基于夹杂物控制工艺的Q235B热轧板失效机理及优化研究

Investigation on the Failure Mechanism of Q235B Hot Rolled Plate and Process Optimization Based on Inclusion Control

本文采用宏观观察、金相分析、扫描电镜分析等方法,对Q235B热轧板加工零件的失效机理进行系统分析。实验结果表明,材料中存在较多夹杂物,是造成零件开裂缺陷的主要原因,材料内部不存在偏析的组织缺陷问题。获得了控制工艺参数对夹杂物产生和分布的影响规律并进行了工艺优化,包括降低转炉炼钢终点氧含量、改进脱氧顺序、改进顶渣改质工艺、改进吹氩工艺、延长静置时间、减少吹氧升温比率、连铸保护浇铸和中间包加覆盖剂等。实际生产数据表明,改进后的产品质量显著提升,夹杂缺陷返修率降为零;通过对改进后铸坯取样分析,炼钢铸坯夹杂物控制水平有显著提高。

This article systematically analyzes the failure mechanism of Q235B hot-rolled plate machined parts using methods such as macroscopic observation,metallographic analysis,and scanning electron microscopy analysis.The experimental results indicate that there are many inclusions in the material,which are the main cause of cracking defects in the parts.There is no segregation in the internal structure of the material.The influence of process parameters on the generation and distribution of inclusions was obtained,and process optimization was carried out,including reducing the oxygen content at the endpoint of converter steel-making,improving the deoxidation sequence,improving the top slag upgrading process,improving the argon blowing process,extending the standing time,reducing the oxygen blowing heating ratio,continuous casting protection casting,and adding a covering agent to the tundish.Actual production data shows that the improved product quality has significantly improved,and the repair rate of inclusions and defects has decreased to zero.Through sampling and analysis of the improved billet,the inclusions control in steel-making billets has significantly improved.