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附录A管材弯曲工艺研究新进展摘要管材成形由于容易满足塑性成形产品轻量化、强韧化和低耗高效、精确制造等方面的要求,在航空航天、汽车工业等许多行业中得到广泛的应用。管材弯曲成形工艺的研究是其中备受关注并得到迅速发展的重要领域之一。介绍了几种新的弯管工艺,阐述了国内外弯管工艺的最新研究进展和发展趋势。关键词管材;弯曲;弯管工艺管材塑性加工是以管材作毛坯,通过塑性加工手段,制造管材零件的加工技术1。管材塑性加工由于容易满足塑性成形产品轻量化、强韧化和低耗高效、精确制造等方面的要求,已成为先进塑性加工技术面向21世纪研究与发展的一个重要方向2。在航空航天、汽车、石油化工、轻工及交通运输等工业部门中,广泛地采用管材制造零件。例如在汽车工业中,采用中空铝型材作车身结构和保险杠,在保持与钢铁制件具有同等的抗冲击强度条件下,能减轻30%40%车体质量,对汽车的轻量化具有十分重要的意义;当汽车发生碰撞等意外事故时,管材结构还可以吸收因碰撞带来的冲击能,保护乘客的安全3。管塑性弯曲成形是管塑性成形技术的重要组成部分。用管材制造的弯曲零件,无论是平面弯曲件,还是空间弯曲件,除大量应用于气体、液体的输送管路外,在金属结构中的应用也十分广泛。因此管材弯曲成形工艺是备受关注并得到迅速发展的重要领域,开展这方面的研究工作,具有十分重要的意义。文中介绍了管材弯曲的几种新工艺,以及国内外研究进展和发展趋势。1、基于成形方式的管材弯曲工艺分类实践中有许多不同的弯管工艺,从不同的角度出发可以有多种不同的分类。工程中通常按弯曲时加热与否可分为冷弯和热弯,根据弯曲时有无填充物可分为有芯弯管和无芯弯管。文献4根据不同的成形方式。无模弯曲成形是指管材弯曲变形区不直接受到模具的作用,最终的形状由工具和工件的相对运动决定,属于高度灵活的柔性加工手段。有模弯曲成形是指通过刚性模具直接作用于弯曲变形区而进行的管材弯曲,要求此刚性模具作用部分尺寸可以补偿制件卸载后发生的弯曲回弹,属于可重复性高而且快速的加工手段。2、管材弯曲的几种新工艺2.1热应力弯曲热应力弯曲是一种利用工件内部温度分布不均匀所产生的热应力来驱动工件变形的成形方法。这种方法不需外力作用,因而也不需要专门加工模具,便于现场操作,是一种柔性加工手段,近年来对这种成形方法的研究逐渐增多。加热热源可采用火焰或激光,加热方式包括局部加热及加热炉内整体加热;冷却方式包括空冷、喷水冷却及浸水冷却。具体工艺取决于实际工况和工件特征。激光成形是对局部材料采用激光加热,通过不对称的加热和冷却,一个楔形区域上产生了压缩变形。通过在轴方向不同区域的反复激光照射加热,可以最终确定管材的形状。因为残余应力对制件质量有影响,所以在工艺设计时需要考虑工件的残余应力分布。这种方法由于可以方便地控制激光功率大小和作用轨迹,因此易于成形空间弯曲件。它不仅可以适用于简单的矩形截面管材,而且可以弯曲复杂截面的管材。但是在弯制多型腔型材时有一些限制,且加工时间长,生产效率低文献5提出的管的热应力弯曲方案是:先将管件在加热炉中均匀加热到某一温度,然后以一定速度水平浸入水中,直至管件完全冷却。管件最终凹向后入水一侧,其弯曲规律如下:内外弧的弯曲程度无明显差别;管件截面扁化,其中沿弯曲半径方向的截面尺寸大于垂直弯曲平面方向的截面尺寸,即同压弯法弯管所造成的截面变化趋势相反;管件弯曲程度及截面变化程度随加热温度的提高而增大;长度直径比值较大的管件,其弯曲效果较好。2.2 基于工具运动控制的无模弯曲如图1所示可以通过控制管端夹具轨迹来实现无模弯曲。管端夹具的运动产生的弯曲力矩使得管材在局部区域产生弯曲塑性变形并发生 图1基于管端夹具运动控制的无模弯曲转移。因此可以实现轴向多曲率半径工件的无模弯曲。通过对轨迹的微分方程进行数值求解,可以得到用于弯曲成形设备上的不同的控制程序。文献6使用这种方法成形得到型的零件。另一种通过控制工具运动实现无模弯曲的方法。管材通过一个导向圆柱轴向送料,在离出口一定距离处有一个移动模,其用球轴承作为支撑点,并且可以在垂直于轴向的平面内移动。根据移动模的位置和偏转方向的不同,管材会产生相应的弯曲。通过轴向的进给运动,可以使管材在包括端部的整个长度上进行弯曲。 这种弯曲设备的基本原理是弯曲原理,它可以用来方便地实现管材的空间弯曲,但却必须为各种截面的管材定制不同的模具。图2展示了利用这种成形工艺得到的弯曲管材。2.3叠加法弯曲叠加法的原理3所示当金属材料在塑性区域内变形时,可以利用一个相对于成形力来说很小的侧向作用,实现弯曲。在具体实现过叠加法原理程中,这个很小的作用力可以通过一个偏转轮施加,其产生了一个很小的力矩,影响金属的流动,从而实现了可控制曲率的弯曲加工。由于零件本身是按弯曲要求生产的,因此可以避免产生诸的截面变形、破裂或起皱问题。叠加法最直接的应用就是管材的挤压生产。实际直型材在挤压过程中由于在挤压模中存在不理想的摩擦条件,因而产生了非常小的摩擦力,引起轻微弯曲现象;反过来说,如果在挤压过程中有效控制这个力,利用其使挤压金属的流动速度产生速度梯度,从而实现制件弯曲。另外通过改变摩擦力作用长度也同样可以产生类似的效果。该工艺的优点是可以比较灵活地控制偏转轮而不必改变挤压模具的设计,甚至复杂的多型腔横截面的型材也可以通过这个方法弯曲。目前开展的大多是平面内常曲率弯曲的研究8,对于空间变曲率弯曲从理论的角度上来说是可行的,但是由于需要对偏转轮的实时控制,因此设备方面还需要进行重大改进。另一个类似的弯曲工艺把叠加法原理运用到扩管设备中。2.4数控机床绕弯绕弯是指将管材夹紧在弯曲模上,随弯曲模一起转动,当管材被拉过压块时,压块即将管材绕弯在弯曲管上,属于成形模弯曲工艺。传统绕弯工艺多是手工绕弯,效率低,质量难以保证。随着数控机床业的发展,采用先进的数控弯管机床实现绕弯工艺,可以大大地提高生产效率,保证产品的质量。由于可以方便地调节工艺参数,因此数控弯管机可以既准确又稳定地完成弯曲、送进、转角等动作,保证了管制件的弯曲准确度。数控弯管机可以自动连续地成形不同曲率半径的空间弯曲件。结合相应的数据库软件系统,控制程序还可以预先修正弯曲回弹量。但是该工艺的模具结构（见图4）比较复杂,制件质量对工艺参数敏感,要求有充分的前期准备和试制工作。尤其是对于弯制薄壁管制件的情况,如果工艺参数选择不当,则很容易出现起皱现象导致零件甚至是模具的报废。如何高效准确地获取这些工艺参数,充分保证弯管产品质量,是数控绕弯工艺的研究热点。3、管材弯曲研究进展上述介绍的新弯管工艺多数属于柔性加工手段,拓展了管料弯曲加工的工艺方法范围。实际生产中弯管工艺往往易产生如图5所示的质量缺陷。(1)在弯曲变形区外侧壁会产生壁厚变薄;(2)在弯曲变形区内侧壁会产生壁厚增大起皱;(3)横截面形状畸变;(4)回弹问题。为了解决上述质量缺陷,目前国内外学者对管材弯曲的研究,主要集中于两个方面:通过理论解析和试验研究的方法对弯管的机理进行研究;通过数值模拟的方法对弯管质量缺陷进行研究并改进工艺。在试验研究方面:通过实验研究,分析了牛角芯棒热推弯管成形过程瞬时应力、应变状态及其演化过程,阐明了弯管成形时的受力、变形特点,揭示了弯管成形过程所遵循的力学原理及其分析求解方法,为牛角芯棒热推弯管成形理论研究奠定了基础。根据弯管加工理论、实验研究和大量实践,总结出了对管材弯曲加工成形精度有重要影响的回弹、伸长和成形半径等参数的确定方法,并可用智能弯管测量仪测取上述数据,以用于指导生产。文献7采用能量原理分析截面变扁率和材料性质及工艺参数之间的关系,理论和实验结果吻合得较好。提出的系统建立了系列数控弯管机床的几何、运动、变形、调试及干涉测试的总体仿真模型和完整的模具库及导管库。该系统采用数控指令驱动,能直接从弯管数据库中读取程序,进行装夹、弯曲、回弹等数控弯管全过程的三维动态显示,并可进行干涉检测处理。对中频感应局部加热弯管在不同钢管材料及规格、不同弯曲半径及弯曲角度等工艺参数时的加载和卸载的力能参数、应力应变进行了理论分析和实验研究。在数值模拟方面:提出了中频感应局部加热弯制大直径钢管的回弹理论,计算结果与有限元模拟结果以及实际弯制的钢管弯头实测的回弹量吻合良好。文献8对管材弯曲时的截面变形作了研究和数值模拟,研究表明截面的变形会明显地减小弯曲力,因此在有限元模拟时,会严重地影响力和截面变形的计算结果。文献9采用商用有限元软件对矩形截面管材弯曲作了数值模拟,在起皱、外侧塌陷、截面变形等方面模拟结果和实际情况相符合。在全面分析无模弯曲成形工艺过程的基础上,对该种工艺过程的复杂边界条件作了合理的处理,建立了无模弯管有限元分析模型,开发了可用于管材弯曲分析的三维刚塑性有限元程序,可预报管材(型材)弯曲后断面畸变的情况,有重要的实用价值。此外,对于管材加工中的起皱现象,虽然涉及因素多、研究难度大,但是由于对精确成形的日益迫切的要求,也引起了国内外学者的关注,发表了一些对管材起皱机理的分析和数值模拟方面的研究报道:文献对管材缩口及轴向压缩过程用分叉理论和弹塑性有限元法进行了起皱的预测,分析了单元尺寸、模具尺寸和材料性能对分叉点的影响;对中空矩形铝管的弯曲起皱进行了预测,对低刚度和高刚度两种材料的皱曲波形进行了描述,并采用能量法分别计算了两种材料起皱的临界应力值;在分析讨论国内外关于板材起皱研究的基础上,提出了采用最小能量法预测薄壁管弯曲成形过程中失稳起皱的新思路;采用商用有限元软件 模拟了数控弯管过程,研究发现管材和防皱块之间的间隙是影响起皱的重要因素,同时随着弯曲半径的减小,截面畸变率和壁厚减薄率将会变大。