Heat Treatment Method For Alloy Steel Of Gears Using Addjusting Phase Transformation Of Normalizing Period

摘要

Normalizing and isothermal heating at the first target temperature, which is the phase transformation temperature (Ac3), using a heat treatment facility equipped with a continuous heat treatment furnace connecting a plurality of heat treatment furnaces to heat treatment the raw material of the gear alloy steel before machining, and the first target temperature A heat treatment method for performing tempering for isothermal heating at a lower second target temperature, comprising: heating the raw material to a first target temperature; a normalizing step of isothermal heating to maintain the raw material at a first target temperature; a control cooling step of cooling the raw material to a second target temperature by controlling the cooling water circulation of the heat treatment facility; A tempering step of isothermal heating to maintain the raw material at a second target temperature, wherein the normalizing step is a primary phase transformation of the austenite single phase to a mixed phase of ferrite and austenite with respect to the raw material, and ferrite again It is characterized in that the phase transformation control for secondary phase transformation of the mixed phase of and austenite into a single austenite phase is performed at least once.