Cryogenic treatment of components

nhramnl · 02-22-2014, 12:11 PM

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.

02-22-2014, 12:11 PM	#15
nhramnl Senior Member Join Date: Feb 2010 Posts: 507 Likes: 8 Liked 358 Times in 83 Posts	Re: Cryogenic treatment of components 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.