1前言拖拉机及农用运输车轴类零件多选用40Cr或45钢，采用粗车后调质热处理工艺，其中，淬火加热主要采用电阻护或盐治沙。这两种类型加热炉，因投资少，在拖拉机及农用运输车行业中得到广泛应用，但它们存在周期护加热淬火一些共性问题。如，淬火后硬度不均匀；弯曲变形比较大 1 Foreword Tractors and agricultural transport shaft parts and more use of 40Cr or 45 steel, roughing after quenching and tempering heat treatment process, of which, the quenching heating resistor or salt control sand. Both of these types of furnaces are widely used in the tractor and agricultural truck industries due to their low investment, but they have some common problems with cycle-hardening. For example, the hardness after quenching is not uniform; the bending deformation is relatively large