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脱方是小方坯连铸常见的质量缺陷,一般认为结晶器磨损严重,钢水在结晶器内冷却不均匀,以及二冷喷嘴状况不佳,二次冷却不均匀等是脱方的主要原因。分析了新疆八一钢铁股份有限公司(以下简称八钢)第一炼钢厂2号连铸机HRB335钢连铸坯脱方的成因:一是HRB335钢水过热度较高,相比过热度较低的HPB235,其坯壳厚度比HPB235的薄,坯壳厚度越薄,出结晶器后液芯长度较长,铸坯就容易变形,出现脱方的概率越大。二是喷淋管不能满足均匀冷却的要求,增大铸坯脱方概率。应对措施:增大二次冷却强度,将HRB335钢的比给水量由1.73 L/kg增加到1.83 L/kg;侧弧喷淋管支管长度由172 mm缩短到127 mm。采取上述措施后,脱方废品率大幅下降。同时,对脱方量在允差范围内的小方坯,采用控制轧制,结果表明:通过控制轧制可以对脱方较轻钢坯进行纠正。
Squared off is a common quality defects of continuous casting billet, the mold is generally considered serious wear and tear, molten steel cooling in the mold uneven, and the second cooling nozzle is not good, secondary cooling is the main reason for the uneven off. The causes of the striping of HRB335 steel continuous casting billet of No. 2 continuous casting machine at No. 1 Steel Plant of Xinjiang Bayi Iron & Steel Co., Ltd. (hereinafter referred to as Bayi Iron & Steel Co., Ltd.) were analyzed: firstly HRB335 steel had higher degree of superheating than low degree of superheat Of the HPB235, the thickness of its billet HPB235 thinner, the thinner the thickness of the shell, out of the mold longer after the liquid core, the billet is easy to deformation, the greater the probability of off-side. Second, the spray pipe can not meet the requirements of uniform cooling, increasing the probability of casting off square. Countermeasures: Increasing the secondary cooling strength, increasing the specific water supply of HRB335 steel from 1.73 L / kg to 1.83 L / kg; the length of the branch pipe of side arc sprinkler pipe shorten from 172 mm to 127 mm. Take the above measures, tripartite rejection rate dropped significantly. At the same time, the controlled rolling of the billet with the off-square within the allowable deviation shows that the lighter steel strip can be corrected by controlled rolling.