高强钢热冲压成形变强度工艺研究

Study on Hot Stamping Forming Technology of High Strength Steel with Tailored Properties

通过冷热分块模具实现了高强钢板热冲压成形变强度工艺,研究了模具温度和冷却速率等工艺参数对于零件力学性能和组织转变的影响规律。结果表明,模具为室温时,零件为完全的马氏体组织;当模具温度为500℃保压120s时,零件为完全的贝氏体组织,零件的强度随模具的温度升高而降低,伸长率则随模具温度升高而升高;通过使用冷热分块模具热冲压的变强度U-形件,维氏硬度由冷却区向加热区梯度逐渐减小,过渡区域长度约为68 mm。这些表明通过冷热分块模具实现变强度热冲压成形零件是可行的。

The hot stamping of high strength steels with tailored properties was realized by using divided die with cold and hot zones. The effects of die temperature and cooling rate on mechanical properties and microstructure transformation of the parts were studied. The results show that when the die is room temperature, the parts are complete martensite microstructure; when the die temperature is 500 ℃ and the pressure is kept for 120 s, the part is completely bainitic microstructure, the strength of the part decreases with the die temperature increasing, and the elongation increases with the die temperature increasing; by using divided die with cool and hot zones, the vickers hardness of the hot stamped U-shape part with tailored properties gradiently decreases from cold zone to hot zone and the length of the transition zone is about 68 mm. These indicate that it is feasible to obtain hot stamping parts with tailored properties by using divided die with cold and hot zones.