C-Si-Mn-B贝氏体钢的疲劳裂纹扩展特性  

CHARACTER OF THE FATIGUE CRACK PROPAGATION IN C-Si-Mn-B BAINITIC STEEL

作　　者：黄维刚[1] 方鸿生[2] 郑燕康[2] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044 [2]清华大学材料科学与工程系,北京100084

出　　处：《金属学报》2001年第9期927-931,共5页Acta Metallurgica Sinica

摘　　要：本文研究了Ｃ－Ｓｉ－Ｍｎ－Ｂ贝氏体钢的疲劳裂纹扩展特性．结果表明，在强度相近的情况下，含１．８％Ｓｉ钢的门槛值△Ｋｔｈ较 ０．６％Ｓｉ钢的低，而且钢中的残余奥氏体对提高△Ｋｔｈ值并非有利．１．８％Ｓｉ钢的△Ｋｔｈ值随钢的屈服强度降低而提高，然而４５０℃回火后，虽然△Ｋｔｈ提高，但裂纹扩展速率也显著提高，这表明４５０℃回火贝氏体脆性促进了疲劳裂纹的扩展。在应力强度因子较高的范围内，疲劳裂纹扩展速率受钢的断裂韧性影响，断裂韧性高，裂纹扩展速率低．Character of fatigue crack propagation in C-Si-Mn-B bainitic steel has been investigated in this paper. The results show that the threshold value DeltaK(th) of steel with 1.8%Si content is lower than that of steel containing 0.6%Si while both of them have the little deference in strength and the retained austenite in steel with higher Si has no benefit for raising the DeltaK(th). The DeltaK(th) Of steel with 1.8%Si has a increase with decrease in yield strength. Although the threshold value DeltaK(th) is higher after tempering at 450 degreesC, the rate of crack propagation will be increased evidently. It is demonstrated that the temper embrittlement at 450 degreesC accelerates fatigue crack propagation rates. In the higher DeltaK range, the fatigue crack propagation rate will be affected by the fracture toughness in steel. The higher fracture toughness in steel is helpful for decreasing the fatigue crack propagation rate.

关 键 词：贝氏体钢 门槛值 疲劳 裂纹扩展速率 断裂韧性 

分 类 号：TG142.2[一般工业技术—材料科学与工程] TG111.91[金属学及工艺—金属材料]