Abstract: A process for treating an article of metal containing material, the process in including subjecting the article to a deep cryogenic treatment at a temperature of -120.degree. F. or lower, subjecting the article to at most a partial tempering treatment, and then nitriding a surface of the article so as to form nitrides near a surface of the article.

Abstract: A process for treating an article of metal containing material having a minimum cross-sectional dimension. The process includes providing the article at ambient temperature or below and completely immersing the article in a cryogenic fluid over a time period at least equal to 10 minutes times a value of the minimum cross-sectional dimension in inches. The process further includes withdrawing the article from contact with the cryogenic fluid, and immediately subjecting the article to a flow of gaseous fluid sufficient to raise the temperature of the article until the article reaches ambient temperature.

Abstract: A process for treating an article of metal containing material such as tool steel so as to improve the properties such as shockability, wearability, stability and hardness of the article. In one embodiment, the process comprises immersing the article at ambient temperature into liquid cryogenic material for a time period up to or equal to a set time period equal to the minimum cross-sectional dimension in inches times ten minutes. The article is then withdrawn from contact with the liquid cryogenic material and immediately subjected to a flow of air sufficient to raise the temperature of the article to ambient temperature in a period of time equal to or less than ten minutes plus ten minutes per minimum cross-sectional dimension in inches.