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推导了轴承钢球的热传导方程,采用球贝塞尔函数给出了热处理过程中钢球瞬态温度分布的解答,应用弹性力学热应力理论得出了热处理过程中钢球径向和切向应力公式,并以半径50 mm的大型轴承钢球为例,对钢球应力分布进行了分析。热处理过程中钢球的表面温度变化剧烈;靠近钢球中心位置为三向拉应力,并且同时达到最大值,开裂容易从中心部位开始发生。靠近钢球表面位置处于二向应力状态,径向应力为0 Pa,切向应力为压应力并达到最大值,导致钢球在锻造过程中产生的表面裂纹扩大,并导致钢球开裂。细化钢球中间部位晶粒,减少在锻造过程中钢球上的裂纹,放缓钢球的加热速度能减少热处理过程中钢球的开裂。
The heat conduction equation of the bearing steel ball was deduced. The solution of the transient temperature distribution of steel ball during the heat treatment was given by the ball Bessel function. The radial and tangential stress of the steel ball during the heat treatment was obtained by using the theory of elastic mechanics heat stress The formula of steel ball stress distribution is analyzed with a large bearing steel ball with a radius of 50 mm as an example. During the heat treatment, the surface temperature of the steel ball changes drastically. Near the center of the steel ball is a three-direction tensile stress, and at the same time, the maximum value is reached, and the cracking easily occurs from the central part. Near the surface of the steel ball is in the state of two-dimensional stress, the radial stress is 0 Pa, the tangential stress is the compressive stress and reaches the maximum value, which leads to the surface cracks generated during the forging of the steel ball and leads to the cracking of the steel ball. Grain refinement in the middle of the grain, reducing the ball in the forging process of the crack, slow steel ball heating rate can reduce the heat treatment process of steel ball cracking.