连轧钢板国际标准制定动态——2007年第35届ISO／TC17／SC12连轧钢板国际标准会议情况汇报

介绍了2007年10月在我国召开的第35届ISO／TC17／SC12连轧钢板及钢带国际标准会议的情况,提出我国应进一步参与国际标准化活动,积极推进采用国际标准的工作。     

Mechanism generating deviations in the rolling load and strip camber on the plate rolling mill

Both the support force inequality on both ends of the roll and the camber are common drawbacks, those were caused by the static indeterminacy of structure design, backlash and offset setting selection on the plate rolling mill. There are many technical literatures for analysing the reasons for generating of the strip camber, which are mainly the external factor analysis, however, the internal cause of the mill roll system is ignored. The negative effects of offset distance setting and side clearances of about 1?mm between the chocks and side surface of the housing window should be considered on the plate rolling mill. In reality, the primary cause of this deviation and the strip camber lies in the interaction between offset distance setting and cross of the rolls. The greater the offset setting value of the plate rolling mill, the greater the generation probability of pressure difference and the camber. Some measures, involving eliminating offset distance setting, effectively controlling the side clearances between chocks and housing window, eliminating initial cross and dynamic cross phenomenon, should be taken to maintain the rolls parallel and to prevent radically the support force inequality on both ends of the roll and strip camber.     

热连轧机刚度差及其对板廓非对称的影响

 针对某2 250 mm宽带钢轧机出现的带钢断面板廓非对称性问题,提出综合1次楔形与3次楔形的不对称度概念来描述和评价板廓的非对称性。其次,采用压靠法获得轧机的弹跳曲线,并利用基于影响函数法的非对称辊系变形模型,计算分析轧机刚度差对带钢板廓非对称性的影响。在生产中,通过轧机设备关键零部件维修和定量预设定轧辊倾辊量达到对因轧机刚度差而引起的板廓非对称性进行控制和消除,从而保证宽带钢板廓的对称性和轧制稳定性。     

关于修订GB3274结构用热轧厚钢板和钢带国家标准中几个主要问题的探讨

就结构用热轧厚钢板和钢带国家标准修订中几个主要问题及理由———牌号及化学成分、力学和工艺性能、表面质量 ,与大家进行探讨。国家标准修订后 ,与国际标准接轨 ,放开化学成分下限和力学性能的上限 ,有利于企业充分发挥成分和工艺的调控功能 ,解决长期以来因成分和性能限制太死 ,造成的成分与性能要求的矛盾。     

Precision online model for prediction of strip temperature in hot strip rolling

Abstract

Investigated via a series of finite element (FE) process simulation is the effect of diverse process variables on some selected non-dimensional parameters characterising the thermomechanical behaviour of the roll and strip in hot strip rolling. Then, on the basis of these parameters, online models are derived for precise prediction of the temperature changes occurring in the bite zone as well as in the interstand zone in a finishing mill. The prediction accuracy of the proposed models is examined through comparison with predictions from a FE process model.     

薄带材轧制的最小可轧厚度理论及数值模拟

 智能制造、电子通信等行业向微型化、集成化方向发展要求不断提升精密轧制带材产品质量,提高厚度精度控制是其中关键组成部分,因此,精密带材轧制过程接触变形区理论研究有着极其重要的意义。以Stone轧制力模型为代表的传统薄带材冷轧理论假设轧辊在接触变形区内保持圆弧状轮廓,利用Hitchcock公式求解接触弧长进而求得平均单位压力,并在此基础上建立了Stone最小可轧厚度理论。在试验及实际生产中很多学者发现有时Stone轧制力计算值与实际值相差甚远,这是由于某些轧制工况下接触变形区内存在中性区,轧辊圆弧状假设不再适用。中性区的存在使轧制力剧烈增大而带材金属延伸变形增加甚微,即轧制难度增大、轧制效率降低。通过对不同厚度薄带材轧制过程进行有限元分析,得到了不同道次压下率下接触变形区轮廓与接触压力分布的变化规律,带材初始厚度越小或道次压下率越大,接触变形区内中性区所占比例越大,接触压力分布趋于椭圆形分布;基于Stone轧制力公式建立了考虑轧制效率的薄带材最小可轧厚度模型,对于一定初始厚度与Stone最小可轧厚度比值,根据轧制工艺参数可计算接触变形区内恰好不存在中性区时的临界道次压下率,以此临界道次压下率为依据可确定高效轧制厚度范围及Stone轧制力模型的适用条件,为精密薄带材轧制生产过程提供理论指导。     

Comparison of two methods of calculating concentration distributions

Summary The principal difference between concentration distributions calculated by the method of [2] and those calculated by the method of [1] is that the former show no discontinuities between the histogram peaks along the concentration axis. This indicates that the method of [2] permits calculation of distributions which are much closer to the actual ones than those found by the method of [1],The value of the total absolute difference between the distributions calculated by these methods passes through at least one maximum, as the original powder mixture is transformed into the homogeneous state.     

