【摘要】 采用XRD、SEM和TEM等研究了650℃长时时效对12Cr-4W-3Co耐热钢显微组织及650℃高温强度的影响。结果表明:650℃时效0～5000h后,该钢的析出相为M₂₃C₆相和Laves相,高温屈服强度逐渐下降;在0～100h区间,屈服强度降低主要是由于马氏体板条回复较快;在100～1000h区间,M₂₃C₆、Laves相析出增加,板条回复减弱导致屈服强度基本不变;在1000～3400h区间,M₂₃C₆、Laves相的长大和板条的继续回复均导致屈服强度降低;在3400～5000h区间,板条的回复基本停止,M₂₃C₆、Laves相少量析出和长大的共同作用导致屈服强度基本不变。更多还原

【Abstract】 The effect of long-time aging at 650℃on microstructure and high temperature strength at 650℃of the 12Cr-4W-3Co heat-resistant steel was studied by XRD,SEM and TEM.The results show that the precipitates were M₂₃C₆ and Laves phase when the tested steel aged at 650℃for 0-5 000 h,the yield strength at high temperatures gradually decreased.The reduction of the yield strength was mainly resulted from the martensite lath recovery during 0-100 h.The yield strength was basically unchanged for the increase of M₂₃C₆ and Laves phases precipitation and the decrease of martensite lath recovery during 100-1 000 h.The growth of M₂₃C₆ and Laves phases and recovery of the martensite lath led to the decrease of yield strength from 1 000 h to 3 400 h. During 3 400-5 000 h,the lath recovery stopped,and the yield strength basically unchanged for some precipitation and growth of M₂₃C₆ and Laves phases.更多还原