连铸圆坯斜轧穿孔变形特征和内折缺陷的探究

Research on Deformation Feature and Infolding Defect in Round Billet Cross-rolling Piercing

通过在斜轧穿孔机上的轧卡试验,揭示连铸坯在穿孔过程中变形特点。试验证明了"隔墙现象"的存在,阐明了连铸坯内部缩孔不会被氧化而产生内折。用正交试验法研究斜轧穿孔参数的变化对内折的影响,确定影响内折的主次因素。试验结果表明轧辊转速和升速比对内折缺陷的影响较大,每一个孔型的穿孔延伸系数接近2时内折率最低。

The author reveals the deformation features of continuous cast billet during piercing via rolling block test on the cross rolling piercer. The test proves the existence of walling phenomenon and that the shrinkage cavities inside billet are not oxidized to form infoldings. An orthogonal test is used to study the influence of cross-rolling piercing parameter variation on the infolding and to determine the main and subordinate factors affecting the infolding. The test results show that the roller rotation speed and acceleration speed affect the infolding defect greatly and that the infolding ratio is the lowest when the piercing elongation coefficient of each pass approximates 2.