【作者】 王洪利；

【导师】 王硕明；

【作者基本信息】 河北理工大学 ， 钢铁冶金， 2005， 硕士

【摘要】 轴承钢应具有高的强度、良好的韧性、抗疲劳性能、抗断裂特性和耐腐蚀性能,同时还要求力学性能的改善不应当恶化钢的焊接性能和加工性能。钢中非金属夹杂物的类型、数量、尺寸及分布对轴承钢力学性能和使用性能的影响很大。针对石钢转炉炼钢厂冶炼GCr15 轴承钢的铁水预脱硫—BOF-LF-VD-CC 现行工艺与条件,采取示踪剂追踪、系统取样、综合分析等手段对轴承钢生产过程中非金属夹杂物类型、来源、数量及分布进行了全面研究。研究表明:（1） 石钢转炉炼钢厂GCr15 轴承钢铸坯中T[O]的平均值为9.3×10^-6,显微夹杂物2.72/mm²,体积率为0.31%,大型夹杂物数量为1.5mg/10kg,达到较高的洁净度水平;（2） LF 处理后钢水中显微氧化物夹杂主要为球状的铬钙酸盐、铬硅酸盐、条状的铬锰酸盐,并成为铸坯中的主要夹杂物;（3） 示踪剂分析表明,铸坯中的显微夹杂物主要来源于中间包液面中间包覆盖剂的污染,其次是结晶器液面保护渣和钢包渣的污染;（4）示踪剂分析表明,铸坯中大型夹杂物主要来源于结晶器液面保护渣的污染,其次是中间包液面中间包覆盖剂及钢包渣的污染,可以检测到钢包渣的影响,但影响较小;（5） 非稳态（开浇、换钢包、浇尾坯）浇铸对钢水的洁净度影响非常显著,如何改善非稳态浇注时期铸坯的洁净度也是提高轴承钢整体质量的关键。利用数学模型系统研究了LF 吹氩过程中钢液的流动行为,确定了最佳的钢包吹氩位置以及适宜的吹氩气量,改善了钢包结构,优化了钢液流动状态,为连铸工序提供具有理想温度和成分的钢水奠定了技术基础。通过对冶炼工艺、相应渣样和铸坯样进行多项分析,系统地研究了夹杂物在铸坯中的分布规律、夹杂物的成因和影响因素,为减少夹杂物提出了合理化的建议。同时,经过优化的钢包流场为夹杂物的充分上浮提供了良好的条件。更多还原

【Abstract】 Bearings steel have not only high strength and good toughness, but also haveresistances to fatigue and corrosion. At the same time, the weld ability and mach inabilityperformance of the steel must not be worsened by the improvement of the mechanical. Theamounts, dimensions and distributions of nonmetallic inclusions have great impact onbearings steel.By way of tracer addition,system sampling,synthetic analysis, study on theamounts,dimensions and distributions of nonmetallic inclusions during the productionprocess and conditions of BOF—LF—VD—CC bearing steel at the BOF steel makingworkshop of SISCO, it is found that : （1） The total oxygen conteut of slab is 9.3×10^-6with the number of the micro inclusions 2.72/mm²,the conclusion volume 0.31percentum and the macro inclusions 1.5mg /10kg,it is high level in cleanliness. （2）Microscopic oxide inclusions in the steel appear to be global silicate inclusions and singlecalcium inclusions after LF furnace,therefore they become the main inclusions in thesteel of slab. （3） It is demonstrated by analyzing the tracer that the micro inclusions in slabmainly come from the the turdish cover material, secondly mold flux and molten steelcontainer cinders. （4） It is demonstrated by analyzing the tracer that the macro inclusionsin slab mainly come from the mold flux, secondly the turdish cover material and moltensteel container cinders. （5） Unsteady casting plays an important role in the cleanliness ofthe steel. How to improve the cleanliness of steel during unsteady state casting plays acrucial part in the whole quality of bearing steel.By way of mathematics model systemic research the flow actions of steel liquid theblowing AR and in LF,which we can find out the best blowing Ar position and fittingamount of blowing Ar. Through these measures,which can improve the frame of moltensteel container and optimize the flowing state of steel liquid,so we can produce perfecttemperature and ingredient steel liquid for CC process.We put forward lots of rationalization suggestions for reducing the inclusions throughresearching the inclusions distribution rules,causing of formation and influencing factorsin slab by way of analysing the smelt techniques,homologize cinders and casting slab. Atthe same time, these measures will provide a good condititos for reducing the amount ofinclusions.更多还原