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U形卡槽的冲压工艺及模具设计【46张CAD图纸+毕业答辩论文】【4副模具】

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U形卡槽的冲压工艺及模具设计【全套CAD图纸+毕业答辩论文】【冲压模具】.rar

A4-全套设计-U形卡槽的冲压工艺及模具设计

四套模具设计图[共47张]

第1套落料冲孔

第1套落料冲孔装配图.dwg---(点击预览)

第1套落料冲孔-13上模座.dwg---(点击预览)

第1套落料冲孔-12垫板.dwg---(点击预览)

第1套落料冲孔-11凸模模柄.dwg---(点击预览)

第1套落料冲孔-10-5X3.4孔凸模.dwg---(点击预览)

第1套落料冲孔-09-5.42孔凸模.dwg---(点击预览)

第1套落料冲孔-08-7.2孔凸模.dwg---(点击预览)

第1套落料冲孔-07-4.5孔凸模.dwg---(点击预览)

第1套落料冲孔-06推件器.dwg---(点击预览)

第1套落料冲孔-05凸模固定板.dwg---(点击预览)

第1套落料冲孔-04凹模.dwg---(点击预览)

第1套落料冲孔-03卸料板.dwg---(点击预览)

第1套落料冲孔-02凸凹模.dwg---(点击预览)

第1套落料冲孔-01下模座.dwg---(点击预览)

第2套冲小孔

第2套冲小孔装配图.dwg---(点击预览)

第2套冲小孔-10模柄.dwg---(点击预览)

第2套冲小孔-09凸模.dwg---(点击预览)

第2套冲小孔-08保护套.dwg---(点击预览)

第2套冲小孔-07导正销.dwg---(点击预览)

第2套冲小孔-06上模座.dwg---(点击预览)

第2套冲小孔-05垫板.dwg---(点击预览)

第2套冲小孔-04凸模固定板.dwg---(点击预览)

第2套冲小孔-03卸料板.dwg---(点击预览)

第2套冲小孔-02凹模.dwg---(点击预览)

第2套冲小孔-01下模座.dwg---(点击预览)

第3套翻边

第3套翻边装配图.dwg---(点击预览)

第3套翻边-09模柄.dwg---(点击预览)

第3套翻边-08导正销.dwg---(点击预览)

第3套翻边-07凸模.dwg---(点击预览)

第3套翻边-06上模座.dwg---(点击预览)

第3套翻边-05垫板.dwg---(点击预览)

第3套翻边-04凸模固定板.dwg---(点击预览)

第3套翻边-03卸料板.dwg---(点击预览)

第3套翻边-02凹模.dwg---(点击预览)

第3套翻边-01下模座.dwg---(点击预览)

第4套弯曲

第4套弯曲装配图.dwg---(点击预览)

第4套弯曲-10顶件板.dwg---(点击预览)

第4套弯曲-09模柄.dwg---(点击预览)

第4套弯曲-08凸模.dwg---(点击预览)

第4套弯曲-07上模座.dwg---(点击预览)

第4套弯曲-06垫板.dwg---(点击预览)

第4套弯曲-05凸模固定板.dwg---(点击预览)

第4套弯曲-04定位板.dwg---(点击预览)

第4套弯曲-03凹模.dwg---(点击预览)

第4套弯曲-02凹模垫板.dwg---(点击预览)

第4套弯曲-01下模座.dwg---(点击预览)

外文文献及翻译

李超外文文献译文.doc---(点击预览)

Ferrasse-2004-Texture evolution duI.PDF---(点击预览)

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关键词：: 形卡槽冲压工艺模具设计全套 cad 图纸毕业答辩论文模具

