Production of thin-walled pipe on a system with a three-roller mill

The manufacture of thin-walled pipe on a three-roller screw-rolling mill is described. The optimal reduction on the reduction mill is noted, and a formula is given for the aperture. A rolling technology for the rear end of the pipe without triangulation is outlined.     

Sleeve piercing on a mill designed by OAO EZTM

In response to the problems arising on introducing a new piercing mill designed by OAO EZTM, the use of continuous-cast billet of a single diameter is proposed for the manufacture of pipe with a diameter of 219–325 mm; the working profile of the mandrel is optimized, with the introduction of alternating curvature; and the conditions of billet heating in the annular furnace prior to piercing are adjusted.     

四辊轧机弹性变形解析模型的研究

在四辊轧机的轧制过程中,现有的辊缝形状解析模型不能直接应用于板凸度的在线控制.针对轧制过程中轧辊的弹性变形和轧辊与轧件间的相互作用,通过对四辊轧机辊系变形和具体的受力状况分析,从理论上推导了直观的辊缝形状函数,明确了它与相关因素的对应关系.为了验证模型的准确性,采用该模型对某"1 4"铝热连轧机的精轧末机架的出口板凸度进行了理论计算.与在线所测得数据进行比较,表明该模型计算结果精度高,误差在15 %以内.     

Asymmetric three-roller sheet-bending systems in steel-pipe production

Various attachments are used to produce components of particular configurations from metal sheet. In particular, sheet-bending roller systems may be classified in terms of the number of rollers (two, three, or four); the type of drive (mechanical, pneumatic, electromechanical, hydraulic); and the roller configuration (symmetric, asymmetric). Three-roller systems are used for the production of cylindrical, oval, and conical components by bending the metal sheet. They may be employed to manufacture pipes, channels, airways, shells, barrels, and sheathes. The operation of three-roller sheet-bending systems is based on the rotation of rollers in opposite directions, so that the sheet is captured and bent to the specified radius. To facilitate sheet supply and the release of the products bent into closed circles, the three-roller sheet-bending systems are combined with a removable front shaft applying a pressure that may be adjusted. In the three-roller systems, the diameter of the upper roller is about 1.5 times that of the lower rollers. In shaping, the rollers perform reversible motion. The upper roller may be raised and lowered to regulate the diameter of the circle produced. In this approach, extremely small sheet sections remain flat. This problem is eliminated by bending the ends of the sheet in a press or in a roller mill. In the present work, a mathematical method is proposed for determining the forces and torques in cold flexure of thick steel sheet on three-roller sheet-bending systems. The calculations permit the determination of the reaction of the roller supports, the residual stress in the wall of the steel sheet, the proportion of the plastic deformation over the sheet thickness, and the relative deformation of longitudinal surface fibers of the sheet in flexure as a function of the roller radius, the roller spacing, the reduction of the sheet by the upper roller, the sheet thickness, the Young’s modulus, the yield point, and the strengthening modulus of the steel sheet. The results may be used at metallurgical and manufacturing plants in the production of large-diameter steel pipe for major pipelines.     

Efficient deformation in the roughing group of the 2000 mill

Efficient rolling of low-alloy steel in the roughing group of the 2000 mill reduces surface defect formation. In the proposed system, the reduction in the first three roughing cells, with horizontal rollers, is reduced by 3–5%. Finite-element simulation is used for quantitative assessment of the efficiency of the proposed approach. It is found that the proposal improves the deformation conditions and reduces the likelihood of crack formation and development in the first passes of the roughing group for the 2000 mill.     

四辊铝箔轧机辊系变形的研究

本文建立了四辊铝箔轧机分割模型，考虑了工作辊温度场、铝箔轧制力不同于带材轧制之处、工作辊边部的压靠。计算结果与实测基本符合，为铝箔轧制板型控制提供理论基础。     

热连轧变形抗力模型的优化改进

改进后的志田茂变形抗力模型是比较经典的变形抗力模型,但该模型没有考虑残余应变对于变形抗力的影响,不能完全适应现场生产的需要。作者在分析研究济南钢铁集团有限公司热连轧厂大量实际生产数据的基础上,在原变形抗力模型中考虑了碳质量分数的影响,增加了对应的影响系数,用于修正残余应变的影响,从而使该模型更贴近于现场实际。模型实际应用结果表明,改进后的模型预报精度明显提高,效果良好。     

Modelling and simulation of deformation zone in cross rolling mill

Based on the three-dimensional models of the deformation zone of Accu-Roll mill described in this paper, simulative software is developed on a PC computer by means of 3-D solid method. Any sections of the deformation zone can be viewed at any position and in any direction so that it is very convenient to analyze characteristics of cross-rolling deformation zone and to pre-set process parameters.     

