控轧温度区间对含Nb热轧多相钢组织和性能的影响

以含Nb微合金化试验钢为研究对象,通过3个不同精轧温度区间的轧制+层流冷却、空冷、超快冷的TMCP工艺获得了含有铁素体、贝氏体、马氏体以及少量残余奥氏体的显微组织.分析了控轧温度区间对含Nb微合金化试验钢显微组织和力学性能的影响.结果表明,在控冷工艺参数相近的情况下,随着精轧开轧温度和终轧温度的降低,试验钢的抗拉强度减小,屈服强度、延伸率和强塑积增大.其中采用850～800℃的温度区间精轧+层流冷却、空冷、超快冷的TMCP工艺时,试验钢的屈服强度、延伸率和强塑积分别达到了513MPa,35%和25235MPa.%的最大值.

Effect of Controlled Rolling Temperature Interval on Microstructure and Mechanical Properties of Hot Rolled Nb-Contained Multiphase Steel

The Nb-contained microalloyed experimental steel was investigated via thermomechanical controlled processing(TMCP)including two-stage rolling with laminar cooling.air cooling and ultra-fast cooling over three different finish rolling temperature intervals.After such a TMCP.the microstructures containing ferrite,bainite,martensite and a bit of retained austenite were obtained.Than the effect of controlled rolling temperature interval on the microstructure and mechanical properties of experimental steel was analyzed.The results show that when controlled cooling parameters are similar to each other,tensile strength decreases but yield strength,percentage elongation and product of tensile strength and ductility all increase with the decreasing starting and final temperatures of finish rolling.With the cooling conditions during TMCP mentioned above.when the temperature interval during finish rolling is 850～800℃,yield strength,percentage elongation and product of tensile strength and ductility all come up to their maximum values,I.e.513 Mpa,35%and 25235 Mpa·%,respectively.