科技简讯

科技简讯薄壁圆形长筒的火焰矫正法铜压力加工行业中，常用感应炉加热挤压坯锭，感应炉的内衬套多为不锈钢（ＩＣｒ１８ＮｉｇＴｉ）薄壁圆形长筒。由于炉子从常温加热到坯锭的挤压温度，升温在很短时间内完成，炉子使用一段时间后，不锈钢内衬筒就会发生变形。当感应炉需...     

新型等温挤压铝锭加热炉

在质量好、效益高的铝挤压制品生产过程中,最重要的先决条件就是尽可能保持挤压出口温度稳定。这就要求加热装置能使挤压锭内的温度呈轴向分布,或者对挤压筒进行不同的加热。德国伊塞隆市的Ｉｎｄｕｔｉｏｎｓ－Ａｎｌａｇｅｎ－Ｓｅｒｖｉｅｓ公司（Ｉ． Ａ．Ｓ）是一家感应加热炉、电阻加热炉及挤压筒生产厂家,最近生产出一种名为 Ｉ．Ａ．Ｓ Ｔｅｍ－Ｐｒｏ－Ｈｅａｔｅｒ的新型加热炉,该加热可使挤压锭的温度呈轴向分布。 这种新型加热炉与目前所用的推进式加热炉不同,它是加热坯锭的头部,这样就适用于各种长度、半径和不同合金的…     

挤压机设计参数的选择(上)

挤压机的设计参数包括工艺参数,力学参数和速度参数。其中工艺参数包括:挤压材料(如铝及铝合金,铜和铜合金),铸锭直径,挤压筒直径,铸锭长度,挤压筒长度,制品外接圆直径,制品长度等;力学参数包括:挤压机吨位,穿孔力,主缸回程力,穿孔回程力,容室锁紧力,容室松开力,制品剪切力,残料分离力等;     

φ160组合挤压筒在铝压机上的使用和改造

挤压筒是在挤压过程中容纳锭坯的容器,因它承受高压、高温的作用而选用耐热工具钢制造(每只造价6万元以上),其使用寿命直接影响挤压生产的成本。现以我厂Φ160挤压筒在1500t挤压机上使用的情况,对其出现的故障、缺陷和相应的改进措施作一分析和探讨。     

挤压筒强度优化设计

挤压筒是铝、铜型材生产用的主要工模具之一,在型材生产时受到金属变形给予的压力、热应力及摩擦力的作用。这些力的共同作用,使挤压筒的径向产生应σ_r,切向产生应力σ_r。作者通过单层圆挤压筒、多层圆挤压筒及多层扁挤压筒强度分析和计算,提出了挤压筒强度的优化设计原理,在实际使用中取得了显著的经济效益。     

包覆挤压钛及钛合金除铜皮酸洗及其残液回收工艺研究

采用铜包覆挤压钛及其合金制品时，其生产的最后一道工序是用酸洗的方法除去制品表面的铜皮。多年来，一直沿用着传统的工艺方法。此工艺方法耗酸量大，平均每吨管坯消耗硝酸412kg，再利用残液制取硫酸铜，平均每吨管坯还要耗费硫酸103kg。由于没有成熟的工艺，仅凭经验生产，硫酸铜的产出率也不稳定，而在最后排放的残液中，还残留有酸和铜离子，造成环境污染。本试验旨在探索以硫酸代替部分硝酸去除钛及钛合金铜皮的酸洗工艺及制取硫酸铜工艺，并在此基础上进行了残液循环使用的尝试，以期改进酸洗工艺，降低酸耗，彻底消除残液排放造成的…     

软铝合金快速加工探讨

<正>在软铝合金快速挤压的可能性及极限范围内,讨论快速挤压的特点、优越性及实现快速挤压的基本条件与关键技术,促进软铝合金快速加工水平。金属挤压的工艺参数很多,如挤压力、挤压温度、挤压速度、挤压变形程度、制品的形状与尺寸、制品的性能要求、锭坯的形状与尺寸、挤压机的能力与挤压筒尺寸等等。但决定挤压制品质量、成品率和生产效率的重要工艺参数主要是挤压速度、挤压温度和锭坯尺寸,如果这三个参数能优化匹配,特别是挤压速度和挤压温度能优化匹配就能成批地生产出成品高、生产效率高,     

