一种合金焊丝模铸锭中心孔洞的成因和措施

Reason and practices for center hole of steel ingot in alloy welding wire steel

高强度合金焊丝钢广泛用于工程机械行业,具有残余元素低、纯净度高的特点,氢、氧、氮气体元素含量均要求严格,国内该系列焊丝材料主要依赖进口。为了进一步开拓系列高端焊丝钢市场,开发了新型高强度合金焊丝钢。生产过程发现模铸钢锭轧制后探伤不合格,取样发现初轧坯横截面低倍中心出现孔洞缺陷,影响材料质量。通过低倍试验和EPMA分析结合材料成分采用Thermo-Calc软件计算固液相线,分析发现钢种固液线差值相对较小是导致钢锭中心孔洞的主要原因。采用优化钢液浇注过热度和模铸浇注时补缩控制,避免了钢锭中心孔洞缺陷的产生。

The high-strength alloy welding wire steel is used in engineering machinery industry, with low residual elements, high purity. And the hydrogen, oxygen, nitrogen contents were controlled in the high-strength alloy welding wire steel. In China, the supply of wire materials mainly relies on importation. New high-strength alloy steel wire was developed in order to explore the high-wire steel market in the future. During the production process, ingot was found unqualified after rolling, by macroscopic test, finding center hole in that bloom cross-section which affects the quality of materials. By macroscopic test, EPMA and Thermo-Cale calculation model, it was found that main reason for occurrence of ingot center hole is comparatively small difference of solid-liquid phase. By optimization of casting liquid steel superheat and ingot casting pouring feeding control, it avoided the ingot center hole defect in the high-strength alloy welding wire steel.