析出相对深冲DP钢组织性能及织构的影响

Effect of participation on microstructures,mechanical properties and texture of deep drawing DP steel

为了研究析出相对深冲DP钢织构的影响机制,采用Thermo-calc热力学软件计算DP钢的平衡析出相,并利用SEM、TEM与XRD等手段分析了两种不同成分的DP钢组织性能与织构演变.研究表明:试验钢的主要析出相为MC_SHP、M7C3、MnS和AlN;与低Mo钢相比,高Mo钢的奥氏体区被缩小,且MoC的析出温度更高,铁素体晶内与沿晶界形成了大量的纳米级MoC析出;860℃退火后,高Mo钢中形成了约3%的均匀弥散分布的马氏体,抗拉强度达到445 MPa,r值为1.5,而低Mo钢发生了贝氏体相变,各项力学性能明显降低;两种试验钢的热轧板织构较弱,冷轧后{223}<110>取向密度稳定增加,退火后均形成了强烈的γ纤维织构,而低Mo钢中{001}<110>织构是导致其r值偏低的主要原因.

To investigate the effect of participation on texture of deep drawing DP steel, the equilibrium precipitates of DP steel was calculated using Thermo-calc thermodynamic software, and the microstructures, mechanical properties and texture evolution of DP steels with different composition were investigated by SEM, TEM and XRD techniques. The results show that the main precipitates of tested steels are MC_SHP, M7C3 , MnS and AIN. Comparing to the steel with low Mo content, the austenite region is narrowed, and the participation temperature of MoC is higher. A large amount of MoC participation is observed in ferrite matrix. After annealing at 860℃, a homogeneous, dispersed distribution of 3% martensite was transformed in the steel with high Mo content, which makes the tensile strength up to 445 MPa, and the r value is 1. 5. However, the bainite transformation happens in the steel with low Mo content, which makes the mechanical properties strongly reduced. The texture in hot-rolled strip of the two steels is slightly weak, and the { 223 } 〈 110 〉 component is stability increasing during cold rolling. The high intensity of γ fiber texture is formed during annealing process, and the lower r value may be contributed to the I001 t 〈 110 〉 orientation in the steel with low Mo content.