外文翻译-轧制速度对机架冷辊跳动剖面影响的研究

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1、Study on the influence of rolling speed on rack cold roll-beating profileLimu Cui, Jiming XiaoFaculty of Mechanical and Precision Instrument Engineering,Xian University of technology, Xi, an 710048Abstract. As a new type of precision plastic forming technology, with material saving, low energy consu

2、mption, less pollution, high efficiency and good performance of products, high-speed cold roll-beating got rapid development. This paper studies the profile determinants of cold roll-beating. The impact of characterized parameters on alveolar outline forming is quantitatively described. The characte

3、rized parameters are alveolar width and alveolar bump height on both sides and so on. At the same time, experiment with single factor of roller rotation speed is performed, analysing the influence law of rolling speed on alveolar profile. Cold roll-beating equipment are carried out on cold roll -bea

4、ting equipment modified from horizontal milling machine, the forming profile is analysed, so as to further improve the processing conditions and process parameters, providing a theoretical basis to deduce the generation of defects. Key words: cold roll-beating, flank profile, simulation, experiments

5、1 IntroductionBased on the plasticity of material, precision plastic forming technology is a less cutting or no cutting method, the work piece is processed under the external force of tool and die. Cold roll-beating forming technology is a near net shape processing method. Taking advantage of the pl

6、asticity of metal, the blank is rolled and struck by high-speed rotating roller, forcing the metal flow, thereby forming the profile of work piece. As a new type of precision plastic forming technology, cold roll-beating forming technology can processed the product with good performance, high effici

7、ency, material saving, low energyconsumption, less pollution and other significant characteristics, which aroused the attention of many scholars at home and abroad 1,2.In 1960s, Grob company of Swiss applied cold roll-beating technology to the machining of spline, but its core techniques still secre

8、t to abroad3. Domestic, the study of cold roll-beating forming technology began in the 1970s, the main research focused oncold roll-beating forming mechanism, rollers design, rollers installation method, parameter optimization4,5,6. Profile forming accuracy is the key factors that influence racktran

9、smission precision and smoothness. During cold roll-beating forming process, the instability of metal plastic flow made alveolar profiles change rule more complicated. Quantitative describe metal flow law to profile change is very difficult. At home and abroad, research on profile change during cold

10、 roll-beating forming is less. Study on the influence of rolling speed to profile form during rack cold roll-bearing forming in this article. On the basis of forming principle, to simulate influence law of rolling speed to alveolar width,alveolar both sides bump height, distance between bump height

11、and alveolar center, alveolar depth by using ABAQUS, to study the effect of rolling speed to alveolar profile, and verified by test, can provide reference for quality control of cold roll-beating forming.2 Cold roll-beating forming mechanismCold roll-beating forming which put the entity material fun

12、ction surface as the research object, local dynamic loading adopted by the way of discontinuous reciprocating struck, metal materials accumulation formed by forcing local flow, gradually required functionality surface formed . Its working principle is shown in the figure 17,8.Figure 1: High-speed co

13、ld roll-beating forming principle diagram3 Simulation analysis3.1 Establishment of simulation modelCold roll-beating dynamic model established in ABAQUS software, forming process simulated in ABAQUS. During cold rolling forming, the contact time between roller and work piece is short, and friction d

14、ecreases under the action of roller rotates, the temperature of deformation part changed slowly, so assume uniform temperature and friction. Due to deforming force generated by the rolling and collisions between roller and work piece,negligible effect of roller rotation on rolling force .The work pi

15、ece material in-compressible and the initial isotropic9,10.In order to shorten calculation time, improve calculation efficiency, the model assumed and appropriate simplified. For does not affect the simulation results, roller shaft save installed, according to a certain movement and spatial relation

16、ship, rollers and work piece model is set up as shown in the figure 2. The roller radius is 72 mm, the work piece length is 13 mm, width is 24 mm and height is 8 mm. Rolling radius is 73 mm, to 1 mm in depth. Choose analytical rigid as roller material, the work piece material is LY12 , density is 27

