The Strengthening Role of Cryogenic Treatment in the Mechanical Properties and Abrasive Wear of Low Alloy Wear-Resistant Steel

The effects of cryogenic treatment on the mechanical properties and abrasive wear resistance of the low alloy wear-resistance steel are investigated. Cryogenic treatment is conducted after different quenching treatments with varied austenitization temperatures of 810, 830 and 850 degrees C. Microstructure evolution is also studied by microstructure characterization methods and thermoelectric power measurement for establishing the mechanism relationships with the property changes. The results show that cryogenic treatment can improve the tensile strength, yield strength and impact toughness of low alloy wear-resistant steel. The effects of cryogenic treatment on mechanical properties have close relationship with the austenite temperature in former austenitization treatment. Abrasive wear resistance of the steel can be improved by up to 20 and 47% with the conduction of cryogenic treatment after quenching at 810 and 830 degrees C, respectively. However, there is no influence on abrasive wear resistance by cryogenic treatment after quenching at 850 degrees C. Wear mechanism of the untreated sample is conventional plowing, microcutting and spalling, which is transformed to the material removal caused by the microcutting with a small degree in the cryogenically treated sample. Cryogenic treatment after quenching promotes the dispersive precipitation of nanocarbides in martensite, which is also austenitization temperature-dependent and has significant role on improving the mechanical properties and wear resistance of the alloy.