超临界汽轮机中压调速汽阀2Cr12NiMo1W1V钢阀杆断裂原因分析
Causes Analysis on Rupture of 2Cr12NiMo1W1V Steel Reheat Interceptor Valve Stem of a Ultra-supercritical Turbine
摘 要
通过宏观形貌分析、化学成分分析、力学性能测试、光学显微镜以及扫描电镜分析等方法对某超临界汽轮机中压调速汽阀2Cr12NiMo1W1V钢阀杆断裂原因进行了分析.结果表明:阀杆断裂的主要原因是其表面的渗氮层脆性超标,运行中当阀杆和与其紧密配合的阀碟发生挤压摩擦时,便会在应力集中的排汽孔处的渗氮层形成裂纹源,并在载荷作用下穿透渗氮层扩展至基体进而引发阀杆断裂;阀杆材料长期在超过其许用温度的环境下使用,造成蠕变老化,同时材料硬度偏高、塑性和韧性储备不足,都在一定程度上加速了裂纹的扩展,缩短了阀杆的使用寿命.
阀杆
渗氮层
脆性
蠕变
硬度
2Cr12NiMo1W1V steel
valve stem
nitriding layer
brittlement
creep
hardness
Abstract
The rupture causes of a 2Cr12NiMo1W1V steel reheat interceptor valve stem of a ultra-supercritical turbine were analyzed by means of macro inspection,chemical compositions analysis,mechanical properties test,optical microscope and scanning electron microscope analysis.The results show that the excessive brittleness of nitriding layer of the valve stem was the main cause for the rupture.Cracks generated in the nitriding layer near exhaust steam holes when the valve stem extruded with the valve disc,then the cracks extended from nitriding layer to the base metal,and finally the valve stem was broken.On the other hand,the valve stem was used in high temperature environment for a long time where the temperature was higher than the designed value,which would reduce the ductility and plasticity and result in creep damage.So the cracks extending velocity was increased and the service life of the valve stem was shorten.
中图分类号 TK14 TG142 TG113.25
所属栏目 质量控制与失效分析
基金项目
收稿日期 2014/4/29
修改稿日期
网络出版日期
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备注张涛(1982-)男,高级工程师,硕士.
引用该论文: ZHANG Tao,TIAN Feng,CHEN Hao,HOU Guo-xin,FENG Ze. Causes Analysis on Rupture of 2Cr12NiMo1W1V Steel Reheat Interceptor Valve Stem of a Ultra-supercritical Turbine[J]. Physical Testing and Chemical Analysis part A:Physical Testing, 2015, 51(4): 278～282
张涛,田峰,陈浩,侯国新,冯泽. 超临界汽轮机中压调速汽阀2Cr12NiMo1W1V钢阀杆断裂原因分析[J]. 理化检验－物理分册, 2015, 51(4): 278～282
被引情况:
【1】彭以超,楼玉民,李望,王贤明, "亚临界300 MW机组高压主汽阀阀杆断裂原因分析",理化检验－物理分册 52, 738-742(2016)
【2】王家庆, "某600 MW燃煤发电机组调门螺栓理化性能检验",理化检验－物理分册 52, 257-259(2016)
【3】郑文祥,吴跃,刘俊建, "给水三通阀阀杆断裂失效分析",理化检验－物理分册 52, 755-758(2016)
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【6】刘英坤,朱峰,伍超群,等.不同表面处理工艺下H13钢的高温耐磨性能[J].理化检验-物理分册,2012,48(10):645-648.
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【8】GB/T11354-2005钢铁零件 渗氮层深度测定和金相组织检验[S].
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