外文翻译--冲压成形与板材冲压

1、<p>　　Characteristics and Sheet Metal Forming dn3-ow  </p><p>　　1.The article overview #pYt<CW  </p><p>　　Stamping is a kind of plastic forming process in which a part is pro

2、duced by means of the plastic forming the material under the action of a die. Stamping is usually carried out under cold state, so it is also called stamping. Heat stamping is used only when the blank thickness is greate

3、r than 8-100mm. The blank material for stamping is usually in the form of sheet or strip, and therefore it is also called sheet metal forming. Some non-metal sheets (such as plywood, mica sheet, asbestos, leather</p&g

4、t;<p>　　Stamping is widely used in various fields of the metalworking industry, and it plays a crucial role in the industries for manufacturing automobiles, instruments, military parts and household electrical app

5、liances, etc. ZL;Ztq?</p><p>　　The process, equipment and die are the three foundational problems that needed to be studied in stamping. 7pEbH/} </p><p>　　The characteristics of the sheet met

6、al forming are as follows: iF, (5xp </p><p>　　(1)    High material utilization A{(~f+h*g </p><p>　　(2)    Capacity to produce thin-walled parts of complex shape. w}`Cv#h

7、 </p><p>　　(3)    Good interchangeability between stamping parts due to precision in shape and dimension. N3m # ^S </p><p>　　(4)    Parts with lightweight, high-strength and

8、fine rigidity can be obtained.</p><p><b>　　=E-~@4q </b></p><p>　　(5)    High productivity, easy to operate and to realize mechanization and automatization. J5nmX,`</p

9、><p>　　The manufacture of the stamping die is costly, and therefore it only fits to mass production. For the manufacture of products in small batch and rich variety, the simple stamping die and the new equipmen

10、t such as a stamping machining center, are usually adopted to meet the market demands. pAdB@0s</p><p>　　The materials for sheet metal stamping include mild steel, copper, aluminum, magnesium alloy and high-

11、plasticity alloy-steel, etc. !xN_ql!(4  </p><p>　　Stamping equipment includes plate shear punching press. The former shears plate into strips with a definite width, which would be pressed later. The lat

12、er can be used both in shearing and forming. 4Q3j4 </p><p>　　2．Characteristics of stamping forming 2f8?&(6G64</p><p>　　（1）．The force per unit area perpendicular to the blank surface is no

13、t large but is enough to cause the material plastic deformation. It is much less than the inner stresses on the plate plane directions. In most cases stamping forming can be treated approximately as that of the plane str

14、ess state to simplify vastly the theoretical analysis and the calculation of the process parameters. <UL_z</p><p>　　（2）．Due to the small relative thickness, the anti-instability capability of the blank i

15、s weak under compressive stress. As a result, the stamping process is difficult to proceed successfully without using the anti-instability device (such as blank holder). Therefore the varieties of the stamping processes

16、dominated by tensile stress are more than dominated by compressive stress. ?a<&uq~  </p><p>　　（3）．During stamping forming, the inner stress of the blank is equal to or sometimes less than the yi

17、eld stress of the material. In this point, the stamping is different from the bulk forming. During stamping forming, the influence of the hydrostatic pressure of the stress state in the deformation zone to the forming li

18、mit and the deformation resistance is not so important as to the bulk forming. In some circumstances, such influence may be neglected. Even in the case when this influence should b</p><p>　　（4）．In stamping f

19、orming, the restrain action of the die to the blank is not severs as in the case of the bulk forming (such as die forging). In bulk forming, the constraint forming is proceeded by the die with exactly the same shape of t

20、he part. Whereas in stamping, in most cases, the blank has a certain degree of freedom, only one surface of the blank contacts with the die. In some extra cases, such as the forming of the blank on the deforming zone con

21、tact with the die. The deformation in these</p><p>　　Due to the characteristics of stamping deformation and mechanics mentioned above, the stamping technique is different form the bulk metal forming: RW,||&g

