外文翻译冷锻技术的发展现状与趋势

1、附录1:翻译（汉）冷锻技术的发展现状与趋势 摘要： 冷锻技术是一种精密塑性成形工艺，具有切削加工不可比拟的优点，广泛应用于各种机械产品关键零部件的制造。本文从冷锻零件的形状、材料、工艺革新、生产率、数值模拟技术和数字化/智能化设计技术应用、以及优化技术几个方面综合论述了冷锻技术的发展现状与趋势。关键词： 冷锻，工艺/模具设计，数值模拟，基于知识的工艺设计，设计优化 。冷锻工艺是一种精密塑性成形技术，具有切削加工无可比拟的优点，如制品的机械性能好，生产率高和材料利用率高，特别适合于大批量生产，而且可以作为最终产品的制造方法（net-shape forming），在交通运输工具、航空航天和机床工业

2、等行业具有广泛的应用。当前汽车工业、摩托车工业和机床工业的飞速发展，为冷锻这一传统的技术的发展提供了原动力，例如，我国1999年摩托车的全国总产量就有1126万多辆，而根据2000年的初步估计，我国汽车的总需求量到2005年将达到330万辆，其中轿车130-140万辆，仅汽车行业的锻件需求在50-60万吨以上。冷锻技术在我国的起步虽然不算太晚，但发展速度与发达国家有很大的差距。到目前为止，我国生产的轿车上的冷锻件重量不足20Kg，相当于发达国家的一半，开发潜力很大。加强冷锻技术开发与推广应用是我国目前的一项紧迫任务。1、冷锻件的形状越来越复杂 冷锻零件的形状越来越趋于复杂，由最初的阶梯轴、螺钉

3、/螺母和导管等，发展到形状复杂的零件，如图1所示为不同尺寸的摩托车花键轴与花键套，花键轴的典型工艺为：正挤压杆部-镦粗中间头部分-挤压花键；花键套的主要工艺为：反挤压杯形件-冲底制成环型件-正挤压轴套。如图2所示为汽车输出轴与输入轴，以及其他冷锻制品。如图3所示为我国采用摆动碾压技术制成的各种汽车/摩托车用锥齿轮、螺旋锥齿轮和其他圆盘类零件，如图4所示为日本某公司生产的冷锻零件，图4所示的涡旋增压器，我国已经列入国家“十五”攻关项目。目前圆柱齿轮的冷挤压技术也成功用于生产。除黑色金属外，目前铜合金、镁合金和铝合金材料的冷挤压应用也越来越广泛。2、持续不断的工艺革新 冷精锻是一种(近)净形成形工

4、艺。采用该方法成形的零件强度和精度高,表面质量好。当前国外一台普通轿车采用的冷锻件总量4045Kg,其中齿形类零件总量达10Kg以上。冷锻成形的齿轮单件重量可达1Kg以上、齿形精度可达7级。持续不断的工艺创新推动了冷挤压技术的发展，80年代以来，国内外精密锻造专家开始将分流锻造理论应用于正齿轮和螺旋齿轮的冷锻成形。分流锻造的主要原理是在毛坯或模具的成形部分建立一个材料的分流腔或分流通道。锻造过程中，材料在充满型腔的同时，部分材料流向分流腔或分流通道。分流锻造技术的应用,使较高精度齿轮的少、无切削加工迅速达到了产业化规模。提出，对于长径比为5的挤压件，如活塞销，采用轴向余料块的方法通过轴向分流可

5、以实现冷挤压一次成形，而且凸模的稳定性很好；对于扁平类的直齿轮成形，采用径向余料块也可以实现产品的冷挤压成形。闭塞锻造是在封闭凹模内通过一个或两个冲头单向或对向挤压金属一次成形,获得无飞边的近净形精锻件。一些轿车精密零件如行星和半轴齿轮、星形套、十字轴等如果采用切削加工方法,不仅材料利用率很低(平均不到40%),而且耗费工时多,生产成本极高。国外采用闭塞锻造技术生产这些净形锻件,省去绝大部分切削加工,成本大幅度降低。冷锻技术的发展主要是开发高附加值的产品,降低生产成本,同时, 它还在不断地向切削、粉末冶金、铸造、热锻、板料成形工艺等领域渗透或取而代之, 也可以和这些工艺相结合构成复合工艺。提出

