一种高Nb-IF钢的组织和织构特征

以一种新型高Nb-IF钢和传统Nb+Ti-IF钢为研究对象,分别进行相同的冷轧及退火处理,对比研究了两种实验钢的微观组织和织构演变特征.结果表明:与传统Nb+Ti-IF钢相比,该新型高Nb-IF钢由于添加了较高含量的C和过量的固定元素Nb从而提高了再结晶温度;875℃退火时,平均晶粒直径由传统Nb+Ti-IF钢的15.4μm细化到12.1μm,大量尺寸在10～30nm之间的细小Nb(C,N)复合析出粒子是其晶粒细化的原因;有利r值的ND∥{111}纤维织构峰值更加尖锐且发展速度较快.EBSD分析结果表明,该新型高Nb-IF钢组织均匀性良好,相邻晶粒取向夹角≤15°的小角晶界及低ΣCSL晶界含量...

Microstructure and Texture of High Nb Interstitial-Free Steel

The microstructures and texture evolution of a novel high Nb bearing IF steel and conventional Nb+Ti bearing IF steel with the same cold rolling and annealing processes were investigated comparatively.The results revealed that the recrystallization temperature of the high Nb bearing IF steel is higher than that of the conventional Nb+Ti bearing IF steel,which is attributed to the addition of relatively high carbon content and excessive Nb which is a carbide forming element. Grain size of the high Nb bearing IF steel annealed at 875 ℃ is finer(12.1 μm) than that of the conventional Nb+Ti bearing IF steel(15.4 μm);furthermore,the tiny Nb(C,N) precipitates(10～30 nm),which can refine grains,are found.The intensity of ND∥{111} orientations(γ-fiber texture) favorable to r-value in the high Nb bearing IF steel is stronger and grows faster,in comparison with the conventional Nb+Ti bearing IF steel.EBSD analyses showed that there is more homogenous microstructure,more small-angle grain boundaries(≤15°) and low ΣCSL boundaries in the high Nb bearing IF steel.