无铬耐指纹板表面皱纹缺陷产生原因分析及对策

Cause Analysis of Cross Breaks of Chromium-Free Fingerprint Resistant Sheet and Corresponding Countermeasures

宝钢分公司冷轧连续退火机组生产CQ钢种耐指纹基板过程中发生的表面皱纹缺陷影响了产品的表面质量。通过对钢板在退火过程和平整过程的影响的分析,表面皱纹缺陷是钢板在连续退火过程中碳、氮等固溶元素在位错周围形成柯氏气团,在塑性变形过程中产生屈服平台导致的。为了消除表面皱纹缺陷,可以采取提高加热温度、降低机组速度、提高一次冷却温度和速度、提高时效温度、加大平整延伸率、增加轧制力等改进措施。结合宝钢生产现场的实际情况,重新制定了退火和平整工艺。

Cross breaks accuring in the process of producing black sheets, a kind of chromium-free and fingerprint resistant CQ steel manufactured on the cold rolling continuous annealing line at Baosteel Branch, would affect the products＇ surface quality. This defect is found connected with a Cottrell gas mass, formed by solid solution elements, like C, N, etc. when they are staying around the dislocation, and this defect also results from yield point elongation in the process of plastic deformation. Countermeasures including raising heating temperature, reducing the line speed, lifting the first cooling temperature and speed, aging temperature, skin-pass rate and rolling force, etc. can be taken to avoid this defect. New annealing and skin-pass process has been re-established on the basis of the concrete conditions at Baosteel＇ s worksite.