Best CNMG 432 insert for Turning 17-4PH

Let me start off by saying that I am new to CNC machining, so please forgive me for my newbieness. LOL

Been running manual machines for 30 years, but there are some things with using a CNC machine now, that I have not really had to think about too much before. My work purchased a used DTMG CKE6136i a couple years ago and I have been teaching myself how to use it when I am not busy.

I need to turn some 17-4 PH material, that has been heat treated to condition H1025. What grade of insert should I get and is there a particular chip breaker that works best? My boss will not let me buy all sorts of inserts for a specific operation, so I need an insert that can be used for both semi-roughing and for finishing. This lathe is limited to how many tool holders I can mount at one time, so I am limited to one external turning tool holder. I am also limited to 3500 RPM spindle speed.

I have searched this forum and found that some people like Sandvik 2025, ISCAR IC907, Tungaloy NS530 and Mitsubishi US735, when turning 17-4ph.

I have been using more SECO brand inserts over the years, when working with 304 and 316 stainless in the manual lathe. In particular CP500 grade.

Any other brand and grades I should look at?

I tend to buy inserts off eBay when I can find good prices, as we don't use a lot of them, so if I can save by getting them there versus a dealer, it makes me look good to the bosses.

Thanks

In a previous life we used a lot of Tungaloy T9015 in a TM geometry. We turned a fair amount of H1150 and had good results. It’s not the optimal high performance choice, but it’s a very economical choice that definitely out performed more expensive offerings in 4xxx steels which are a similar cutting condition.

If you're going to use Seco, use the TM0501 or TM1501 grade.

Seco does it right when it comes to grades:
First letter (T or M) for turning or milling; second letter (P,K,M,S,N,H) for material,
the numbers are the relative hardness vs. toughness range: 0501 is REALLY hard, 3501 is really tough.
And if the last number is a 1, it's the new silver Duratomic.

I like Ingersoll inserts but their grades list is a train wreck: 5080, 8115, 7100, 3010, 7015, 9215.............

jhearons said:

In a previous life we used a lot of Tungaloy T9015 in a TM geometry. We turned a fair amount of H1150 and had good results. It’s not the optimal high performance choice, but it’s a very economical choice that definitely out performed more expensive offerings in 4xxx steels which are a similar cutting condition.

Click to expand...

We use T9215 in TM geometry, basically the newest revision of what you used. Performs very well in H1150 and H900.

I don't really recommend stainless geometry inserts for 17-4 unless you're cutting it in the annealed condition. Generally it machines much more like an alloy steel than an austenitic stainless, which most stainless inserts are optimised for.

Seco has a "suggestion" app.
They recommend this insert:
CNMG433W-M6 TP2501
590SF
.1 D.O.C.
.0125 IPR

Secotools.com

For Mitsubishi, I do a lot of stainless turning with VP10RT and VP15TF grades. Much lower DOC and higher SFM than what you're likely to be turning, but they work amazing in my application.

gregormarwick said:

I don't really recommend stainless geometry inserts for 17-4 unless you're cutting it in the annealed condition. Generally it machines much more like an alloy steel than an austenitic stainless, which most stainless inserts are optimised for.

Click to expand...

^ That.

Once heat treated, 17-4 basically loses all of its "stainlessy" machining properties. And then
should be treated more like a hardened alloy steel. Even in the solution treated condition, its
no where near as bitchy as 304 is.

Bobw said:

^ That.

Once heat treated, 17-4 basically loses all of its "stainlessy" machining properties. And then
should be treated more like a hardened alloy steel. Even in the solution treated condition, its
no where near as bitchy as 304 is.

Click to expand...

I use the same insert (CNMG) that I use on 4140 pre-hard.

Bill