Abstract: Structure of heat-resistant steel 1 Crl2Ni3Mo2VN quenched at 1 040 T for 1 h oil cooling, furnace cooling (5 T/min) , 1 °C./min and 0. 5 °C/min cooling and mechanical properties of the steel quenched at 1 040 °C for 1 h with different cooling rate + tempered at 565 °C for 2 h have been studied. Test results show that martensite structure of the steel quenched with four cooling rate is obtained, but A_KV2 value of the steel by quenching, oil cooling and tempering is 156. 5 J, while that by quenching, 5 ~0. 5 °C/min cooling and tempering is 40. 5 - 16. 5 J. The thermal decomposition of retained austenite in steel slow-cooled is main reasons for impact energy marked decreasing, i. e. during quenching slow- cooling at 720 ~ 820 °C, a large amount of carbide precipitates at original austenite grain boundary led to obvious decreasing alloying elements and carbon content in residual austenite and poor stability of residual austenite in quenched structure.

Key words: Heat Resistant Steel 1 Crl2Ni3Mo2VN, Quenching Cooling Rate, Structure, Mechanical Properties

摘要： 研究了1040℃1h油冷、炉冷(5℃/min)、1℃/min、0.5℃/min冷却后耐热钢1Cr12Ni3Mo2VN的组织和该钢1040℃1h不同冷却速度淬火+565℃2h空冷后的力学性能。试验结果表明,该钢4种冷却速度淬火均可得到马氏体组织,但油冷+回火的AKV2值为156.5 J,而5～0.5℃/min冷却+回火时为40.5～16.5 J。残余奥氏体发生热失稳分解是导致试验钢淬火缓冷后冲击韧性显著下降的主要原因;在淬火缓冷过程中720～820℃这一温度段,由于原奥氏体晶界上碳化物的大量析出,使残余奥氏体中合金元素和碳含量的显著减少,造成淬火组织中的残余奥氏体稳定性大幅度下降。

关键词: 耐热钢1Cr12Ni3Mo2VN, 淬火冷却速度, 组织, 力学性能