Basic study on the process combination of deposition welding and subsequent hot bulk forming

Today most technical parts and components are made of monolithic materials. Nevertheless, the previously used monolithic materials reach their technological and constructive limits, so that an improvement of the component properties can be realized by hybrid parts. Forging of previously joined semi-finished products to net shape hybrid components is a promising method to produce functional adapted parts in a few process steps. This new process chain offers a number of advantages compared to other manufacturing technologies. Examples are the production of specific load-adapted forging parts with a high level of material utilization, an improvement of the joining zone caused by the followed forming process and an easy to implement joining process because of the simple geometries of the semi-finished products. This paper describes the production process of hybrid steel parts, which are produced by a combination of a deposition welding process with a subsequent hot forging (upsetting) or cross-wedge-rolling. It could be shown that the innovative process chain enables the production of hybrid parts whereby the forging processes lead to an improvement of the mechanical properties of the laser deposited material.     

Investigation of the coating thickness of plasma-transferred arc deposition welded and cross wedge rolled hybrid parts

Most of today’s technical parts and components are made of monolithic materials. These mono-material components produced in established production processes reach their limits due to their respective material characteristics. Thus, a significant increase in production quality and efficiency can only be achieved by combining different materials in one part. Bulk forming of previously joined semi-finished products to net shape hybrid components that consist of two different materials is a promising method to produce parts with locally optimized characteristics. This new production process chain offers a number of advantages compared to conventional manufacturing technologies. Examples are the production of specific load-adapted forged parts with a high level of material utilization, an improvement of the joining zone caused by the following forming process and an easy to implement joining process due to the simple geometries of the semi-finished products. This paper describes the production process of hybrid steel parts, produced by combining a plasma-transferred arc deposition welding process with a subsequent cross wedge rolling process. This innovative process chain enables the production of hybrid parts. To evaluate the developed process chain, coating thickness of the billet is analysed before and after cross wedge rolling. It could be shown, that the forming process leads to an improvement of the coating, meaning a more homogeneous distribution along the main axis.     

特装重卡传动轴等强度轻量化设计

为了减轻特装重卡传动轴的重量,同时不降低其强度,对主要零部件进行了重新设计,对零部件毛坯的锻造工艺和机加工工艺进行了重新规划。设计了万向节总成,确定了万向节的规格,通过计算最终确定轴管尺寸为Φ150 mm×7 mm,通过对比相关的性能指标,对花键轴进行了选型,改进了端面齿突缘叉和花键轴毛坯的锻造工艺以及花键轴的机加工工艺,最终实现了特装重卡传动轴总成轻量化设计制造。实践结果表明,在不降低传动轴性能的前提下,通过减小关键零部件毛坯的下料尺寸,提高了材料利用率,传动轴总成减重6.76 kg,减重8.45%,实现了传动轴的轻量化设计。     

高铝锌基合金ZA27液态模锻工艺参数研究

叙述了用ZA27合金采用液态模锻工艺生产圆环零件的研究,确定了ZA27合金液态模锻最佳工艺参数,对常规铸造件和液态模锻件组织特征进行了对比分析。结果表明:液态模锻工艺生产的零件机械性能优于常规铸造件。     

用高氮钢制造复杂高强度零件(英文)

High performance components, e.g., fasteners, nowadays are usually made out of cold forged and heat treated steels like steel 1.5525 (20MnB4). To overcome the problems of heat treatment, e.g., low surface quality, new workpiece materials for cold forging should be found to achieve the needlessness of heat treatment after cold forging. One possible material is given by high nitrogen steels like steel 1.3815 (X8CrMnN19-19). Due to the high strain hardening of these materials the process and tool design for an industrial batch process are challenging and should be conducted by FE-simulation. The numerical results show that, high strength tool materials, like PM-steels or cemented carbides, in most cases, are inevitable. Additionally to the selection of suitable tool materials, the tool layout should be developed further to achieve a high loadability of the tools. The FE-models, used for process and tool design, are validated with respect to the materials’ flow and occurring forming force to assure a proper design process. Also the comparison of strength of components made out of steel 1.5525 in quenched and tempered conditions and steel 1.3815 in strain hardened condition is done. The results show that the component made of steel 1.3815 has a significantly higher strength than the component made of steel 1.5525. This shows that by the use of high nitrogen steels a high performance component can be manufactured by cold forging.     

