离子渗氮化合物层对H13钢热疲劳性能的影响

Effect of Plasma Nitrided Compound Layer on Thermal Fatigue Behavior of H13 Steel

采用Uddeholm热疲劳试验方法 ,用机械磨去法和在等离子体气氛内加氩的方法除去化合物层 ,并与有化合物层的热疲劳试样进行对比 ,以研究化合物层对H13钢热疲劳性能的影响。研究结果表明 ,化合物层所具有的高硬度和高强度 ,能使其推迟热疲劳裂纹的萌生 ,并在一定程度上阻止热裂纹向基体内部扩展 ,但有化合物层试样的热裂纹在表面扩展较快 ,经 30 0 0周热循环后 ,观察到横断面的热裂纹宽度较大、数量较多。

With the Uddeholm self-restricted method,the effect of compound layer of plasma nitriding on thermal fatigue behavior of H13 steel was studied by the way of polishing the compound layer and adding Ar during plasma nitriding to remove the compound layer.The results show that the compound layer of plasma nitriding can delay the nucleation of thermal fatigue crack and hold back the propagation of thermal fatigue crack from surface to substrate in some extent because of its high hardness and strength.On the other hand,the thermal fatigue crack expands faster on the surface with compound layer than that without it.After 3000 cycles of thermal fatigue test,thermal fatigue crack with the compound layer is wider and the number is more in cross section than that without compound layer.