High-pressure crushing thermal processing method for steel ball special for bearing of 5MW (Megawatt) large wind turbine unit

The invention relates to a high-pressure crushing thermal processing method for a steel ball special for a bearing of a 5MW (Megawatt) large wind turbine unit. The method consists of the steps of quenching, tempering and detecting. In the quenching and heating step, the shielding gas flow is sectionally controlled. As a characteristic that a wind power steel ball is large in size so that the working allowance in the machining process is large and a characteristic that the cooling rate of Na2CO3 solution is greater than that of oil at high temperature are adequately utilized, the thermal treatment crushing value is greatly increased based on a carbon-denuded layer/decarburized layer within working allowance depth. The depth of the carbon-denuded layer/decarburized layer is realized by controlling the size and the time of the shielding gas flow. Tests show that for the high-pressure crushing wind power balls with the outer diameter being over 40.0000mm, the primary crushing yield reaches 100%. Through the tests