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安钢第一炼轧厂方坯结晶器铜管过钢量超万t安阳钢铁股份公司第一炼轧厂组织技术力量对方坯连铸机结晶器进行了革新改造,取得明显成效。2006年一季度,结晶器铜管平均过钢量比去年提高3530t/支,最高达10866t/支。该厂方坯连铸机结晶器原由ABB公司专为结晶器电磁搅拌器配套使用。随着生产节奏加快,受设计限制,结晶器平均连拉3000t左右就需更换铜管,成为制约作业率和连拉炉数的主要因素。为发挥铸机生产潜力,对结晶器总成结构进行大胆改造;对进、回水箱容积进行优化,扩大回水箱容积和进、回水管径,提高了结晶器冷却水流量和流速。在水套法兰上…     

方坯结晶器铜管三维温度场与热应力的分析

在对小方坯结晶器钢管内热流传递理论的基础上,研究了钢坯及结晶器内温度的传递规律。利用有限元法对结晶器钢管的温度场及热应力场进行了系统研究,并对不同拉速、冷却强及设计锥度的条件下铜管的温度场和热应力场进行了研究。提出了预应力结晶器设计的理论基础,提高连铸机的拉速及改善铸坯的质量,为实际生产提供了一定的理论指导。     

薄板坯连铸机结晶器的主要特点及其技术进步

介绍了薄板坯和中薄板坯连铸机结晶器的形状和主要特点,对比分析了不同类型结晶器内钢液的表面积、钢液流动、结晶器传热、薄板坯厚度、拉坯速度等对连铸过程和铸坯性能的影响,讨论了鞍钢ASP采用的先进技术,指出近年来新建和改造的薄板坯连铸机结晶器厚度呈现增加的趋势,从而解决了设备运行的一些问题,改善了铸坯的品种质量.     

弧形半径不同的连铸机结晶器铜管统一互换的研究

对弧形连铸机结晶器铜管圆弧半径的公差进行了探讨和计算，得出了孤形半径差异不大的连铸机在生产相同规格铸坯时，结晶器铜管可实现统一互换的结论。经生产实践验证，效果良好。     

连铸Φ600mm大圆坯结晶器锥度设计

在连铸过程中,结晶器锥度对提高连铸机的产量,改善铸坯的质量,延长结晶器的寿命都起着决定性的作用。采用有限元方法计算了Φ600 mm大圆坯连铸过程铸坯的温度收缩、结晶器内温度分布及变形,并通过结晶器的内腔尺寸计算出圆坯结晶器锥度。结果表明:铸坯尺寸越大,结晶器长度应适量减小;如果采用双锥度,从弯月面到弯月面以下200 mm,结晶器锥度为2.33%/m,从弯月面下200 mm到结晶器出口锥度为0.78%/m;如果采用连续变化的锥度,锥度从最大的2.89%/m到最小值0.14%/m呈线性连续变化。     

高效连铸小方坯喷淋结晶器应用实践

喷淋结晶器利用喷嘴将高压水喷到铜管表面使之强化冷却,通过控制冷却强度分布,提高弯月面区冷却强度,增加铸坯初凝坯壳厚度,避免铸坯菱变、角裂,降低漏钢率,同时实现喷淋冷却强度均衡,提高了冷却效率,比水缝式结晶器提高连铸机拉坯速度10%。     

连铸大断面矩形坯管式结晶器关键技术及应用

通过分析连铸大断面矩形坯管式结晶器特点,对结晶器特性参数、冷却参数和足辊结构关键技术优化设计,提高结晶器铜管使用寿命,避免铸坯鼓肚和漏钢,提高连铸坯质量。     

特钢φ800mm特大圆坯连铸机的新技术

介绍了由中冶赛迪工程技术股份有限公司承建的某特钢800 mm特大圆坯连铸机,及该连铸机采用的新型辊列设计、机头快换装置、结晶器与扇形段1自动对中装置、FEMS位置无级调节装置、拉矫机热坯压力调节模式、拉矫机快换装置、引锭杆低位存放装置等新技术。该机生产的钢种、拉速、铸坯内部质量等效果,验证了该连铸机工艺、装备的合理性、先进性。     

