一、前言武钢第二炼钢厂连铸生产线自1978年投产后,在产品质量方面,一直存在严重的铸坯中心裂纹缺陷,有个别月的中心裂纹废达2000余吨,占坯产量的3％左右。1984年全年中心裂纹废为13362吨,占当年产量的1.05％,中心裂纹废占铸坯废的60.3％,为铸坯废之首。这样,严重地影响了产品质量和经济效益的提高,造成了很大的浪费。为了解决这一问题,武钢公司于1980～1982年、1985～1986年分两次组织人员进行了攻关。经过几年的工作,于1986年取得了全面的成功,中心裂纹得到了有效的控制。现就此方面情况叙述如下。二、中心裂纹的形态及对成品质量的影响 1.中心裂纹的形态连铸坯中心裂纹是一种存在于铸坯横断面中心部位、呈锯齿状的肉眼可见的开口裂纹,它一般在铸坯内呈不连续的岛状分布,如图1所示。图2所示系超声波探伤中心裂纹坯的典型例子,涂有白铅油的部分为中心 I. Introduction WISCO No.2 Continuous Casting Production Line of Steelworks has been put into operation since 1978. In terms of product quality, there have been serious cracks in the center of the billet. There are some 2,000 tons of cracked center cracks in a month, accounting for 3 %about. In the whole year of 1984, 13,362 tons of cracks were cracked at the center, accounting for 1.05% of the total output of the year. The central cracked scrap accounted for 60.3% of the slab scrap, which was the first of the slab scrap. This has seriously affected the improvement of product quality and economic benefits, resulting in a great waste. In order to solve this problem, Wuhan Iron and Steel Company in 1980 ~ 1982, 1985 ~ 1986 organized two personnel to tackle the problem. After several years of work, it achieved overall success in 1986, and crack control in the center was effectively controlled. The situation in this respect is described below. Second, the shape of the center of the crack and the impact on the quality of the finished product 1. The shape of the central crack Billet central crack is a kind of existence exists in the center of the cross-section of the slab, jagged macroscopic open crack, it is generally in the slab Within the discontinuous island-like distribution, shown in Figure 1. Figure 2 shows a typical example of a cracked center of an ultrasonic testing center, the part coated with white lead oil as the center