硼对780 MPa低碳贝氏体钢组织和力学性能的影响

试验低碳贝氏体钢（/%:0.08C,0.11~0.13Si,1.10~1.20Mn,0.008~0.009P,0.002S,0.21~0.23Ni,0.020~0.021Ti,0.003~0.004Nb,0~0.0010B,0.000 7~0.0008O,0.0031~0.0033N）由50kg真空感应炉熔炼,轧成45mm钢板,并经930℃淬火,610℃回火。研究了0.0010%硼对780 MPa低碳贝氏体钢45mm板组织和力学性能的影响。结果表明,硼可显著提高试验钢的淬透性,不含硼试验钢淬火后得到粒状贝氏体,0.0010%硼试验钢淬火后得到板条贝氏体。硼明显改善试验低碳贝氏体钢的力学性能,含0.0010%硼试验钢淬、回火后的抗拉强度834MPa和屈服强度771MPa远高于不含硼试验钢的抗拉强度702MPa和屈服强度591MPa,实际生产中应加入适量硼可使低碳贝氏体钢得到板条贝氏体。

Effect of Boron on Structure and Mechanical Properties of 780 MPa Low Carbon Bainite Steel

The tested low carbon bainite steel (/%: 0.08C, 0.11~0.13Si, 1.10~1.12Mn, 0.008?0.009P, 0.002S, 0.21~0.23Ni, 0.020~0.021Ti, 0.003?0.004Nb, 0~0.0010B, 0.0007~0.0008O, 0.0031~0.0033N) is melted by a 50kg vacuum induction furnace, rolled to 45mm plate, quenched at 930℃ and tempered at 610°C. The effect of 0.0010% boron on structure and mechanical properties of 45mm plate of 780MPa low carbon bainite steel has been studied. Results show that boron can remarkably improve the hardenability of tested steel, the structure of quenched tested steel without bearing boron is granular bainite, and the structure of quenched 0.0010% boron tested steel is lath bainite. The boron can obviously improve the mechanical properties of tested low carbon bainite steel, the tensile strength 834MPa and yield strength 771MPa of quenched-tempered bearing 0.0010% boron tested steel is higher than the tensile strength 702MPa and yield strength 591MPa of quenched-tempered without bearing boron tested steel. Adding suitable boron in steel in practical production the low carbon bainite steel can get lath bainite structure.