S355NL耐低温热轧H型钢冲击性能异常的原因分析

Analysis of Unqualified Toughness of S355NL Low Temperature Hot Rolled H Section Steel

针对山钢股份莱芜分公司S355NL级HE800B规格热轧H型钢冲击性能不合的问题进行分析,确定钢中存在的大尺寸含氧化钛夹杂物以及钢中的混晶缺陷组织,为恶化冲击性能的主要原因。通过优化工艺,采用硅钙钡、铝锰铁复合脱氧,提高脱氧效果;通过喂入钛线,提高Ti的微合金化效果作用;通过VN、VFe混合加入减少钢中氮含量。以上措施的实施,有效解决了大型夹杂物以及混晶组织缺陷,提高了产品的冲击性能。

An analysis was conducted on the issue of inadequate impact performance of S355NL grade HE800B hot-rolled H section steel at the Shandong Iron and Steel Co.,Ltd.Laiwu Company.The presence of large-sized inclusions containing titanium oxide and mixed crystal defects in the steel were identified as the main reasons for deteriorating impact performance.By optimizing the process and using silicon calcium barium,aluminum manganese iron composite for deoxidation,the deoxidation effect is improved.By feeding titanium wire,the microalloying effect of Ti is improved.By mixing VN and VFe,the nitrogen content in the steel is reduced,effectively solving large inclusions and mixed crystal structure defects,and improving the impact performance of the product.