热连轧机水平振动及其与轧制参数影响关系

 研究了热连轧机轧辊水平振动机制、水平振动与轧制过程参数间的影响关系。考虑间隙、轧辊偏移距和非线性阻尼等影响因素,建立了板带轧机工作辊水平振动非线性动力学模型,同时建立了轧机水平振动与轧制过程参数的关系模型。对某厂热连轧机F2机座进行水平振动测试试验,工作辊水平振动剧烈,中后期振幅达到4.5 g,甩尾时超过5 g,振动优势频率为40和118 Hz;同时对振动过程进行仿真,研究了轧件厚度、轧制速度和张应力参数对水平振动的影响。结果表明：仿真分析水平振动加速度幅值达到4.8 g,对比仿真和实测的振动曲线,可知仿真与实测结果相符;轧件的厚度越薄,对轧辊振动影响越大;轧制速度变化对水平振动影响较大;相比其他因素,张力对轧机水平振动的影响较小。     

轧制塑性变形对W-Cu复合材料组织性能影响

对不同Cu含量[20%～50%(质量分数)]的热挤压后的W-Cu合金坯料进行轧制,通过对比得出最佳轧制工艺参数,并制备出微观组织均匀、致密度高、性能优异的W-Cu合金板材。结果表明:轧制力随着道次轧下量的增加而逐渐增大,并且当一次轧下量超过60%时,轧制力急剧增加;随着轧制变形量的增加,Cu相发生变形,W相形状基本不发生变化,但W相有细化的趋势;轧制变形能在保持W-Cu合金热挤压后高组织均匀性、高致密度、高性能的基础上获得薄板甚至是箔材。     

菌式穿孔机及Accu－Roll型轧机阶梯形轧制过程控制系统

对于斜轧机，使用阶梯形轧制方式，能有效地改善咬入条件并减少轧件尾卡的可能性。本文介绍这种新型轧制方式的控制系统软件包及其主要功能。成都无缝钢管厂φ２５０ｍｍＡｃｃｕ－Ｒｏｌｌ轧管机组的实际运行结果表明，该控制系统灵活方便，运行可靠，提高了作业率和钢管成材率，取得了较好的经济效益。     

Stressed state and kinematics in the rolling of powder materials on a metal substrate

A one-dimensional mathematical model for powder materials on a metal substrate rolling process has been developed on the basis of a numerical recurrent solution of static equilibrium conditions in the finite difference form for a specified elementary volume of metal. The correct account of the laws concerning the relative density distribution, mechanical properties, and econometric parameters, and also the presence of the elastically deformed metal substrate in the deformation confinement volume are the peculiarities of this model. Translated from Poroshkovaya Metallurgiya, Nos. 1–2(411), pp. 13–21, January–February, 2000.     

2250热连轧R2轧机轴向力生成机理

针对某2250热连轧R2轧机轴向力过大导致传动系统的主电机轴承座和水平轴轴承座移位事故的问题,研制了轴向力在线监测系统并对轴向力进行长期在线监测.从理论上剖析了轧机轴向力生成的主要原因并进行了计算机仿真研究和探讨,得出轴向力的大小与辊系交叉角密切相关.通过减小辊系轴承座与牌坊之间的间隙来控制交叉角的大小,从而可以有效地减小轧机轴向力,这一结果得到现场实验验证.     

Experimental and theoretical analysis of roll flattening in the deformation zone for ultra-thin strip rolling

For ultra-thin strip rolling, the conventional rolling force models are no longer applicable. To obtain accurate rolling force in the shape and gauge control process, Fleck proposed a new roll flattening model. In this study, experimental analysis, finite element simulation, and theoretical analysis were conducted to evaluate the Fleck model. The experiments and simulations show a clear neutral zone in the deformation zone with decreasing strip thickness. The finite element simulation results show that the proportion of the elastic unloading zone is small, when an elastic unloading phenomenon appears in the neutral zone. Thus, to simplify the rolling force model, the effect of an elastic zone could be ignored. Based on this finding, we develop a rolling force model with quick calculation speed, high precision, and convenient online application. Finally, the accuracy of the simplified model is verified by the measured rolling force.     

