Cryogenic treatment of metal Essay Example | Topics and Well Written Essays - 500 words

Cryogenic treatment of metal - Essay Example Untempered martensite should, therefore, have treatment below the minimum critical temperatures of the metal so as to enable diffusion of the excess carbon from the body-centre tetragonal structure hence it creates a more stable structure. Tempering leads to an even distribution of alloying elements in precipitation-hardening alloys like super alloys of aluminum (L.K. Zhang. 148). The elements cause internal reactions, which results in the formation of inter-metallic phases referred to as precipitates. The precipitates formed during tempering strengthen the alloys. In addition, multistep tempering can result in the formation of several precipitates that effect to high strength alloy. Cryogenic treatment is carried out in metals in the process to enhance metallic wear characteristics. Cryogenic metal treatment is quite a new metal treatment process in engineering and is one of the most utilized metal treatment processes in the industry (Xiaojun Jianga 62). Utilization of cryogenic temperature (below -2400 F) is a new application in metal treatment especially in the ultra-cold realm. The method was tried in early 1940s, but it was found to produce thermal stresses because of the rapid cooling of the metal in liquid nitrogen. Because of the formation of thermal stresses, cryogenic treatment was not in use for industrial purposes until late 1960s. Cryogenic metal treatment process was improved to the use of gaseous nitrogen, which results in reduced formation of thermal stresses (L.K. Zhang. 32). There are three major cryogenic treatment process established in mechanical engineering. Initially, the metal is slowly cooled down from ambient atmospheric temperatures to cryogenic temperatures. Cooling of the metal parts slowly leads to a reduction in the formation of thermal stresses. Slow cooling process also ensures that the general