摘要
大钢锭铸造过程中产生皮下夹渣缺陷的主要因素有热流分布、温度梯度、锭模初始温度和卷渣量等,其中锭模与底盘处的倒角大小是影响热流分布及钢液初期翻滚程度的重要因素。针对某钢厂6.8 t 17CrNiMo6钢锭尾皮下夹渣质量问题,利用ProCAST软件对不同倒角的锭型在凝固过程中温度场和流场的变化规律进行数值模拟,分析影响钢锭质量的因素,对钢锭中可能存在的缺陷及位置进行了预测和验证,并提出了悬挂保护渣和增大倒角的工艺改进方案。研究表明:钢锭倒角处底部优先于钢锭侧壁凝固,其中R=150 mm比R=100 mm晚200 s左右凝固。提高锭模温度到600℃可使钢锭坯壳凝固时间推迟500 s;锭模与底盘处采用倒角连接可减少皮下夹渣,当倒角R=150 mm时,皮下夹杂缺陷率可降低到1.423%。
The entrapped slag problem under skin of the tail steel ingot can be attributed to the distribution of the heat flow and temperature gradient, initial temperature, mold slag entrapment rate and so on. The chamfer between ingot mold and base plate is the main factor that influences the liquid steel flow distribution and initial boiling degree of the large steel ingot. In this paper, Pro CAST software was used to simulate the variation of solidification temperature field and flow field of different mold casting chamfer to improve quality defects under the skin of 6.8 t 17 CrNiMo6 steel ingot in a factory. The possible positions of defects in the ingot, and the factors influencing the liquid steel flow distribution and quality of large steel ingot were forecasted, the process improvement project of hanging slag and enlarging chamfer at the chamfer connection to reduce the slag volume were proposed also. The results show that the bottom solidified prior to the side wall of the chamfer for steel ingot, and the solidified time for chamfer radius of 150 mm was 200 s later than 100 mm. Besides, the solidified shell appearance time could be delayed for 500 s when the mold temperature were improved to 600 ℃. It has revealed that the chamfered end connection between the ingot mold and base plate could reduce the entrapped slag under the ingot skin. As a case, the defect rate of entrapped slag under the ingot skin was reduced to1.423%when the chamfer radius was set as 150 mm.
出处
《铸造》
CAS
CSCD
北大核心
2017年第3期254-257,共4页
Foundry
基金
江苏永钢集团有限公司<钢锭工艺优化及质量控制>横向课题
关键词
模铸钢锭
数值模拟
倒角
夹渣
mold casting ingot
numerical simulation
chamfer
entrapped slag