22、t;H>P  </p><p>　　（1）．The importance or the strength and rigidity of the die in stamping forming is less than that in bulk forming because the blank can be formed without applying large pressure per

23、unit area on its surface. Instead, the techniques of the simple die and the pneumatic and hydraulic forming are developed. S7E(YMV  </p><p>　　（2）．Due to the plane stress or simple strain state in com

24、parison with bulk forming, more research on deformation or force and power parameters has been done. Stamping forming can be performed by more reasonable scientific methods. Based on the real time measurement and analysi

25、s on the sheet metal properties and stamping parameters, by means of computer and some modern testing apparatus, research on the intellectualized control of stamping process is also in proceeding. {sW`^5a$L  </p&

26、gt;<p>　　（3）．It is shown that there is a close relationship between stamping forming and raw material. The research on the properties of the stamping forming, that is, forming ability and shape stability, has beco

27、me a key point in stamping technology development, but also enhances the manufacturing technique of iron and steel industry, and provides a reliable foundation for increasing sheet metal quality. folai  </p>

28、<p>　　（1）．Definition of the stamping property of the material. JiW?</p><p>　　（2）．Method to judge the stamping property of the material, find parameters to express the definitely material property of t

29、he stamping forming, establish the relationship between the property parameters and the practical stamping forming, and investigate the testing methods of the property parameters. okv,qV  </p><p>　　

30、（3）．Establish the relationship among the chemical component, structure, manufacturing process and stamping property. 0]O]SP*  </p><p>　　The raw materials for stamping forming mainly include various me

31、tals and nonmetal plate. Sheet metal includes both ferrous and nonferrous metals. Although a lot of sheet metals are used in stamping forming, the most widely used materials are steel, stainless steel, aluminum alloy and

32、 various composite metal plates. T~yy#6T  </p><p>　　5．Stamping forming property of sheet metal and its assessing method =Qg"J 3A  </p><p>　　The stamping forming property of th

33、e sheet metal is the adaptation capability of the sheet metal to stamping forming. It has crucial meaning to the investigation of the stamping forming property of the sheet metal. In order to produce stamping forming par

34、ts with most scientific, economic and rational stamping forming process and forming parameters, it is necessary to understand clearly the properties of the sheet metal, so as to utilize the potential of the sheet metal f

35、ully in the production. O</p><p>　　There are direct and indirect testing methods to assess the stamping property of the sheet metal. %P-,FVP-1  </p><p>　　Practicality stamping test is the

36、most direct method to assess stamping forming property of the sheet metal. This test is done exactly in the same condition as actual production by using the practical equipment and dies. Surely, this test result is most

37、reliable. But this kind of assessing method is not comprehensively applicable, and cannot be shared as a commonly used standard between factories. "?X4p4</p><p>　　The simulation test is a kind of ass

38、essing method that after simplifying and summing up actual stamping forming methods, as well as eliminating many trivial factors, the stamping properties of the sheet metal are assessed, based on simplified axial-symmetr

39、ic forming method under the same deformation and stress states between the testing plate and the actual forming states. In order to guarantee the reliability and generality of simulation results, a lot of factors are reg

40、ulated in detail, such a</p><p>　　Indirect testing method is also called basic testing method its characteristic is to connect analysis and research on fundamental property and principle of the sheet metal d

41、uring plastic deformation, and with the plastic deformation parameters of the sheet metal in actual stamping forming, and then to establish the relationship between the indirect testing results(indirect testing value) an

42、d the actual stamping forming property (forming parameters). Because the shape and dimension of the specime</p><p>　　Hans Gastrow Molds 130 Proven Designs . 3rd edition . Munich : Hanser Publisher , 2002 .30

43、0-307 .</p><p>　　n~y2q!<8{52W</p><p>　　2．冲压成形的特点 8W[5</p><p>　　生产时间中所采用的冲压成形工艺方法有很多，具有多种形式饿名称，但塑性变形本质是相同的。冲压成形具有如下几个非常突出的特点。</p><p><b>　　K^+jvg$6</b>

