Effect of the Parameters of Helical Rolling on the Magnitude of the Circumferential Stresses that Develop in Solid Semifinished Products

It is shown that increasing the degree of deformation increases the tensile circumferential stresses in the semifinished product. Although these stresses are considerably greater than the ultimate and yield strengths of the metal, no lamination or internal cavities were seen in tests that were conducted.__________Translated from Metallurg, No. 3, pp. 47–52, March, 2005.     

Obtaining Reliable Information on Energy-Saving Regimes for the Heating of Continuous-Cast Semifinished Products Prior to Rolling

Reducing the amount of fuel used to heat continuous-cast semifinished products before rolling is an important problem in modern high-speed rolling operations. The heating furnaces of high-speed rolling mills are usually operating under nonsteady conditions, which makes it difficult to realize energy-saving regimes for heating the metal. Modern continuous furnaces are multi-zone units, and the prescribed temperature regime in each heated zone is maintained by controlling the consumption of fuel. From the standpoint of responsiveness and accuracy in obtaining the desired quality of heating and — in particular — reducing fuel consumption, the most promising approach is to instead control the temperature regime in the different heating zones on the basis of the temperature of the surface of the metal. The metal's surface temperature is most accurately measured using optical pyrometers installed in a side wall of the furnace. The article presents a block diagram showing how an energy-saving regime for heating continuous-cast semifinished products can be implemented in a modern continuous furnace on the basis of the temperature of the surface of the metal t_sfc(τ).     

非对称轧制过程的参数

本文提出了非对称轧制过程的全粘着三角形上限解模型,并建立了模型参数关系.采用约束优化的方法对变形功率进行极小化处理,确定了模型参数,进而研究了轧制条件对轧件弯曲、压下量分配等参数的影响.对轧辊速度不匹配时轧制参数的研究表明,文中方法和有限单元法分析及实验研究结果吻合.     

Obtaining Hollow Semifinished Products Based on Copper Alloys for Electrical Purposes by Means of Screw Rolling

Russian Journal of Non-Ferrous Metals - A process for obtaining semifinished products in the form of pipes made of copper alloys for electrical purposes by means of screw rolling is proposed. The...     

Influence of Rolling and Annealing Modes on Properties of Sheet Semifinished Products Made of Wrought Aluminum Alloy 1580

Russian Journal of Non-Ferrous Metals - This article analyzes the processability and properties of sheet products made of a large grade 1580 alloy ingot with a lower scandium content in...     

Efficiency of the Inertia Friction Welding Process and Its Dependence on Process Parameters

It has been widely assumed, but never proven, that the efficiency of the inertia friction welding (IFW) process is independent of process parameters and is relatively high, i.e., ~70 to 95 pct. In the present work, the effect of IFW parameters on process efficiency was established. For this purpose, a series of IFW trials was conducted for the solid-state joining of two dissimilar nickel-base superalloys (LSHR and Mar-M247) using various combinations of initial kinetic energy (i.e., the total weld energy, E _o), initial flywheel angular velocity (ω _o), flywheel moment of inertia (I), and axial compression force (P). The kinetics of the conversion of the welding energy to heating of the faying sample surfaces (i.e., the sample energy) vs parasitic losses to the welding machine itself were determined by measuring the friction torque on the sample surfaces (M _S) and in the machine bearings (M _M). It was found that the rotating parts of the welding machine can consume a significant fraction of the total energy. Specifically, the parasitic losses ranged from 28 to 80 pct of the total weld energy. The losses increased (and the corresponding IFW process efficiency decreased) as P increased (at constant I and E _o), I decreased (at constant P and E _o), and E _o (or ω _o) increased (at constant P and I). The results of this work thus provide guidelines for selecting process parameters which minimize energy losses and increase process efficiency during IFW.     

纯铜棒材三辊螺旋轧制过程数值模拟

三辊螺旋轧机适合于多品种、小批量、难变形材料的小尺寸管棒材开坯。通过对三辊螺旋轧制辊形设计和轧制过程进行研究,根据轧辊辊形计算方程,获得三辊螺旋轧机轧辊各段辊形参数。采用Simufact.Forming软件模拟了纯铜棒材三辊螺旋轧制过程。结果显示,纯铜棒材在三辊螺旋轧制过程中的变形规律为圆形—三角形—圆形的连续过程,轧件在变形段温度可达360℃左右,在轧辊与轧件接触区域内的最大应力为590MPa,最大等效塑性应变为3.8。轧辊在Z轴方向上所受最大载荷为43k N,而在X、Y轴方向上的最大载荷为350k N。Z方向的轴向力有助于铜棒的轴向咬入和抛出,X、Y方向的径向力主要起到减径和定径的作用。     

矩形管材的轧制

轧制方法生产矩形管材罕见于文献报道。作者的实验表明,矩形管材轧制过程可分为三个阶段,即咬入阶段、轧制建成阶段和甩出阶段。在四辊组合孔型中轧制矩形管材,最难咬入角是在咬入阶段:β≥α_i-Q/n;轧制建成阶段产品精度保证,而其他两个阶段则不然。     

镁板材轧制工艺及性能(续)

板材的力学性能决定于冷轧变形量与冷轧后的退火规范，它们对性能的影响起着很大的作用。材料的力学性能通过其状态代号表示：“O”表示完全退火，而“H”则表示不同的冷变形程度。     

镁板材轧制工艺及性能

目前全世界镁合金加工材的产量约20kt／a，其量虽少，却很重要，在航空航天器、赛车、电子产品等的关键零部件中获得了应用。本文对镁合金板材的轧制工艺及性能进行了全面的论述。     

Influence of Pass Parameters on Retained Mandrel Rolling Process

 Roller pass is one of the key factors affecting the product quality in the retained mandrel rolling process. The metal flow condition of rolling deformation area was researched using the FEA (finite element analysis) software Marc. The influences of the pass bottom radius, the sidewall radius, the sidewall angle, the roller shoulder fillet radius, as well as the roller gap on the rolling process under the conditions of different friction were discussed. Based on these results, the changes of the workpiece exit width, the mandrel axial force, the rolling force, and the rolling torque associated with various parameters were determined, which would provide the basis for designing the pass and determining the rolling condition reasonably.     

薄板坯连铸连轧流程的"临界参数"

根据薄板坯连铸连轧技术“临界紧凑”的工程实质,提出了薄板坯连铸连轧流程的“临界参数”概念,并对流程中的几个关键“临界参数”进行了分析。分析结果为薄板坯连铸连轧流程的优化提供了依据。     

铝材轧制加工过程中的摩擦特点及其影响

摩擦在铝材轧制生产过程中起着至关重要的作用，它影响着产品质量、轧辊的磨损和轧制过程的力能消耗。本文在分析铝材轧制过程摩擦特点、摩擦磨损机理的基础上，着重分析了摩擦对轧制过程、轧制压力、变形区、最小可轧厚度和产品质量的影响。采取合适的工艺润滑，是减少摩擦与磨损，降低轧制压力，提高生产效率和产品质量的有效途径。