板坯连铸机辊缝控制技术在生产中的应用

针对酒钢碳钢薄板厂6号连铸机板坯中心裂纹问题,对辊缝设定值进行了改进,并进行了生产实践,最终通过多方面共同努力,成功克服了板坯中心裂纹,使连铸坯质量合格率由97％左右提高到99．7％以上。     

板坯连铸机全程辊缝控制新技术

本文对板坯连铸机全程辊缝控制技术的设备组成、控制原理和工作原理、冶金效果及其使用情况进行介绍，并分析其特点和功能。     

大板坯连铸机扇形段的预变形优化研究

结合辊缝实际测量数据和扇形段结构特征的分析,查明了引起板坯铸机扇形段内部辊缝变大的主要原因.基于扇形段内弧辊架梁受力特征的分析,提出了一种扇形段预变形优化方法.按照扇形段内部辊缝变大的程度确定铸机实施调整的区域,实施后将扇形段内部辊缝增大量控制在0.2mm以内.     

板坯连铸机辊缝收缩的仿真计算研究

合理的辊缝收缩是减少铸坯中心缩松、缩孔的重要手段。为研究某厂2#板坯连铸机辊缝设计的合理性,文中结合铸机结构特点,在测试和分析钢种特性的基础上,对辊缝收缩进行了仿真计算。结果表明：辊缝收缩的设定与钢种有密切关系,不同钢种应采用不同的辊缝收缩制度。该铸机辊缝设计不能很好满足包晶钢品种的要求,需对结晶器宽面设置锥度,针对不同类钢种适当延长扇形段压下区域和增加压下量,对提高连铸坯质量有重要意义。     

特厚板坯连铸机在线开口度精度控制浅析

为了减少首秦400mm连铸机铸坯中心偏析,提高产品质量,通过ASTC辊缝标定技术、手测辊子开口度、调整驱动辊开口度及对拉拔锁紧螺母力矩严格控制,中心偏析得到了很好的控制,一般控制在C类2.0以下。结果表明:中心偏析与铸坯凝固末端轻压下位置附近的辊缝开口度有着密切的联系,对轻压下位置附近的辊子开口度进行严格控制,可以减少铸坯中心偏析。     

一种新型连铸机用辊缝测量仪

针对目前市场上连铸机二冷段用辊缝仪不可在线测量且使用不便的缺点,介绍一种分体式辊缝仪,可在线测量辊缝值、辊列对弧精度和辊子转动状况.一套辊缝仪由多个分体单元组成,各分体单元简单连接在引锭链上,测量时不需要更换引锭头,简单易用,可显著提高辊缝仪的使用效率、减轻劳动强度.     

连铸特厚板坯易发质量缺陷的控制

连铸特厚板坯易发生角裂、中心偏析和内部夹杂物等缺陷,影响特厚板质量。采用理论分析、仿真计算、实验室和生产现场试验的方法,研发了防止特厚板坯角部裂纹技术、特厚板坯均质化控制技术、内部夹杂物控制技术。实施结果表明,生产特厚板坯质量良好,无角部裂纹,中心偏析水平集中在C0.5～C1.5范围内,特厚板探伤合格率达96%。本研究成果对生产特厚板坯时控制质量具有重要意义。     

特厚板坯连铸机弯曲段设计研究

本文建立了特厚板坯连铸机弯曲段设计模型,利用有限元分析软件COSMOSworks分别计算了正常浇注、坯头通过及更换中间包三种情况下弯曲段框架的强度及变形情况,为弯曲段的设计提供理论依据.     

特厚板坯连铸机零号段设备设计研究

特厚特宽板浇筑时金属收得率低且内部组织缺陷严重,本文阐述了立式连铸生产特厚断面铸坯的重要性和必要性,介绍了零号段的设备结构及关键技术。在零号段窄边分别设置窄边辊子用以支撑铸坯窄边,在辊套上间隔布置有环形槽,防止积水造成铸坯表面的冷却不均匀性造成的裂纹。在零号段合理设置窄边喷淋冷却配管,保证铸坯窄面的凝固收缩。在浇铸700 mm厚度的铸坯时,窄边设置两个喷嘴;在浇铸700 mm以下铸坯时,窄边设置一个喷嘴,居中布置。仿真结果表明,铸坯凝固早期坯壳生长均匀,四边坯壳厚度基本相同,有效地防止了鼓肚及角裂的发生,保证了铸坯的内部质量。本文可为钢铁企业新建特厚板坯连铸机、零号段改造工程提供技术支撑和指导。     

420 mm特厚板坯连铸机生产实践

特厚板材作为一种当前具有较高附加值的板材产品受到钢铁企业的重视。连铸生产特厚板坯与模铸相比具有生产高效且节约能源的优点,因此,钢铁企业不断改建或新建连铸生产线生产特厚板坯。重点阐述了中冶赛迪自主设计的用于生产420 mm特厚板连铸生产线的特点、相关技术和在新余钢铁公司的工业应用。生产实践表明,该连铸机已经可以稳定生产最大厚度为420 mm的连铸板坯,铸坯表面和内部质量优良,轧制板材满足用户要求。     

