304不锈钢低周疲劳断裂特性的研究*

摘要

Low cycle fatigue fracture proper-ties are investigated through the tension-compression fa-tigue testing on 304 stainless steel. Based on the analysis of experimental data, low cycle S-N curve, the conditions fatigue limit (N=105), the relationship between life and strain under different stress and the relationship between life and plastic strain energy could be obtained. Observa-tions of fracture surfaces show that fatigue cracks initiate with multi-initiation sites from the specimen surface and fracture morphology relate to stress level .%在应力控制条件下对304不锈钢试样进行拉压疲劳试验，研究其低周疲劳断裂特性。对试验数据处理，得到304不锈钢在应力控制下的低周S-N曲线并拟合出低周应力寿命的表达式；利用表达式计算出304不锈钢的疲劳极限；分析在不同应力下应变与寿命之间的关系以及加载次数与塑性应变能之间的关系；对断口进行观察表明：裂纹萌生于试样表面，且具有多源性，应力大小影响断口形貌。