作者：谢少雄1, 李久楷2, 侯方2, 刘永杰2, 王清远1,2, 张军辉3
作者单位：1. 四川大学空天科学与工程学院, 四川 成都 610065;
2. 四川大学建筑与环境学院, 四川 成都 610065;
3. 上海电气电站设备有限公司上海汽轮机厂, 上海 200240
关键词：CrMoW转子钢;高温超高周疲劳;夹杂物;硬度
摘要：
利用旋转弯曲疲劳试验机,研究CrMoW转子钢在常温与600 ℃条件下的超高周疲劳特性。对试验数据采用三参数模型拟合,用扫描电子显微镜(SEM)对疲劳断口进行分析。研究结果发现,600 ℃下的S-N曲线呈现直线下降的趋势,不存在传统意义上的疲劳极限。高温会加速试样的氧化,促进裂纹的萌生与扩展,降低材料的疲劳寿命。断口分析表明:疲劳裂纹主要萌生于试样表面,很少发现裂纹萌生于内部的情形。在600 ℃下,裂纹萌生区普遍发现有夹杂物。对试验前后转子钢硬度值进行测量,没有发生明显变化。
Very high cycle fatigue behavior of CrMoW rotor steel at different temperature
XIE Shaoxiong1, LI Jiukai2, HOU Fang2, LIU Yongjie2, WANG Qingyuan1,2, ZHANG Junhui3
1. School of Aeronautics and Astronautics, Sichuan University, Chengdu 610065, China;
2. College of Architecture and Environment, Sichuan University, Chengdu 610065, China;
3. Shanghai Electric Power Generation Equipment Co., Ltd., Shanghai Turbine Plant, Shanghai 200240, China
Abstract: Rotating bending fatigue tests were performed to evaluate the very high cycle fatigue properties of CrMoW rotor steel at room temperature and 600 ℃. The experimental data was fitted by three parameter models and the fracture morphology was observed by SEM. The results show that the S-N curve presents a continuously descending shape at 600 ℃ and a conventional fatigue limit is not obtained. The oxidation of the specimen is accelerated at the elevated temperature. Accordingly, the crack initiation and crack propagation are also promoted so that the fatigue life is decreased. From the result of fractography, the fatigue fracture mainly occurs on the surface of the specimen and the interior crack initiation is hardly found. The inclusion is generally observed in the crack initiation area at 600 ℃. It is also found that the hardness value of the materials has no obvious changes before and after the test.
Keywords: CrMoW rotor steel;high temperature very high cycle fatigue;inclusion;hardness
2015, 41(10): 13-17 收稿日期: 2015-05-14;收到修改稿日期: 2015-06-19
基金项目: 国家自然科学基金(11327801,11172188,11302142)
作者简介: 谢少雄(1989-),男,甘肃天水市人,硕士研究生,专业方向为材料的疲劳与断裂。
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