44、</p><p>　　（3）．冲压成形时，板材毛胚内应力的数值等于或小于材料的屈服应力。在这一点上，冲压成形与体积成形的差别很大。因此，在冲压成形时变形区应力状态中的静水压力成分对成形极限与变形抗力的影响，已失去其在体积成形时的重要程度，有些情况下，甚至可以完全不予考虑，即使有必要考虑时，其处理方法也不相同。 EjP{5 V'k</p><p>　　（4）．在冲压成形时，模具对板

45、材毛胚作用力所形成的约束作用较轻，不像体积成形（如模锻）是靠与制件形状完全相同的型腔对毛胚进行全面接触而实现的强制成形。在冲压成形中，大多数情况下，板材毛胚都有某种程度的自由度，常常是只有一个表面与模具接触，甚至有时存在板材两侧表面都有于模具接触的变形部分。在这种情况下，这部分毛胚的变形是靠模具对其相邻部分施加的外力实现其控制作用的。例如，球面和锥面零件成形时的悬空部分和管胚端部的卷边成形都属这种情况。 *@tvsvB</p&g

46、t;<p>　　由于冲压成形具有上述一些在变形与力学方面的特点，致使冲压技术也形成了一些与体积成形不同的特点。 CV;H</p><p>　　由于不需要在板材毛的表面施加很大的单位压力即可使其成形，所以在冲压技术中关于模具强度与刚度的研究并不十分重要，相反却发展了学多简易模具技术。由于相同原因，也促使靠气体或液体压力成形的工艺方法得以发展。</p><p>　　'

47、_'I$r.I0 </p><p>　　因冲压成形时的平面应力状态或更为单纯的应变状态（与体积成形相比），当前对冲压成形汇中毛胚的变形与 力能参数方面的研究较为深入，有条件运用合理的科学方法进行冲压加工。借助于电子计算机与先进的测试手段，在对板材性能与冲压变形参数进行实时测量与分析基础上，实现冲压过程智能化控制的研究工作也在开展。 <` y 1"</p><p>

48、;　　人们在对冲压成形过程有离开较为深入的了解后，已经认识到冲压成型与原材料有十分密切的关系。所以，对板材冲压性能即成形性与形状稳定性的研究，目前已成为冲压技术的一个重要内容。对板材冲压性能的研究工作不仅是冲压技术发展的需要，而且也促进了钢铁工业生产技术的发展，为其提高板材的质量提供了一个可靠的基础与依据。 Ye;=?~?4</p><p>　　3．冲压变形的分类 Ma&|Z]1&  

49、</p><p>　　冲压变形工艺可完成多种工序，其基本工序可分为分离工序和变形工序两大类。 t;a}s,=[b</p><p>　　分离工序是使胚料的一部分与另一部分相互分离的工艺方法，主要有落料、冲孔、切边、剖切、修整等。其中又以冲孔、落料应用最广。变形工序是使胚料的一部分相对于另一部分产生位移而不破裂的工艺方法，主要有拉深、弯曲、局部成形、胀形、翻边、缩径、校形、旋压等。 aS2B

50、!J6~t</p><p>　　从本质上看，冲压成形就是毛胚的变形区在外力的作用下产生相应的塑性变形，所以变形区内的应力状态和变形特点景象的冲压成形分类，可以把成形性质相同的成形方法概括成同一个类型并进行体系化的研究。 uCagxj</p><p>　　绝大多数冲压成形时毛胚变形区均处于平面应力状态。通常认为在板材表面上不受外力的作用，即使有外力作用，其数值也是较小的，所以可以认为垂