资源描述：

摘要IV

ABSTRACTV

１前言1

1.1 模具加工及金属薄板冲压加工的特点及优势1

1.2 课题讨论及难点分析2

1.3 课题总体设计思路3

2工艺分析及工艺方案确定5

2.1零件三维造型图5

2.2工件的零件图5

2.3工艺分析5

2.3.1翻边高度计算6

2.3.2冲小孔工艺分析6

2.3.3弯曲部分工艺分析6

2.4工艺方案的确定6

3落料冲孔模的设计9

3.1毛坯尺寸计算9

3.2 排样9

3.3 确定模具压力中心10

3.4 冲压力的计算10

3.4.1 落料力10

3.4.2冲孔力11

3.4.3卸料力11

3.4.4推件力11

3.4.5总冲压力11

3.5冲压设备的选择11

3.6工作部分尺寸计算12

3.6.1落料凸、凹模刃口的尺寸计算12

3.6.2冲孔凸、凹模的刃口尺寸13

3.7冲孔落料复合模的设计14

3.7.1落料冲孔复合模结构的设计14

3.1.2 落料冲孔复合模主要零件的设计15

4冲小孔模的设计21

4.1确定模具压力中心21

4.2冲孔力的计算21

4.3冲压设备的选择21

4.4冲孔凸、凹模刃口尺寸计算21

4.5冲小孔模的设计22

4.5.1冲小孔模结构的设计22

4.5.2冲小孔模主要零件的设计22

5翻边模的设计26

5.1确定模具压力中心26

5.2翻边力的计算26

5.3冲压设备的选择26

5.4翻边模刃口尺寸计算26

5.5翻边模的设计27

5.5.1翻边模结构的设计27

5.5.2翻边模主要零件的设计27

6弯曲模的设计30

6.1确定模具压力中心30

6.2弯曲力的计算30

6.3冲压设备的选择30

6.4翻边模刃口尺寸计算30

6.5弯曲模的设计31

6.5.1弯曲模结构的设计31

6.5.2弯曲模主要零件的设计32

7结论36

谢辞37

参考文献38

摘要

本课题所设计的零件是较为典型的U型弯曲件。工件一侧有一个直径为1.8mm的小圆孔和翻边，另一侧有三个孔，且在U型卡槽底部有三道褶边。通过对零件各部分进行计算分析后最终确定加工工序。经计算得翻边可以一次成型，工件整个成型过程所涉及的工序有：落料、冲孔、冲小孔、翻边、弯曲五步。在对零件进行工艺分析后，确定最终工艺方案为：落料冲孔复合，冲小孔、翻边、弯曲顺次进行。在确定工艺方案的基础上对主要模具进行设计，分析工件成型过程，并画出模具装配图及零件图。在本次设计中主要对落料复合模以及冲小孔模、翻边模、弯曲模进行设计。

关键词：落料冲孔；冲小孔；翻边；弯曲

Punching Process Analyzed and Die Design of the U Shape Groove

ABSTRACT

Typical bended workpiece of U shape with three folds was designed in this graduation project. Two hoes are flanged on one side with a Φ1.8 mm hole. There are three holes on the other side. The process was determined by calculating and analyzing. Flanging can be shaped by one step after calculating. Five steps as blanking, punching, punching a small hole, flanging and bending were included. Analyzed the technics of parts, the final process was determined as four steps: blanking-punching compound, punching a small hole, flanging and bending. Besides, the main dies were designed, the process was analyzed, and the die assembly and workpiece pictures were drawed. In this graduation project, blanking-punching compound die, punching a small hole die, flanging die and flanging die were designed.

Key words: blanking-punching compound; punching a small hole; flanging; bending

１前言

1.1 模具加工及金属薄板冲压加工的特点及优势

随着汽车工业的快速发展，服务于汽车生产的模具近年来也快速发展[1]。服务于汽车生产的模具和塑料模具使用量最大的两大类。此外，还有铸造模具、锻造模具、橡胶模具、粉末冶金模具及拉丝模具和无机材料成型模具等。在汽车工业十分发达的国家，为汽车服务的模具往往要占到全部模具生产量的40%以上。经过多年发展，我国目前为汽车服务的模具约已占到了全部模具产量的1/3左右[2]。在这些模具中，冲压模具在模具行业和汽车覆盖件模具，直接关系到汽车车型，因此其地位尤为重要。要生产出大量的各式各样的汽车，先进技术装备必不可少，而模具就是汽车先进技术装备中的重要装备。“现代工业，模具先行”、“没有高水平的模具，就没有高水平的产品”，这已成为人们的共识。不管是汽车还是模具，虽然近年来发展迅速，我国已成为生产大国，但离生产强国的距离还很远。然而，要成为制造业强国，要成为汽车、模具等的制造强国是我们的目标。为了向汽车行业提供更为先进的技术装备，必须不断提高汽车冲压模具的冲压模具的水平与能力。

金属薄板冲压成形是现代工业生产中一种非常重要的制造技术[3]，金属薄板及其制品在冲压成形过程中所表现出的成形性能或成形性，是横跨薄板冶金制造和冲压成形生产两大行业之间的交叉性工程技术，即冲压成形性能及其应用。冲压加工是靠冲压设备和模具实现对板料毛坯的塑性加工过程。冲压加工具有许多十分明显的优点，它利用冲压设备与冲模的简单的运动完成相当复杂形状零件的制造过程，而且并不需要操作工人的过多参与，所以冲压加工的生产效率很高，产品质量稳定，一般情况下，冲压加工的生产效率为每分钟数十件。又由于冲压加工的操作十分简单，为操作过程的机械化与自动化提供了十分有利的条件。因此，对某些工艺成熟的冲压件，生产效率可达每分钟数百件，甚至超过一千件以上。

