精密锻造在汽车工业中的应用

近年来,由于精密锻造技术的迅速发展,推动了汽车制造业的进步。冷锻件和温锻件越来越多地用到汽车工业中,产品形状越来越接近最终形状。本文介绍几种精密锻件,例如汽车联动器和齿轮,也介绍了CAE技术在精密锻造中的应用。精密锻造将随着未来工艺和相关技术的进步得到相应发展,如材料、模具、模具冷却和润滑技术。     

全国冷温锻及有色金属锻造技术研讨会召开

随着我国汽车业和经济的发展,冷温锻件生产和有色金属锻件生产在锻造行业内显得越来越重要,为推动我国该领域的技术发展,中国锻造协会于1999年4月19～22日在江苏姜堰市召开了全国冷温锻及有色金属锻造技术研讨会。     

提高上海锻造技术水平途径的探讨

一、上海锻造行业的发展上海锻造行业是在五十年代中发展起来的。随着机械工业的发展,锻造行业经过多次调整、改组和改造,得到迅速发展。目前已初步形成比较完整的锻造生产体系,具备了一定的生产能力。据1980年统计,本市锻造生产厂点占全市机电工业企业总数的10.9%,其中市局系统占56%,郊县系统占44%.职工共有18000余人,占全市机电职工总数的1.4%。锻造设备拥有量占全市金切机床的15%,年产锻件能力约40万吨。本市也初步建立了大锻件生产厂点,锻件质量有所提高,如船用锻件已获国际船级社的认可。手工工具和手术器械是本市锻件制品的主要出口产品。近年来上海锻造生产中也采用了一些新工艺、新技术,如:年产量达25万件的精密模锻圆锥齿轮;汽     

大型不锈钢锻件锻造表面缺陷的火焰清理技术

本文介绍了在碳钢和普通合金钢大锻件锻造表面缺陷火焰清理技术基础上发展的大型不锈钢和其它高铬钢锻件锻造表面缺陷火焰清理技术,阐述了其原理及应用,并对这一技术在提高大型不锈钢锻件的精度、节约能源和原材料等方面的经济效益进行了分析。     

大型电站转子锻造工艺分析

大型电站转子是当前大型锻件中比较有代表性的技术密集型产品,它具有重量大、体积大、质量要求高、生产周期长、冶金缺陷较多、以及生产难度高等特征。是尖端锻造技术的代表。随着我国电力行业,尤其是火电行业的快速发展,对电站核心设备之一的转子锻件无论是数量和质量需求都大幅增加。因此,进一步探索转子锻造工艺,提高其产品质量已经是十分紧迫的任务。本文中,笔者立足于自身多年从事金属材料研究及锻造工艺研究的实际经验,结合相关理论,就大型电站转子锻造工艺做简要分析。     

锻造加工过程自动化技术的应用

用工业机器人取代人工操作,在机械加工行业已经成为一种发展趋势,备受使用单位的青睐。不仅如此,在锻造行业的应用也很广泛。锻造加工过程的自动化技术,主要应用于加热炉锻件推送、锻造过程中锻件装卸、模具模腔润滑与冷却、锻件锻后整形与切边等环节。锻造加工自动化技术的应用,提高了生产自动化程度,保证了锻件表面质量,减少机械加工的切削余量,极大提高生产效率。     

光学高温计的构造和使用

当我们对某种牌号的钢进行锻造时,锻造温度、锻造工艺和锻件质量的关系,是非常密切的。为了使锻件能够达到图纸上要求的技术条件,必须很好的掌握加热过程和锻造温度。不然的话,在锻造时将因温度过高,使锻件结晶颗粒变大,而降低了机械性能,或因温度过低,而使锻件产生裂纹。但是我们应该怎样来判别锻件温度的高低呢?用眼睛去判别,必须具有相当丰富的经验,并且不能十分准确。例如高合金钢锻件的温度,用眼     

