大规格Q420B热轧角钢轧制中间道次开裂缺陷分析

 为了解决Q420B大规格角钢热轧过程出现折叠和划伤较多的问题，利用数值模拟的方法对W蝶式孔型的变形特点进行研究，通过对W蝶式孔型第5道次孔型斜度进行优化，大规格角钢生产过程出现的表面质量问题得到了明显的改善。结果表明,W蝶式孔型变形虽然可以用小型钢坯轧出大规格的角钢，但是需要对角钢的侧翼进行多次弯折，表面的金属流动剧烈，易产生表面质量缺陷；利用W蝶式孔型生产22号角钢时，第6道次有出现折叠的倾向，经过孔型工艺优化后，现场划伤和折叠缺陷率明显降低。

Analysis of crack defects in Q420B angle steel #br# during hot rolling process

 In order to solve the problem of more folding and scratching in the hot rolling process of Q420B large size angle steel， the numerical simulation method is used to study the deformation characteristics of W butterfly type. By modifying the hole profile of the fifth pass of the W butterfly type， the surface quality problems in the production process of large size angle steel have been significantly improved. The results show that a larger size of angle steel can be rolled out with a smaller billet by the W pass system，but the angle steel needs to be bent several times for the W pass system. Due to the violent metal flow on the surface，the steel is easy to produce surface quality defects. When the W butterfly pass is used to roll the No.22 angle steel，the fold tends to occur in the sixth pass. After the pass optimization，the rates of scratches and folding defects are obviously reduced.