随着计算机技术的发展和有限元软件算法的改进完善,采用数值模拟的方法对实际生产进行模拟是一种被证明是行之有效并且具有很大潜力的途径。采用计算机进行模拟仿真,可以大大地减少试验的工作量,减少时间和人力物力消耗,并且可以方便地改变工艺参数,以系统探索工艺参数对成形的作用和影响。管材弯曲的研究工作方法,也越来越多的由解析试验方法向数值模拟方法转变。但是,由于管材弯曲建模的复杂性,不能简单地用轴对称或平面模型描述。研究人员在进行解析和数值建模时,为了降低三维计算工作量,通常都提出了一些假设前提,这使得研究结果和实际生产出现不小的差距。目前对普通壁厚管料弯曲的模拟的研究比较完善,但是对于薄壁管易压缩失稳出现起皱的情况,还是不能准确判断和正确处理,因此这方面的研究也是管料弯曲研究领域的热点。对于弯曲回弹问题,试验方法取得一定进展,建立了一些基础参数数据库,但是试验工作量非常大,如何用数值模拟方法研究回弹问题,依然是一个难点,有待进一步发展。4、结语(1)管塑性加工由于容易满足塑性成形产品轻量化、强韧化和低耗高效、精确制造等方面的要求,在航空航天等许多行业中得到了广泛的应用,因此管材弯曲工艺备受关注并得到了迅速发展。(2)基于成形方式的分类是管材弯曲的一种新的分类方法。热应力法和基于工具运动控制的无模弯曲可以实现柔性制造;重叠法具有避免产生截面变形等缺陷的特点,可以直接生产弯管制件;数控绕弯可以进行高效批量化生产,符合现代化生产的需要。(3)国内外对于弯管的研究工作,主要集中于试验研究和数值模拟两个方面。数值模拟方法被证明是一种行之有效并且具有潜力的研究方法,对弯管质量缺陷的研究工作越来越多地采用了有限元模拟方法。对管料弯曲建模、薄壁管弯曲起皱和弯曲回弹的研究正成为国内外研究关注的热点。气体的压力作用下喷射到冷却板上,合金凝固后可获得具有细小等轴晶粒组织的坯料。该坯料可用于半固态成形加工用的坯料。这一方法在制备大过共晶铝硅合金等特殊材料的坯料方面有一定的优势,但成本较高。(4)控制结晶过程及晶粒细化法。该方法是通过对合金液体加入晶粒细化剂或控制冷却速度等,以使合金凝固后的固相晶粒不为枝晶状而为非枝晶状(近似等轴晶)。由于这种方法在几种坯料生产方法中成本最低,因而具有较大的发展前途。1.2半固态成形用设备(压力机)目前欧洲、美国及日本等国已生产出专门用于半固态加工的成套设备(压力机),也可以在现有压铸机或锻压设备的基础上改造。半固态加工时温度的控制半固态加工的温度是该加工工艺的主要参数之一。这是因为该温度决定了液相和固相的比例,它对零件加工时所采用的压力以及获得零件的强度、健全性都有重要的影响。目前多采用热电偶、超声波等方法测控。半固态加工用的模具半固态加工用模具的设计可参考压铸模、冲压模等的设计,但必须考虑半固态加工的实际条件。和压铸相比,半固态坯料的温度低,流动时间短,呈层流状;和冲压相比,半固态坯料的流动性远高于固态且成形压力低。有研究表明,半固态加工所用的冲压力仅为传统锻压方法的1/5左右。由于冲压力的降低,对模具材料的要求也降低,可以用非金属材料(如陶瓷、石墨等)制作模具。在发达国家,半固态加工的模具设计多采用计算机模拟设计。已用于半固态成形的铝合金最早用于半固态成形的为亚共晶铸造铝合金(356,357)。这两种合金在发达国家采用半固态成形已实现工业化生产。后来,他们又开发了过共晶成分的390铝硅合金。这种合金中的初晶硅相,在电磁搅拌生产坯料的方法中,被细化并均匀地分布在合金中,提高了合金的强度和耐磨性。有关锻铝合金用于半固态成形加工的技术正处于研究开发阶段。铝合金半固态成形技术的发展趋势铝合金的半固态成形加工主要用于汽车工业中零件的生产。而汽车工业持续要求降低车体重量和减少环境污染,这就要求半固态成形技术能提供高强度的铝合金以替代钢和铸铁制零件等。因此,半固态成形加工技术有广阔的应用前景。半固态成形加工技术今后应在低成本制备半固态加工用坯料、成形设备研制、成形模具设计及成形过程计算机模拟以及开发适合于半固态加工用的新型铝合金材料方面进行深入研究。附录BState of the Art of the Bending Process and Research of TubeAbstract: With the characteristic of high efficiency,forming precision and strength/weight ratio product and low consumption,tube froming processes find an wide application in modern industries such as aero-space and automobile.Tube bending process is one of the most important tube forming processes are introduced,as well as advancement and trend of relative research report. Key word: tube ; bending ;bending process Pipe plastic property process is acting as Mao Pi with pipe ,and by means of the plastic property process measure,manufactures the pipe spare parts process technology.Pipe plastic property is processed meeting the light quantification of produce that the plastic property takes shape thanks to easily、High efficiency of powerful with consumes slowly 、Accurately manufactures and so on the respect demand has become the significant orientation 2 to the 21 centuries research and development of well-developed plastic property process technology.Aviation spaceflight is living 、Motor vehicle 、Mineral oil chemical industry 、Widely adopt the pipe spare parts in the industry department such as light industry and communications and transportation and so on.In for instance being living the auto industry empty the mould material in adopting acting as bodywork composition and the bumper ,and is living to maintain having below the same resisted shock intensity term,and be able to eases 30% against the iron and steel finished piece 40%The automobile body quality have the fully significant sense to the light quantification of motor vehicle;When the motor vehicle happen to run into and so on when the unforeseen mishap,the pipe composition still may suck up the shock capacity brought as a result of ruing into,and safeguards the security 3 of passenger.It is the significant component part ruing the plastic property forming technique that tube plastic property crookedly takes shape.In the way of the crooked spare parts of pipe,no matter is crooked on plane , nevertheless crooked in room,except for the greats quantity are used to gas 、Outside the liquid pipeline route,the application that is living in the metal structure is also fully