2.25Cr1Mo0.25V钢高温蠕变条件下微观组织的演变

Evolution of Microstructure for 2.25Cr1Mo0.25V Steel under Condition of Elevated Temperature Creep

研究了高温蠕变过程对加氢反应器母材用钢显微组织的影响。试样经焊后模拟热处理后,对其常温拉伸、高温拉伸及相同载荷、不同温度下的高温持久强度进行分析,并对试样的断口以及微观组织分别在光镜、扫描和透射电镜下进行观察,重点对高温蠕变持久过程中位错的演变和析出相的聚集长大规律进行了研究。结果表明,在210 MPa加载应力下,随测试温度的升高,马氏体板条逐渐退化,位错密度逐渐降低,析出相尺寸粗化严重,导致高温持久断裂时间显著降低。

Effects of elevated temperature creep process on microstructure of base metal steel for hydrogenation reactor have been researched. Normal temperature tension, high temperature tension and high temperature lasting strength under same loading and different temperatures of the specimen have been analyzed after simulated heat treatment after welding, furthermore fracture and microstructure of the specimen have been observed under light microscope , scanning electron microscope and transmission electron microscope, dislocation evolution and gathering and growing rule of precipitated phase in the lasting process of elevated temperature creep have also been researched mainly. The result showed that under loading stress of 210 MPa, as testing temperature increasing, lath martensite degraded and dislocation density decreased gradually, precipitated phase size roughened seriously to result in evident reduction of elevated temperature lasting fracture time.