高频淬火态新型叶片钢的疲劳性能

Fatigue behavior of high-frequency induction hardened blade steel

对一种新型叶片钢在室温大气、80℃22%NaCl溶液和95℃水蒸汽中进行腐蚀疲劳试验,测定了此钢在不同腐蚀环境下的拉压疲劳S-N曲线,利用金相显微镜和显微硬度计分析了显微组织和显微硬度的分布,用扫描电镜分析了疲劳断口。结果表明,80℃22%NaCl溶液和95℃水蒸汽分别使新型叶片钢的疲劳极限比室温大气下的疲劳极限降低了32.60%和11.84%。疲劳源都位于试样表面。80℃22%NaCl溶液中的腐蚀疲劳断口没有明显的疲劳辉纹,室温大气和95℃水蒸汽中的疲劳断口都出现了疲劳辉纹,后者的疲劳断口还出现了大量的解理裂纹。

The fatigue behavior of a new kind of blade steel after high-frequency induction hardening was investigated by corrosion fatigue tests in atmosphere at room temperature,80 ℃ 22% NaCl solution and 95 ℃ steam,respectively.S-N curves of tension and compression fatigue in these three kinds of corrosive environments were measured.The microstructure and microhardness distribution of the blade steel after high-frequency induction hardening was analyzed by using optical microscope and microhardness tester.Fatigue fracture was studied by scanning electron microscope.The results show that 80 ℃ 22% NaCl solution and 95 ℃ steam have a significant impact on the fatigue properties of the blade steel.The fatigue limits in these two kinds of corrosive environments are reduced by 32.60% and 11.84% respectively compared with that in atmosphere at room temperature.Fatigue source is located on the surface of the blade steel.No obvious fatigue striations are observed on the fatigue fracture which happened in 80 ℃ 22% NaCl solution,whereas a lot of fatigue striations appeared in fatigue fracture in atmosphere at room temperature and 95 ℃ steam.Besides,many cleavage cracks appeared in the latter fatigue fracture.