Abstract: Structure and mechanical properties of steel 20SiMn3NiA normalized at 860 ℃, oil quenched at 900 ℃ for 40 min and tempered at 180~650℃ for 90~150 min have been studied. Results show that the better tempering temperature of steel is 200~250℃,the  lath martensite, fine slim rod precipitated carbide and residual austenite are obtained in the steel tempered at 230  ℃ and with steel tempered at 250  ℃ the tensile strength(Rm)is more than 1500 MPa and the impact energy(Axv)is higher than 80J with excellent combination of strength and toughness as the steel 20SiMn3NiA  is tempered at 320  ℃,the precipitated carbide is continuous lamellar distribution in steel led to lower impact energy of steel and thMeastea0Iie3NiSeelm2p0et3～,T6e0m0pr,rsutbuvrieo,uMsetapneirclriPttesrst.ies

Key words: Steel , 20SiMn3NiA, Temper, Structure, Mechanical Properties

摘要： 研究了20SiMn3NiA钢860℃正火,900℃40 min油淬,180～650℃90～150 min回火的组织和力学性能。结果表明,该钢较佳的回火温度为200～250℃,230℃回火后得到板条马氏体、细棒状碳化物析出相和残余奥氏体,在250℃回火时该钢的抗拉强度(Rm)超过1 500 MPa,冲击韧性(AKY)超过80 J,有较好的强韧性匹配。20SiMn3NiA钢在320℃中温回火时,碳化物析出相呈连续的片状分布,使得该钢的冲击韧性值很低,当在320～600℃区间回火时,20SiMn3NiA钢具有明显的回火脆性。

关键词: 20SiMn3NiA钢, 回火, 组织, , 力学性能