作者：侯方¹, 李久楷¹, 谢少雄², 刘永杰¹, 王清远^1,2, 张军晖³

作者单位：1. 四川大学建筑与环境学院, 四川 成都 610065;
2. 四川大学空天科学与工程学院, 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：汽轮机转子钢;超高周疲劳;高温;非金属夹杂物

摘要：

利用自主研发的高温超声疲劳实验系统,开展CrMoW转子钢常温及600 ℃下的超高周疲劳实验。为新型超超临界汽轮机转子提供高温超高周疲劳数据,实验结果表明高温会极大降低转子钢的疲劳强度。S-N曲线在常温及600 ℃下均呈现连续下降型,且600 ℃下S-N曲线在整个疲劳寿命周次内保持一定下降趋势。断口分析发现,常温下疲劳寿命107周次试件的疲劳裂纹以内部萌生为主,600 ℃下疲劳破坏的内部夹杂萌生方式与表面萌生方式均分布于整个疲劳寿命。夹杂物尺寸分析表明,高温降低疲劳裂纹内部萌生夹杂物的临界尺寸。

Very high cycle fatigue behavior of rotor steel for the steam turbine under room temperature and 600 ℃

HOU Fang¹, LI Jiukai¹, XIE Shaoxiong², LIU Yongjie¹, WANG Qingyuan^1,2, ZHANG Junhui³

1. College of Architecture and Environment, Sichuan University, Chengdu 610065, China;
2. School of Aeronautics and Astronautics, Sichuan University, Chengdu 610065, China;
3. Shanghai Electric Power Generation Equipment Co., Ltd., Shanghai Turbine Plant, Shanghai 200240, China

Abstract: Very high cycle fatigue tests on CrMoW rotor steel at room temperature and 600 ℃ were conducted by using an autonomous development system. Experimental results display that high temperature will largely degrade fatigue performance. The S-N curves at room temperature and 600 ℃ both present continuously descending and keep a certain downtrend in the whole fatigue life namely 10¹⁰ cycles. Fractograph of specimens show that the fatigue cracks are primarily generated from inside where the fatigue life is more than 1×10⁷ cycles under room temperature. It is found that the surface initiation mode and the inclusion initiation mode are uniformly distributed in the whole fatigue life. The study on inclusion size reveals that the critical size of the inclusions in inclusion initiation mode is decreased due to high temperature.

Keywords: steam turbine rotor steel;very high cycle fatigue;high temperature;nonmetallic inclusion

2016, 42(2): 9-14  收稿日期: 2015-10-27;收到修改稿日期: 2015-11-30

基金项目: 国家自然科学基金(11172188,11327801,11502151)

作者简介: 侯 方(1990-),男,陕西汉中市人,硕士研究生,专业方向为金属超高周疲劳行为与断裂机理。

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