Heat treatment of slewing bearing steel is to put solid metal or alloy into certain medium then undergoes three process: heating, heat preservation, and cooling to change steel organization and get required performance. Different from other processing technology (such as forging, casting, welding, machining), purpose of heat treatment is not to change shape and dimension of steel but to change internal organization and performance of steel.
Heat treatment is alternately and repeatedly used among cold working, hot working, and other manufacturing process of mechanical parts or dies. According to its application, Heat treatment usually divided into pre-heat-treatment and final heat-treatment, and location of processing line as bellow :forging/casting→pre heat treatment→machinery (rough) processing →final heat treatment→mechanical (fine) processing.
Final heat treatment, such as quenching+tempering, etc, known as the heat treatment that enables the workpiece to meet the performance requirements under use condition. Pre heat treatment, such as annealing, normalization, known as the heat treatment that eliminates defects caused by former process or get organization and ready for subsequent machining and final heat treatment.