6、的热锻-冷锻复合塑性成形技术。热锻-冷锻复合塑性成形技术是将热锻和冷锻结合起来的一种新的精密金属成形工艺，它充分利用了热锻和冷锻各自的优点：热态下金属塑性好，流动应力低，因此主要的变形过程用热锻来完成；冷锻件的精度高，因此零件的重要尺寸用冷锻工艺来最终成形零件。热锻-冷锻复合塑性成形技术出现于20世纪80年代，90年代以来取得了越来越广泛的应用，用该技术制造的零件，已取得了精度提高、成本降低的良好效果。 图1 图2 图 3 图 43、数值模拟技术用于检验工艺和模具设计的合理性用冷锻工艺成形零件时，由于金属在冷态下发生塑性变形，其变形抗力很大，因此，零件的变形比较困难，变形过程中容易出现金属充不

7、满、锻件出现裂纹等缺陷。同时，过大的变形抗力会严重降低模具的使用寿命。长期以来,我国金属塑性成形的工艺设计和模具设计一直采用传统的凭经验、实验方法。这种设计方法难以满足净形制造工艺的要求。随着计算机技术的飞速发展和70年代塑性有限元理论的发展，许多塑性成形过程中很难求解的问题可以用有限元方法求解。在冷锻成形工艺领域，通过建模和合适的边界条件的确定, 有限元数值模拟技术可以很直观地得到金属流动过程的应力、应变、模具受力、模具失效情况及锻件可能出现的缺陷情况。这些重要信息的获得对合理的模具结构,模具的选材、热处理及成形工艺方案的最终确定有着重要的指导意义。目前的有效的数值模拟软件是以刚塑性有限元法

8、为基础建立起来的,这些软件有:DEFORM,QFORM，FORGE，MSC/SUPERFORM等。运用有限元数值模拟技术可用于检验工艺和模具设计的合理性。如提出了一种由空心坯成形直齿圆柱齿轮的新工艺: 预锻分流区-分流终锻, 用三维有限元数值模拟软件DEFORM-3D 进行了数值模拟研究, 得到了锻造载荷-行程曲线以及整个成形过程的应力、应变、速度分布等, 并与传统的闭式镦挤工艺模拟的结果进行了比较。分析表明, 传统的闭式镦挤成形直齿圆柱齿轮, 成形载荷大, 不利于齿形的充填。采用预锻分流区-分流终锻新工艺, 可以大幅度降低成形载荷,并明显改善材料的充填性, 可以获得齿形角部饱满的齿轮。 用三

9、维大变形弹塑性有限元法对齿轮冷精锻成形过程进行了数值模拟,对以闭式模锻为预锻和以闭式模锻、孔分流及约束分流为终锻的两步成形模式的变形流动情况进行了数值模拟分析。数值分析结果及工艺实验表明在终锻中采取分流,尤其是约束孔分流措施对于降低工作载荷和提高角隅充填能力等方面十分有效。4、数字化智能设计系统的应用4.1 CAD/CAM技术在冷锻成形工艺/模具设计中的应用为了适应现代生产对锻模开发的短周期、高质量、低成本要求，将先进的设计理论与方法以及计算机技术，尤其是CAD技术的引入传统的锻模设计过程是锻模设计领域的必然趋势。模具CAD技术以其高自动化、高精度和高效益等优势正持续推动着传统的模具设计与制造

10、方法的变革。自20世纪70年代以来，国外许多单位开始对锻模CAD/CAM进行了广泛的研究，美国Ohio州的贝特尔哥伦布实验室的T.Altan等人首先开发了轴对称锻模CAD系统。前苏联的捷捷林等专家系统研究了模锻设计自动化和最优化原理，从方法学、算法模型等方面提出了全套的理论，并开发了回转体类锻件的自动化设计系统。国内在这方面的起步较晚，上海交通大学、清华大学、华中理工大学、哈尔滨工业大学和南昌大学等单位基于一定的平台，开发了适用于不同种类锻件的设计系统，但多数仅仅限于二维系统。到目前为止，虽然众多的研究人员先后开发了适用于不同零件的锻模设计系统，实现了工艺和模具设计若干环节的自动化和智能化，但