wide-ranging .The crooked forming technology of pipe this respect research work,and have the fully significant sense hence being accepting the significant territory that the concern obtain the swift development in every possible way.Introduced some kinds of fresh technology that pipe is crooked in the script,along with the home and abroad is researched to make progress and development tendency.1 .Based on , forming means crooked technology of pipe is classified That to possess much in the practice distinct flexed runs technology,may possess much kinds of classifications difference through the distinct angle departs .During usually according to crooked heat whether or not to be divided into cold bend and temperature flexing in the project,and having or not the filler may be divided into processing the rush pith to flex the tube to flex the tube during on the basis of crooked with not is not the rush pith.The literature 4 is on the basis of the forming means of difference.Not is not the standard crookedly to take shape is the crooked deformation district of pipe directly is not subjected to the pattern action, ultimate form shape is through means and the work relative movement resolution ,and pertains to highly the agile flexible process measure.It is crooked by means of the stiff pattern direct action to crooked deformation district but pipe that is underway to possess the standard crookedly to take shape,and requires this stiff part of dimensions of pattern action may compensation finished piece down load what afterwards happen the crooked time pellet,and pertains to the tall but also fast process measure of repeatability.2 .Crooked some kinds of fresh technology of pipe 2.1 Warmhearted stress is crooked One kind of temperature of use work inside that the warmhearted stress is crooked is distributes,and the uniform warmhearted stress coming into being comes drive work the person who becomes deformed the forming means.This kind of means does not require the function of outside force,and as a result also not needing the special process pattern,is convenient for the operation at field,and is one kind of flexible process measure,and grows in number one by one to this kind of forming means research in the past few years.Heating the heat source may adopt flame either laser,and heats that the means consists of that the part is heated the heating furnace the entirety to heat;The cooling means consists of that it is cool to empty 、Spouting the water-cooling yet reaches the cooling reted.Concrete technology is decided by actual operational mode and the work feature.It is adopting laser to heat to the part stuff that the laser takes shape,by means of not symmetrical heating and cooling,the wedge form comes into being on the area compresses the deformation,By means of be living.Reversal laser in distinct areas of shaft orientation illuminates to be heated,and may finally fix pipe form shape.For remains stress possess the effect to the finished piece quality,the necessaries are consider that work remains stress distributes when being living the technological design.This kind of means is since may dominate conveniently laser service rate size and the action locus,hence being easy to crooked in forming room.It not merely may be applicable to easy rectangle section pipe,but also may crooked complex section pipe.Yet is living to flex possess some limits when manufacturing the many types of cavity mould material,and process time elder , the production efficiency is later drop. Tube that the literature 5 the is propose crooked scheme of warmhearted stress is:Shall Guan be living in the heating furnace evenly to heat earlier, afterwards with the specified velocity level macerate in the water,and becomes cool completely till Guan up some temperature.Guan finally hollowly enter the water side backward,and such crooked regular pattern is as follows:The crooked degree of inside and outside arc does not there is not the obvious disparity;In