影响退火钢板表层Mn析聚的因素及提高2030钢板抗锈蚀能力的对策

Factors Favoring the Segregation of Mn in the Surface Layer of Annealed Sheet Steel and Counter-measures to Improve Rust-resistance of the Sheets out of 2030 Mill

从 2 0 3 0与 1 42 0两冷轧单元工况上的差异出发 ,考察了 2 0 3 0CAPL和 2 0 3 0BAF中影响Mn等易氧化元素在钢板表面富集的因素。结果表明 ,退火温度、退火时间、退火前清洗介质中含Si与否、钢卷冷轧时的变形量等对Mn等的析聚有较大的影响 ;宝钢 2 0 3 0冷轧板表面Mn等元素的过度析聚也归因于退火温度 (过高 )、退火时间 (过长 )、CAPL退火前清洗介质中含有Si、钢卷冷轧时的变形量与退火温度时间的不完全匹配等的共同作用。考虑到 2 0 3 0冷轧单元对这些关键因素进行严格地控制和匹配较为困难 ,提出了“退火后轻微酸洗处理”的提高2 0 3

Possible factors that favor the segregation of Mn in the surface layer of annealed sheet steel,which had been proved to account for the easier rusting of steel sheets,were examined.It was found that annealing temperature,annealing period,whether the cleaning medium contains Si species or not,reduction ratio of cold rolling,etc.greatly influenced the segregation of Mn into the surface layer during annealing.The abnormal segregation of Mn in the surface layer of annealed sheet steel out of 2030 mill of Baosteel was attributed to the higher annealing temperature,longer annealing period,Si borne cleaning medium,and the mismatch of annealing temperature and period for the cold rolling reduction ratio.Because the frequent alternation in size and mechanical performance requirements of the product sheets would make it difficult to have an accurate control of the annealing temperature and period as well as to have annealing temperature and annealing period well matched for the cold rolling reduction ratio,an approach to improve rust resistance of sheet steel produced by 2030 mill of Baosteel--'slight pickling after annealing' was put forward.