The fatigue life of cast steel G42CrMo4 in two different heat treatment conditions was investigated at room temperature (RT), 473 K and 773 K up to the range of very high cycle fatigue (VHCF), that is, 10⁹ cycles. The fatigue life is determined by casting defects, the hardness of the steel matrix and by temperature. Fatigue life data were discussed in correlation with crack‐initiating defects analysed on fracture surfaces. The SN curves obtained at RT and at 473 K show a large scatter. However, the SN curve at 773 K exhibits a larger slope parameter and a significantly reduced scatter. It is shown that the fatigue behaviour of the cast steel G42CrMo4 changes from 473 to 773 K in the range of VHCF. The fatigue lives of the specimens tested at 773 K were described with a crack growth model.

中文翻译：

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铸钢G42CrMo4在高温下的超声疲劳测试

研究了G42CrMo4铸钢在两种不同的热处理条件下在室温（RT），473 K和773 K下的疲劳寿命，直至达到非常高的循环疲劳（VHCF）范围，即10 ⁹个循环。疲劳寿命取决于铸件缺陷，钢基体的硬度和温度。讨论了疲劳寿命数据，并分析了断裂表面上的裂纹引发缺陷。在室温和473 K下获得的SN曲线显示出较大的散布。但是，在773 K处的SN曲线显示出较大的斜率参数和显着减小的散射。结果表明，在VHCF范围内，铸钢G42CrMo4的疲劳行为从473 K变为773K。用裂纹扩展模型描述了在773 K下测试的试样的疲劳寿命。