芜湖新兴铸管方圆坯连铸机热试成功

正2016年3月21日,芜湖新兴铸管三山炼钢4#连铸机热负荷试车一次成功。该连铸机为R17米弧形连续矫直4机4流方圆坯连铸机,实现了大圆坯与大方坯的共线生产,其中核心设备结晶器液压振动装置和拉矫机为中冶京诚具有完全自主知识产权的专利产品。该连铸机工艺和装备技术水平的可靠性、先进性和稳定性能满足新兴铸管对高品质钢种的生产要求,走在国内外同类企业前列。芜湖新兴铸管前身是1958年建厂的芜湖钢铁厂。2003     

板坯生产事故分析

通过对板坯连铸机生产过程中出现的塞棒失控、中间包包盖掉料、浸入式水口穿钢、结晶器液面翻钢等问题跟踪研究与分析,从技术和管理角度制定了解决措施,使板坯连铸机生产稳定顺行,铸坯质量不断得到提高。     

7号连铸机的NKK液位PID控制参数及结晶器流场优化

本钢三连铸的单流宽板坯连铸机从达涅利公司引进,于2008年12月4日建成投产,结晶器液位控制采用NKK技术。介绍了7号连铸机生产超低碳钢过程中,结晶器液位出现不稳定性波浪的原因,并通过改进NKK液位控制工艺,微调PID控制参数,以及优化结晶器流场等措施,提高了宽幅汽车板生产时的结晶器液位控制精度,并且解决和消除了不稳定型波浪的问题,使宽幅汽车板的轧制成材率大幅提升。     

微合金化钢连铸坯边角部无缺陷生产技术开发

以邯宝炼钢厂板坯连铸机为依托,以实际生产的典型铌、钒、钛微合金化钢为研究对象,系统研究了板坯表面裂纹缺陷形成机理,确定了倒角结晶器窄边铜板的最佳角度和最佳倒角长度;设计并开发了具有组合式冷却水道的倒角结晶器窄面铜板,适用于带倒角连铸坯的新型支撑足辊系统;结晶器窄侧锥度的设计及应用管理,有效支撑了带倒角连铸坯的窄边,解决了角纵裂及角纵裂漏钢的难题,提高了结晶器窄边铜板的使用寿命,同时为连铸的高拉速提供了保证。项目突破了倒角结晶器技术工业化应用的技术瓶颈,从根本上解决了微合金化钢连铸板坯角部横裂纹问题,成功实现了大规模工业化稳定生产。     

降低CSP薄板坯连铸机漏钢率的生产实践

结合邯钢CSP生产实践,对CSP连铸机漏钢原因进行了分析并提出了预防措施。生产实践表明,通过加强中间包及结晶器的准备工作,提高开浇操作水平,可有效减少开浇漏钢。通过优化钢水成分,提高钢水纯净度,优化保护渣性能,加强结晶器铜板表面质量的检查,提高格栅表面质量,提高水口材质,保持结晶器合适的锥度,控制结晶器热流比及拉速,可有效减少浇注过程中的漏钢事故。     

连铸新方法的探索

阐述目前采用结晶器振动的连铸生产方式的局限性和其存在的问题,分析了铸坯的缺陷种类和其产生的原因。介绍新开发的非振动式结晶器的原理及其优越性,介绍了如何用非振动式结晶器生产高质量的圆坯、大圆坯及中空管坯的方法。     

Refinement of primary carbides in AISI DC 53 cold work tool steel by thin section copper permanent mould casting and water atomization

In this study, as alternative methods to conventional production methods involving thin section copper permanent mould casting (fast solidification) and water atomization (rapid solidification) of AISI DC 53 cold work tool steel have been investigated. Thin slabs obtained by copper mould casting was homogenized at 1150 °C for one hour and then hot rolling was be applied. After hot rolling, conventional heat treatment have been applied to thin slabs. The same heat treatment procedure have been performed for a commercially available AISI DC 53 which is manufactured by thick section ingot casting and rolling. In order to investigate also the effect of rapid solidification on AISI DC 53 tool steel, steel powder was produced by water atomization technique. Experiments have revealed that thin steel slabs in permanent copper mould and rapidly solidified tool steel powder by water atomization have a more refined primary M₇C₃ carbides than commercially available steel.     

