为了分析氧化物冶金钢中不同类型夹杂物的形核能力及其对大线能量焊接性能的提升效果，对TiCa、TiMg试验钢进行了模拟焊接热循环并利用氧化物冶金技术实现了不同钢种的工业化生产。结果表明，在1 400 ℃峰值温度等温30 s后，TiMg复合夹杂物可有效钉扎奥氏体晶界移动，并在后续冷却过程中作为形核质点诱导针状铁素体形核。为了保持氧化物冶金技术所需的氧含量，建立了转炉SiMn预脱氧加TiMg脱氧的优化工艺路线。采用新技术冶炼的钢种具有200 kJ/cm气电立焊性能。-40 ℃下HAZ冲击韧性达到200 J，焊接接头内观察到大量针状铁素体板条组织。

In order to analyze the nucleation ability and different kinds of inclusions in oxide metallurgy steel and its effect on the improvement of high heat input welding properties，simulated welding thermal cycle on TiCa and TiMg steels were executed and industrial production by oxide metallurgy has been carried out. It was showed that the movement of austenite grain boundaries was retarded by TiMg oxides at 1 400 ℃ and held for 30 s. Acicular ferrites were also induced at cooling process. In order to keep the oxygen content of oxide metallurgy technology， SiMn predeoxidation and TiMg deoxidation process was built. EH420 experimental steel produced by new process with excellent welding ability， which can bear heat input of 200 kJ/cm by electrogas welding. Impact energy of HAZ at -40 ℃ was 200 J and numerous acicular ferrite plates were formed in the welded joint.