17-4 H900....Does it really cut that nice?

david n · Apr 14, 2016

Posted in the General section too...................

It's been quite a while since running the stuff, but I know 17-4 annealed machines like crap. H1150 is nice. But in condition H900(min 40RC), how does it compare to H1150 or 4140HT? I need to OD thread, OD groove, drill, bore, and part off. Feeds n speeds? Inserts? Or can I run with what I got? TIA

eaglemike · Apr 14, 2016

I machine this stuff almost daily. Milling, VF2. Using Hocut.
Sharp tools help. I use carbide end mills, inserted facing cutters and light profiling, cobalt for drilling. My parts are pretty small, and I'm conservative on speeds and feeds. My SWAG would be roughly 20 percent slower than H1150, right around there......... Pay attention to the sound and vibration. Once they start to go, deterioration is fairly quick. Not catastrophic quick, but if the operator is distracted, it might get ugly......
Hope this helps a little......

Eta: it's really not bad, but not as easy as H1150 either....

MattMSConsulting · Apr 14, 2016

I made a bunch of rod ends and other parts out of that stuff years ago. H1150, I'm not as familiar with. With like a WNMG, you can rough pretty aggressively with a hard grade and no coolant. I assume you are running coolant, not oil. Threading, if you're single pointing with a topping insert, you might have to play with doc and stuff. Those topping inserts just would not break a chip some times and leave a small, wiry rat's nest. I think the name of the game is using tough grades of carbide and cutting fast enough that the cutters are cutting freely and feeding aggressively enough that your sending the heat out with the chips.

moonlight machine · Apr 14, 2016

I love the finish you can get on the stuff, like a mirror! It's tough though, but not all that bad. It is pretty expensive though so you don't want to scrap much of it.

doug925 · Apr 14, 2016

David,

The carbide grades and chipbreakers will determine how easily you can cut this stuff. Get a few tailored inserts for that material, and you should be fine.
The drilling (if not an indexable drill) will be the real bitch.

HH1150 cuts really nicely, but the H900 is (obviously) a tad bit harder. It will probably just mean dropping your SFM 20-25% (a total WAG on those numbers)
How good is your relationship with your insert mfg salesman???? (Assuming he knows his $hit)

Doug.

david n · Apr 14, 2016

Well I have 3 choices for this part, 17-4 H900, 13-8 H950, or 440C(machine then harden to 50-55RC). Take your pick...........................

eaglemike · Apr 14, 2016

I would go 17-4.......

kevin66 · Apr 14, 2016

I have turned a lot of H1150 and H900. As long as you use a hard carbide grade and keep your sfm about 80% of what you run H1150 at it machines good. With that being said though, if you have to use HSS tooling (drills,taps)things become a lot more difficult.

Kingbob · Apr 14, 2016

I'd stay away from 440c, I don't know how hard your parts need to be but I have regularly dealt with 440c that has been hardened to a point where it rivals stellite 6 for unmachineability.

Moriboy · Apr 14, 2016

17-4 H900 is cake, as long as you have a good machine and good tooling. Even drilling (with coolant thru carbide drills) is a breeze..

440 would be my last choice.

Sent from my iPhone using Tapatalk

implmex · Apr 14, 2016

I've successfully cut 17-4 at condition H900 too, but it's not as forgiving as it is in condition H1150 as others have remarked.
But here's a question for all of you with experience using this stuff.
Have any of you machined it in condition H1150, then sent it out for solution annealing and then had it hardened to condition H900?
It's extra heat treat steps and the solution annealing process is a high temperature process so you'd have to vacuum anneal it to avoid scaling it, but it might work for those special things like deep tapped holes etc etc.

Having said that I don't seem to have as much problem as some are reporting just cutting it in the annealed condition.
Sure it's a bit gummy but it's not AWFUL; at least not the stuff I've cut.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com
Clarus Microtech

david n · Apr 14, 2016

Marcus,

I've been contemplating that too.....cuttin H1150, getting it annealed and then hardened to H900. Maybe too much trouble? But when it comes down to it..............which would machine better....annealed or H900? Annealed is gummy 'n stringy and H900 is hard and may eat some toolin too?

Bobw · Apr 14, 2016

implmex said:
Have any of you machined it in condition H1150, then sent it out for solution annealing and then had it hardened to condition H900?
It's extra heat treat steps and the solution annealing process is a high temperature process so you'd have to vacuum anneal it to avoid scaling it, but it might work for those special things like deep tapped holes etc etc.

Kind of defeats the purpose of a PH(precip. hardening) grade, doesn't it? The whole point is that it is a simple heat treat that results in little
material movement. Then again, 17-4 has some awesome properties.... You would have to anneal it, solution treat it, then precipitation harden it.
It probably wouldn't be pretty or cheap.

Has anybody ever machined 17-4 in the true annealed state? Not "solution treated" like you buy it? I have no idea what that is like since
you can't even buy it annealed.

implmex · Apr 14, 2016

Yeah Bobw; you're right.
It does defeat the purpose a bit, but when you've got a tapped hole 4:40 and 3/4" deep, and the designer wants it tapped all the way to the bottom etc etc.
As I say' I've never tried it, but I just accept the gummy annealed stuff and grit my teeth until it's done.
One day, just for shits and giggles....
Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com
Clarus Microtech

doug925 · Apr 14, 2016

Ugh!!!

Somebody mentioned the unmentionable. 440 Mod!
I hate 440 :nutter:

Doug.

Bobw · Apr 14, 2016

implmex said:
Yeah Bobw; you're right.
It does defeat the purpose a bit, but when you've got a tapped hole 4:40 and 3/4" deep, and the designer wants it tapped all the way to the bottom

Had a job in 304 many moons ago. Deep thread for a ball detent, 8-32 or something, close to an inch deep.. Drilled for a
form tap, ran the form tap as deep as I could (hole was at the bottom of a clevis), and then hand tapped with a cut tap..
The cut tap went real easy, barely had to cut anything... This was a "make it work" job, not a "to the print" job.

You could also smack the designer up side the head. Then there is also the outside possibility that the thread depth actually
has a purpose, but generally not.

Sorry about the crappy thread, but at least its not a 2-56 or 00-96 going that deep.

Bigtoy302 · Apr 14, 2016

I used to turn tons of 17-4 H900 (Hydraulic cylinder rods). Machines nice. Just don't get too happy on the SFM. Sandvik 1025 CNMG is you friend. For threading I use Vardex VTX inserts. Full form usually. Insert drills for drilling, they squeal but plow through.

John Welden · Apr 14, 2016

I've machined a million shit tons of h900. Mills and turns fine. Drilling and tapping kind of sucks. Carbide coolant through helps a lot.

SND · Apr 15, 2016

If its got any size/tight tolerances don't mess with HT, it moves, even more so from annealed state.
Sure it may suck a bit to drill/tap it vs aluminium, but at least it ain't C-276, 625 or A-286...

Ox · Apr 15, 2016

I've never even heard of 13-8.
Is this an available material?

I spent half of December searching for unobtainium. I know that the spec sheets are out there for the designers, but to actually find material available short of a mill run?

-----------------

I am Ox and I approve this h'yah post!

17-4 H900....Does it really cut that nice?

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