【作者】 曹伟；

【导师】 王雨；

【作者基本信息】 重庆大学 ， 冶金工程， 2007， 硕士

【摘要】 洁净钢的生产已成为21世纪钢铁材料发展的主流之一,对于大多数企业来说,在现有装备条件下开展各种工艺流程下的钢水洁净度调查和研究,据此优化生产工艺、确定产品发展战略,是比较经济合理的方法。20MnSi螺纹钢是常用的建筑材料,在混凝土材料中起着减震、支撑等作用。本论文以水钢“转炉—吹氩—小方坯连铸”工艺生产20MnSi螺纹钢为基础,对钢水及铸坯洁净度进行了研究,结论如下:①通过过程系统取样,采用大样电解、氧氮分析、金相观测、扫描电镜、电子探针等手段,对现工艺条件下冶炼-连铸过程20MnSi钢水和铸坯的夹杂物行为进行了研究,明确了钢水及铸坯洁净度状况,为优化生产工艺,提高20MnSi钢洁净度提供了依据。②研究表明:吹氩前钢液T[O]为157.73ppm,夹杂量平均为2550mg/10kg钢;吹氩后T[O]和夹杂量分别降低30.77ppm和850mg/10kg钢;中间包浇铸前期T[O]为130.33ppm,夹杂量为579.79mg/10kg钢,浇铸后期T[O]和夹杂量分别增加1.33ppm和53.39mg/10kg钢;铸坯中T[O]为74.79ppm,夹杂量平均为251.88mg/10kg钢。这说明水钢20MnSi与国内外洁净钢生产企业有较大差距,提高其洁净度还有较大的工艺改进空间。③分析表明:影响现工艺下钢水及铸坯洁净度的主要影响因素有脱氧制度、吹氩制度、中间包结构,另外非稳态浇铸时钢包下渣、中包渣吸收夹杂能力差、结晶器卷渣也降低了钢水及铸坯洁净度。生产操作和工艺的波动也是不可忽略的因素。④对影响钢水及铸坯洁净度的因素进行了分析,从改变夹杂物类型的角度和促进夹杂物上浮排除的角度分别对脱氧制度和吹氩制度、中间包结构进行了探讨;同时为避免大包下渣、钢液的二次氧化、结晶器卷渣等也提出建议,为炼钢-连铸的洁净化生产奠定了基础。更多还原

【Abstract】 The manufacture of cleanliness steel has been the developing mainstream of the steel material in 21th century. For most corporations, putting forward the reasonable measures is a feasible way to meet the trend through the producing and technologic researches of typical steel.20MnSi reinforced steel is one of the construction materials in common use, which has the fuctions of damping and sustaining. The cleanliness of 20MnSi produced by the route of converter—ladle furnace—three strands billet caster in Shuicheng steel was studied and the factors affecting the cleanliness were found and discussed.①By sampling in each process, combining large sample electrolysis, oxygen and nitrogen analysis, metallographical observation, SEM and EDS etc, the behavior of inclusions in liquid steel and billet was studied during smelting-casting, and the cleanliness level was educed, which provided proofs to optimize technology and improve the cleanliness of 20MnSi.②Total oxygen contents are 157.73×10-6 and the total amount of the inclusions is 2550mg/10kg of the liquid steel before Ar stirring, 30.77×10-6 and 850mg/10kg decrease respectively after Ar stirring, 103.49×10-6 of liquid steel in tundish with 579.79mg/10kg for prophase, 1.33×10-6 and 53.39mg/10kg decrease respectively for anaphase, 74.79×10-6 T[O] and 251.88mg/10kg of inclusions in billet. The results showed that it had a large distance between 20MnSi in Shuicheng and other developed companies, however, there are improving space for 20MnSi cleanliness.③Through the analysis upwards, the factors mostly affecting the cleanliness of 20MnSi liquid steel and billet were deoxidization system, Ar stiring system, the structure of tundish, and the slags down from ladle during unstable casting period, the low ablity of tundish slags for absorbing inclusions and the entanglement of mould fluxes accounting for the low cleanliness of 20MnSi, the fluctuation of operation and technology during the production could not be ignored.④The factors influenting 20MnSi liquid steel and billet were analysed. The deoxidization system, Ar stiring system and the structure of tundish were discussed for changing the pattern of inclusions and boosting the removement of inclusions apart, and there ware some suggestions for avoiding the slags form ladle, the second oxidization of the liquid steel and the entanglement of mould fluxes, all of these bulit basement of clean steel production for shuicheng steel corporation.更多还原