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本文叙述了利用放射性同位素示踪原子法对采用绝热板保温帽在上小下大FX7.1型钢锭模中浇注低、中碳钢钢锭的凝固试验,测定出注后20、40、60、70、80、100分钟的凝固曲线.结果表明:在钢锭凝固的初、中期,帽部钢水的凝固速度比钢锭本体为慢,可发挥帽部钢水向本体的填充作用;到钢锭凝固的末期,中碳钢在注后100分钟锭肩口下部出现明显的金属架桥现象,阻碍了帽部钢水向本体的填充,致使在锭中、下部轴心处形成断续的二次缩孔.采用绝热板保温帽在上小下大FX7.1型钢锭模中浇注低、中碳钢,无论钢锭头部的保温效果如何改善,都不能从根本上消除二次缩孔.论文根据钢锭的凝固曲线,阐述了绝热板钢锭的凝固机理,并提出了上小下大模型浇注镇静钢要降低高宽比和锥度,同时提高绝热板、保温剂的绝热性能,才有利于改善绝热板钢锭的质量.本试验证明,以酚醛树脂做结合剂的绝热板比以纸浆做结合剂的绝热板保温效果好,可在生产中推广使用.
This paper describes the use of radioactive isotope tracer atomic method of insulation panels with insulation panels in the small big under the big FX7.1 steel ingot casting low carbon steel ingot solidification test determined after the injection of 20,40,60,70 , 80 and 100 min.The results show that the solidification rate of the molten steel in the cap is slower than that of the ingot in the initial and intermediate stages of solidification of the ingot and the filling of the molten steel in the cap can be performed to the body. Carbon steel 100 minutes after the note ingot shoulder mouth under the obvious metal bridging phenomenon, hinder the cap to fill the body of molten steel, resulting in the spindle, the lower axis of the formation of intermittent secondary shrinkage. Adopting insulation board insulation The cap can not eliminate the secondary shrinkage cavities fundamentally, no matter how the heat preservation effect of the head of the ingot is improved, the pouring of low and medium carbon steel in the big small-size FX7.1 ingot mold can not eliminate the secondary shrinkage cavities fundamentally.According to the solidification curve of ingot, The solidification mechanism of ingot ingot and the proposed small and large mold casting cast steel to reduce the aspect ratio and taper, while improving the insulation board, insulation agent of the insulation properties, it is conducive to improving the quality of ingot ingot .This test proved , With phenolic tree Binding agents do better than the heat insulating plate binding agent to the pulp to make insulation panel insulation effect, promote the use of in production.