小方坯重压下技术的工程实践

Project practice of heavy reduction technology of billet

小方坯重压下技术是一项解决铸坯内部质量的全新技术。本文首先描述了中冶连铸小方坯重压下工程实践的铸机技术特点,然后基于在180 mm×180 mm断面小方坯72A钢种的大量单辊重压下（5～20 mm压下量）结果,讨论了重压下的几个关键问题,包括重压下和宽向延展、重压下和裂纹、重压下冶金效果等。实践结果表明：重压下能显著提高铸坯内部质量,消除缩孔、改善疏松和偏析,提高铸坯中心致密度;相比较于多辊轻压下,单辊重压下更不容易导致压下裂纹。

Heavy reduction is a new technology that can effectively improve the internal quality of the billets. In this paper,features of this technology were described in details and the industrial practice were carried out by CCTEC during the casting of 72 A billets（180 mm×180 mm）,in which 5-20 mm reduction was achieved by a single pair of roller. Several key aspects of this technology was discussed,including the heavy reduction itself and the brought ductility in the width direction of the billet,the relationship between heavy reduction and formation of inner cracks,improvements in the product quality etc. The obtained results indicated：Internal qualities of the billets were effectively enhanced,with faded cavity,minimized porosity and segregation;Compared to common soft reduction technology by multiple rollers in several segments,cracks can be more effectively prevented.