冲压加工用的原材料多为冷轧板料和冷轧带材[4]。原材料的良好表面质量使用大量生产方式、高效而廉价的方法获得的。在冲压加工中这些良好的表面质量又不容易遭到破坏，所以冲压件的表面质量又不致遭到破坏，所以冲压件的表面质量好，而成本都很低廉。这个特点，在汽车支撑件件的生产上表现得十分明显[5]。

利用冲压加工方法，可以制造形状十分复杂的零件，能够把强度好、刚度大、重量轻等相互矛盾的特点融为一体，形成十分合理的结构形式。冲压加工时，一般不需要对毛坯加热，而且也不像切削加工那样把一部分金属切成切屑，造成原材料的损耗，所以它是一种节约能源和资源的具有环保意义的加工方法。

冲压产品的质量与尺寸精度都是由冲模保证的[6]，基本上不受操作人员的素质与其他偶然因素的影响，所以冲压产品的质量管理简单，也容易实现自动化与智能化生产。冲压件的尺寸精度与表面质量好，通常都不需要后续的加工而直接装配或作为成品零件直接使用。

冲压加工是一种高生产率的加工方法的，如汽车车身等大型零件每分钟可生产几件，而小零高速冲压则每分钟可生产千件以上。由于冲压加工的毛坯是板材或卷材，一般又在冷状态下加工，因此较易实现机械化和自动化，比较适合配置机器人而实现无人化生产[7]。

冲压加工的材料利用率较高，一般可达70%～85%，冲压加工的能耗也较低，由于冲压生产具有节材、节能和高生产率等特点，所以冲压件呈批量生产时，其成本比较低，经济效益高[8]。

冲压件与铸件、锻件相比，具有薄、匀、轻、强的特点。冲压可制出其他方法难于制造的带有加强筋、肋、起伏或翻边的工件，以提高其刚性。由于采用精密模具，工件精度可达微米级，且重复精度高、规格一致，可以冲压出孔窝、凸台等。

冷冲压件一般不再经切削加工，或仅需要少量的切削加工。热冲压件精度和表面状态低于冷冲压件，但仍优于铸件、锻件，切削加工量少。

冲压是高效的生产方法[9]，采用复合模，尤其是多工位级进模，可在一台压力机上完成多道冲压工序，实现由带料开卷、矫平、冲裁到成形、精整的全自动生产。生产效率高，劳动条件好，生产成本低，一般每分钟可生产数百件[5]。由于冲压加工方法具有前述的许多优点，现在他已经成为金属加工中的一种非常重要的制造方法。

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JB092-内容预览-U形卡槽的冲压工艺及模具设计.jpg