探讨精密锻造工艺

正精密锻造是在普通锻造的基础上逐渐发展起来的一种少无切削新工艺,经过几十年已经发展成为由热精锻、温精锻、冷精锻、复合精锻、等温精锻等组成的多类别、应用广泛、科技含量高的新型材料成形技术。随着制造业的发展,精锻技术的日趋成熟,在汽车、船舶、航空航天、军事等行业中得到广泛应用。如日本丰田汽车厂在1996年发表资料说,该厂在1987年精锻件重量占全部锻件质量11.6%,到1991年发展到19.5%。     

辊子类锻件成形模具设计

正辊子类锻件是目前锻造生产厂最常见的锻件产品之一。在国民经济飞速发展的今天,我国锻造技术,特别是锻造模具设计及应用上取得了丰硕成果。但与国外先进技术相比,尤其在根据产品类型及生产环境选取适合的模具方面,还存在不小差距。笔者根据生产经验,对辊子类锻件的生产模具进行了创新设计。1.模具工艺分析辊子类锻件模具选用,直接决定着锻件表面质量和内部性     

复杂零件的精锻成形技术及关键装备

精密塑性成形是先进制造技术的主要内容之一，对于制造行业提高材料利用率、节能减排有着重要意义。据2003-2004年美国锻造工业协会出版的锻造工业发展指南介绍，未来的核心指标为：锻件材料用量减少15％，废品率减少90％；模具寿命比现在延长10倍，单件模具费用减少50％；锻件平均成本降低60％。日本作为当今世界锻造大国，年产精密锻件70万t，其精密锻件占模锻件总量的37％，每辆轿车冷精锻件79个品种，重达56kg。     

1000MW超超临界汽轮机转子锻件研制

国内1000MW级超超临界机组设计、制造和运行,在"十一五"期间已经取得国产化成功,但对于其中的核心锻件如高压、中压、低压转子等,一直未实现国产化;同时,国外对核心锻件的制造技术也采用严密封锁,拒绝相关的锻件制造技术的出口。上海重型机器厂有限公司通过自主创新,实现了MW级超超临界汽轮机转子锻件的制造技术突破,使MW级超超临界汽轮机转子锻件实现了国产化。     

Hot shape forging of gas turbine disk using microstructure prediction and finite element analysis

The Waspaloy, a Ni-based superalloy, has been widely used for forging material of gas turbine disk since it requires the high tensile strength at high temperature and good resistance to low cycle fatigue. The purpose of this study is to develop a forging process of turbine disk that satisfies the hot deformation characteristics of Waspaloy. Generally, the hot forging of superalloy has been subjected to isothermal forging since the available temperature range of forging is narrow. However, the non-isothermal forging was used to make a turbine disk in this study. Therefore, the analyses of temperature variation and deformation behavior of the material were important to obtain the sound forging products. The hot compression test was carried out to know formability at high temperature and microstructure evolution during hot deformation. In order to define the optimum forging conditions including material temperature, strain rate, strain, microstructure evolution and forging load, the commercial finite element analysis code was used to simulate the forging procedure of turbine disk. The hot forged turbine disk was heat-treated for obtaining the high temperature properties. The cut-off tests on the heat-treated forged disks were carried out. Experimental results were compared with the simulation results by FE analysis. Test results were in good agreement with the simulations. This study shows that the superalloy turbine disk can be manufactured by the semi-closed die forging.     

DESIGN AND MANUFACTURE OF STRAIGHT BEVEL GEAR FOR PRECISION FORGING DIE BY DIRECT MILLING

In the manufacture of straight bevel gears, a precision forging method has been mainly used in recent years and the precision forging die has been usually manufactured using electric discharge machining. However, it is difficult to content the high productivity and low manufacturing cost using electric discharge machining because the gears are produced through a process of several steps. In this article, a design and manufacture of a straight bevel gear for a precision forging die by direct milling is developed in order to improve the productivity and manufacturing cost for the gear production. The tooth profile of a straight bevel gear generated by a quasi-complementary crown gear instead of a usual complementary crown gear is introduced. For this study, first the numerical coordinates on the tooth surface of the straight bevel gear were calculated and the tooth profiles were modeled using a 3D-CAD system. Afterward, the direct milling of the precision forging die of the straight bevel gear in the hardened state was carried out using a CNC milling machine based on a CAM process through the calculated numerical coordinates.     

