退火加热过程中Nb-Ti深冲DP钢组织与织构的演变

Evolution of microstructure and textures in Nb-Ti deep drawing dual-phase steel sheet during annealing heating

观察了C-Mn-Nb-Ti系深冲双相钢在连续退火加热过程中组织与织构的特点及其演变规律,分析了织构形成机制及其影响因素。结果表明:试验钢710℃时开始发生再结晶,840℃时再结晶基本结束,800℃时开始发生奥氏体相变。再结晶初期的硬度下降以及再结晶的体积分数增加程度均比再结晶后期幅度大。在回复阶段和再结晶初期,α和γ纤维织构强度均较高;再结晶程度较高的时候,所有取向的密度值均出现了不同程度的下降,最后要低于回复期和再结晶初期的织构强度;再结晶后期,析出粒子部分回溶,{111}面织构强度迅速提升,860℃时织构强度最高;温度继续升高,基体中固溶碳含量增加,γ纤维织构强度又有所降低。

Characteristics and evolution of microstructure and texture in C-Mn-Nb-Ti deep drawing dual-phase steel sheet were observed during annealing heating,and the mechanism of texture formation and the influenced factors were also analyzed. The results show that,the recrystallization temperature of the test steel starts at 710 ℃,and basically completes at 840 ℃. Austenitic phase transformation temperature starts at 800 ℃. The degree of reducing hardness and increased in the volume fraction of recrystallization at the early stage of the recrystallization better than that at later stage. The specimens obtained higher strength of α and γ fiber texture at the beginning of annealing heating; The value of all density orientation decreased differently at high degree of recrystallization. The texture intensity is highest at 860 ℃ due to precipitation particles partly back to dissolved and the intensity of {111} texture rapidly increased,then the strength of γ fiber texture reduced with a rise of carbon content in matrix.