Cryogenic treatment of components

[nhramnl]

Did a bunch of research and here's what I learned:

1) The part should be "triple-tempered" before cryo treatment. This means cycling the part 3 times to a temperature determined by the thickest section of the part. No quench.

2) Now the first step of cryo. The temperature of the part should then brought down slowly, the rate of descent determine by the thickest section.

3) The soak time is not automatically 24 hours (as most places suggest). It should be determined by the thickest section.

4) The part should be brought up to ambient slowly, again with the rate of ascent determined by the thickest section.

5) The process helps very little if the triple-temper step is omitted (cryo treatment only).

Even with the proper sequence, the process doesn't make a huge difference in surface hardness or resistance to cracking. It helps, but not by a large percentage. Take a crankshaft for example:

Cast crank - 13-15 percent improvement
Forged crank - 20-24 percent improvement
Billet crank - 28-32 percent improvement

So basically, the better the metallurgy and metal forming process, the more cryo helps.

[Adger Smith]

Quote: "So basically, the better the metallurgy and metal forming process, the more cryo helps. "
Isn't that another reason to cryo treat? The higher the quality of the part the more built in stress it has to be relieved.
Just like your favorite beverage relieves your stress!!

[SSDiv6]

Originally Posted by nhramnl

Did a bunch of research and here's what I learned:

1) The part should be "triple-tempered" before cryo treatment. This means cycling the part 3 times to a temperature determined by the thickest section of the part. No quench.

2) Now the first step of cryo. The temperature of the part should then brought down slowly, the rate of descent determine by the thickest section.

3) The soak time is not automatically 24 hours (as most places suggest). It should be determined by the thickest section.

4) The part should be brought up to ambient slowly, again with the rate of ascent determined by the thickest section.

5) The process helps very little if the triple-temper step is omitted (cryo treatment only).

Even with the proper sequence, the process doesn't make a huge difference in surface hardness or resistance to cracking. It helps, but not by a large percentage. Take a crankshaft for example:

Cast crank - 13-15 percent improvement
Forged crank - 20-24 percent improvement
Billet crank - 28-32 percent improvement

So basically, the better the metallurgy and metal forming process, the more cryo helps.

Without getting in to an engineering dissertation or thesis, there are a lot of incorrect assumptions you are making. If you are quoting statements from other sites, they need to hit the books again as regards to the science of metallurgy!

Not all steels behave in the same way and not only you have to address the composition of the casting, but you also if it is a forging. Also, the tempering curves are affected which can make the part change its hardness.

Therefore, tempering of a part is not always required because you are not using cryogenics as a quenching agent.

[nhramnl]

Go ahead and get into an engineering dissertation. I didn't post what I learned to confuse people. And it isn't entirely from books; some of it is from metalurgical engineers, one of whom owns and operates a cryo treatment business that does work for the aeronautics industry. But if you know more and can correct my information, have at it. No hard feelings on my side.

[RJ Sledge]

It worked for me on the cast rocker arms, and I used it on valve springs after that, they seemed to last for ever. I am not saying this stuff works better than waving a magic feather over your parts and saying a prayer. I was convinced by the lack of rocker arm failures. Make up your own mind.

Like Adger told me about the time he used the "honing oil" from his shop to see if it would work in the SBC motor he built...........some things work and some things don't......or do they?? How about it Adger ?

RJ

[Adger Smith]

Yep, that hone oil did just what I wanted it to do. Broke those rings in and honed the valve guides. Well, almost. The crank and bearings didn't do so good. :~) LOL!
No a serious note. Since I've had my first Pro flite I've taken the planetaries apart and done a cryo and rem finish on all the components. I've done it for several comp customers and a few high end circle track customers. I feel it adds life and actually runs cooler because of the surface tension the trans fluid now sees. yes, you do have to hone the gears where the rollers are after the treatment....Just my .02. on cryo...
Now, hold my beer and watch this R.J.!

[SSDiv6]

Originally Posted by Adger Smith

Yep, that hone oil did just what I wanted it to do. Broke those rings in and honed the valve guides. Well, almost. The crank and bearings didn't do so good. :~) LOL!
No a serious note. Since I've had my first Pro flite I've taken the planetaries apart and done a cryo and rem finish on all the components. I've done it for several comp customers and a few high end circle track customers. I feel it adds life and actually runs cooler because of the surface tension the trans fluid now sees. yes, you do have to hone the gears where the rollers are after the treatment....Just my .02. on cryo...
Now, hold my beer and watch this R.J.!

Adger, I didn't know you were a Mad Scientist!

[Adger Smith]

Yep, and I'm looking for that Magic Feather. I know there is one out there because RJ can't find one and uses Cryo instead....

[ss wannabee]

Does this mean dry film coating of valve springs...like HPC...is not too popular
anymore?

[Adger Smith]

I think someone figured out it shed the oil that cooled the springs. They said it was like wrapping your springs in a blanket and keeping them hot. So much for spring life. Shucks, the ads for that coating told me that it pulled heat out. Gosh this is so confusing. Help, RJ!