高强双相钢DP780性能稳定控制技术的研究

RESEARCH ON PERFORMANCE STABILITY CONTROL TECHNOLOGY OF HIGH STRENGTH DUAL PHASE STEEL DP780

双相钢组织由铁素体基体与约20%的在铁素体晶界上的岛状马氏体构成,软相铁素体决定了钢的塑性,硬相马氏体决定了钢的强度,其具有低屈强比、高的初始加工硬化速率、良好的强度和延性配合等特点,已发展成为一种汽车用高强度新型冲压用钢,广泛用于生产门内柱、保险杠等安全件。双相钢作为高强系列的代表产品,由于其优良的性能特点,一直是汽车用高强度冲压用钢的首选,但由于合金加入量较多,产品组织极易出现冷却不均匀,从而导致产品性能波动大,造成用户在冲压过程中发生开裂等质量问题。通过分析其成分、组织、性能演变规律,模拟工艺参数对双相钢组织性能的演变规律,实现了双相钢DP780力学性能的稳定控制。

The microstructure of dual phase steel is composed of ferrite matrix and about 20% island martensite at ferrite grain boundary.Soft phase ferrite determines the plasticity of steel,while hard phase martensite determines the strength of steel.It has low yield ratio,high initial work hardening rate,good strength and ductility.It has been developed into a new type of high strength stamping steel for automobile,which is widely used in the production of door post,bumper and other safety parts.Dual-phase steel,as the representative product of high-strength series,has always been the first choice for automotive high-strength stamping steel because of its excellent properties.However,due to the large amount of alloy added,the structure of the product is prone to uneven cooling.As a result,the product performance fluctuates greatly,causes the customer to crack in the stamping process and so on quality problem.By analyzing the evolution law of composition,microstructure and properties,and simulating the evolution law of process parameters on the microstructure and properties of dual-phase steel,the stable control of mechanical properties of dual-phase steel DP780 is realized.