Cryogenic Hardening versus Std. heat-treating? 2

[Lovison]

Can you explain when one would want to do cryogenicly harden instead of heat-treating it and why?

We use mostly hard iron materials (some stainless) moving medium to high percent of solids and at temperatures from ambient to 1500 Deg. F.

What are the good points and bad points for each process.
Why are there so many hardening processes - you can never know which one is best.

If you harden materials you usually can't weld repair them without propagating the crack. Does the same apply to a part that has been cryogenic hardened?

Need some background information and procedures to review plus feel a little more knowledgeable about the subject when asked.

Thanks



Wayne E. Lovison
service-parts@naglepumps.com

 

[alpinecryo]

Hi Wayne, I'll try to clear up some things. First, cryogenic treatment is an enhancement to heat treating, not a replacement. You cannot take a piece of soft tool steel and increase the hardness one point through treatment. The transformation of the grain structure that takes place during heat treating is further completed during the cryogenic process. Minute carbide particles also precipitate to the surface during the process, giving more wear resistance without increasing brittleness. Some materials respond better to treatment than others. There is also a stress relief that happens during cryogenic treatment. Some of what happens is a mystery. Why does an elkonite spot welding electrode last longer after cryogenic treatment? It does and the customer is happy, but I can't explain it. The is best thing is to try it. It works on carbide inserts and no one can really explain it. It works on some types of stainless.
Most cryogenic treaters are egear to prove the process and will treat some parts for you at no cost to you. I'll be happy to talk with you more, if you like. E-mail me and I'll send you my toll free number and we can talk at length.
There is also a link to my web site at the top of the Cryogenic Engineering section of this site. Doug Dougb

 

[Lovison]

01-29-2002

Doug,

I have a few more questions but I need some time
to gather up my thoughts. Chinnia also replied
so I have more data to review. I appreciate your
thread and details are falling into place.

I will get back to you shortly.

Thanks Again,

Wayne E. Lovison
service-parts@naglepumps.com

 

[skeptic]

I'm real interested on a fundamental level in the result of this process. Have cryogenic treatment processes yielded evidence of their validity in a non-anecdotal way? In other words, do objective (non-commercial) data exist that demonstrate before & after mechanical property changes in say, a piece of steel?

This is a great topic, and I feel darned motivated to learn something about it. Thanks in advance for pointing me in the right direction.

 

[snehamishra]

Can you tell me what sort of cryogenics technology is used in space craft engines

 

[Lovison]

To: skeptic and snehamishra

Please review web sites below;

http://www.In2cryo.com/howitworks.html

and

http://cvip.csufresno.edu/~rlk16/cryo.html

This subject is new to me as well. Its not really understood by those who do this process. There are no ASME or ASTM procedures for this type of hardening. There are many who say it does remarkable things and others who say it depends on what you are trying to accomplish.

I'm in the research stage gathering information that will hopefully allow me to make a decision. Suggest test pieces be assembled and sent to a facility doing these types of hardening processes. Then you can compare the results.


Wayne E. Lovison
service-parts@naglepumps.com

 

[bille]

Howdy,, have a friend that has a cryo tempering service... started a couple years back... my experineces?,,,, did some disposable razor blades, drill bits, sawzall blades, a coring bit 16" in diameter( for concrete), some brake rotors and brake pads for my truck, and gears and bearings in a ford 9" rearend...
Results????? cryo'd rotors have yet to warp- stop harder than ever... razorblades dont rip your skin - last longer..... the coring bit's life was almost tripled,,,, other drill bits last longer as well.. the gears- i cant say... still driving the truck.

 

[mcguire]

Cryogenic treatment is effective for martensitic steels which have a lot of carbon and/or alloy giving a low MS temperature. These steels retain soft austenite in the microstructure after quenching only to room temperature.
Cryogenic cooling finishes the job;really nothing much more, no magic. Since martensite expands when treansforming from austenite by 4%, it will change residual stress, perhaps beneficially depending on what it was before cryo-quenching.

 

[bille]

... guitar strings stay in tune much longer.... brass section instruments sound better after treating... what else????????..... that's where the real investigating is needed- where 's the martensite in a tuba?

 

[Burdy]

I've tried to investigate this myself, there are very few hard facts that are published, although there appear to be an awful lot of these treatment labs about, it is remaining a 'black art' because they do not publish their results.
The common single point where benefit can be seen is on components which are involved in cutting, whether that is machine tools or razor blades.
A number of Automotive manufacturers are now treating crankshafts.

 

[Frederick]

Cryogenic processing has been proven by scientific research. The work of Dr. Randall Barron is well known. A recent research project for hte US Army Aviation and Missile Command performed by Illinois Institute of Technology proved that cryogenic processing (it is not a tempering process) doubled the life of gears. Research by Dr. Yuntian Theodore Zhu and Jianyu Huang at Los Alamos National Laboratory proved the process real, but did not explain its work. The University of Trento, Trento Italy also recently published a paper on the wear resistance of H13 and M2 steels that were subjected to cryogenic processing. A Masters Thesis was published by a student at Illinois Institute of Technology last fall that gave independent, unbiased proof that something is happening in the sub-microstructure of the metals. Dr. David Collins has published numerous reserarch papers on the subject. Johns Hopkins University just published a paper on the use of cryogenic processing on copper. In other words, this is a process that has been proven to exist. We don't know precisely why it works, but it does. By the way, airplanes flew for over 25 years before we could explain exactly why.

AS for uses, there are quite a few. Over one half of the Winston Cup racers are using parts processed by one company alone. The US postal service specifies the process for use on brake disks for their deliver vans.

The process is real, It just needs some research. That should not prevent its paractical use in the mean time.