特厚板尾部面积缺陷的成因分析

Property and cause analysis for tail area defect of ultra-heavy plate

研究了钢锭成材特厚板的尾部超声探伤缺陷的性质，介绍了模铸法生产大钢锭过程中，炉外精炼工艺、浇铸工艺以及浇铸用辅助材料对大钢锭内部质量的影响。通过对模铸用辅助材料、成品样及汤道样的能谱及化学分析可知，尾部面积缺陷的主要来源应该是钢液中的脱氧产物Al2O3以及少量没有被渣料吸附的复合化合物。针对缺陷的形成原因，制定了有效的改进措施，每月探伤的钢板尾部面积缺陷发生率由1．25％～2．25％降低到0．38％，最高降低幅度达到83．11％。

The properties of tail ultrasonic flaw detection of ultra-heavy plate made fromingot were studied. The influences of refining process, casting process and accessorymaterial for casting on internal quality of heavy ingot were discussed. The resultsshowed that the existence of deoxidizing product Al2O3 and a little amount of compositecompounds in liquid steel were the main reason of tail area defect. Improving measureswere put forward according to the reason of forming defects. The occurrence rate of tailarea defect of steel plate during monthly flaw detection was decreased from 1.25 %2. 25 % to 0. 38 % and the highest decreasing ratio reached 83.11%.