

This material used to be some 75% of the work I've done in my old place.

[Joe788]

We do lots of 17-4 in H1150 condition. Heat treated before machining. Not sure how H1150 compares to H1025.

 

At H1150, it seems pretty stable. Not great tool life but fairly predictable. Dynamic paths work wonders.

[YoDoug®]

We do lots of 17-4 in H1150 condition. Heat treated before machining. Not sure how H1150 compares to H1025.

 

At H1150, it seems pretty stable. Not great tool life but fairly predictable. Dynamic paths work wonders.

 

+1 get it heat treated first then Dynamic for as much of the milling as possible or high feed cutters. I like Nice solid carbide HiRoc drills if the holes are not too deep. Threadmill any threaded holes.

 

 

 

[chipman]

Not sure how H1150 compares to H1025.

 

According to our supplier (Earle M. Jorgensen) H1150 is 33 rc and H1025 is 38 rc.

[MrFish]

We machine this stuff every day and the biggest issues we have is when the parts haven't been annealed after recieving it from the supplier as there are so many different grades of 17-4 that one block can machine quite different to the next rapidly reducing cutter life. We use MQL with both tipped and solid endmills with good results.

We only heat treat to H900 condition most of the time and for parts the size of your fist the stability is very good, anything larger or with thin cross section and I would be finishing any critical areas once hardened. Again solid carbide and MQL works great on the hard stuff.

[MIL-TFP-41]

Mitsubishi AJX cutters (their high feed flavor) eats this stuff for breakfast. Dynamic paths also work very well. I have never found this stuff particularly tough to deal with....very predictable tool life.

[?Mark]

Mitsubishi AJX cutters (their high feed flavor) eats this stuff for breakfast. Dynamic paths also work very well. I have never found this stuff particularly tough to deal with....very predictable tool life.

It's just the opposite when 17-4 ph is in annealed condition.

[K2csq7]

We do a few part #'s of this stuff, no problems, but I've never had the pleasure of seeing it in the annealed condition. By the sounds of it, hopefully we never will

[Aeroguy]

Well Depending on the shape and features of the final part, you could rough out some of the extra material, then send it for heat treat, then finish the part. If you have thin wall sections then make sure you leave a decent amount of stock on them, say 0.100" per side before sending it out. As long as you use nice sharp tools to finish it,( I like Hanita Varimill II) it should cut really nice in the hardened state. Drill any holes with carbide drills and thread mill wherever possible.

[chipman]

Drill any holes with carbide drills and thread mill wherever possible.

 

Are the carbide drills and thread milling a must, Can it be drilled with hss or cobalt?

Or tapped conventionally?

[Guest CNC Apps Guy 1]

I prefer machining fully hardened material. Usually, you can machine it faster and get better surface finishes and it's more stable.

 

Taps and HSS drills??? I guess, if you gotta, but dayum... you'll be making things harder on yourself for sure.

[MIL-TFP-41]

Are the carbide drills and thread milling a must, Can it be drilled with hss or cobalt?

Or tapped conventionally?

 

It can be drilled with HSS & tapped...cobalt is even better here. Tapping....you better be using something other than water soluble coolant. Carbide drills smoke everything & the tool life can be great.....unfortunately not every feature can be threadmilled....having an M00 in your program along with a note for the operator to use tapping fluid is a must.

[Aeroguy]

Yeah, you can use HS cobalt drills, but get good ones so that they last longer. Smaller sized threads can be done with good taps (prototype by dormer are good). But if you want to get good tool life and no broken taps to be burned out then carbide and threadmills is the way to go.

 

Are the carbide drills and thread milling a must, Can it be drilled with hss or cobalt?

Or tapped conventionally?

[guyrenaud]

Use cobalt drills at the minimum with agressive feed to reduce work hardening. Emuge taps with TiLan coating work great. If the machine is running water soluable and you don't want to contaminate it use straight (un-deluted)coolant for a tapping fluid.

[jambone]

Go with ISCAR end mills on pre-hard mat'l, use the xxxx and get toolpaths from masterCAM or Feed Mill and hold onto your marbles while you laugh in disbelief of how easy this stuff actually is to work with. Good Co drills and Emuge taps are fine, make sure that if you are using WS coolant that you have increased consentration. !!!17-4 does not like to be tickled, get the mat'l and chips out of there fast!!!

[Adam123]

I've been trying to find info on annealing 17-4. This thread is as close as I could find. When starting the annealing process, you can toss them into a pre-heated oven correct?

[Matthew Hajicek - Singularity]

 

The AL 17-4 Precipitation Hardening Alloy is furnished in the annealed condition. This is also called the solution heat treated condition, or Condition A. Annealing is conducted by heat treating at approximately 1900°F (1040°C) to 1950°F (1065°C) and cooling to room temperature. In this condition, the material possesses a martensitic structure. As a martensitic structure, the AL 17-4 alloy possesses a relatively high strength and hardness in the annealed condition. The strength and hardness of the material is generally somewhat lower in the H 1150 overaged condition.

http://www.specialtysteelsupply.com/brochure/17-4-technical-data.pdf

 

 

I just got some .040" 17-4 sheet to try making medieval armor out of.  It is WAY more difficult to dish than anything else I've used, even Ti6Al4V. Gonna have to make a trip hammer or something.