11、是尚未有成熟的锻模CAD/CAM系统推向市场，许多工程设计人员只能采用通用的机械CAD/CAM软件进行结构的详细设计。4.2 基于知识的设计技术及其在冷锻成形工艺/模具设计中的应用冷锻成形工艺和模具设计是知识和经验密集型的过程，模具设计人员在长期工作中积累的经验与知识(Know-how)对模具设计有着十分重要的影响。传统的CAD技术脱离了设计领域知识,缺乏对设计过程知识的支持,难以胜任模具开发"高质量、短周期、低成本"的要求。因此,需要将传统的锻模CAD技术提升到基于知识的设计层次。而实现这一飞跃的途径是将人工智能（Artificial Intelligence, AI）技

12、术、基于知识的工程（Knowledge-based Engineering, KBE）技术引入冷锻成形工艺/模具设计领域，与传统的CAX技术相结合，开发基于知识的设计支持系统。基于知识的工程（Knowledge Based Engineering, KBE）主要指应用知识来解决各种工程问题，是人工智能技术在工程中的应用。由于冷锻成形工艺/模具设计是一个包含了对知识的继承、集成、创新和管理的复杂过程，引入基于知识的设计方法以后，跨领域专家的经验与知识共享能够使得设计更加富有创造性和预见性，而且领域专家知识在整个产品的设计生命周期内的一致性保证了产品开发的成功率，大大节省了开发时间，提高了设计质量

13、。从而使整个设计模式从经验设计向科学设计转变。美国哥伦布贝特尔实验室开发出基于知识的预锻几何尺寸的设计系统，因设计预锻件的形状为空间几何体，须对其几何形状进行操作，故不能单纯地用一般语言来描述推理过程。对于零件的几何信息，采用框架方法表示，在框架中用不同的槽，定义出组成零件的基本成分和它们之间的拓扑关系。设计规则是用产生式规则表示，用OPS工具进行推理。J. C. Choi和C. Kim开发了基于知识的冷锻件和热锻件集成工序设计系统，并分别建立了冷、热锻件工艺设计规则。 基于知识设计方法在冷锻成形工艺及模具的设计中的应用，将彻底改变塑性成形传统的依靠设计人员个人经验，设计过程中反复修改、设计效

14、率不高的状态。它使用人工智能、模式识别、机器学习等技术在设计过程中从系统知识库中提取合适的知识指导冷锻成形工艺及模具设计。目前，该项技术正在进一步发展之中，近年来，基于知识设计方法已成为锻造成形工艺/模具设计智能化技术研究的一个热点课题。 5、优化技术的引入随着竞争的日益加剧，低成本、高质量和高效率是制造业所追求的目标。在锻造行业，为提高设计效率、降低制造成本和提高产品质量，必须对锻造工艺过程中影响锻件质量的各项工艺参数进行优化。由于锻造变形是一个十分复杂的问题，对于其工艺参数的优化采用传统的设计方法很难达到预期的效果，随着计算机技术和塑性有限元理论和技术的不断发展和日益完善，以有限元法为代表

15、的数值模拟方法已广泛应用于各种金属成形问题的求解分析。因此，基于有限元分析的优化设计方法在冷锻成形工艺/模具设计中的应用不仅是可能的，也是一种必然趋势。从实际应用的角度来看，基于有限元分析的优化方法中最具代表性的方法有基于灵敏度分析的优化方法和基于目标函数值的拟合优化方法两种。基于灵敏度分析的优化设计方法属于梯度型优化设计方法。该方法在具体实施时，首先确定目标函数和设计变量，然后找出它们之间的关系，推导目标函数对设计变量的灵敏度导数公式，根据设计变量的现有值求解出这些灵敏度信息，再利用优化算法确定设计变量的最优搜索方向，得到更优的设计变量，再求解灵敏度信息，如此反复，直到优化迭代收敛。 基于目