冲小孔模装配图.jpg

翻边模装配图.jpg

落料冲孔模装配图.jpg

弯曲模装配图.jpg

内容简介：: Materials Science and Engineering A368 (2004) 2840Texture evolution during equal channel angular extrusionPart I. Effect of route, number of passes and initial textureS. Ferrassea, V.M. Segala, S.R. Kalidindib, F. AlfordaaHoneywell Electronic Materials, 15128 East Euclid Avenue, Spokane, WA 99216, USAbDepartment of Materials Engineering, Drexel University, 32nd Chesnut Street, Philadelphia, PA 19104, USAReceived 4 July 2003; received in revised form 8 September 2003AbstractIt is shown that equal channel angular extrusion (ECAE) is an effective technique to control texture of metals and alloys. Two processingparameters,therouteandnumberofpasses,exertanimportantinfluenceontextureevolution.Routesdefineorientationsallowingthecreationofnumerousnewcomponents.Beforefourpasses,dependingonrouteandinitialtexturestrength,alltypesoftexturestrength,fromweaktoverystrong, are created, whereas after four passes, a global texture weakening is observed for all routes and medium to strong to very weak texturesare produced. A simple Taylor model shows that crystallographic slip mechanically activated by simple shear is the governing mechanismfor evolution of texture orientations. However, after four passes, the creation of submicron-grained structures with high misorientations isbelieved to limit crystallographic slip and weaken textures. 2003 Published by Elsevier B.V.Keywords: Equal channel angular extrusion; Texture of metals and alloys; Taylor model1. IntroductionSubmicron-grained (SMG) materials (with a grain sizeless than 1?m) are attractive technical alternatives becausethey exhibit unusual physical and mechanical properties1,2. Intensive plastic deformation has been proven as aneffective method to produce SMG materials. Several tech-niques are capable of achieving the required strain levels35. Of particular interest, the method of equal channelangular extrusion (ECAE) allows for the production ofbulk pieces of SMG materials by simple shear 68. Mi-crostructures and properties of ECAE processed materialshave been of high interest for the last 5 years 816. Veryfine grain sizes (1?m) result in unusual effects such asideal plastic behavior, high strength, enhanced ductility andtoughness, and low temperature superplasticity. Recentlysome studies have focused on textures of ECAE deformedmetals 1737. Texture analysis is of great relevance tomechanisms of grain refinement during ECAE. At this stagea few particular textures corresponding to various cases ofECAE deformation and die angles have been investigatedCorresponding author.or modeled. The intent of this paper is to present a sys-tematic study of texture formation in materials subjectedto room temperature ECAE processing with a die angleof 90and various numbers of passes and routes. Thisstudy clarifies the potential of ECAE technology to controltexture.2. Experimental2.1. Original material and ECAE processingHighpurityAl0.5Cualloywasinitiallycast,homogenizedand solutionized. This single phase, high stacking fault en-ergy (SFE) alloy is a convenient material to analyze textureevolution under processing. All samples were submitted totwo ECAE passes via route C 1012 followed by anneal-ing at 250C, 1h in order to produce an uniform and strongoriginal texture with a recrystallized grain size of 60?m.Also, some samples were subsequently deformed by fourpasses route C and annealed at 300C, 1h to produce a weaktexture with a recrystallized grain size of 100?m. Becauseof significant interest in texture development for flat prod-ucts, ECAE was performed for flat billets (Fig. 1) 38,39. A0921-5093/$ see front matter 2003 Published by Elsevier B.V.doi:10.1016/j.msea.2003.09.077李超S. Ferrasse et al./Materials Science and Engineering A368 (2004) 284029Y X Z BILLET AFTER ECAEORIGINAL BILLET POSITION SHEAR PLANE Fig. 1. ECAE of flat billet.special note should be added on the definition of processingroutes for this case. Different routes, which define selectedshear planes and directions, may be attained by billet rota-tions about axis x, y or z (Fig. 1) at subsequent passes. Simi-larly to the elongated billets that are usually studied 40, inroute A, no change in billet orientation occurs between eachpass. In route B, the sample is alternatively rotated 90about z axis at each pass (Fig. 1). In route D, the sampleis rotated continuously +90about the z axis at each pass.In route C, the sample is continuously rotated +180aboutthe z axis.1Note that z axis is the rotation axis of route Band D for flat billet instead of the x axis for elongated bil-let. For the strong initial texture, routes A, B and D werestudied for number of passes 1, 2, 3, 4, 6 and 8 and, forroute C, all passes from one through eight were observed.For the weak initial texture, only experiments via routes Aand D from one to four passes were done. ECAE experi-ments were performed at room temperature and a low ramspeed (0.75mm/s). The processing of each route