Casting/mould interfacial heat transfer during solidification in graphite,steel and graphite lined steel moulds

Heat flow between the casting and the mould during solidification of three commercially pure metals, in graphite, steel and graphite lined steel moulds, was assessed using an inverse modelling technique. The analysis yielded the interfacial heat flux (q), heat transfer coefficient (h) and the surface temperatures of the casting and the mould during solidification of the casting. The peak heat flux was incorporated as a dimensionless number and modeled as a function of the thermal diffusivities of the casting and the mould materials. Heat flux transients were normalised with respect to the peak heat flux and modeled as a function of time. The heat flux model proposed was used to estimate the heat flux transients during solidification in graphite lined copper composite moulds.     

低碳低硅铝镇静钢铸坯表面凹陷的成因及控制

分析唐钢板坯连铸机生产的低碳低硅铝镇静钢铸坯表面凹陷缺陷的产生原因。结果表明,表面凹陷缺陷的产生由结晶器内弯月面处坯壳冷却不均造成,采取了防止结晶器跑锥,提高结晶器锥度,防止弯月面处铜板变形,选择合适性能的保护渣,选择合理的拉速、钢水过热度,合理控制结晶器流场等措施,最终消除了铸坯凹陷缺陷,提高了铸坯表面质量。     

Relationships between the surface quality of a single crystal copper ingot and the process parameters of a heated mould continuous casting method

The relationships between the surface quality of a single crystal copper ingot and the process parameters of heated mould continuous casting method were studied experimentally using our own design of horizontal heated mould continuous casting apparatus, and the mechanism by which process parameters affect the surface quality of a single crystal copper ingot is analyzed in the present paper. The results show that the process parameters affect the surface quality of a pure copper ingot by affecting the position of the liquid-solid interface in the mould. The position of the liquid-solid interface in the mould must be controlled carefully within an appropriate range, which is determined through a series of experiments,in order to gain a single crystal copper ingot with good surface quality.     

Prediction of burn-on and mould penetration in steel casting using simulation

Abstract

Burn-on and penetration defects in steel casting are principally caused by localised overheating of the sand mould or cores. Such overheating can cause liquid metal to compromise the mould surface and entrain onto the surface of the mould. A method has been developed to predict likely burn-on and penetration defect locations as part of a standard casting simulation. The method relies on determining, from simulation results, the locations where the mould is above a certain critical temperature. The critical temperature is generally above the temperature at which the steel is fully solidified. By measuring the time periods during which these locations in the mould are above the critical temperature, burn-on and penetration defects can be predicted. The method is validated through comparison with previous experimental data. Several parametric studies are conducted to investigate the sensitivity of the predictions to the choice of the critical temperature, the interfacial heat transfer coefficient between the steel and the mould, the pouring temperature, and the mould material. The results of one case study are presented where burn-on or penetration defects observed on a production steel casting are successfully predicted.     

越南某钢厂小方坯连铸试生产失稳性诊断分析

越南某钢厂六流方坯连铸机在投产后的试生产过程中,生产很不稳定,事故停机频发,拉坯速度不超过2.5 m/min,试生产前期主要是漏钢停浇,后期主要是中间包快换水口盲板自动关闭停浇。通过对生产现场的工艺条件、操作流程、设备配置与工作状态等各方面的观察和排查,结合连铸漏钢机制、自动停浇诱因对事故进行了分析,提出从浇注操作的规范与熟练、结晶器振动的可靠性、水口质量、结晶器卷渣、切后铸坯拥堵的人工干预等方面进行改进的措施。逐步落实各项改进措施后,目前该厂生产平稳,拉速达到了3.25 m/min,漏钢及水口盲板自动关闭停浇等生产事故得到了显著改善。