DRC2000热模锻压力机优化设计

DRC2000热模锻压力机是在引进世界先进生产技术基础上,经过不断改进、完善,充分吸收MP、SP热模锻压力机的优点而设计的,具有重量轻、刚性好、传动平稳、结构可靠、导向精度高、维修操作方便等特点,用于进行成批大量的黑色和有色金属的模锻和精整锻件,锻件精度高,材料利用率高,生产率高,易实现自动化,同时对工人的操作技术要求低,噪声和振动小,是现代锻造生产不可缺少的高精锻设备。     

A double control forming technology combining die casting and forging for the production of Mg alloy components with enhanced properties

A double control forming technology combining the die casting and forging was firstly proposed for the production of Mg alloy components with enhanced properties. In this technology, high-speed filling of liquid melt and high-pressure forging of partially solidified melt were performed by using injection and forging systems of a double control forming device. Some Mg alloy motorcycle wheel components were produced by die casting and double control forming to verify the improvement of the mechanical properties of components formed by double control forming. The results showed that double control forming was an alternative technology for producing the complex Mg alloy components with enhanced properties. Average tensile strength and elongation of Mg alloy components produced by double control forming were greatly improved in comparison with die casting. The average tensile strength was enhanced from 126.8 MPa to 213 MPa and elongation was improved from 3.5% to 7.2%. The optimal process parameters were obtained according to the results of orthogonal experiments, which involved pouring temperature of 675 °C, injection speed of 2 m/s and die temperature of 210 °C. The improved nucleation frequency in the melt caused by the forging pressure led to successful grain refinement of the microstructure of the component produced by double control forming. The defects were removed from the microstructure due to plastic deformation caused by the forging pressure. A refined and densified microstructure led to an enhancement of mechanical properties of Mg alloy component produced by double control forming.     

铝合金锻件折迭与裂纹的控制

针对三通阀、轴承盖、油堵3种类型的铝合金模锻件 ,在生产中出现的折迭与裂纹的质量缺陷 ,进行了分析 ,并相应提出技术措施加以改进 ,取得了满意的效果。并总结归纳出预防铝合金模锻件产生折迭与裂纹的六点经验     

MICROSTRUCTURAL EVOLUTION AND CONTROL IN SUPERALLOY FORGINGS

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薄壁曲面零件的锻造成形工艺

某产品上用的一重要零件为薄壁曲面类零件,实际生产中主要采用机械加工制作,工序多,时间长,并浪费原材料.本文采用锻造成形工艺,锻模设计为曲面分模面模具结构,实现了薄壁曲面零件的锻造成形.零件成形后,无需再进行后续机械加工,产品的尺寸和形状均可直接达到使用要求.经过工艺试验和小批量的试生产考核,其尺寸和形状均能满足图纸技术要求,并且产品尺寸和形状的一致性好.与机械加工工艺相比,锻造成形工艺大幅度提高了产品生产效率和材料利用率,极大降低了生产成本.     

液态压铸锻造双控成形技术研究

压铸锻造双控成形技术不仅可以像压铸一样控制零件形状和尺寸，而且由于锻造可以使零件产生塑性变形并消除压铸产生的气孔、疏松等缺陷，从而使强度得到较大提高，并且可以通过热处理提高强度。铸锻双控成形工艺主要适合生产形状复杂和高强度要求的汽车零部件和其他结构件。介绍了压铸锻造双控成形技术实现方法和所生产零件的性能。     

基于正交试验法的齿类温锻件冲孔工艺优化

冲孔作为齿类温锻件生产过程中必不可少的一道工艺,其冲头磨损一直是冲头失效的主要形式,严重影响冲头使用寿命。以某双离合自动变速器的二档从动齿温锻件冲孔过程作为研究对象,分析了齿类温锻件冲孔过程中影响冲头模具寿命的主要因素,并将冲头最大磨损量作为表征冲头使用寿命的参数。通过正交试验和有限元模拟相结合的方法,定性分析了冲孔过程各工艺参数对冲头磨损的影响规律,并最终确定齿类温锻件的最优冲孔工艺。经过实际生产验证发现,优化后的冲孔工艺将冲头模具的使用寿命由原有的4000件左右提高至接近9000件,有效地提高了冲头的使用寿命。     

Influence of tribological conditions on cold forging of gears

Gears are integral and vital machine elements in the field of drive and transmission technology. With regard to economic and ecological aspects, cold forging represents a promising approach compared to conventional cutting processes for producing highly-loadable gears. A possible extrusion process for manufacturing helical gears is the so-called “Samanta”-process. In comparison to conventional extrusion processes, an additional ejector system is avoidable. Thus, in particular for helical gears, a negative impact on the gear quality by the ejector operation is prevented. Furthermore, the process chain during the component production cycle is shortened which leads to a more efficient production. The achievable gear accuracy as well as insufficient tool life are major challenges while establishing the “Samanta”-process in industry. To enable an industrial application, basic process understanding as well as knowledge about the influences on the process results is required. For influencing component and process properties within cold forging, approaches from the tribological system can be generally used. The aim of this study is to analyze the influence of the friction conditions on selected component and process properties within cold forging of gears by the “Samanta”-process. For adjusting the occurring friction, various lubrication systems were applied, which have been qualified using a double cup extrusion test (DCE-test). The results reveal that the lubrication system determines the friction conditions during forming. Within cold forging of helical gears by the “Samanta”-process, the friction influences the resulting strain hardening of the components and the required maximum forming force as well as the energy amount.     