was care-fully controlled. Well lubricated 75mm 75mm 15mmsamples were processed in a die with sharp corners and an-gle of 90(Fig. 1) that corresponds to a true strain per pass = . Texture measurementMeasurements of crystallographic texture were obtainedwith a Phillips XPert diffractometer. Textures were inves-tigated along the mid-thickness of a billet section parallelto the xy plane (Fig. 1). Partial pole figures on the 111,200 and 220 planes were generated. The Beartex soft-ware 41 was used to process the raw data, correct eachpole figure for background and defocusing, and calculate theorientation distribution function (ODF) 4143. An analy-1Some authors use the term BAfor route B and BCfor route D. Inthis case, routes B and D are not presented as basic routes but rather asdependent of routes A and C.sis of fibers (orientation tubes) was performed by examin-ing the ODF at constant values of 0, 5, 10, 15, 20, 22.5,25, 30, 35, 40 and 45 according to the Roe/Matthies con-vention preferred in Beartex with Euler angles , , (seeTable 1). Also, Beartex (option COMP) estimates the in-tegral intensity of the orientation distribution (OD) insidea given sphere in the orientation space that represents thevolume fraction of grains possessing a given orientation in-side the chosen sphere. A 5spread around the compo-nent was considered. Texture or OD index, which is theroot-mean-squared (RMS) value of peak ODF, was also usedto evaluate texture strength 44,45. It was assumed that ODindex between 1 and 3 times random (t.r.) corresponds torandom-to-weaktextures,between3and5t.r.correspondstoweak-to-medium textures, between 5 and 20 t.r. correspondsto medium-to-strong textures and above 20 t.r. correspondsto extremely strong textures. Finally, for each pole figure,the extrusion axis of the last pass (x axis in Fig. 1) is alwaysoriented along the x direction indicated in Fig. 4, and a per-pendicular to the plane of pole figure is parallel to z axis inFig. 1.2.3. Texture modelingA computer code based on a Taylor type crystal plasticitymodel was used to predict texture for simple shear defor-mation 45,46. It is applicable at low homologous tempera-tures where plastic deformation is mainly accomplished bycrystallographic slip. Other deformation mechanisms suchas shear banding, twinning, grain boundary sliding and rota-tion, as well as effects of grain shape and size, are not takeninto consideration. Despite this simplicity, it was found thatthe model provides reasonable predictions for texture evolu-tion in single-phase, from medium to high stacking fault en-ergy cubic metals whatever the deformation mode 45,46.In simulations, 300 and 100 orientations were chosen to gen-erate the weak (near random) and strong original textures,respectively.30S. Ferrasse et al./Materials Science and Engineering A368 (2004) 2840Table 1Basic description in the ODF space and inverse pole figure of principal fibers encountered for each routeMajor typesof Fxy fiberLimits of location of fiber in (001)inverse pole figure (spreading dueto ECAE route/pass).Name of fiber for each route(x = name of route)Range of Euler angles ( )(for typical ODF -cross sections)and corresponding range of planeFx1FA1, FB1, FD1 FBD1(N = 2 for route B, D)FC1 (route C, N odd)(215255 1030 0) = (106)(102),(180230 1025 25) = (218)(214),(135190 520 45) = (118)(113)FC1 (route C, N even)(220255 3040 0) = (203)(101),(200250 2040 25) = (213)(212),(180190 1525 45) = (115)(112)Fx2FA2, FB2, FC2, FD2(2045 4050 22.5) = (212),(35015 3550 45) = (223)(334)Fx3FA3, FB3, FC3, FD3, FBD3(N = 2 for routes B, D)(95130 1535 0) = (103)(304),(90120 2535 15) = (7210)(416),(80110 2545 25) = (213)(212),(35100 2035 45) = (113)(112)3. Results3.1. Initial texturesThe strong initial texture (OD index = 21.7 t.r.) containsprincipally three major orientations (Table 2 for N = 0).This atypical texture corresponds to the strongest texturesencountered in traditional forming processes. The weak ini-tial texture has an OD index of 2.6 t.r. (Table 2 for N = 0).3.2. Evolution of texture orientationTable 1 displays the definition of principal fibers found foreach ECAE route. Tables 25 describe major orientations(with Euler angles , , (Roe/Matthies) and correspondingxyz?uvw? ideal description) and associated fibers. Textureorientation evolves similarly for both types of initial textureswith some notable features.First, starting texture exerts a limited influence by shift-ing or weakening orientations for one and two passes(Tables 25; see route A and D in Fig. 2a and b). At a highernumber of passes, influence of the original texture on orien-tation disappears. For example, for three and four passes viaroute D (Fig. 2c and d) inverse pole figures exhibit similarorientations either for a strong or random initial texture.Second, ECAE route has a tremendous impact on textureorientation especially at low number of passes. In fact, allorientations created with the four considered routes covera significant area of the standard triangle (Tables 25,Figs. 25). For example, with a strong initial texture, asmany orientations as (102)?241? (route A), (212)?425?