应用刚塑性体的变分原理求解钢轨万能轧制过程的力能参数

为了简化钢轨万能轧制过程的三维几何模型,首先把带箱形孔型立辊简化为等效的平辊,然后分别给出轨腰、轨头及轨基的运动学许可速度场,求出在此速度场下相应变形区的塑性变形功率以及速度间断面上消耗的功率,计算中考虑了由于前滑和后滑而产生的摩擦功率.根据刚塑性体的变分原理求解水平辊和两个立辊轧制力和轧制力矩的近似解.通过比较理论值和实验值可知,利用变分原理求出的力能参数近似解稍大于实验值但最大误差不超过20%,因此根据变分原理进行力能参数计算和轧制工艺参数设定及优化是比较可靠的.     

Method of calculating the power and force parameters of the cold rolling of porous materials with the aid of a computer

Conclusions On the basis of a comparative analysis of results of numerical experiments carried out by various methods, it is shown that the method proposed by the authors is well suited for practical calculations, with the aid of a computer, of the power and force parameters of the cold rolling of strip. In the present stage of development of cold rolling as a process for the manufacture of powder metallurgy strip, the method could be used for providing starting data in the design of the mechanical units of metal powder rolling mills.Translated from Poroshkovaya Metallurgiya, No. 7(151), pp. 11–21, July, 1975.     

钛粉粒度对轧制烧结多孔钛板力学性能的影响

对不同粒度钛粉的流动性、松装密度和振实密度进行分析, 经轧制和烧结制备出满足湿法冶金需求的多孔钛板, 研究了钛粉粒度对轧制烧结多孔钛板力学性能的影响。结果表明: 轧制烧结多孔钛板的最大孔径和孔隙度随钛粉粒度的减小而减小, 钛板密度、剪切强度、抗弯强度、抗拉强度及伸长率均随钛粉粒度的减小有所增加; 当钛粉粒度范围为89~104 μm时, 粉末轧制烧结多孔钛板的综合力学性能较高。     

Effects of powder material and process parameters on the roll compaction,sintering and cold rolling of titanium sponge

ABSTRACT

Roll compaction is a powder metallurgy process that has the potential for cost reduction in the production of titanium parts. In this study, experiments were carried out to investigate the effects of powder type and size on the roll compaction and subsequent sintering and cold rolling behaviour of titanium powder. Powders used ranged in upper sieve sizes from 0.15 to 3?mm. Strip density was found to increase with decreasing powder size while thickness decreased. Following sintering in the range of 800–1200°C, cold rolling was performed with various levels of thickness reduction. Average (across the width) densities of up to 88% were achieved, with higher density regions in the middle of the strips reaching up to 99%. Roll force was measured during cold rolling and found to increase with increasing final (post-cold rolling) density and also with increasing roll gap reduction amounts.     

大断裂区域片岩地层巷道围岩大变形类型与机理研究

通过对大断裂区域片岩地层巷道工程中出现的大变形问题进行分析研究,将大变形类型划分为岩性决定型、结构决定型、地形偏压型和爆破扰动型。在对大变形形成机理分析的基础上,提出了综合治理措施,现场应用中取得了良好的效果,可为矿山等其它类似地下工程施工提供借鉴。     

悬臂轧机油膜轴承烧坏的原因分析与管理对策

对悬臂轧机油膜轴承烧坏的原因进行全面分析，并提出相应的管理对策．     

幂律流体延伸表面逆来流边界层特性分析与数值模拟

首先利用量级分析理论对幂律流体延伸表面边界层流动进行分析,得到边界层厚度的量级和影响因素;引入量纲为1变量,将动量边界层的控制方程转化为量纲为1的控制方程组.数值求解了具有不同幂律指数n的流体在平板逆来流且平板运动参数ζ不同的情况下的层流边界层流场,分析了幂律指数n和平板运动参数ζ对动量边界层厚度、量纲为1速度分布和量纲为1剪切力分布的影响规律.结果表明,速度边界层的分布不仅和平板运动参数有关,而且和幂律指数有关.     