锻模成组设计

应用成组技术相似性原理,进行锻模成组设计。使几何形状、尺寸相似的零件的锻模能共用,节约了人力、物力,及时满足了用户的需求,在竞争中赢得市场和经济效益。     

轿车等速万向节星形套闭塞模锻成形技术研究

介绍轿车等速万向节星形套闭塞模锻工艺的必要性,通过数值模拟方法研究该工艺过程,研制出了可生产应用的闭塞模锻液压模架,并进行了工艺试验,研究结果对汽车关键零部件闭塞模锻工艺选择和模具设计提供了技术指导.     

锻压钢球自动分拣热处理装置设计

针对河北某公司人工分拣锻压钢球热处理的生产工艺,设计了一种锻压钢球自动分拣热处理装置。该装置为机-电-气技术的结合体,整体为盘形桶体结构,盘面上设置了可变间距的圆形道轨。安装在固定盘部件上的转盘部件在动力装置的驱动下实现可调速间歇旋转,当钢球进入道轨后随转盘部件旋转而滚动旋转降温,在盘面上16个旋转间歇位置开设有圆孔,其上装有测温设备进行实时监控,与温控设备联动的气动装置控制活动道轨动作,以实现钢球下落。整套装置自动控制,可实现自动分拣适合淬火温度锻压钢球至热处理池淬火以及不适合淬火温度低温钢球至升温设备的有效分流。解决了原生产工艺因人为不确定性因素而造成的钢球表面硬度不均匀、不稳定等一系列质量问题,降低了生产成本,提高了生产效率。     

Pressured-assisted injection forging of thick-walled tubes

Numerous engineering components may be created in a hollow form without detracting from their performance requirements; the difficulty, however, is in the conversion of tubular materials into such components. Hollow components may be formed from tubular materials if these can be prevented from collapsing during the forming cycle. Further, die-filling during injection forging, is especially difficult at the terminal stages of the process; the use of a pressurising medium within the material could effect die-filling more effectively.The scope for the forming of thick-walled tubes into hollow components was investigated using different pressurising media to support the material during the forming cycle. A tubular hexagonal form was the basis for the evaluation of the forming requirements of the process. Several pressurising-media were tested experimentally to determine suitability and the process was stimulated using FE techniques to establish the “optimal” processing sequence.The pressurising-medium influences the forming sequence for the production of a component of acceptable quality. The forming sequence has three distinct stages. Injection forging of the tube has to be proceeded by an initial internal pressurisation while subsequent injection has to be matched by increases in pressurisation; the final stage is characterised by a rapid increase in pressurisation to complete the filling of the die. Failure to establish the correct sequence will result in different forms of failures; the correct sequence will enable the production of a component of “uniform” wall-thickness.     

Effects of processing parameters in P/M steel forging on part properties: A review part I powder preparation,compaction, and sintering

In the last decade, powder metallurgy (P/M) technology has made marked advances in competitive manufacturing. P/M offers design opportunities that are not possible with other methods, as well as significant cost savings. In the automotive industry, P/M forgings are being developed for applications requiring good high- cycle fatigue properties. The processing parameters, material characteristics, individual stages of compaction and parts production, deformation and densification mechanics and tooling, and preform design influence the properties of the P/M part and related economics. Therefore, a review of the various parameters involved in the different stages of P/M steel forging in net-shape manufacturing and their implications on resulting properties of the P/M parts is presented in a three part review. Key parameters in steel powder preparation, compaction, and sintering of P/M forging and their effect on part properties are described in Part I. Part II discusses issues of forging the sintered compact, and Part III reviews currently available analysis methods for studying the powder forging process.     

Effects of processing parameters in P/M steel forging on part properties: A review part II forging of sintered compact

In the last decade, powder metallurgy (P/M) technology has made marked advances in competitive manufacturing. P/M offers design opportunities that are not possible with other methods, as well as significant cost savings. The processing parameters, material characteristics, individual stages of parts production, deformation and densification mechanics and tooling, and preform design influence the properties of the P/M part and related economics. Therefore, a review of the various parameters involved in the different stages of P/M steel forging in net-shape manufacturing and their implications on resulting properties of the P/M parts is presented in a three-part review. Part I discussed the issues of powder preparation, compaction, and sintering in the stages of preparing a sintered compact. This review (Part II) identifies key parameters in forging the sintered compact that influence the properties of the powder forged part. Part III reviews currently available analysis methods for studying the powder forging process.     

圆柱从动齿轮坯新型锻模设计

论述了圆柱从动齿轮坯原锻模存在的问题 ,提出了新型锻模结构。使用新型锻模 ,锻件无飞边 ,敷料减少80 % ,显著降低材料消耗和生产成本