对内衬产生龟裂挤压简的修复及预防龟裂的改进措施

针对3150T挤压机挤压筒内衬产生龟裂后,无法将内衬从挤压筒中取出的难题,利用钢铁在高温条件下遇氧气燃烧的原理,通过专门设计的配套装置对产生龟裂的挤压筒内衬进行切割、取出,并对挤压筒内壁进行检查修复,使其可以重新投入生产使用.同时,通过分析挤压筒内衬产生龟裂的原因,采取了相应的改进措施.实践证明,此修复办法及改进措施均有效可行.     

挤压铝型材整体壁板用扁挤压筒有限元优化设计

采用弹性有限元法对生产大型铝合金整体壁板用扁挤压筒进行了应力分析,考察了扁挤压筒在不同内压,不同尺寸和不同装配应力下的应力分布状况,提出了可行设计方案和新的设计思想,为扁挤压筒的优化设计提供了理论依据。     

扁挤压筒型腔有限元应力分析及形线优化

本文对８５０ｘ３２０ｍｍ扁挤压筒内套进行了有限元分析计算，运用优化设计理论对扁挤压筒型腔进行计算机辅助形状优化设计，确定了使应力集中系数降为最小的最优形线，为延长扁挤压筒使用寿命提供了一条有效途径。     

汽车热传输铝合金复合带(箔)生产技术及工艺装备的开发

本文全面地介绍了汽车热传输系统的特点、分类,详细论述了汽车热传输铝合金复合带(箔)的特点、材料选择、生产工艺技术以及产品的规格、用途及国内目前的产能和产量、消费与需求情况及市场分析,同时对其生产工艺装备的特殊要求及我国的开发状况也进行了讨论。     

三相工频感应器用于铜材透热

在热挤压成型的铜材生产工艺中，需要对不同规格的铜铸锭进行加热，而采用感应加热是大家都熟悉的一种加热方法。结合目前挤压设备的挤压力和铸锭直径都在逐渐加大的情况，对直径大于250mm的铜铸锭加热，选择工频感应加热，感应器设计为三相工作，采用三台单相磁饱和调压器组成供电电源；保证了铜铸锭温度的均匀性，尤其对于铜合金（黄铜）铸锭，不易出现铸锭表面温度过高造成的铅、锌或锡的析出现象。更换不同直径的铸锭所对应的感应器时，由于没有电抗器，所以三相平衡调整方便。整套系统工作稳定，操作维修简单。     

挤压工艺参数对挤压过程影响规律的仿真模拟研究

研究对象是某6063工业铝型材,将建立好的三维模型导入到有限元Altair Hyperxtrude分析软件进行仿真模拟,通过改变型材挤压工艺参数（挤压比、棒料预热温度、模具预热温度、挤压筒预热温度、挤压速度）,研究其对金属流动的规律,基于直交表Taguchi方法分析各挤压工艺参数对型材截面速度分布和挤压力的影响规律.结果表明:对于型材截面流动均匀程度指标参数,最佳挤压参数为挤压棒料外径205 mm、挤压垫速度3.2 mm/s、棒料预先加热温度480 ℃、挤压模具预先加热温度470 ℃、挤压筒预先加热温度440 ℃;对于挤压力指标参数,棒料外径200 mm、挤压垫速度1.4 mm/s、棒料预先加热温度490 ℃,挤压模具预先加热温度480 ℃、挤压筒预先加热温度460 ℃.      

Flow behavior of the billet surface layer in porthole die extrusion of aluminum

In this study, the effects of some direct extrusion parameters on the flow behavior of the billet surface layer in porthole die direct extrusion of aluminum were investigated. Extrusion parameters to be changed were friction conditions on the container wall, temperature, and stroke. To detect the flow pattern of the surface layer, two types of billets were used. The flow of the surface layer could be divided into an inward flow along the back face of the billet and a forward flow along the boundary of the dead zone. The container friction strongly influenced the balance between two flows, while the extrusion temperature had little influence on the flow pattern. The paths that the billet surface layer followed in the welding chamber through the porthole were revealed clearly. Once the surface layer flows into the porthole, it appears on the outer face of the extrudate or just below it. Especially, the surface layer, which follows the inward-flow path, penetrates into even the welding plane of the tube, resulting in the welding defect.     

