正火温度对低活化马氏体钢组织及力学性能的影响  

Effect of normalizing temperature on microstructure and mechanical properties of reduced activation martensitic steel

作　　者：郑涛 李永旺 吴裕[2] 卓洪[2] 施瀚超 刘超红[2] Zheng Tao;Li Yongwang;Wu Yu;Zhuo Hong;Shi Hanchao;Liu Chaohong(Welding and Plastic Forming Institute,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Science and Technology on Reactor Fuel and Materials Laboratory,Nuclear Power Institute of China,Chengdu Sichuan 610213,China)

机构地区：[1]中国航发北京航空材料研究院焊接与塑性成形研究所,北京100095 [2]中国核动力研究设计院反应堆燃料及材料重点实验室,四川成都610213

出　　处：《金属热处理》2022年第12期103-108,共6页Heat Treatment of Metals

摘　　要：对低活化马氏体钢丝材进行1000~1100℃保温60 min的正火处理,随后在790℃保温90 min进行回火处理,研究正火温度对低活化马氏体钢丝的显微组织及力学性能的影响。结果表明,正火后,丝材的显微组织由粒状珠光体转变为板条状马氏体,碳化物粒子大部分回溶于基体中,正火温度的升高加速碳化物粒子的回溶,在1100℃实现完全回溶;原奥氏体晶粒尺寸随正火温度升高显著增大(由1000℃的7.4μm增至1100℃的34.9μm)。回火处理后,马氏体板条尺寸变宽,板条间的位错密度显著降低,析出相沿晶界、晶粒内部析出、球化及长大,其中M_(23)C_(6)(M以Cr为主)相为短棒状,分布在晶界,而MX(M以Ta为主)相为椭球状,分布在马氏体板条内部。经1000℃×60 min正火+790℃×90 min回火后能够获得最佳的综合力学性能,其抗拉强度为745.7 MPa,断后伸长率为18.9%。Reduced activation martensitic steel wires were normalized at 1000-1100℃for 60 min and then tempered at 790℃for 90 min,and the effect of normalizing temperature on microstructure and mechanical properties of the reduced activation martensitic steel wires was investigated.The results show that after normalizing,the microstructure of the reduced activation martensitic steel is transformed from granular pearlite to lath martensite,and the carbide particles are partially dissolved in martensite matrix.With the increase of normalizing temperature,more carbide particles can be dissolved into the matrix and completely dissolved at 1100℃,and the grain size of prior austenitic increases(from 7.4μm at 1000℃to 34.9μm at 1100℃).After tempering,the lath spacing of martensitic widens,and the high-density dislocations are rapidly recovered and disappeared,while precipitated phases are precipitated,spheroidized and grow up along grain boundary and inside,the M_(23)C_(6)(M is dominated by Cr)phases are short rod shape,which are distributed on the grain boundary,while the MX(M is dominated by Ta)phases are elliptic shape,which are mainly distributed in the lath martensitic.The reduced activation martensitic steel has the best comprehensive mechanical properties after normalizing at 1000℃for 60 min and tempering at 790℃for 90 min,with tensile strength of 745.7 MPa and elongation of 18.9%.

关 键 词：低活化马氏体钢 正火温度 显微组织 力学性能 析出相 

分 类 号：TG156.4[金属学及工艺—热处理]