铝带热连轧头部变厚度轧制工艺和应用

带卷头部压伤是影响铝合金热轧带卷成品率的主要质量缺陷之一。为了有效控制该缺陷的产生,首先分析其产生的原因和机理,确定了采用穿带时依次改变各机架辊缝对带卷头部进行变厚度轧制的解决方案,建立了变厚度轧制的工艺数学模型,可实时计算各机架辊缝的调整量和调整速度,以达到增大带卷头部与内圈卷面间接触面积、减少带卷头部压伤缺陷的目的。在生产现场采用该方法后,头部压伤的不良比例由之前的5%降至1%左右,同时可以提高卷取机的最大允许卷取厚度。     

Causes and methods of alleviating variations in the shading of tin plate during temper rolling

The Ispat Karmet metallurgical plant has made a study of the reasons for the formation of “ring-shaped bands” on the backup rolls of its temper-rolling mill and the associated variation in the shading of tin plate rolled on the mill. The plant examined the interactions that take place in the stands of the mill and used the findings to determine the mechanism responsible for the formation of the above-mentioned defects. A method of alleviating these problems was also developed. Improvements that were introduced have led to a fivefold increase in the amount of time that the backup rolls of stand No. 2 remain in service without the formation of the ring-shaped bands. The measures that were adopted have also signficantly reduced the intensity of the variable shading on the tin plate.     

Complex rolling of thin strip

Research on the energy and kinematic parameters of complex rolling processes is reviewed. Means are proposed for reducing the rolling forces and improving the surface quality of the strip by complex rolling, as well as minimizing roller-replacement rates.     

钢冷轧乳化液稳定性及对冷轧润滑的影响

研究了影响不同类型乳化液稳定性的因素,包括乳化剂的比例和总含量对阴离子乳化油稳定性的影响,乳化剂的HLB值(Hydrophile Lipophile Balance)和总量对非离子乳化油稳定性的影响.研究发现乳化剂的比例和乳化剂的HLB值对乳化油和乳化液的稳定性影响明显.通过研究不同浓度下乳化液的稳定性对其吸附性和摩擦系数的影响发现:乳化液的稳定性在一定范围内时,其润滑效果可达到最佳.在冷轧实验中也发现:应根据冷轧的实际规程和要求来选择乳化液的稳定性和合适的含量,以便使冷轧高效正常地进行.     

过程控制级模拟轧钢系统的研制及在热轧试车中的应用

宝钢集团上海第一钢铁有限公司(后面简称一钢)新建的不锈钢工程1780热轧项目中,为了能在较短周期内完成所有的应用软件开发与测试任务,特别研制了模拟轧钢功能。本论文主要阐述利用计算机的集成思想,结合热轧工艺,来开发模拟轧钢功能,以及利用模拟轧钢进行现场各种情况的模拟测试。     

板带钢乳化液摩擦学性能与轧制工艺特征

采用不同的基础油及添加剂配制板带钢轧制乳化液后,通过四球摩擦磨损试验机考察了基础油及添加剂对乳化液摩擦学性能的影响,并通过冷轧实验对各乳化液的轧制工艺润滑效果进行了实际验证.结果表明:运动黏度和皂化值是根据实际的润滑需求选择基础油的主要参数,且基础油的选择影响添加剂的分散与稳定;极压抗磨剂对轧制乳化液的摩擦学性能有显著的提高作用;纳米六方氮化硼(h-BN)作为新型纳米润滑添加剂,不但自身具有优异的摩擦学性能,而且与传统添加剂有良好的协同提高作用;在使用含纳米氮化硼的乳化液进行润滑的冷轧过程中,各轧制工艺特征参数(轧制力、轧制功率等)有显著的降低,初步体现了良好的纳米润滑效应.