Abstract: The production flow sheet for test steel 12Cr2Mo (/%: 0.09C, 0. 30Si, 0. 34Mn, 0.007P, 0. 006S, 2, 10Cr, 0. 93Mo, 0. 014A1) 406 mm x 40.5 mm tube is 120 t BOF-LF-RH-410 mm x 530 mm bloom casting-forging to 0390 mm tube stock-460 mm ASSEL mill rolling to tube. With using JMatPro software to calculate phase equilibrium diagram of test steel, it is obtained that the steel 12Cr2Mo phase transition point Ac₃ is 862 ℃; and the Ac₁ is 781 °C, and the examination on structure and mechanical properties of test steel normalizing-heat-treated at 910 °C and tempered at 700 ℃ has been carried out. Results show that the matrix structure of normalized-tempered test steel 12Cr2Mo is bainite + minor ferrite, and a large amount of irregular M₂₃C₆ precipitate at grain boundary and in intragranular, a small amount granular M6C carbides precipitate along grain boundary and a large amount fine pin-like Mo₂C carbides precipitate in intragranular, and the mechanical properties of steel is excellent- strength /R_el 515 ~520 MPa and R_m 640 ~650 MPa, plasticity A 22% ~ 25% and Z 76% 80% , and impact energy at -60 TJ A_KV 268 ~293 J.

摘要： 试验用12Cr2Mo(/%:0.09C,0.30Si,0.34Mn,0.007P,0.006S,2.10Cr,0.93Mo,0.014Al)406 mm×40.5 mm钢管的生产流程为120tBOF-LF-RH-410mm×530mm连铸-锻制∞90mm管坯-460mmASSEL机组轧制成管。采用JMatPro软件计算实验用钢平衡相转变图,得出12Cr2Mo钢相变点Ac₃为862℃,Ac₁为781℃,并对910℃正火,700℃回火处理的试验钢进行组织和力学性能检验。结果表明,试验12Cr2Mo钢正火-回火后的基体组织为贝氏体+少量铁素体,同时大量不规则的M₂₃C₆碳化物在晶界和晶内析出,少量颗粒状的M₆C碳化物沿晶界析出,大量细小针状的Mo₂C碳化物在晶内析出,该钢力学性能优良-强度R_el515~520 MPa,R_m640~650 MPa,塑性A 22%~25%,Z 76%~80%,以及-60℃冲击功A_Kv 268~293 J。

关键词: 高压锅炉用钢12Cr2Mo, 热处理, 组织, 合金碳化物, 力学性能