酸溶铝在ML08A1钢中行为的研究

对ML08AI钢中酸溶铝的行为进行了分析，探讨了酸溶铝对夹杂物和钢材性能的影响，认为在生产此钢种时，应有效提高钢的纯净度，控制钢中全铝含量在0．03％～0．06％，酸溶铝与总铝的比值不小于95％。     

Electrode reactions in dc electroslag remelting of steel rod

Abstract

The non-metallic inclusion content increased significantly when a steel rod of Fe-Ni was remelted by dc electroslag remelting. The silicon content increased slightly. The manganese and sulphur contents did not change. The total aluminium content in the ingot was max. 0·7%, while that in the electrode was only 10 ppm. The aluminium cations Al³+ in the slag are reduced to metallic aluminium at the slag/electrode interface, while O² - anions are oxidised to dissolved O in the metal pool. This Al and O subsequently recombine to form alumina inclusions in the metal pool. The inclusion content was dependent on the alumina content in the slag. When a rod of plain carbon steel was remelted, however, the increase in nonmetallic inclusion content was as little as one-tenth of that for the remelted Fe-Ni rod. The non-metallic inclusion content was independent of the polarity of the electrode.     

The influence of aluminium deoxidation and sulphur content on oxide modification and machinability of steel

The influence of Al-deoxidation and various amounts of sulphur on Ca-treated steel has been investigated. The effect of sulphur ar aluminium on the modification of oxide inclusions has been reasoned by theoretical thermodynamic equilibrium analysis. The type inclusion formed depends on the aluminium and sulphur contents. For complete oxide shape control in which CaO-rich inclusions forr the sulphur content must be relatively low for Al-killed steel. The oxide inclusion type of the experiments was in surprisingly goc agreement with the prediction of thermodynamics. The influence of calcium and sulphur on the machinability and mechanical properties has also been demonstrated as well as the improvement of isotropy in steel obtained by Ca-addition.     

电弧炉炼钢硅钡合金脱氧剂的作用

生产实践表明，电弧炉炼钢利用BaSi合金代替部分Al作为脱氧剂能有效地降低合金结构钢和弹簧钢[Als]含量，可提高其表面质量和减少轴承钢点状废品。     

无取向电工钢中酸溶铝含量对夹杂物的影响

 为提高无取向电工钢成品性能及优化生产,采用SEM-EDS等分析方法分别对比分析了无取向电工钢生产时,不同酸溶铝含量的生产工艺对钢中夹杂物的影响。研究表明,当钢中酸溶铝含量w(Als)为0.2%～0.4%时,精炼过程所生成的夹杂物为高熔点的Al2O3和球状的MgO-Al2O3类夹杂物;当钢中w(Als)小于0.005%时,精炼过程所生成的夹杂物主要为塑性硅铝锰酸盐类夹杂;各工位夹杂物平均数量呈递减的趋势,且w(Als)为02%～0.4%的高碱度渣系控制生成的夹杂物总量低于后者。     

超低碳钢夹杂物控制技术探讨

本文综述了超低碳钢的夹杂物起源,并以日本等先进钢厂的实践经验为基础,对Al2O3夹杂物的产生的工艺过程、影响因素重点进行了讨论,包括渣钢间二次氧化行为、RH处理中夹杂物行为、夹杂物的上浮行为以及铸坯的皮下气泡等.钢包渣改质是控制二次氧化的重要手段,RH加铝前自由氧含量尽可能降低,将浇铸时的氩气量降低均为控制超低碳钢的Al2O3类夹杂物的有效措施.     

生产硅钙、硅钙钡系列合金杂质的控制与精炼

介绍了Ba-Ca．Si、Ca-Si系列合金在冶炼时对各种杂质C、S、P、Al、夹杂、夹渣的控制及Ba-Ca．Si、Ca-Si合金的炉外精炼的原理、精炼方法、操作、效果介绍。指出杂质的控制与精炼是生产纯净铁合金的必然选择。     

稀土合金包芯线代替铝条在沸腾钢生产中的应用研究

利用稀土对氧和硫有强亲和力的特性，结合包钢生产的Ｑ_（２３５Ｆ）、Ｈ_（０８Ａ（Ｅ））二个钢种，用稀土合金包芯线代替铝条，进行两次工业试验研究，观察其制止沸腾钢“上呕”的作用，取得与刺铝相似的效果。检验分析数据表明，在低倍组织、力学性能、夹杂形状等方面，刺稀土合金包芯线轧坯优于中注管刺铝轧坯。     