immediate future of Guan section in it is more than crooked plane orientation of the uprightness section dimensions along the bending radius orientation section dimensions,with is getting near flexed that the law flexed the section that the tube created to change tendency contrary;Guan crooked degree and section changing the degree and broad with heating the temperature raise;Guan of length diameter ratio,such crooked effect is better.2.2 Baseded on , the means movement control nil standard is crooked May by means of control Guan no standard crooked clamping apparatus locus achieving.Crooked moment that Guan clamping apparatus movement is come into being causes that is living pipe,and the crooked plastic deformation of part area coming into being is complicated by to bear to transfer.Hence the nil standard that may achieve the axial much curvatures radius work is crooked.By means of carries on the numeric value resolution to the locus differential equation,difference that may obtain is used on the crooked forming installation control procedure.The literature 6 employs this kind of means to take shape and obtains S Spare parts of mould.Another kind does not there is not the means that the standard is crooked by means of do means movement achieving.The stuff is send by means of the direction cylinder axial by the pipe,and being living to part from to export surely to possess the standard removing away from the part,such is in the way of the ball bearing as the centre of resistance,moreover may be living that the uprightness in is removed the axial plane inner place.The pipe be able to come into being relevant crooked to the difference on the basis of the place to remove the standard with the yawing orientation.What it is by means of the axial moves forward to the movement,and may cause pipe be living to consist of the entire length of butt to make progress line bend.The fundamental rule of this kind of crooked installation is MOS It is crooked that it may be used for conveniently achieving pipe room,yet have to act as the different sections pipe customization differences patterns to the crooked rule.Opening up before ones eyes utilizes this kind of crooked pipe that forming technology obtain.2.3 The superimpose law is crooked When the metal material is living when becoming deformed inner place the plastic property area,may utilize one relatively with takes shape force Very little cross acting force,Achieve crookedlyBeing living concrete realization passing through superimpose law rule Cheng Zhong,this very little acting force may be bring to bear on by means of the yawing wheel,such come into being one very little moment,effect metal going from place to place,thereby yet achieved the crooked process of control curvature.May avert coming into being that various sections become deformed since the fact that the spare parts in itself are according to crooked demand manufacture、Split either creases the problem.The most immediate application of superimpose law is a pipe press manufacture.The actual upright mould material is living in the press process thanks to being living that the press is the not ideal rub term in the standard,as a result coming into being very much little friction,The crooked appearance is aroused lightly;Saying the other way round , in the press process effectively this force in case being living,such causes going from place to place velocity the metal come into being the velocity gradient to the use,thereby the realization finished piece is crooked.Besides also may come into being equally analogous effect by means of revising friction action length.That the technology strong point is may comparatively agile dominate the yawing wheel but need not revise the press pattern design,and it is crooked that the mould material in even to the extent that complex tranverse section of many types of cavity also may pass this means.The crooked research 8 of constantly curvature that the politically progressive