51、直于板面方向上的应力为零，使板材毛胚产生塑性变形的是作用于板面方向上相互的两个主应力。由于板厚较小，通常都近似地认为这两个主应力在厚度方向上是均匀分布的。基于这样的分析，可以把各种形式冲压成型中的毛陪变形区的受力状态与变形特点，在平面应力的应力坐标系中与相应的两向应变坐标系中以应力与应变坐标决定的位置来表示。 PX9y?PuP</p><p>　　4．冲压用原材料 !@2OZN+  </p&

52、gt;<p>　　冲压加工用原材料有很多种，它们的性能也有很大的差别，所以必须根据原材料的性能与特点，采用不同的冲压成形方法、工艺参数和模具结构，才能达到冲压加工的目的。由于人们对冲压成形过程板材毛胚的变形行为有了较为深入的认识，已经相当清楚的建立了由原材料的化学成分、组织等因素所决定的材料性能与冲压成形之间的关系，这就使原材料生产部门不但按照冲压件的工作条件与使用要求进行原材料的设计工作，而且也根据冲压件加工过程对板材性

53、能的要求进行新型材料的开发工作，这是冲压技术在原材料研究方面的一个重要方向。对  冲压用原材料冲压性能方面的研究工作有： ~bXP U'</p><p>　　（1）原材料冲压性能的含义。 R>d(o.oOt</p><p>　　（2）判断原材料冲压性能的科学方法，确定可以确切反映材料冲压性能的参数，建立冲压性能的参数与实际冲压成形间的关系，以及冲压性能参数的

54、测试方法等。 , p5$+#r</p><p>　　（3）建立原材料的化学成分、组织和制造过程与冲压性能之间的关系。 TK*[&l0<</p><p>　　冲压用原材料主要是各种金属与非金属板材。金属板材包括各种黑色技术和有色金属板材。虽然在冲压生产中所用金属板材的种类很多，但最多的原材料蛀牙是钢板、不锈钢板、铝合金板及各种复合金属板。 aY>AG<

55、;/p><p>　　5．板材冲压性能及其鉴定方法 i-#*S8</p><p>　　板材是指对冲压加工的适应能力。对板材冲压性能的研究具有飞行重要的意义。为了能够运用最科学与最经济合理的冲压工艺过程与工艺参数制造出冲压零件，必须对作为加工对象的板材的性能具有十分清楚的了解，这样才有可能充分地利用板材在加工方面的潜在能力。另一方面，为了能够依据冲压件的形状与尺寸特点及其所需的成形工艺等基本

56、因素，正确、合理地选用板材，也必须对板材的冲压性能有一个科学的认识与正确的判断。 DseQDJTPf  </p><p>　　评定板材冲压性能的方法有直接试验法与间接试验法。 !M)W</p><p>　　实物冲压试验是最直接的板材冲压性能的评定方法。利用实际生产设备与模具，在与生产完全相同的条件下进行实际冲压零件的性能评定，当然能够的最可靠的结果。但是，这种评定方法不具

57、有普遍意义，不能作为行业之间的通用标准进行信息的交流。 u^LI#;. </p><p>　　模拟试验是把生产中实际存在的冲压成形方法进行归纳与简单化处理，消除许多过于复杂的因素，利用轴对称的简化了的成形方法，在保证试验中板材的变形性质与应力状态都与实际冲压成形相同的条件下进行的冲压性能的评定工作。为了保证模拟试验结果的可靠性与通用性，规定了私分具体的关于试验用工具的几何形状与尺寸、毛胚的尺寸、试验条件（冲压

58、速度、润滑方法、压边力等）。 MM\ k+</p><p>　　间接试验法也叫做基础试验法。间接试验法的特点是：在对板材在塑性变形过程中所表现出的基本性质与规律进行分析与研究的基础上，进一步把它和具体的冲压成形中板材的塑性变形参数联系起来，建立间接试验结果（间接试验值）与具体的冲压成形性能（工艺参数）之间的相关性。由于间接试验时所用试件的形状与尺寸以及加载的方式等都不同于具体的冲压成形过程，所以它的变形性质