Optimisation of Inclusion Chemistry by Improved Steel Cleanliness and Optimum Calcium Treatment

SMSII, Bokaro Steel Plant produces ~ 2.0 million tons of low carbon aluminium killed (LCAK) steels per annum. Calcium treatment is done regularly at the end of ladle treatment to avoid clogging of submerged entry nozzles (SEN). With calcium consumption of 0.23 kg/t, inconsistent calcium in steel, SEN clogging and slide gate erosions were reported. Nozzle clogging during casting of LCAK steels was primarily caused by deposition of complex oxide and sulfide inclusions and slide gate erosion by excess calcium in steel. Optimum calcium in steel was essential to achieve desired inclusion composition conducive to smooth casting and eliminate slide gate or SEN erosion effectively. With calcium consumption of 0.12kg/ton optimum calcium content in steel could be achieved through i) improved steel cleanliness, ii) restricted CaS formation and iii) optimum aluminium content in steel. Process optimisation resulted in reduction in aluminium consumption by 1.0 kg/t and improvement in steel cleanliness with consistent total oxygen level of ≤ 42 ppm. Desired inclusion characteristics conducive to longer sequence length was achieved and evidenced through EPMA. Erosion of slide gate plates could be eliminated completely.     

铝型材常温封孔技术及维护管理

从铝型材的封孔机理出发，说明了封孔槽液中的Ni^2 浓度，F^-浓度，pH值，温度以及杂质等因素对铝材封孔质量的影响，并提出了在实际生产中槽液维护和管理的具体措施，对提高型材质量，减少成本和提高经济效益有一定的意义。     

Steel Cleanliness during Secondary Metallurgy of High‐grade Quality Electric Steels

A statistical analysis is carried out of the influence of process parameters on the total oxygen content of high‐grade quality electric steels in the ladle furnace station. Furthermore, the micro‐inclusions are microscopically investigated. The results show that total oxygen content (O_tot) and inclusion type are affected by degradation of the magnesite ladle lining and aluminium addition during tapping.     

铝脱氧钢中尖晶石夹杂物的生成与转变

研究了140 t LD-LF-RH-CC流程冶炼超低氧钢时精炼过程铝脱氧钢中夹杂物的变化。试验钢出钢过程加足够的铝脱氧,以尽快降低钢液中溶解氧。为使Al₂O₃转变为钙铝酸盐夹杂,选用CaO-Al₂O₃精炼渣系,渣中含3.00%～8.42%SiO₂。结果表明,精炼时钢液中夹杂物的变化趋势为:纯Al₂O₃→尖晶石夹杂→CaO-Al₂O₃-MgO复合夹杂物,炉渣中8.42%SiO₂炉次夹杂物转变慢于3.00%SiO₂炉次;当炉渣CaO/Al₂O₃为1.60时,钢中夹杂物大多转变为低熔点CaO-Al₂O₃-MgO复合夹杂。精炼渣的成分控制应为(%):55～60CaO,35～40Al₂O₃, 5～10MgO。     

Evolution of the distribution function of the composition of oxide inclusions for the growth model of a disperse system formed during deoxidation

The growth model for nuclei of oxide inclusions growing during the process of steel deoxidation is proposed. The evolution of the inclusion composition has been analysed by solving the continuity equation for the probability-density function f(x,t) (where x is the oxide mole fraction). The calculations were carried out for model parameters and for steel deoxidation by aluminium or silicon-manganese. The result obtained cannot be verified due to the lack of any functional dependence relating chemical composition to inclusion radius.     

