cryogenic tempering anyone?

[HIRAH]

does anyone have any experience with cryogenic tempering? it looks like an interesting process. but i'm wondering how it compares to heat treating in a real world fixturing situation. the fixture would be made from s7 tool steel and between 50-56 rockwell.

[lgreeves]

A tool & die shop I worked for looked in the process. We used S7 and H13. The clames are very impressive but they couldn't compete with the lead time that we provided because we heated in-house. That was 10 years ago.

[Stepper Monkey]

I only have experience with it relative to gunsmithing, but from what the folks who have had it done experienced with it, it is a pretty exceptional process.
Of course, stress relieving of barrels so they dont twist when heated (keeps the first few shots from "walking", or changing impact point as the barrel heats up) is a lot different than what it does to hardness of tooling.
One gunsmith was impressed enough that he had some of his tooling treated for the hell of it. He said he could chamber and broach more barrels between sharpenings, and that he thought the tools seemed to last longer, but that was hardly empirical testing by any means... Seems worth looking into though.

[Geof]

You should do a search both on cnczone and a full web search. It has been discussed on the zone a few times.

One thing you will find is some people swear by it and some swear at it. It does not replace normal heat treating and tempering but is an added step. When used on high speed steel cutting tools it might give enhanced tool life under some conditions and have no noticeable effect in others.

[NC Cams]

We do it a lot with our camshafts. Its main advantage is to eliminate retained austenite that may exist as a result of insufficient tempering AFTER you have already hardened and tempered the part using traditional heating/quenching methods.

You don't just dump the stuff in liquid nitrogen and call it a day. You cryo it and then let it soak there. Afterwards, you do a low temp stress relieve. Ask around and look for shops that specialize in tool steels.

[RICHARD ZASTROW]

We used cryogenic tretment on D-2 & D-5 rotary dies. It greatly improved cutting die life and reduced cracking on the cutting edges. The main reason was to stabilize the metal and it worked well for that application. The high heating, tempering, drawing and cryogenic treatment were one continuous process in a computerized electric controled atmosphere heat treating unit. The cryogenic cycles were liquid nitrogen baths.

[Geof]

I revived this thread because I found a good link about cryogenic treatment that I had not seen before.

http://www.sme.org/cgi-bin/find-arti...&&SME&#article

I should be honest , I did not "find" it. Seraph posted a link in this thread and I found this in the same magazine.

http://www.cnczone.com/forums/showth...492#post494492

[RICHARD ZASTROW]

Geof, Kinda corroborates my $0.02 above, eh? (or can't I say that here?)

Dick Z

[Geof]

Originally Posted by RICHARD ZASTROW Geof, Kinda corroborates my $0.02 above, eh? (or can't I say that here?) Dick Z

Sure you can say that. Say what you like I will not complain.

One of the biggest annoyances from my past is related to cryogenic treatment. Are you familiar with big wood chippers, huge rotating discs with HSS cutting blades clamped in. Replacing the blades was many hours and it had to be done about every three to five shifts. I figured this was an ideal application for cryogenic treatment but thirty years ago I did not have the capital to start something. Then a guy I had met at a high tech company I did some work for showed up with a whole bunch of money looking for a potential joint business opportunity; so I told him to study up on cryogenic treatment. He must have looked at all the wrong references and spoken with all the wrong people because he came back with a totally negative impression and wondered why I had made that suggestion; which he considered a total waste of time. Needless to say he took his money elsewhere.

[RT_CINE]

I work for a cryogenic treatment facility. S7 tool steel is an excellent candidate for cryogenic treatment because of its high carbon content. Cryo treatment should be done after a typical heat treatment. Cryo does not take place of that. Cryogenic treatment will also not change the Rockwell Hardness of a material. Instead it improves the microstructure, precipitates the eta-carbides, and improves the materials wear resistance.

Take a look at our site...it has a lot of information

http://www.nitrofreeze.com

Cryogenic Treatment Page