Cryogenic processing of AISI P20 tool steel: Evaluation of mechanical properties and microstructure

The service breakdown of machine components is always a challenging task for the technical engineers, which slows down the production process. Thus there is a rise in maintenance and repair costs. Among several production practices, the cryogenic treatment is one of the outstanding technique which is employed to boost the lifetime of machine components by enhancing the mechanical properties and thereby reducing the probabilities of failures. In present-day and modern technology there is significant use of cryogenic treatment for improving the performance of tool steels. It is a supplementary treatment in which the parts are treated below the sub-zero temperature for various cryo-soaking hours. In this work, an attempt is made to evaluate the consequences of cryogenic treatment on mechanical properties and microstructure of AISI P20 tool steel. The Brinell hardness and Charpy impact strength of work materials are found by varying the cryo-soaking time. A metallurgical microscope is used for assessing the microstructures of the work material under various conditions of cryogenic treatment. The brinell hardness and charpy impact strength of the specimens without austenization and with cryo-treatment were found as 285 HBW, 313 HBW and 8 Joule/mm2, 14 Joule/mm2 respectively for 15 h, 25 h and tempering for 1 h respectively.. Also, with austenization and with cryo-treatment the brinell hardness and impact strength 538 HBW, 506 HBW and 10 Joule/mm2, 8 Joule/mm2 for 15 h, 25 h and tempering for 1 h respectively.