Thanks Jim
No issue
I just was thinking about it. I will call the folks and find out what is what. I may want to surface harden the gears and shafts and forks then temper. It would seem like galling and chipping maybe a problem under loading with the gears, maybe not with the proper lube.
I will ask them about distortation and the like with what I'm doing, They appear to know what is what.
Eaton has made steel parts for a long period of time in heavy duty apps. Thanks for the input. I will post what garner has to say.
Got any Idea on the 8620 hardness as audi has it OTS maybe numbers from eaton could be helpful ??
Not sure what they will say about the alumimum case.. most likely nothing! maybe something...steel plate install seems like it!
I saw the picture of the spider gears in the diff fractured from shock.. what will help this steel be more resilient ?? there has to be a process to help rather the go to a new material or fab process for the parts.
Add more steel always helps in mechanical loading... The factory did what was best for their application, It may not be able to be improved without replacement, TBD.
Best
Here what they say
Cryogenic Treatment
Cooling to a low (cryogenic) temperature, usually -100 to -320 F, to stabilize microstructure and dimensions; typically for high alloy (tool) steel parts. The treatment is carried out after quenching, or more appropriately after the first temper, to transform Retained Austenite to Martensite which is then tempered.
Garner Heat Treat, Inc. utilizes the latest in Computerized Vacuum Technology. This assures precision in heat processing by providing distortional and dimensional stability. The 5-Bar Vacuum Furnace offers unparalleled control in heating and quenching operations. The 5-Bar's ability to perform interrupted quenching minimizes the potential for distortion and cracking. Skilled operators using advanced tools and methods, evaluate each part and setup loads to minimize distortion and optimize dimensional stability.
Deep Cryogenic Process
Garner Heat Treat, Inc. offers deep cryogenic processing of products to -320oF. Cryogenic processing increases dimensional stability, wear resistance, and the performance of most alloys through conversion of retained austenite to martensite and through precipitation of finer carbides.
GHT's -320oF deep cryogenic process improves performance and increases the life of most products provided to customers.
GHT's deep cryogenic process is completely computer controlled. Products are slowly cooled to -320oF at a predetermined rate based on the material size, type, and hardness. After soaking for the specified time interval, the products are slowly ramped-up to room temperature then tempered at the appropiate tempering temperature.
Garner Heat Treat, Inc., offers deep cryogenic processing of products to -320oF. Cryogenic processing increases dimensional stability, wear resistance, and the performance of most alloys through conversion of retained austenite to martensite.
Wear Improvement of Shallow Cryogenic (-120) vs Deep Cryogenic (-320) Cycle
-320oF deep cryogenic processing allows GHT to offer customers improved performance and increased life of metal tools and parts. Other deep-freeze methods reach only -120oF. Our innovative cryoprocessing takes metals beyond deep freeze to cryogenic levels transforming almost all soft retained austenite to hard martensite. This creates a significantly denser molecular structure resulting in a larger contact surface area that reduces friction, heat, and wear. The computer controlled ramps virtually eliminate thermal shock.
Benefits of Deep Cryogenic Processing
Conversion of most retained austenite to martensite. Stabilizes alloys without changing shape or size of product. Cryogenically treating welds returns the metal to its original state. Increased durability and wear life.
What Does Deep Cryogenic Treating do?
These ultra-cold temperatures, below -310oF, will greatly increase the strength and wear life of all types of vehicle components, castings and cutting tools. In addition, other benefits include reduced maintenance, repairs and replacement of tools and components, reduced vibrations, rapid and more uniform heat dissipation, and improved conductivity. Cryogenics process is like an insurance policy for your tools and components.
http://www.timken.com/timken_ols/steel/handbook/table.asp
on the 8620..
I;m not a Metallurgist by any stretch... This is cool stuff however...