17、70 kg/m3, the elastic modulus is 73GPa , Poissons ratio is 0.33.Figure 2: The finite element model of cold roll-beating forming3.2 Rolling speed effects on profileWhen roller hits blank, rolling gear addendum directly hit on the blank surface, form the alveolar bottom. And metal on both sides of rol

18、lers, a part formed alveolar wall squeezed by rollers, the other part formed the bumps on either side of alveolar along roller side wall upward mobility, then the bump flow to the part of less resistance, thus forming the outline of alveolar shape, as shown in the figure 3. The alveolar width is B,

19、alveolar bump on the left side is hL, the right is hR , the distance between alveolar center and bump height is L, alveolar depth is H.Figure 3: Schematic diagram of alveolar profileDuring cold roll-beating forming, roller rotation speed is one of the key factors affecting metal plastic flow, on the

20、 condition of different rolling speed, the metal material of heat, heat conduction rate, deformation temperature, deformation rate, the flow of metal are not identical, thus large difference existed in the final forming of alveolar outline. When rolling model remains unchanged, and under the conditi

21、on of other parameters do not change, change the rolling speed, the alveolar profile has changed. As shown in figure 4, the changes of rolling speed affect the alveolar profile. When roller revolution speed increases from 500r/min to 750r/min, alveolar bottom stress is large, the stress mainly conce

22、ntrated in the root. When roller revolution speed is 1000 r/min, alveolar become wider, stress of alveolar root and on either side of alveolar are large, alveolar profile shape out of rules and a slight deviation between alveolar profile shape and roller. Revolution speed increases to 2000 r/min, le

23、ss stress and scattered into the work piece, the stress concentration in root and work piece inside. When the revolution speed reach to 3000 r/min, there is no obvious change in alveolar profile surface stress, but stress between two alveolar bump is large, the inside of work piece is not directly e

24、xposed to roller , but the stress is large too. Revolution speed is 4000 r/min, the alveolar profile is relatively perfect, alveolar root and alveolar flank and the work piece internal stress is moderate, the distribution is uniform.（a）n=500（b）n=750（c）n=1000（d）n=2000（e）n=3000（f）n=4000Figure 4: Alveo

25、lar profile under different rolling speedIn ABAQUS software, at different rolling speed, each alveolar parameters measuring and data analysis. Observe the change trend of alveolar parameters; curves are as shown in the figure 5 to figure 8.Figure 5: Alveolar width curve changed by rolling speedFigur

26、e 6: Alveolar both sides bump height curve changed by rolling speedThe figure 5 is alveolar width curve changed by rolling speed, the roller revolution speed increasing, the alveolar width increases firstly and then decreases to substantially unchanged when reaching a certain rotating speed. Strain

27、rate increased by roller revolution speed increasing, the true stress becomes large, alveolar width also increases. The revolution speed is higher, each time interval of roller stroke blank metal is shorter. In a certain period of time, the number of roller hit gear blank increased, the first work p

28、ieces material is flowing as plastic, the next struck again, which made the flow resistance of materials reduced in a certain extent, rolling deformation force also decrease, the strain rate decreased, so the space width decreases.The figure 6 is the alveolar both sides bump height curve changed by

29、rolling speed, the alveolar both sides bump height increased by the revolution speed increasing. In a certain range of rolling speed increased, caused the strain rate changed small, the degree of materials hardening is litter, alveolar both sides increased quickly. With the revolution speed continue

30、s increasing, the material hardening degree is high, and the metal flow decreased, thus alveolar both sides decreased.Figure 7: Alveolar depth curve changed by rolling speedFigure 8: The curve of distance between bump and alveolar center changed by rolling speedThe figure 7 is the alveolar depth cur

31、ve changed by rolling speed, the alveolar depth increased by the roller revolution speed increasing. When the roller revolution speed increases, the number of the alveolar bottom metal hit by roller per unit time increased, metal flow rate increased, plastic strain increased, the alveolar depth incr

32、eases. The greater the rolling speeds, the stronger the dynamic impact effects. While the plastic deformation region concentrated, limit of plastic deformation zone and elastic deformation area will become smaller, and the elastic strain zone decreases, alveolar depth decreases.The figure 8 is the c