at the moment is for the most part inner place the plane changes into curvature as to the room crookedly being supposed to on theory angle,yet thanks to the fact that the necessaries adjust the yawing wheel real-time control,hence still need to importantly improve the installation.Another analogous crooked technology is utilized the superimpose law rule up enlarged ruing installation.2.4 The APT coils to be flex Coiling to flex is by on the taut crooked standard being living of pipe clip ,adapts to the crooked standard turning in company,serves as pipe has been to be getting near cake hour,is getting near cake soon pipe to coil to flex being living on the crooked tube,and pertains to the crooked technology of forming block.That the handwork coils to flex is coil to flex technology to be mostly that to the tradition,and the effectiveness is later drop,and the quality is difficult to,In the wake of the APT trade development,adopt the well-developed digital control to flex the ruing machine tool achieving to coil flexing technology,and may lift the production efficiency,quality of guaranty produce enormously.Since may regulate conveniently the technology parameter , hence the digital control flexed Guan Ji may be not only accurately but also steadies completed crookedly 、Send 、The crooked degree of accuracy of tube finished piece in the movements such as street corner and so on.Crooked in the room that Guan Ji may continuously take shape the distinct curvatures radius is voluntarily flex in the digital control.Uniting the relevant data bank software system,the control procedure still may be amend crooked time pellet and measure beforehand.Yet that the technology pattern composition is comparatively more complex,it is susceptible that the finished piece quality adjust technology parameter,the demand possess sufficiently earlier days get ready and the development work.Especially manufactures the thin wall tube finished piece situation as to flexing,in case the technology parameter selection is unsuitably,has arise the appearance creased to cause the spare parts even to the extent that is reporting something as worthless of pattern piece easily.How the high efficiency is accurately gained these technology parameters,sufficiently to flex ruing the produce quality,is the digital control coils flexed the technology research heat。3.The crooked research of pipe makes progress Above-mentioned introduction fresh flexed to run the technology majority pertaining to the flexible process measure,and spread crooked process of the Guan Liao technology means limit.Flex in the actual manufacture quality fault runs technology frequently easily to come into being.(1)The breastwork being living outside the crooked deformation district side wall be able t to come into being is thick and changes into slight; (2)The breastwork being living inner place the crooked deformation district side wall be able t to come into being thickly broadens creasing; (3)The section form shape distortion; (4)Go back to play the problem.In order to resolve the above-mentioned quality faul,at the moment a learned man in home and abroad adjust the research that pipe is crooked,and main lumping is to two respects:The means is researched to mechanism flexing the tube by means of what theory analysis and equipment were researched;The means by means of the numeric value imitation adjust to flex to run the quality fault and researches modification technology.The equipment research respect is living:Research by means of the test,and analysis the strong temperature of ox horn rush pith pushing to flex the tube and takes shape the instantaneous stress of process 、The condition meet an emergency reaches such evolution process , and accepting force when flexing the tube to take shape 、The deformation distinguishing feature promulgated to flex the tube to take shape that the mechanics rule that the process was followed reaches such and analyses the resolution means,and