16、标函数值的拟合优化方法来源于外推法。这种方法用简单的插值函数来近似逼近目标函数和设计变量之间的函数关系，通过求解这个近似函数的极值点来逼近真实函数的极值点。该方法用在锻造工艺参数优化时，目标函数值是通过有限元程序来实现的。目前，一些通用的有限元分析软件如(DEFORM、Marc)已广泛应用于锻造成形过程的数值模拟，可十分方便地计算出应力、应变等信息，因此，基于目标函数值的拟合优化方法可使有限元程序与优化算法分离，适合不同的锻造成形工艺，对于锻造成形过程的参数优化比较方便。虽然基于有限元分析的锻造工艺优化技术的研究与应用已取得了不少成果，但目前仍处于起步阶段。从目标函数的构建、优化设计变量的选取

17、到优化方法的具体应用可以看出,该领域的研究还存在一些问题。（1）基于灵敏度分析的优化方法的研究和应用已取得了不少的成果，由于该方法属于梯度型优化方法，因此其收敛速度比较快。但它在实际的应用中还存在一些缺点：在优化设计过程中需要求解目标函数相对于优化设计变量的灵敏度信息(即导数)，对于复杂的金属塑性成形过程的灵敏度信息的推导困难。该方法要求将求解灵敏度信息的程序代码嵌入到数值分析程序代码中，需要编写有限元分析代码和优化算法代码，编程工作量大。同时该方法优化程序通用性差。（2）基于目标函数值的拟合优化方法的优点是优化算法与有限元程序分离，可充分利用功能强大的商用有限元分析软件的优势，该方法的通用性

18、较强。它的主要缺点是收敛速度比较慢，同时由于在拟合问题中，但设计变量取得较多时，会出现许多复杂的问题如适定性问题，使得拟合过程失败。（3）锻造成形是一个复杂的过程，其理想锻件不仅应具有符合设计要求的精确外形，而且应具有均匀的变形、合理分布的变形力和理想的质量（无宏观和微观缺陷）等。上述各个方面，都是锻造生产所追求的目标，因此对锻造过程优化设计进行多目标优化十分必要。目前这方面的研究比较少。6、结论 冷锻技术成形精度比温锻和热锻都要高,在精密成形领域有着其独特的优势。本文从冷锻零件的形状、材料、工艺革新、生产率、数值模拟技术和数字化/智能化设计技术应用、以及优化技术几个方面综合论述了冷锻技术的发

19、展现状、分析了冷锻技术目前存在的问题并指出了今后发展的方向。冷精锻是一种(近)净形成形工艺，有着十分广阔的应用前景。附录2：翻译（英）State of The Art and Advance of Cold Forging Technology Abstract: Cold forging is a kind of precise forming technology, and has the unique advantages compared to the traditional machining technology. In this paper, the start of art a

20、nd advance of the cold forging technology is systematically illustrated in the aspects of part shape, part material, process innovation, and production efficiency, application of numerical simulation and knowledge-based design, and design optimization technology. Keywords: cold forging, process/die

21、design, numerical simulation, knowledge-based design, design optimization The cold forging craft is one precise plastic forming technology, has the machining incomparable merit, like product machine capability good, the productivity high and the material use factor is high, suits specially in the ma

22、ss production, moreover may take the final product the manufacture method (net-shape forming), in profession and so on transportation tool, aerospace and machine tool industry has the widespread application. The current automobile industry, the motorcycle industry and the machine tool industry rapid

23、 development, has provided the driving force for the cold forging this tradition technology development, for example, our country in 1999 the motorcycle national ultimate output has more than 11.26 million 1 , but will act according to 2000 the preliminary estimate, the our country automobile achiev

24、es 3.3 million total demand to 2005, passenger vehicle 130-140 ten thousand, only automobile profession forging demand above 50-60 ten thousand tons 2 . Cold forging technology in our country's start although does not calculate too late. But the development speed and the developed country have t

