热时效对多元微合金化310S不锈钢显微组织和冲击性能的影响

复合添加钼、铌、钨和钽等元素对310S不锈钢进行多元微合金化,固溶后分别在不同温度(650,800℃)和不同时间(500,1000,2000h)进行热时效处理,研究了热时效对试验钢显微组织和冲击性能的影响。结果表明:在650℃时效处理后,试验钢显微组织为奥氏体,第二相除了M23C6相外还存在Fe2MoC相和Cr7C3相;在800℃时效处理后,试验钢晶内有大量针状第二相析出;试验钢在不同温度时效处理后,随着时效时间的延长,其冲击吸收功均逐渐降低;和650℃时效相比,在800℃时效处理后试验钢的冲击吸收功降幅增大,断裂方式由韧性断裂向脆性沿晶断裂转变。

Effect of Thermal Aging on Microstructure and Impact Property of Multi-micro-alloying 310S Strainless Steel

310Sstainless steel was multi-micro-alloyed by composite addition of molybdenum,niobium and tungsten,etc.,and then treated by thermal aging at different temperatures(650,800℃)for different times(500, 1 000,2 000h)after solution treatment.The effects of thermal aging on microstructure and impact property of the tested steel were studied.The results show that after aging at 650 ℃,the microstructure of the tested steel consisted of austenite.In addition to M23C6phase,there were also Fe2MoC phase and Cr7C3phase in the second phase.A large number of needle-like second phases precipitated in the grain of the tested steel after aging at 800℃. After aging at different temperatures,the impact absorption energy of the tested steel decreased gradually with the aging time prolonging.Compared with that after 650℃aging treatment,the impact absorbing energy of the tested steel decreased greatly after aging at 800 ℃,and the fracture mode changed from ductile fracture into brittle intergranular fracture.