摘要
12Cr2MoWVTiB具有一定的淬硬和再热裂纹倾向,焊后热处理对其接头力学和使用性能至关重要。对焊态和不同热处理温度下的接头金相组织、硬度及拉伸、冷弯性能进行了测定,探明随着热处理温度的提高,接头组织由回火马氏体+少量颗粒状贝氏体逐步转变为回火贝氏体+索氏体的混合组织。晶粒有长大现象。同时接头强度和硬度呈下降趋势,760℃之后,由于焊接残余应力得到大幅度释放,沉淀相的弥散强化作用增强,强度下降趋势不明显。试验表明,(750℃～780℃)/1h焊后热处理制度均可满足使用性能要求,为了抑制沉淀相对韧性的不利影响,以(750℃～760℃)/1h热处理制度为佳。
12Cr2MoWVTiB steel alloy has certain sensitivity of hardened and reheat craeking,postweld heat treatment plays a pivotal role in mechanical properties and operating performance characteristics of welded joint.In this study,analyzed the chemical constitutions of welding seam,microstructure,furthermore,investigated the mechanical properties of bend,tension and impact of welded joint as welded and under different temperature of postweld heat treatment.And indicated that as temperature of postweld heat treatment increases,microstrncture of welded joint turns from tempering martensite＋granular bainite to mixture of tempering bainite＋ sorbite gradually,grain size largens.And strength and hardness of joint show a trend of decreasing.When the temperature reaches 760 ℃ ,this trend become less obvious,because the sharply relaxation of welding residual stress and the dispersion strengthening of precipitated phase.It found that all （750℃-780 ℃）/1 h heat treating regimes can comform to operate performance characteristics.In order to prevent the adverse influence of precipitated phase on toughness, （750℃-760 ℃）/1 h heat treating regimes is preferred.
出处
《电焊机》
北大核心
2010年第2期114-116,共3页
Electric Welding Machine
