氢还原除鳞后的冷轧带钢退火工艺

Annealing process of cold-rolled steel strip after hydrogen reduction descaling

采用氢还原法去除带钢表面氧化铁皮绿色环保,但氢还原后的带钢表面出现脱碳现象,且内部组织粗化,冷轧及退火后可能遗传给成品带钢。本文对氢还原后的热轧带钢进行了冷轧和退火试验,研究了氢还原除鳞后的冷轧带钢在退火过程中的组织性能演变规律,分析了退火温度和退火时间对带钢组织性能的影响。结果表明：经过氢还原除鳞的冷轧带钢退火后内部组织发生了回复、再结晶和晶粒长大现象,退火温度越高,退火时间越长,晶粒长大越严重。与酸洗除鳞的冷轧带钢不同,经过氢还原除鳞的冷轧带钢再结晶退火时间相应缩短,在相同条件下,退火后基体晶粒尺寸相对较大,表面脱碳层内的晶粒长大更为明显,其抗拉强度降低10～20 MPa,伸长率提高3%～5%。

Hydrogen reduction descaling is an environmentally friendly process for hot-rolled steel strip. However, the surface decarbonization and grain coarsening of the steel strip could occur after hydrogen reduction,which can cause some defects of the finished strip. Experiments of cold rolling and recrystallization annealing were performed on the hot-rolled strip steel after hydrogen reduction. The influence of annealing time and temperature on microstructure and properties of the strip steel was studied. The results show that the recovery,recrystallization and grain growth are generated in the strip steel descaled by hydrogen reduction. And the annealing temperature is higher and the time is longer,the grain growth is more obvious. Compared with the cold rolling strip steel by pickling descaling,the cold rolling strip steel after hydrogen reduction descaling exhibits shorter recrystallization annealing time,and the grain size becomes larger,the tensile strength decreases by 10-20 MPa,and the elongation rate increases by 3%-5%,correspondingly.