(route D), (416)?413? (route C), (304)?463? (route C)and, (7210)?491? and (104)?451? (route B) are created.Such orientations are fairly unusual compared to thoseobtained by traditional forming operations.Third, ODF analysis indicates that a limited group offibers containing one or several major orientations are asso-ciated with each route irrespective of number of passes andoriginal texture (Tables 15; Fig. 6). The number of fibersvaries from three to six but only one or two fibers are pre-dominant for each route. These main fibers are noted FA3and FA2 for route A (Fig. 6), FBD2 for routes B and D attwo passes, FD1 for route D after three passes, FB3 and FB1for route B after three passes, and FC3 and FC1 for route C(Table 1). The large number of fibers reflects the asymmetryof textures created during ECAE as evidenced by the (111)pole figure obtained after one pass for a random initial tex-ture (Fig. 5b). Its patterns are similar to a plane rolling tex-ture 19,45 with a rotation of 1015about y axis, which isdirectly responsible for the observed asymmetry. At a highernumber of passes, textures remain planar and asymmetricand gradually different from the rolling case.Fourth, there is also some similarity between the tex-tures created by different routes as evidenced by pole fig-ures (Figs. 5 and 6) and deformation fibers (Table 1). For agiven fiber and cross-section in the ODF space, the effectof route on orientation is to change the angle and, in alesser extent, the angle . As a result, since angles and S. Ferrasse et al./Materials Science and Engineering A368 (2004) 284031Table 2Major orientations and corresponding fibers for route ANumber passes NMajor orientations (Notation: Euler angles():xyz?uvw?: % total volume with 5spread)Corresponding fiberRoute A (strong initial texture)Original (N = 0)(10.954.745): (111)?123?: 16(10526.50): (102)?281?: 14(1102426.5): (215)?551?: 9.3N = 1(11926.50): (102)?241?: 17.62FA3(34643.345): (223)?212?: 7.62FA2N = 2(13826.50): (102)?221?: 8.66FA3(3136.726.5): (213)?364?: 8.6FA2N = 3(126.726.50): (102)?231?: 7.45FA3(2136.726.5): (213)?243?: 6.1FA2N = 4(26.536.726.5): (213)?264?: 9.42FA2(13826.50): (102)?221?: 4.62FA3(16915.845): (115)?321?: 4.32FA1N = 6(126.726.50): (102)?231?: 6.66FA3(22833.70): (203)?342?: 5.8FA1(3136.726.5): (213)?364?: 3.42FA2N = 8All major orientations 3.1Route A (weak initial texture)N = 0(8025.245): (113)?8111?: 4.3N = 1(046.745): (334)?223?: 5.8FA2(22226.50): (102)?221?: 5FA1(12818.40): (103)?341?: 4.01FA3N = 2(126.726.50): (102)?231?: 6.22FA3(26.548.226.5): (212)?122?: 5.4FA2(16213.245): (116)?421?: 5.4FA1N = 4(23326.50): (102)?231?: 4.63FA1(13619.545): (114)?401?: 4.54FA1(26.536.726.5): (213)?364?: 3.7FA2affect (xyz) plane and ?uvw? directions, respectively, eitherthe major orientation inside a fiber changes or a new fiberwith new orientation is produced. The specific denominationmentioned earlier takes into account these similarities. Afiber name has the form Fxy, where a letter x corresponds tothe considered route (respectively A, B, C, D) and a numbery corresponds to a specific set of angles , . Three majortypes of fibers Fx1, Fx2 and Fx3 were identified as shown inTable 1. Each of these fibers exhibits similar values for theTable 3Major orientations and corresponding fibers for route BNumber of passes NMajor orientations (Notation: Euler angles():xyz?uvw?: % total volume with 5spread)Corresponding fiberRoute B (strong initial texture)N = 2(048 26.5): (212)?425?: 24.24FBD2(21615.845): (115)?241?: 8.07FBD1(13826.50): (102)?221?: 5.04FBD3N = 3(2603674): (2710)?941?: 15.49FB3(11818.490): (013)?631?: 5.23FB1N = 4(1003616): (7210)?491?: 12FB3(230.5140): (104)?451?: 8.05FB1N = 6(230.5140): (104)?451?: 12.46FB1(1003616): (7210)?491?: 10.2FB3N = 8(230.5140): (104)?451?: 9.19FB1(18013.245): (116)?331?: 8.21FB1(1003616): (7210)?491?: 7.48FB3set of angles , for most of the routes and passes (for ex-ample, from around (230, 0) to (180, 45) for Fx1 (Table 1),but specific values of angles and, to some extent, dependon deformation path. Table 1 shows the area of the inversepole figure as well as the range of planes and Euler anglescovered by each of these major fibers (for example, Fx1,when regrouping all studied routes corresponding to FA1,FB1, FC1, FD1 and FBD1 fibers). Fig. 6 shows fibers FA1,FA2 and FA3 in ODF space after the first pass.32S. Ferrasse et al./Materials Science and Engineering A368 (2004) 2840Table 4Major orientations and corresponding fibers for route CNumber of passes NMajor orientations (Notation: Euler angles():xyz?uvw?: % total volume with 5spread)Corresponding fiberRoute C (strong initial texture)N = 2(034.514): (416)?413?: 43.3FC3(221.82650): (102)?221?: 10.5FC1N = 3(25418.40): (103)?3111?: 7.5FC1(111.546.518.4): (313)?231?: 6.6FC3N = 4(13036.910): (304)?463?: 15.05FC3FC1 3.75FC1N = 