冷轧带肋钢筋直径与拉丝机卷筒直径的匹配

采用被动式工艺生产冷轧带肋钢筋须经过减径、成型两台轧机连续轧制．要求钢材的秒流量相等，否则将造成断线停产或线材在拉丝机卷筒上打滑，致使卷筒严重磨损．用双层卷筒拉丝机提供动力生产冷轧带肋钢筋时，线材直径与卷筒直径的匹配是在一个小的调整范围，通过轧机拉力控制在一定范围变化，可保证成品尺寸符合公差要求而不产生打滑，从而避免了卷筒严重磨损．     

楔横轧小断面收缩率轧件螺旋组织缺陷研究

轧件发生局部变形是楔横轧的主要工艺特征,尤其小断面收缩率轧件轴向流动能力弱,内外变形差异显著导致楔横轧成形困难.除了容易产生心部破坏缺陷,在轧件表层一定范围内出现的螺旋组织缺陷,也会降低产品的机械性能.本文通过轧制实验,展示出轧件螺旋组织缺陷宏观上呈现为车削后在表层一定深度范围内沿展宽螺旋线分布的亮带,微观上由轧件表面折叠向内部延伸呈带状分布的组织形态.结合有限元数值模拟方法研究了缺陷产生的主要原因,发现由于成形区的金属发生沿展宽负向的金属流动,导致轧件形成沿展宽螺旋线分布的表面折叠和小轴向应变带.同时,螺旋带附近较大的径向压缩使轧件由表面向内部沿折叠裂纹方向组织具有方向性.采用对模具楔尖倒圆角局部改善金属沿负展宽方向的轴向流动,可以既消除表层螺旋组织缺陷,又避免轧件心部损伤风险,使成形质量满足使用要求.经实验验证,确定了模具楔尖圆角的最优取值.     

DANIELI concepts and experiences in thin slab casting and rolling technology for HRC production—the evolution of a winning process route to face increasing market requirements

The direct rolling process for hot strip production,where the thin slab caster is connected directly to the mill,has gained market share rapidly because of its remarkable advantages in terms of energy savings and investment cost over the conventional hot strip mills. However,the unquestionable advantages of the first-generation applications of this plant concept also entail significant limitations both in productivity and steel grades that can be produced. Since his first pioneering applications,Danieli considered strategic the development of new technical solutions specifically conceived to overcome these limitations with the goal of increasing plant production volumes and enlarging steel grade product mix,in order to cover the gap between "Conventional mill" and "Thin slab casting and rolling" process routes. In order to reach this goal,Danieli has developed a complete portfolio of plant lay outs adopting Thin Slab Casting and Rolling technologies,each of them conceived to guarantee the optimal CAPEX and OPEX parameters in fitting with market requirements our Customer intend to target.in terms of productivity,steel grades and coil dimension product mix. Danieli TSR(Thin Slab Rolling) fTSR(flexible Thins Slab Rolling) QSP(Quality Strip Production) and ETR(Extra Thin Rolling) plant configurations are analyzed in this paper. With this diversified approach,Danieli solutions are most appropriate answers to thin slab casting and rolling to produce hot rolled coils with superior quality and an extremely diversified range of steel grades. Already,this approach has allowed Danieli plants to:①exceed the threshold production of 3.0 Mt/a with 2 casting strands in operation as done in Tangshan Iron and Steel plant in P.R.China since 2005;②expand the product mix to include virtually all the steel grades used for flat product applications,including the most demanding ones,such as peritectic(in Essar Algoma Canada and Benxi Iron and Steel,China),micro-alloyed,and silicon steels,for the most sophisticated applications,such as automotive and pipe manufacturing,including Arctic applications,(as done in OMK plant in Russia);③extend the range of final strip thicknesses to include ultra thin gauges,down to 0.8 mm(as in Ezz Flat Steel,in Egypt).     

冷连轧机动态变规格机架速度控制策略及规律

针对冷连轧机动态变规格特性,提出了以变规格前的带钢张力设定值为控制目标的变规格机架速度控制策略.通过建立张力作用下带钢弹性变形的数学解析模型,推导计算了单步小压下变规格时变规格机架的速度控制规律,并根据流量相等原则对变规格后的冷连轧机前面机架进行速度设定.当变规格前后带钢的几何尺寸或材料特性差异较大时,提出利用楔形段方式完成动态变规格,采用上述张力控制目标策略推导计算了楔形段动态变规格方式每个中间厚度的轧制速度和辊缝设定值控制规律.本策略可将变规格造成的厚度偏差控制在变规格机架之间,同时避免了变规格机架与其他机架轧制因素通过张力的耦合,使轧制过程的动态变规格控制易于实现.