25、he very big disparity. So far, Our country produces on passenger vehicle cold forging weight insufficient 20Kg,Is equal in the developed country one half, The development potential is very big, Strengthens the cold forging technology development and the promoted application is a our country at prese

26、nt urgent duty.1、 Cold forging shape is more and more complexThe cold forging components shape more and more tends to complex, by initial steps and ladders axis, bolt/The nut and the drive pipe and so on, develop to the shape complex components, like chart 1 shows for the different size motorcycle s

27、pline shaft and the splined tube, the spline shaft typical craft is: Is pushing among the strut bracing department - upsetting the part - extrusion spline; The splined tube main craft is: The counter- extrusion cup shaped - flushes the bottom to make annular - to extrude the axle sleeve. Like chart

28、2 shows for the automobile output shaft and the input axis, and all that cold forging products. Like chart 3 shows for our country uses swings each kind of automobile which the roller compaction technology makes/The motorcycle with the bevel gear, the spiral bevel gear and other disc class component

29、s 1 , like chart 4 showed the cold forging components which produced for Japanese some company, the vortex pressure intensifier which chart 4 showed, our country already includes the country "15" the attack project 3 . At present the cylindrical gears cold extrusion technology also succeed

30、s uses in producing. Besides the ferrous metal, at present the copper alloy, the magnesium alloy and the aluminum alloy material cold extrusion application more and more is also widespread.2 、Continues the unceasing craft innovationThe cold finish forge is one kind (is near) only forms the shape cra

31、ft. A use this method forming the components intensity and the precision is high. The quality of surface is good. The current overseas ordinary passenger vehicle uses cold forging total quantity 40 45Kg.Tooth profile class components total quantity reaches above 10Kg. The cold forging forming gear s

32、ingle unit weight may reach above 1Kg; the tooth profile precision may reach 7 levels.Continued the unceasing craft innovation to impel the cold extrusion technology development, since 80's, Domestic and foreign precisely will forge the expert to start to diverge the forging theory to apply in t

33、he spur gear and the helical gear cold forging forming. The divergence forging main principle is partially establishes a material in the semi finished materials either the mold forming the divergence cavity or diverges the channel. In forging process, Material while filling cavity, the partial mater

34、ials flow to the divergence cavity or diverge the channel. Divergence forging technology application, Caused to compare the high accuracy gear to be few, not to have the machining rapidly to achieve the industrial production scale. Like the literature 1 proposed that, regarding the major axis compar

35、ed to is 5 extrusions, like the piston pin, uses axial Yu Liaokuai the method to be possible to realize through the axial divergence coldly extrudes a time of forming, moreover the raised mold stability is very good; Regarding the flat kind of spur gear forming, uses radial direction Yu Liao kuai al

36、so to be possible to realize the product cold extrusion forming.Unenlightened forging is in seals up in the concave mold is unidirectional through either two drift or to approaches an extrusion metal forming, Obtains does not have the edge nearly only the shape fine forging. Some passenger vehicle p

37、recise components like planets and rear axle shaft gear, star type wrap, cross axle and so on if uses the machining method, Not only the material use factor is very low (equally not to 40%),Moreover consumes the man-hour, The production cost is extremely high. Overseas uses the unenlightened forging

38、 technology to produce these only shape forging, Omits the major part machining, the cost large scale reduces.The cold forging technology development mainly is develops the high added value the product, Reduces the production cost, At the same time, It also in unceasingly to the cutting, the powder

39、metallurgy, the casting, the hot forging, domain seepage and so on sheet forming craft or displaces, Also may unify the constitution compound craft with these crafts. Like the literature 4 proposed hot forging - cold forging compound plasticity forming technology. The hot forging - cold forging comp

40、ound plasticity forming technology is one kind of new precise metal forming craft which unifies the hot forging and the cold forging, it has fully used the hot forging and the cold forging respective merit: Under the thermal state the metal plasticity good, the mobile stress is low, therefore the ma

41、in distortion process completes with the hot forging; The cold forging precision is high, therefore the components important size finally forms the components with the cold forging craft. The hot forging - cold forging compound plasticity forming technology appears in the 1980s, since the 90's h