利用高频磁场连续分离铝熔体中夹杂物的理论分析

分析了高频磁场作用下铝熔体连续处理时夹杂的去除效率。计算结果表明，夹杂去除效率随管径的增大而降低，而随夹杂平均停留时间的延长以及磁感应强度有效值的增加而增加。提高去除效率的有效途径是增大磁感应强度或降低分离器管径，但减小管径的同时需要相应地提高磁场频率。     

涟钢HMPT—BOF—RH—CSP单联法生产DQ级钢工艺实践

介绍了涟钢HMPT—BOF—RH—CSP工艺路线生产DQ级钢的实践情况。通过对现场数据的采集和分析,着重对钢中碳质量分数、氧质量分数、硫质量分数、w（Als）等参数以及温度、钢水可浇性的控制情况进行了分析讨论,并就该工艺过程中所存在的增碳、温降过大、回硫、钢中夹杂含量过高等问题提出了改进性建议,指出加强对铁水脱硫扒渣工艺的管理、提高转炉控制水平、优化RH精炼工艺、采用无碳钢包及低碳覆盖剂等是进一步提高该工艺控制水平的重要途径。     

90 t钢包喂丝的工艺实践

总结了以LD-LF(WF)-CC生产流程生产20、34Mn6、BTN/1等钢时,在90 t钢包中以2.4~3.0m/min的喂丝速度喂硅钙线(Φ13 mm)和铝线的工艺实践。工艺实践表明,当喂入钙量达200×10^-6时,钢中残余钙含量至最大值35×10^-6,钙处理时钢水平均脱氧率为25%,钢中夹杂物数量明显减少并使钢中夹杂物变性;当钢包喂铝线时,随喂丝速度由1.5 m/s提高至3.0 m/s时,铝的回收率由25%提高至70%。一般铝的收得率为60%~70%,CaSi的收得率为15%~20%。     

150t 顶底复吹转炉-150 t钢包炉生产60Si2Mn(A) 弹簧钢的 工艺和质量

采用150 t顶底复吹转炉-150 t LF精炼(加铝1．2 kg／t、钡合金1．0 kg／t、Ar气搅拌、喂SiCa线)-165 mm×165 mm方坯连铸机生产60Si2Mn(A)弹簧钢。LF末期钢中氧含量为(15～25)×10^-6,残余铝含量0．020％-0．030％。铸坯的低倍组织、二次枝晶间距和电解夹杂物分析结果表明,铸坯的组织致密;钢中大部分夹杂物为尺寸≤20μm的颗粒状SiO₂、球形(Mn,Fe)O·SiO₂和MnS,说明钡合金的使用,有利于降低钢中氧含量和改变夹杂物的形态。     

Inclusion characterisation for clean steelmaking and quality control

Abstract

Improving steelmaking and casting processes to adapt to the requirements of internal and external customers involves continuous monitoring and evaluation of existing and development of new steel refining practices. Internal quality control of semifinished products requires tools that can correlate product defects to process anomalies. This article focuses on use of techniques such as measurement of complete steel and slag chemistry, inclusion analysis, process analysis and thermodynamics to assess the influence of process conditions on product properties. Examples from both long and flat products, including low carbon aluminium killed steels, medium carbon aluminium killed steels, advanced high strength steels and free machining steels, are presented to explain the benefit of using these tools to understand the process conditions necessary for clean steelmaking and thus improve product quality.     

铝镇静冷镦钢纯净度的控制

邢钢在生产含Al 0.03%～0.06%铝镇静钢的实践中,通过控制精炼渣渣系、钢水搅拌和钢液钙处理等夹杂物控制技术,将Al2O3夹杂物变性为Ca/Al=0.9～1.3的低熔点钙铝酸盐夹杂物,改善了钢水的浇注性,提高了钢水纯净度,线材T[O]≤2.5×10-5.     

Modification of oxide inclusions in calcium-treated Al-killed high sulphur steels

A study has been carried out to understand the modification of alumina inclusions in Al-killed high sulphur steel with calcium treatment. For calcium treatment to be effective, a general practice is to desulphurise the steel to prevent the formation of solid CaS inclusions that are harmful to steel quality and final properties. To avoid this additional desulphurising step, the authors developed a new approach of calcium treatment of steel at an industrial scale. This approach involves treating the liquid steel with calcium treatment at low aluminium levels which enables formation of liquid calcium aluminate inclusions (C12A7) in the melt and then adding remaining amount of required aluminium. Based on this principle, Al-S diagram has been developed and calcium treatment has been modified accordingly. The inclusion transformation and morphology were studied using scanning electron microscope /energy dispersive spectroscopy analysis and. activity of CaS was calculated.