pushes to flex the tube in the interest of the strong temperature of ox horn rush pith to take shape that theory is researched the base.Process theory on the basis of flexing the tube、The test is researched and greats quantity carrying out,and summed up out that the pair crooked process of pipe takes shape that the accuracy possess the significant effect pellet going back 、Certain means extending with forming radius and so on parameter,and the usable intellect flexed the tube measurement instrument and fathoms get the above-mentioned data , and in order to be used the direction to give birth to.The literature 7 adopts energy rule analysis section to change into the relationship between flat rate and stuff nature and the technology parameter,and theory and test are kill to coincide better.Propose TUBEMOD The system was establish the geometry that the ruing machine tool is flex in the set digital control 、Movement 、Deformation 、Total imitation pattern and integrated pattern storehouse and conduit storehouse that debug and interference are tested.Ought to systematically adopt the digital control order drive,and be able to directly read aloud get through flexeds the ruing data bank NC The clip is packed to the order 、It is crooked 、Go back the three dimensions dynamics display that Guan Quans process is flex in the digitals control such as pellet and so on , and may intervene the examination to handle.To the medium frequency reaction partly heats flexed the tube to be living distinct steel tube stuff and the standards 、Loading and down load when the technology parameters such as distinct bending radius and crooked angle and so on force capacity parameter 、Theory is analysis and the test is researched is meet an emergency to be underway that by the stress.The numeric value imitation respect is living:Processing the medium frequency reaction partly heats to flex to manufacture the going back to play theory of great diameter steel tube , and the computational solution is simulated result along with practice against the finite element and is flex that the steel tube manufacture bend factor the person who fathoms the amount going back to the pellet coincide well.The literature adjust that the section of pipe when crooked becomes deformed to act as to research and the numeric value is simulated,and researches making known that the deformation in section be able to obviously decrease crooked force , hence being living that the finite element is simulated the hour,gathering seriously computational solution that effect and section become deformed.The literature adopts commercial finite element software MARC The numeric value simulates crooked acting as to pipe in rectangle section , and is living to crease 、Outside sinks 、The respects such as section deformation and so on simulates the result one another to accord with the actual situation.Is living completely analyses not their is not on crooked forming technology process of the standard base,the complex boundary condition to that kind of technology process do the rightful handle,and establish nil standard flexing ruing the finite element analytic modeling,and opened up the usable three dimensions plastic property finite element orders only a short while ago to the crooked analysis of pipe,yet predicts crooked queens of the pipe ( mould material ) section distortion situation,and possess significant pragmatic value.Moreover,as to the creasing appearance in the pipe process,although it is much to relate to the element 、The research difficulty greatly,yet thanks to adjust the accurately forming pressing increasingly demand, also aroused the concern of home and abroad a learned man,and is used some creasing mechanism analysis and the numeric value imitation respect research cover to pipe:The literature shrinks to pipe,and rim and the axial condensation process plastic property finite element method in the way of tee-offs theory and pellet has been carried on the calculation