GCr15SiMn钢轴承套圈开裂原因分析

采用光学显微镜、扫描电镜等检测分析手段,对GCr15SiMn钢轴承套圈开裂原因进行了分析.结果表明:引起套圈开裂的主要原因是由于锻造比不够,始锻和终锻温度偏高,造成套圈组织中存在碳化物偏析以及碳化物呈网状分布,使材料的脆性显著增大.在淬火过程中,由于热应力和相变应力的作用导致轴承套圈萌发裂纹,进而在磨削工序外力作用下裂纹扩展而失效.     

10Ni3MoVD锻件焊接裂纹敏感性试验研究

采用多种试验方法对抗拉强度级别为610MPa的-50℃低温高强钢锻件10Ni3MoVD焊接冷裂纹和再热裂纹敏感性进行试验和综合评定,为该锻件焊接和焊后热处理工艺的制订提供了可靠的依据。     

基于资源环境属性的锻造工艺能耗分析

论文介绍了锻造工艺能耗高、排放大的特点,并对锻造工艺的资源消耗和环境影响属性进行分析,建立锻造加工资源环境过程模型。根据过程模型建立了锻造工艺能耗矩阵和排放矩阵,并以2.5吨皮带锤为例,对能耗进行计算和分析。     

开式变量泵控油压机系统控制特性研究

为解决大功率自由锻造油压机高能耗的问题,设计了一种开式变量泵控油压机系统。采用ADAMS和AMESim建立了开式变量泵控油压机系统联合仿真平台,对其常锻工况和快锻工况的控制特性进行了仿真研究。基于600kN锻造油压机实验平台,对其常锻工况和快锻工况的控制特性进行了验证,并将验证结果与仿真结果进行了对比。研究结果表明:开式变量泵控油压机系统能够满足技术要求,即常锻时操控性好,卸压无冲击,运行平稳;快锻（锻造频次80次/min）时,位置控制精度小于1mm。     

Precision forging technology for aluminum alloy

Aluminum alloy is a preferred metal material for lightweight part manufacturing in aerospace, automobile, and weapon industries due to its good physical properties, such as low density, high specific strength, and good corrosion resistance. However, during forging processes, underfilling, folding, broken streamline, crack, coarse grain, and other macro- or microdefects are easily generated because of the deformation characteristics of aluminum alloys, including narrow forgeable temperature region, fast heat dissipation to dies, strong adhesion, high strain rate sensitivity, and large flow resistance. Thus, it is seriously restricted for the forged part to obtain precision shape and enhanced property. In this paper, progresses in precision forging technologies of aluminum alloy parts were reviewed. Several advanced precision forging technologies have been developed, including closed die forging, isothermal die forging, local loading forging, metal flow forging with relief cavity, auxiliary force or vibration loading, casting-forging hybrid forming, and stamping-forging hybrid forming. High-precision aluminum alloy parts can be realized by controlling the forging processes and parameters or combining precision forging technologies with other forming technologies. The development of these technologies is beneficial to promote the application of aluminum alloys in manufacturing of lightweight parts.     

Approximate-model Based Estimation Method for Dynamic Response of Forging Processes

Many high-quality forging productions require the large-sized hydraulic press machine (HPM) to have a desirable dynamic response. Since the forging process is complex under the low velocity, its respon...     

焊接齿轮的热处理工艺研究

通过对中碳调质钢焊接齿轮采取焊前低调、焊后留磨量高调热处理工艺的研究实践，既保证了产品性能和变形量的要求，又简化了锻造工序、节约了材料、有利于多规格的批量生产，现已成功地应用于生产实践之中。