冷轧压下率对含Nb细晶高强IF钢织构形成机制的影响

Effect of cold rolling reduction on mechanism of texture formation in a Nb-IF steel

以含Nb细晶高强IF钢热轧板为研究对象,研究了冷轧压下率对实验钢冷轧织构以及再结晶织构形成影响。结果表明,退火后铁素体晶粒细化,强度提高。实验钢经冷轧后主要的织构为{112}<110>、{111}<112>、{111}<110>、{001}<110>,并且随冷轧压下率增加,织构组分无变化,各组分强度整体增加。再经退火后,在α线上织构减弱,甚至一些织构逐渐消失。提高冷轧压下率时,织构峰值逐渐由{001}<110>转为{111}<110>。对于γ取向线,峰值由{111}<110>取向变为{111}<112>取向,最终{111}<112>比{111}<110>取向强度大。实验钢再结晶机制由定向形核和选择生长共同作用的结果,并且随冷轧压下率增大,{111}面织构强度增大,所以r(塑性应变比)值增大,深冲性能提高。

A fine-grain and high-strength Nb-IF steel under hot rolling was employed to study the effects of cold rolling reduction on cold rolling texture and formation of recrystallization texture. The results show that the main texture of the cold rolled steel is { 112} < 110 >,{ 111} < 112 >,{ 111} < 110 >,{ 001} < 110 >. With the increasing reduction,texture components of the tested steel are not changed,and strength of the components increases. Ferrite grain size of the annealed test steel is refined,and its strength increases. The texture on the α-line of the annealed test steel weakens,and even some of the textures have gradually disappeared. With the increasing cold rolling reduction,the texture peak gradually moves from { 001} < 110 > to { 111} < 110 >. For the line of γ-orientation,texture peak moves from { 111} < 110 > orientation to { 111} < 112 > orientation,eventually the density of { 111} < 112 > orientation is stronger than that of{ 111} < 110 > orientation. Recrystallization mechanism of the experimental steel is both oriented nucleation and selection growth,and with the increasing cold rolled reduction,the intensity of { 111 } surface texture increases,so the r value increases,and deep drawing performance is improved.