Unit for accelerated cooling of reinforcement bars in the line of a 330 mill after deformation

Donetsk Polytechnic Institute. Kramatorsk Metallurgical Plant. Translated from Metallurg, No. 1, p. 32, January, 1990.     

二十辊轧机支撑辊组变形及板形调控分析

 板带材的产能和质量是一个国家工业水平发展的重要标志,铜板带材的生产能力和地位更加显著。森德威二十辊轧机是冷轧铜板带材轧制生产的关键设备,其最外层A、D支撑辊组的弯曲变形是最重要的板形调整手段之一。支撑辊组鞍座位移变化可以使支撑辊芯轴发生弯曲变形,变形会反映到背衬轴承上并且向下依次传递给中间辊和工作辊,最终影响板厚和板形。传统的假设折线法和超静定梁法将芯轴和背衬轴承考虑为一个整体,而忽略了两者之间的变形对整体支撑辊组变形的影响。因此,基于有限元方法进行仿真拟合各段背衬轴承弯曲变形得到简化后的一次函数表达式,将各段背衬轴承拟合结果汇总进而得到整体的支撑辊组弯曲变形的线性表达式,再结合辊系弹性变形模型和金属塑性变形模型构成的板形预报模型评估支撑辊组变形程度对板形和板厚的影响。研究结果表明,对上辊系中的4个鞍座施加不同的位移组合之后,板厚和板形分布在整个板宽方向上并非局部变化,而是呈现整体的变化趋势,且4个鞍座对板形和板厚的调整效果并不相同;在施加同样的鞍座位移条件下,中部鞍座比边部鞍座对板形和板厚的影响效果更加显著,并且即使在支撑辊组中心两侧施加对称的鞍座位移,其对板厚和板形的影响也是非对称的。     

硬质薄规格镀锡板平整轧制变形行为与辊形技术

以某厂镀锡板连退机组双机架HCM平整机为研究对象,理论分析结合有限元仿真和现场实验,对硬质薄规格镀锡板的平整轧制变形行为进行了研究,揭示了硬质薄规格镀锡板平整时轧制力偏大、实际延伸率达不到设定目标延伸率以及实物板形质量较差的原因,确定了相应的解决问题的技术思路.在此基础上,运用基于有限元仿真的辊形设计方法和软件,研制了新的中间辊端部辊形.生产应用结果表明,该中间辊端部辊形能够有效地减轻压靠、稳定实现设定的目标延伸率且实际平整轧制力降低10%～20%,而且还可以根据需要在正常平整轧制力下使实际延伸率增加0.1%～0.2%.     

四辊轧机辊系弹性变形高效计算方法

 为解决普通影响函数法计算速度慢的缺点,在分析普通影响函数法计算精度与计算速度主要影响因素的基础上,提出了一种新型四辊轧机辊系弹性变形高效计算方法。该方法采用高次多项式描述辊间压力与轧制压力的横向分布,减少了轧辊挠度的计算量;与普通影响函数法相比,求解辊间压力的线性方程组阶数显著降低,大大降低了计算时间。采用该方法后,四辊轧机辊系弹性变形的单次计算时间不超过1 ms,计算精度与划分单元数为100的普通影响函数法计算精度相差很小,为板形在线设定提供了理想的必要条件,并可推广应用于其他机型。     

冷连轧变形抗力模型的优化

采用原始静态变形抗力模型,并考虑入口、出口弹性变形轧制力对模型的道次影响系数,进行计算优化,建立了1个优化的变形抗力模型。2种模型的对比表明,优化的模型精度更高,提高了轧制力的计算精度。     

Theoretical evaluation of the shape of the deformation zone in the press piercing mill

An analysis of metal deformation in the press piercing mill is presented in the paper. Interpenetration of the groove surface and billet surface was the base of the theoretical solution. Bulging of the material in front of the deformation zone was taken into consideration. The analysis resulted in the determination of strains within the deformation zone. Equations which describe the billet surface were derived and the contact interface was determined.     

用有限元法对Φ550粗轧机机架结构应力、变形的分析

本文采用8节点等参数单元,对φ550粗轧机机架进行了有限元分析,较准确地反映出机架的变形特征和应力分布,为φ550粗轧机的设计提供了理论依据.