超高强钢BR1500HS热成形性能研究

Research on Hot Stamping Properties of Ultra-high-strength-steel BR1500HS

通过对硼钢进行两组不同的热处理试验，即模具淬火和直接水淬处理，研究了硼钢BR1500HS的热成形性能。模具淬火试验中，采用正交试验对比分析不同工艺条件下硼钢的力学性能和组织状况，发现加热温度和保温时间对热成形件力学性能影响较大，并确定最佳工艺参数为：加热温度930℃，保温时间4-5min，水流速度0．75m／s以上；在直接水淬火试验中，分析加热温度（此时等同于淬火温度）与保温时间对硼钢板力学性能的影响规律，结果表明当加热温度达到某个数值（如840℃）时，保温时间对硼钢板的力学性能影响极小，当加热温度低于某个数值（如840℃）时，需延长保温时间才可以获得较高力学性能的硼钢板。对比分析两组试验，直接水淬火的硼钢板的抗拉强度更高，但相对较脆，热冲压生产中采用模具淬火可获得屈强比更高，综合性能优异的热冲压件。

Hot stamping properties of BR1500HS would be studied by two different heat treatment tests of the steel, such as die quenching and water quenching treatment. It is found that heating temperature and holding time had a significant influence up on mechanical properties, and the optimum parameters have been defined as heating temperature at 950~C, holding time for 4 min and the minimum flow velocity of 0.75m/s, based on the microstructure and mechanical properties analyzed at different heat treatment conditions in the test of die quenching. While in the test of water quenching in which the influence of heating temperature （equal to quenching temperature now） and holding time on mechanical properties of boron steel was studied, it is also found that holding time has little effect on mechanical properties when heating temperature lowered certain value （such as 840℃） in which case, Boron Steel with high mechanical properties can obtained by prolonging the holding time. It can be found from the comparison between the two tests that Boron Steel treated with water quenching outperforms the other one on the tensile strength but the material is relative fragile, and that die quenching is the better way to obtain higher yield rate and hot stamping parts with comprehensive performances in the course of hot stamping production.