Study on the continuous roll forming process of swept surface sheet metal part

Continuous roll forming (CRF) is an effective process to manufacture swept surface parts of sheet metal. The forming tool in CRF is a pair of small-diameter bendable forming rolls, a swept surface is formed continuously after the rotating rolls sweep out the whole sheet metal blank. The two bent rolls and the non-uniformly distributed roll gap along the rolls’ length make the sheet metal bent in longitudinal and transverse directions simultaneously, the cross-section curve of the formed swept surface is controlled by the curved profile of the forming rolls and the spine curve is controlled by the differential elongations of sheet metal generated by roll gap. In this paper, a necessary condition for the formation of a swept surface is proposed and analyzed, the parametric equations of the formed surface in CRF are derived and the method to determine the roll gap for forming a given swept surface is presented. The numerical simulations and analyses on the CRF processes demonstrate the validity of the presented theoretical models. The experimental and measured results show that the formed surfaces are in good agreement with the desired surfaces, and swept surface parts with good forming precision can be obtained by CRF process.     

Influence of microstructure on the premature failure of a second-intermediate sendzimir mill drive roll

Although a precise understanding of roll failure genesis is complex, the microstructure of a broken roll can often unravel intrinsic deficiencies in material quality responsible for its failure. This is especially relevant in circumstances when, even under a similar mill-operating environment, the failure involves a particular roll or a specific batch of rolls. This paper provides a microstructural insight into the cause of premature breakage of a second-intermediate Sendzimir mill drive roll used at a stainless steel sheet rolling plant under the Steel Authority of India Limited. Microstructural issues influencing roll quality, such as characteristics of carbides, tempered martensite, retained austenite, etc., have been extensively studied through optical and scanning electron microscopy, electron-probe microanalysis, image analysis, and x-ray diffractometry. These are discussed to elucidate specific microstructural inadequacies that accentuated the failure. The study reveals that even though retained austenite content is low (6.29 vol%) and martensite is non-acicular, the roll breakage is a consequence of intergranular cracking caused by improper carbide morphology and distribution.     

CVC 四辊轧机有载辊缝解析模型

运用梁的弯曲变形理论,基于工作辊和支撑辊之间的变形协调关系,直接导出了辊间压力分布及辊间弹性压扁系数的解析表达式,从而较精确地求出轧辊的弹性变形,并由此得到较精确的辊缝解析解。     

连铸机扇形段远程自动调节辊缝的液压系统及其控制方案的分析

分析了近年来从国外引进的板坯连铸机采用液压电气控制实现扇形段辊缝自动调节的基本工作要求,液压控制原理及各控制方案的特点。开关阀的控制方式已成功用于西安重型机械研究所设计制造的攀钢2#大方坯连铸机的轻压下系统。     

冷轧机轧制过程中轧辊垂振的研究

以冷轧机系统的垂振为研究对象,结合近年来冷轧机垂振问题的研究成果,得出冷轧机垂直振动的振源在辊缝.冷轧机在高速轧制时,辊缝润滑状态发生变化导致辊缝阻尼改变,从而引起轧机的垂直振动.建立了冷轧机简化模型,并对冷轧机轧制过程进行仿真,分析了辊缝阻尼与轧机垂直振动之间的关系,得出辊缝阻尼变小导致轧机的垂直振动.通过增大辊缝间的摩擦系数和增设阻尼设备的方法维持合适的辊缝阻尼,可消除轧辊的垂直振动,保证轧机平稳运转.     

Through-thickness shear strain control in cold rolled silicon steel by the coupling effect of roll gap geometry and friction

Through-thickness shear strain distribution in cold rolled non-oriented silicon steel under different roll gap geometries and friction coefficients was analyzed by finite element method (FEM). Cold rolling textures were also investigated quantitatively to validate the calculated shear strain distribution. The results showed that both direction and magnitude of shear strain through thickness depend sensitively on the two rolling parameters. The coupling effect of roll gap geometry and friction was satisfactorily explained based on their contributions to shear strain and the involved mechanisms. A shear strain distribution diagram (SSDD), which can clearly characterize the shear strain state with roll gap geometry, friction and through-thickness position as variables, was proposed to serve as a convenient tool for through-thickness shear strain control.     

冷态辊缝测量偏差分析及扇形段结构的优化

介绍了三铰链点扇形段结构特点,对某板坯铸机扇形段存在冷态辊缝偏差的原因进行了系统的分析,结合扇形段结构原理提出了改进的措施,优化后实际辊缝值偏差能够控制在0.1～0.3 mm范围内,满足了工艺控制标准。本文对扇形段的设计及改造具有一定的指导意义。     

冷轧机轧制过程中的轧辊振动研究

以冷轧机轧辊垂直振动为研究对象,在分析冷轧机振动机理的前提下,建立轧机垂直振动简化模型,运用数值仿真方法,分析了轧制压下量、摩擦系数及辊缝阻尼的轧制工艺参数对轧机垂直振动的影响。分析结果表明:减小轧机压下量有利于提高轧机振动临界速度;增加辊缝摩擦系数有利于减小轧辊的振动位移;增加辊缝阻尼能够有效降低振动幅值。在此基础上提出了抑制冷轧机垂直振动方法为:优化各道次压下量,以使轧制临界速度由1340 m·min-1提升到1520 m·min-1;适当降低乳化液浓度,以使辊缝摩擦系数增大,此调节过程应考虑窜流现象;增设液压衬板减震器或多孔阻尼减震器,以增加辊缝阻尼。