研究不同调质工艺处理的石油套管用36Mn2V钢的0℃冲击性能.用金相显微镜、扫描电子显微镜和透射电子显微镜观察与分析钢的奥氏体晶粒大小、冲击断口形貌、钢中淬火未溶第二相以及回火碳化物的析出行为.结果表明,当回火温度一定,淬火温度在890℃时,淬火未溶第二相的数量较少而且奥氏体晶粒未过分长大,冲击功最大.当淬火温度一定,冲击功随着回火温度的升高而增大.回火温度较低时(500℃),钢中碳化物主要在晶界和马氏体板条界面上呈连续状析出,冲击功较低；回火温度较高时( 620℃),碳化物多在晶内析出而且铁素体呈等轴状,冲击性能较好.%Impact property at 0 ℃ of 36Mn2V steel used for petroleum casing after different quenching and tempering processes was researched. The size of austenite grains, fracture surface of impact specimens, undissolving secondary particles and precipitation behavior of carbides in the steel were characterized by optical microscope, SEM and TEM respectively. The results showed that relatively small numbers of undissolved particles and the modest size of austenite grains were obtained by quenching at 890 ℃, and tempering at certain temperature could exhibit the maximum impact energy. As the quenching temperature was the same, the impact energy increased with the increasing of tempering temperature. While the carbides in the steel were precipitated along the grain boundary and the lath interface at a low tempering temperature ( such as 500 ℃) , and the impact energy was poor. Carbides precipitated mainly in the grains and equi-axed ferrites of the steel were observed at the higher tempering temperature ( such as 620 ℃ ) , the impact energy was fine.
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