33、urve of distance between bump and alveolar center changed by rolling speed. The distance between bump and alveolar center increased first and then decreased by the roller revolution speed increasing. The changing trends of distance between bump and alveolar center are related to bump and alveolar de

34、pth. The change rules are roughly the same with bump and alveolar depth.4 Study of cold roll-beating experimentThe purpose of this experiment is that according to the cold roll-beating experiment, by changing the roller revolution speed to measure the final alveolar forming outline, then compares an

35、d analysis the experiment results and simulation results. The experiment is carried out with self- developed cold roll- beating experimental equipment, and the roller material is 40Cr, the work piece material is LY12 and red copper.4.1 The device of experimentThis experiment is done on the horizonta

36、l milling machine; the cutter is replaced by the special cold-roll beating device. As shown in the figure 9 is the physical picture of cold-roll beating device.4.2 Analysis of experiment resultsIn this paper, the cold-roll beating experiment is conducted on hard aluminum and red copper, the roller m

37、odule is 2mm, and the roller revolution radius is 49mm, rotation radius is 24mm .As shown in the figure 10 is the cold roll-beating results of aluminum, the roller revolution speed is 1500r/min. In the picture the alveolar outline can be clearly seen, the addendum rolled up can be obviously observed

38、 in the local amplification figure, this is because metal flow that the roller extrudes the alveolar bottom. At the same time, the bump height of middle alveolar both sides is roughly equal, and the outline is uniform and symmetric, the two are consistent with the previous simulation results. This i

39、s due to that the metal of close to middle alveolar side is extruded by the two rollers, the metal flowing restricted at a certain extent, so there was no obvious difference of bumps on both sides.As shown in the figure 11 is the cold roll-beating results of copper, the depth of the roller hit into

40、the work piece is 1mm, the feed speed of work piece is 60mm/min, the roller revolution speed is 1500r/min. From the figure the metal plastic liquidity of copper is bigger than the hard aluminum can be clearly seen along the tangential; the hardness of copper is smaller than hard aluminum. When the d

41、epth of the roller hit into the work piece at the equal lever and the same with the feed speed of work piece , the bigger hardness, the smaller metal plastic liquidity. The materials have lower hardness, the plastic flow is relatively easy, so the metal plastic liquidity of copper along tangential i

42、s bigger than hard aluminum. The metal flowed along tangential not only affects the contour shape of material, but also should increase the operation to get rid. This not only waste materials, but also make the processing time longer, reduce the production efficiency, so research the alveolar profil

43、e of roller and process parameters is a key to improve the quality of cold-roll beating forming.Figure 9: Cold roll-beating machineFigure 10: Hard aluminum cold roll beating test resultsFigure 11: Copper cold roll-beating test results5 Conclusion(1) Using the alveolar width, alveolar bump on both si

44、des, the distance between alveolar center and bump height, alveolar depth to quantitatively show the alveolar profile after formed. The dynamic simulation models of cold roll-beating established in the ABAQUS, and the rack cold roll-beating simulated, the results of simulation analyzed.(2) Conductin

45、g the single factor variables experiments by changing the roller revolution speed, analyzing the metal flow law, then get the influence law of roller revolution speed to alveolar profile. In the later phase, multiple factors experiments and study interactions between multiple factors will conducted,

46、 which supply more theoretical basis for improve the quality of cold roll- beating.AcknowledgementThe corresponding author was Limu Cui. This research is supported by National Natural Science Foundation of China (Grant No. 51475366, 51475146) and Natural Science Basic Research Plan in Shaanxi Provin

47、ce of China (Grant No. 2016JM5074).References1. Zhang Lu, Li Yan, Yang Mingshun, et al. Recent Development of Incremental Forming J. Aerospace material process, pp. 32-38(2011)2. Zhao Ning, Mao Yongjie. The modern machinery manufacturing technology and development trend J. Science and technology inn

