轴承钢大尺寸夹杂物的来源分析及其应对策略

Source Analysis and Prevention Strategies of Large-Size Inclusions in Bearing Steels

对轴承钢中出现的3种非典型的大尺寸夹杂物进行了定性分析并确定了其来源。转炉钢被发现有直径超过50μm的合金铬铁夹杂物,系精炼阶段补加的合金剂铬铁未完全熔融所致;转炉钢还被发现有带尖角的大尺寸SiC夹杂物,系临时调整精炼渣系时所加入的SiC造渣料未完全熔融并卷入钢液所致。稀土深脱氧电炉钢中发现点链状、长度近900μm的聚集态稀土氧硫化物,其来源为连铸中间包水口结瘤物。根据分析结果,分别对转炉钢和电炉钢提出了应对大尺寸夹杂物的策略。

Three typical large-size inclusions in bearing steel were qualitatively analyzed and their sources were determined.A ferrochrome inclusion with a diameter of more than 50μm was found in BOF steel,which is caused by the incomplete melting of the alloy ferrochrome added in the refining stage.A large-size SiC inclusion with sharp corners was found in BOF steel,which is caused by the SiC slagging material added during the temporary adjustment of the refining slag system that was not completely melted and involved in the molten steel.A point-chain-like aggregated rare earth oxysulfide with a length of nearly 900μm was found in the RE deep deoxidized EAF steel,and its source is the nodules at the nozzle of the continuous casting tundish.According to the analysis results,strategies for dealing with large-size inclusions were proposed for BOF steel and EAF furnace steel respectively.