汽轮机主汽门2Cr12NiMo1W1V门杆断裂原因  

Fracture Reasons for 2Cr12NiMo1W1V Steel Main Valve Stem of A Turbine

作　　者：句光宇 JU Guangyu(Datang Huazhong Electric Power Experimental Research Institute,China Datang Group Research Institute of Science and Technology Co.,Ltd.,Zhengzhou 450001,China)

机构地区：[1]中国大唐集团科学技术研究院有限公司,大唐华中电力试验研究院,河南郑州450001

出　　处：《热加工工艺》2020年第22期162-164,共3页Hot Working Technology

摘　　要：对材质为2Cr12NiMo1W1V的断裂主汽门门杆进行宏观观察、光谱分析、力学性能检验及显微组织分析。试验结果表明:主汽门门杆材料组织和性能处于正常状态,断裂原因与材料本身无关;门杆断裂起源于排孔壁处,在渗氮层的应力集中区域发现多处裂纹,裂纹是在门杆服役过程中产生的。对汽轮机门杆排汽孔壁、平衡孔壁不应进行渗氮处理,因为,如果渗氮工艺控制不当,就会在应力集中部位产生裂纹,并发生脆性断裂。在渗氮工艺不好控制的情况下,门杆外表面变截面处也应有保护措施。Macroscopic observation, spectral analysis, mechanical property test and microstructure analysis were carried out for the sample came from the 2Cr12NiMo1W1V fracture main valve stem. The results show that, the structure and properties of the main valve stem are in normal condition, and the reason of fracture is independent of the material itself. The fracture of the stem originates from the exhaust hole wall, and many cracks are found in the stress concentration region of the nitriding layer. The cracks occur during the service of the stem. Nitriding treatment should not be carried out on the exhaust hole wall of steam turbine stem and balance hole wall. If the nitriding process is not properly controlled, the cracks will occur at the stress concentration and brittle fracture will occur. Under the condition that nitriding process is not well controlled, it should also be protected at the variable cross section of the outside surface of the stem.

关 键 词：排汽孔壁 渗氮层 应力集中 脆性断裂 渗氮工艺 

分 类 号：TG111.91[金属学及工艺—物理冶金] TG162.75[金属学及工艺—金属学]