creasing , and analysis the cell dimensions 、Pattern dimensions and stuff the effect to the tee-offs spot of performance ; What it is to middle the emptying rectangle tube crookedly creased the calculation,and has been underway the description to lets drop stiffness and the high stiffness two kinds of stuffs lines tune wave pattern,and adopts the energy method to calculate two kinds of interface stress values that the stuff creases separately;Being living to analysis the discussion home and abroad to crease on the base which researched, and processing to adopt the minimal energy method to forecast that the thin wall tube loses in the crooked forming process firm what creases fresh thinking on plate; Adopt commercial finite element software PAM STAMP the digital control fled ruing the process , and researching discovering pipe and the gap provided against between the lines lump is the significant element that the effect is creased, moreover in the wake of decreasing of bending radius , thick Bao Shuai reduce of section distortion rate and breastwork be able to change into great.Development and finite element software algorithm in the wake of the calculating machine technique improves consummately,and to adopt numeric value imitation means to adjust practice to give birth to simulate is kind being demonstrated is effectual moreover method that have the very great latent capacity.Adopting the calculating machine to carry on analog simulation,and may decrease greatly equipment amount of work,and decreases time and the labor power resource uses up,moreover may revise conveniently the technology parameter , the parameter adjust forming action and effect with system exploration technology.The also more and more transform through the analysis equipment means to the numeric value imitation means the crooked research work means of pipe.But,can not simply depict since crooked model building of the pipe complexity in the way of either plane pattern.Research fellow is living when carrying on analysis and the numeric value model building,and in order to cut down by three dimensions calculation amount of work , wholly processing some usually assumes the prerequisite,and this causes to research result and practice and gives birth to having arise the not little disparity.Research that adjust the crooked imitation of thick Guan Liao of ordinary breastwork is at the moment comparatively improved,yet as to the thin wall Guan Yi compresses losing the situation that the firm emergence is creased,and nevertheless can not accurately decide handing with correctly,hence this respect research also is the crooked research territory heat-point of Guan Liao.As to crooked time pellet problem,the equipment means is acquired the specified progress,some base parameter data bank were establish,yet equipment amount of work is very much great , and how in the way of numeric value the problem is goes back to play in the imitation method study,and as before is a difficulty,and awaits to develop further.4. Knot Tongue (1)Tube plastic property is processed meeting the light quantification of produce that the plastic property takes shape thanks to easily 、High efficiency of powerful with consumes slowly 、Accurately manufactures and so on the respect demand is living in much professions such as aviation spaceflight and so on to obtain the wide-ranging application,hence the crooked technology of pipe accepts the concern to obtain the swift development in every possible way.(2)Based on,forming means classification is one kind of fresh method of partition that pipe is crooked.The warmhearted stress law crookedly as the nil standard based on means movement control may the realization flexible be manufacture;The reduplication law has to avert the distinguishing feature to come into being the faults such as section deformation and so on,and may directly give birth to flexing the ruing finished piece;High efficiency lot manufacture may be carried on in digital control coiling curve,and accords with the modernize manufacture necessaries.