42、ave obtained the more and more widespread application, with this technical manufacture components, have obtained the precision to enhance, the cost reduction good effect. Chart 1 Chart 2 Chart 3 Chart 43 、values simulations technology uses in the rationality which examines the craft and the mold des

43、igns.When with cold forging craft forming components, because the metal in cold condition under has the plastic deformation, its resistance to deformation very big, therefore, components distortion quite difficult, in the distortion process is easy to appear the metal to be sufficient does not fill,

44、 the forging has flaw and so on crack. At the same time, the oversized resistance to deformation can seriously reduce the mold the service life. Since long ago, our country metal plasticity forming technological design and the mold design always uses the tradition to depend on the experience, the ex

45、perimental technique. This design method satisfies only the shape manufacture craft request with difficulty.Along with the computer technology rapid development and the 70's plastic finite element theory development, in many plasticity forming process is very difficult the question which solves

46、to be possible to use the finite element method to solve. In cold forging forming craft domain, through modeling and appropriate boundary condition determination, The finite element value simulation technology may very direct-viewing obtain the flaw situation which the metal mobile process the stres

47、s, the strain, the mold stress, the mold expiration situation and the forging possibly appears. This important information obtaining to reasonable mold structure. The mold selection, the heat treatment and the formed craft plan finally determination has the important guiding sense.The present effect

48、ive value simulation software was establishes take just the plastic finite element method as the foundation. This software include: DEFORM, QFORM, FORGE, and MSC/SUPERFORM and so on. Use in the rationality utility the finite element value simulation technology which examines the craft and the mold d

49、esigns. Like the literature 5 proposed one kind forms the straight tooth cylindrical gears by the hollow billet the new craft: Hammers the divergence area - divergence end to hammer in advance, Has conducted the value simulator study with three dimensional finite element value simulation software DE

50、FORM-3DTM, Obtained the forging load - traveling schedule curve as well as the entire forming process stress, the strain, the velocity distribution and so on, and pushed the craft simulation result with the traditional closed type to carry on the comparison. The analysis indicated, the traditional c

51、losed type pushes the formed straight tooth cylindrical gears, the formed load is big, does not favor the tooth profile filling. Uses of hammers the divergence area - divergence end to hammer the new craft in advance, May large scale reduce the formed load. And the distinct improvement material fill

52、s the nature, May obtain the tooth profile angle department full gear. The literature 6 has carried on the value simulation with the three dimensional big distortion ball plastic finite element method counter gear cold finish forge forming process. To as hammered in advance take the closed type drop

53、 forging with by the closed type drop forging, the hole of divergence and the restraint divergence two steps of formed patterns distortion mobile situation which hammered for the end has carried on the value simulation analysis. The numerical analysis result and the craft experiment indicated hammer

54、s in the end and adapt to the divergence. Restrains the hole of divergence measure regarding to reduce the work load and to enhance the angle corner in particular to fill aspect and so on ability is extremely effective.4 、Digitized intelligences design system application4.1 、CAD/CAM technology in co

55、ld forging forming craft/In mold design applicationIn order to adapt the modern production the short cycle which develops to the forging die, high grade, the low cost request, the advanced design theory and the method as well as computer technology, in particular the CAD technology introduction trad

56、ition forging die design process will be the forging die design domain inevitable trend. The mold CAD technology by its high superiority and so on automation, high accuracy and high benefit is continuing to impel the traditional mold design and the manufacture method transformation. Since the 20th c

57、entury 70's, the overseas many units have started to forging die CAD/CAM has conducted extensive research, American Ohio state Battle - Columbus laboratory Thurman and so on Altan has first developed the axial symmetry forging die CAD system. Former Soviet Union's expert system and so on Cze

58、choslovakia forest has studied the drop forging design automation and the optimized principle, from aspect and so on methodology, algorithm model proposed the complete set theory, and has developed the solid of revolution class forging automated design system.Domestic is late in this aspect start, Shanghai unit and so on Jiao tong University, Qinghai University, Huazhong University of Science and Technology, Harbin industrial university and Nanchang University based on the certain platform, developed has been suitable for the different type forging design system, but most