5(270140): (104)?010?: 4.66FC1(26.54826.5): (212)?122?: 2.54FC3N = 6(1103616): (7210)?582?: 11.6FC3(23433.70): (203)?352?: 5.7FC1N = 7(24218.40): (103)?361?: 4.66FC1(18811.445): (117)?341?: 3.36FC3N = 8(136.518.40): (103)?331?: 14.71FC3(257450): (101)?8498?: 8.75FC1Fifth, for any route, less variation in orientation is seenas the number of passes N augments. Some principal fibersand orientations are gradually selected and conserved as Nincreases. Texture evolution can then be described by sim-ple rules, which show how processing macromechanics in-fluences texture: For route A, material distorsion is close to monotonic,which results in a few gradual changes in orientations(Figs. 2 and 5, Table 2). Mainly, the same planes, (102)and (213), are involved. This type of linear evolution issimilar to that found in rolling; For route D, after three passes, no significant changes inthe ODF or pole figure is observed whatever the originaltexture (Fig. 2; Table 5). This status quo can be surprisingsince a rotation of 90is continuously done at each pass.Table 5Major orientations and corresponding fibers for route DNumber of passes NMajor orientations (Notation: Euler angles():xyz?uvw?: % total volume with 5spread)Corresponding fiberRoute D (strong initial texture)N = 2(04826.5): (212)?425?: 24.24FBD2(21615.845): (115)?241?: 8.07FBD1(13826.50): (102)?221?: 5.04FBD3N = 3(19720.426.5): (216)?221?: 9.57FD1Major orientation in FD2, FD6, FD3 3N = 4(22226.50): (102)?221?: 13.34FD1FD2, FD3, FD6 3.8N = 6(223.518.50): (103)?331?: 7.4FD1Major orientation in FD3, FD2, FD6 2.5N = 8Major orientation in FD1, FD2, FD3 3. A similar observationwas made in 21. It can be argued that the amount of defor-mation involved at each pass is so high ( = 1.16) that anyoriginal influence is diminished. Even in route C, despitethe inversion of simple shear and because of hysteresis, the38S. Ferrasse et al./Materials Science and Engineering A368 (2004) 2840Fig. 8. Inverse (001) pole figures predicted by modeling for a weak initial texture after two passes via route D (a), four passes via route D (b), and fourpasses via route A (c).components obtained after two passes differ from the origi-nal texture 22. Finally, as the number of passes increases,especiallyafterfourpasses,lesschangeintextureorientationoccurs. There is rather a global spreading around some finalorientations for each route that results from texture weak-ening and structural transformations as explained below.4.2. Evolution of texture strengthA global weakening of texture from medium to very weakis observed as the number of passes augments, especially af-ter three or four passes, whatever the initial texture. Texturalrandomization is enhanced by weaker initial textures 22,and, in decreasing order of influence, for routes D, A and C(in the last case for odd numbered passes). It is still possibleto obtain medium-strong textures after four passes as shownin routes B or C (for even numbered passes) with a stronginitial texture. Texture softening at increased passes wasalso found in 18,28,31,35. Contrary to experiments, com-puter simulation predicts continuous texture strengtheningfor all routes when number of passes augments. Predictionsin orientation also become less accurate at high strains.These contradictory results prove that crystallographic slipis not the only mechanism responsible for texture evolutionduring ECAE 47,48. In particular, the simple Taylor codedoes not consider all microstructural changes occurring dur-ing ECAE 28,4548. The abundant literature concerningECAE 837,47,48 shows that at high strains, a sub-micronstructure is created (see part II, Fig. 1). Break up and refine-mentofmicrostructuresisinducedmechanicallybydynamicrecrystallization, which is believed to involve mechanismssuch as grain/subgrain rotation, flow localization in shearbands and their intersections 9,10,12,15,33,4751. Thesemechanisms contribute to diminish texture strength afterthree passes. Basically, the areas belonging to each fiber atfirst passes are divided into highly stressed and misorientedSMG structures, which disperse more X-rays and weakenfibers.The occurrence of texture spreading at high deformationswas reported for different processes including, for example,rolling after 9095% reduction 44,5255. Most of theseobservations were made for strains, which were not as largeas in this study. As ECAE extends plastic straining to veryhigh levels, it is possible to create weak, almost random tex-tures by promoting mechanically induced dynamic recrys-tallization.In resume, ECAE was proven as an effective techniquefor grain refinement to sub-micron size in massive billetsS. Ferrasse et al./Materials Science and Engineering A368 (2004) 284039by severe plastic deformation 837,47,48,52. In terms oftexture control, it appears the most promising to vary differ-ent routes for a low number of passes (N 4) and stronginitial texture. The tool angle is also a possible parame-ter, which can affect texture 