(3)The home and abroad is as to research work flexing the tube,and main lumping to the equipment is researched and numeric value simulating two respects.Numeric value imitation means one kind by demonstrates being effectual moreover have latent capacity research means adjust to flex to run quality fault research work more and more adopting the finite element imitation means.To the crooked model building of Guan Liao 、The crooked research creasing with crooked time pellet of thin wall tube is becoming the heat-point that the concern was researched in the home and abroad.Gas pressure spurts on the cooling plank below the action,and the compound metal solidifies afterwards the crystalline grain blank such as may obtaining have tiny and so on.That that blank is usable the blank that appearance formed was employed to semi.This means is living to prepare the serious offence in all glittering silicon compound metal and awaits that the particular stuff blank respect possess the specified preponderance,yet the cost is taller.(4) Control crystal process and crystalline grain are carefully divided the law.That means is by means of accedes to compound metal liquid the crystalline grain is carefully divided that dose either dominate cooling velocity await,and in order to cause the compound metal solidifies queen to solidity one another crystalline grain not to act as glittering shape but act as non- glittering shape ( awaiting a crystalline substance approximately ).The cost is the least in some kinds of blank manufacture means since the fact that this kind of means is living,as a result having the great development future.1.2 Semi solidity the appearance to take shape in the way of installation ( process ) Europe at the moment 、The state nation such as the U.S. and Japan and so on gives birth to out is specially used semi to solidity appearance process complete sets of equipment ( process),and also may be living to reform on now available die-casting engine either the forging and pressing installation base.1.3 Semi temperature when solid the appearance to process control One of the main parameter that semi temperature to solidity appearance process is that process technology.This is for that temperature resolving liquid phase and the admittedly proportion one another , pressure which adopt when it is processed to the spare parts along with obtains spare parts intensity 、The quality amplifying wholly possess the significant effect.Adopt thermocouple at the moment more 、The means such as ultra-audible sound and so on are observed and control.1.4 Semi solidity the pattern that use was processed to the appearance Semi solidity the appearance to process in the way of the pattern the design and may refer to the die-casting standard 、The design that the press standard awaits,yet have to consider semi solidity the actual term of appearance process.Being contrast with die-casting,semi temperature to solidity the appearance blank is late drop,and going from place to place time is brief,and presents laminar flow shape;Being contrast with the press,semi solidity that the appearance blank fluidity incomparably is more than to solidity the appearance and takes shape that the pressure lets drop.Processed research to make known , semi solidity the appearance to process press force which employ merely 1/5 who act as traditional forging and pressing means and masters.Since the of press force,also cuing down to the pattern stuff demand,may be in the way of nonmetal stuff ( in case ceramics 、The graphite awaits ) the pattern is manufacture.Being living the developed country,semi solidity that the appearance process pattern design adopts the computer simulation design more.1.5 Used semi to solidity the forming aluminum alloy of appearance Is used earliest semi solidity the appearance forming to act as the more
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