Effect of a shell on the change in shape of a porous billet during isostatic pressing. 1. stress deviator with isostatic pressing

Isostatic compaction of a porous billet in an incompressible container is considered. The behavior of the container as well as the matrix phase of a porous billet is assumed to be described by power law equations. Macroscopic deformation of a billet is controlled by flow theory for a compressible body with a smooth potential. It is established that the stressed state in a billet is not isostatic. Materials Science Institute, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1–2, pp. 36–42, January–February, 1997.     

Pressing prismatic and screw profiles from copper M4

Pressing methods of prismatic and screw metallic profiles are considered. An example of cold pressing of a billet from copper M4 with the formation of a solid square-cross-section profile is presented. Conventional pressing (extrusion) and extrusion followed by torsion pressing (extrusion and screw pressing (ESP)) are compared by mechanical characteristics, energy intensity, and the destruction character of copper samples. Herewith, the ESP of the billet was performed in one facility during the united production process. Pressing prismatic and screw profiles for one pass at room temperature was performed for copper billets Ø11.7 × 60 mm. The billet was loaded with a puncheon with the help of a hydraulic press. After the deformation treatment, solid prismatic and screw copper profiles with a square cross section of 8 × 8 mm were formed. The results on mechanical properties, deformation regularities, and destruction mechanism during the uniaxial tension of the samples made of technical copper M4 in the delivery state and after hardening are presented. Mechanical tests for uniaxial tension of the samples with a working size of Ø3 × 15 mm were performed using an UTS-20k testing machine at a constant loading speed of 3.33 × 10^–5 m s^–1. A certain increase in the strength of copper subjected to extrusion for one pass at room temperature is established. Screw pressing after extrusion provides higher plasticity compared with the initial state and extrusion. A fractographic research of sample ruptures is performed using a Hitachi TM 3030 scanning electron microscope in the secondary electron mode. It is shown that the destruction mechanism of copper samples in the delivery state, as well as after extrusion and ESP, is qualitatively identical. The destruction of the samples of copper M4 both in the initial state and after the deformation treatment according to the specified modes occurred according to the viscous fracture mechanism. It is revealed that ESP-subjected copper possesses larger energy intensity in connection with an increase in plasticity. The rupture in a fibrous zone for the ESP-subjected sample differs by the tier arrangement of pit blocks. Large pits and micropits in all states of copper are present both in the fibrous zone and in the peripheral cut zone.     

挤压筒的简化设计

挤压筒是铜材生产的关键模具之一,工作时需要承受高温、高压、高摩擦的作用。本文从挤压筒的结构、选材及强度校核几方面,通过分析计算,提出了挤压筒简化计算的原理,在实际使用中取得了显著的经济效益。     

由C12200管材生产简析含磷类管材表面起泡问题

通过对C12200铸锭的切片分析,提出挤压过程含磷类管材表面起泡的新见解。     

连续挤压应用过程中常见缺陷浅析与措施

连续挤压技术是一种新型高效加工技术,在铜加工领域得到日益广泛的应用,目前已成功应用于生产铜和铜合金母线、换向器用铜银合金异型排、电气化铁道用铜及铜合金接触线杆坯等制品,制品综合性能优越,并大大缩短了工艺流程,节约了生产成本。但在实际应用过程中,在工艺和产品质量控制上还存在一定问题,本文就常见制品缺陷进行分析,并提出切实可行的解决措施。     

Optimization of the uniformity of a metal flow during continuous extrusion by the Conform method

The scheme of plastic deformation of a billet in a container is considered as part of continuous extrusion by the Conform method. A mathematical model of the motion of a viscoplastic Bingham liquid is used to determine the metal velocity distribution in the plastic-deformation zone. As a result, the optimum angle between the longitudinal axes of the die and container is estimated. This angle is found to be one of the main factors affecting the nonuniformity of deformation when a metal flows into the die. The calculated results are compared to experimental data.