2325. Severe deformation(N 4) combined with optimal route is another attractiveoption to produce SMG materials with either very weak ormedium-strong textures. However, a careful choice of ECAEprocessing characteristics must be attained in order to in-duce simple shear and control texture 56.5. Conclusions1. ECAEisaneffectivetechniquetocontroltexturestrengthand orientation. Compared to conventional techniquesECAE offers a large variety of parameters for textureevolution. Two of them, the number of passes and thedeformation route, are the most important.2. Numerous orientations, which covers most of the areasof the standard triangle have been obtained. The ECAEroute provides a radical and influential mechanism fortexture transformation at a low number of passes (N 4).3. All types of texture strength have been obtained by con-trolling the number of passes: from medium to verystrong for a low number of passes (N 4).4. A simple Taylor model shows that crystallographic slipenhanced by simple shear is the major mechanism thatdefines texture orientation during ECAE. It explains rea-sonably well major orientations and fibers obtained foreach route. A few classes of fibers, which are character-istic of the ECAE simple shear deformation mode wereidentified.5. The Taylor model fails to predict texture strength be-cause various mechanisms other than crystallographicslip become important at high levels of deformation.These mechanisms favor mechanically induced dynamicrecrystallization and produce sub-micron grained struc-tures, which tend to be weak and, in some cases, nearrandom textures. Routes A and D are the most effectivefor texture randomization.6. Initial texture plays a limited role on texture orientationand a significant role on texture strength at the earlieststage of deformation. For route C, its influence is thestrongest.AcknowledgementsThe authors wish to express appreciation to other contrib-utors to this work, especially Prof. H.R. Wenk and Dr. D.Damodaran.References1 R.W. Siegel, in: M. Nastasi, D.M. Parkin, H. Gleiter (Eds.), Proceed-ings of the NATO ASI Mechanical Properties of Ultrafine-GrainedMaterials, Quebec, 1993, p. 509.2 C. Suryanarayana, Bull. Mater. Sci. 17 (1994) 307346.3 V.Y. Gertsman, R. Birringer, R.Z. Valiev, H. Gleiter, Scripta Metall.30 (1994) 229234.4 H.J. Zughaer, J. Nutting, Mater. Sci. Technol. 8 (1992) 11041107.5 I. Saunders, J. Nutting, Met. Sci. 19 (1984) 571575.6 V.M. Segal, Invention Sertificate of the USSR, No. 575,892 (1977).7 V.M. Segal, V.I. Reznikov, A.E. Drobyshevky, V.I. Kopylov, Russ.Metall. 1 (1981) 971974.8 R.Z. Valiev, N.A. Krasilnokov, N.K. Tsenev, Mater. Sci. Eng. A 137(1991) 3540.9 R.Z. Valiev, R. Chmelik, F. Bordeaux, G. Kapelski, B. Baudelet,Scripta Metall. Mater. 27 (1992) 855855.10 V.M. Segal, Mater. Sci. Eng. A 197 (1995) 157164.11 M. Furukawa, Z. Horita, M. Nemoto, R.Z. Valiev, T.G. Langdon,Acta Mater. 44 (11) (1996) 46194629.12 S. Ferrasse, V.M. Segal, K.T. Hartwig, R.E. Goforth, Metall. Mater.Trans. A 28A (1997) 1047.13 M.V. Markushev, C.C. Bampton, M.Y. Murashkin, D.A. Hardwick,Mater. Sci. Eng. A 234236 (1997) 927.14 P. Berbon, N. Tsenev, R.Z. Valiev, M. Furukawa, Z. Horita, M.Nemoto, T.G. Langdon, Metall. Mater. Trans. A 29A (1998) 2237.15 Y. Iwahashi, M. Furukawa, Z. Horita, M. Nemoto, T.G. Langdon,Metall. Mater. Trans. A 29A (1998) 2245.16 T. Mukai, M. Kawazoe, K. Higashi, Mater. Sci. Eng. A 247 (1998)270274.17 I.V. Alexandrov, Y.D. Wang, K. Zhang, K. Lu, R.Z. Valiev, in:Z. Liang, L. Zuo, Y. Chu (Eds.), Proceedings of the ConferenceICOTOM, vol. 11, 1996, pp. 929940.18 S.R. Agnew, J.R. Weertman, Mater. Sci. Eng. A 244 (1998) 145153.19 O.V. Mishin, V.Y. Gertsman, G. Gottstein, in: Z. Liang, L. Zuo, Y.Chu (Eds.), Proceedings of the Conference ICOTOM, Xian, vol. 11,1996, pp. 10151020.20 O.V. Mishin, G. Gottstein, Philos. Mag. A 78 (2) (1998) 373388.21 S.R. Agnew, U.F. Kocks, K.T. Hartwig, J.R. Weertman, in: J.V.Cartensen, T. Leffers, O.B. Pedersen, B.F. Sorensen, G. Winter (Eds.),Proceedings of the Conference of 19th Ris International Symposiumon Material Science, Ris Nat. Lab., Roskilde, Denmark, 1998,pp. 201206.22 M.A. Gibbs, K.T. Hartwig, L.R. Cornwell, R.E. Goforth, E.A.Payzant, Scripta Metall. 39 (12) (1998) 16991704.23 A. Tidu, F. Wagner, T. Grosdidier, W.H. Huang, P.W. Kao, C.P.Chang, in: J.A. Szpunar (Ed.), ICOTOM 12, vol. 1, Montreal, Canada,1999, pp. 694699.24 A. Tidu, W.H. Huang, P.W. Kao, T. Grosdidier, C.P. Chang, J. Phys.IV 10 (2000) 10211.25 W.H. Huang, L. Chang, P.W. Kao, C.P. Chang, Mater. Sci. Eng. A307 (2001) 113118.26 L. Dupuy, E.F. Rauch, J.J. Blandin, in: T.C. Lowe, R.Z. Valiev(Eds.), Investigations & Applications of Severe Plastic Deformation,Kluwer, New York, 2000, pp. 189195.27 I.V. Alexandrov, in: T.C. Lowe, R.Z. Valiev (Eds.), Investigations& Applications of Severe Plastic Deformation, Kluwer, New York,2000, pp. 103108.28 J.J. Beyerlein, R.A. Lebensohn, C.N. Tom, Mat

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