48、ovation and application, pp.125(2013)3. Wang Zhongren, Teng Bugang, Tang Zejun. New Development on Technology of PlasticityJ. China Mechanical Engineering, 20(1), pp. 108-112(2009)4. Cui Fengkui, Zhu Wenjuan, Wang Xiaoqiang, Zhang Fengshou. Current research and development trends of high-speed cold

49、rolling technologyJ. Journal of Henan Polytechnic University (Natural Science), 31(2), pp. 191-195(2012)5. Li Yan, Yang Mingshun, Li Bin, et al. Dynamics Simulation and Analysis of Lead Screw Cold Roll-BeatingJ. Journal of Xian University of Technology, 25(4), pp. 383-387(2009)6. Cui Fengkui, Guo Ch

50、ao, Li Yuxi. 40Cr Steel Plastic Flow Stress and Constitutive RelationsJ. Journal of Henan Polytechnic University (Natural Science), 33(6), pp. 1-5(2012)7. Zhang Lu, Yang Mingshun, Li Yan, et al. Analytic method and its modification for deformation force of high-speed cold roll-beating formingJ. Jour

51、nal of Plasticity Engineering, 18(5), pp. 1-7(2011)8. Cui Fengkui, Xu Yongfu, Zhao Wei.Research on metal microstructure deformation of splines manufactured by cold rolling,milling and cutting processesJ. Forging and Stamping Technology, 33(2), pp. 70-74(2008)9. Zhang Lu, Li Yan, Yang Mingshun, et al

52、. Study on Metal Flowing of Lead Screw Cold Roll-beating FormingJ. China Mechanical Engineering, 23(13), pp. 1623-1628(2012)10. Zhao Zhiyuan,Yang Mingshun, Yuan Qilong, et al. Deformation Force Simulation of Lead Screw Cold Roll-beating Based on ABAQUSJ. Foundry Technology, 32(8), pp. 1165-1169(2011

53、)轧制速度对机架冷辊跳动剖面影响的研究栗木翠, 鸣鸣小机械精密仪器工程系,西安理工大学, 西安, 710048抽象 . 作为一种新型精密塑性成形技术, 具有的 材料节约、能耗低、污染少、效率高、产品性能好、高速冷滚打得到了飞速的发展。本文研究了冷滚轧的剖面决定因素。定量描述了特征参数对肺泡轮廓形成的影响。其特征参数为牙槽宽度和牙槽凹凸高度。同时, 对滚子转速单因素进行了试验, 分析了轧制速度对牙槽剖面的影响规律。对卧式铣削机改造的冷滚轧设备进行了冷辊跳动设备的分析, 对成形剖面进行了进一步的改进, 为进一步提高加工条件和工艺参数提供了理论依据, 为推断出缺陷的产生。 关键词: 冷辊跳动, 侧面

54、剖面, 模拟, 实验1介绍在材料塑性的基础上, 精密塑性成形技术是一种减少切削或无切削的方法, 工件在刀具和模具的外力下加工。冷弯辊成形技术是一种近净形状加工方法。利用金属的塑性, 通过高速旋转滚筒轧制和撞击毛坯, 迫使金属流动, 从而形成工件轮廓。冷弯辊成形技术作为一种新型的精密塑性成形技术, 可以加工出性能好、效率高、材料节约、能耗低的产品。消费、污染等显著特征, 引起国内外众多学者的关注 12 .1960年, 瑞士格劳博公司将冷轧辊技术应用于花键的加工, 但其核心技术仍为海外保密 3 。国内, 冷轧辊成形技术的研究始于 1970, 主要研究集中在冷滚轧成形机构、滚筒设计、滚筒安装方法、参

55、数优化 45、6 。型材成形精度是影响机架的关键因素传动精度和平滑度。在冷弯辊成形过程中, 金属塑性流动的不稳定性使得牙槽剖面的变化规律更为复杂。定量描述金属流动规律对剖面变化是非常困难的。国内外对冷弯辊成形过程中剖面变化的研究较少。在机架冷辗压成形过程中, 轧制速度对型材形态的影响研究。在形成原理的基础上, 模拟了轧制速度对牙槽宽度的影响规律,牙槽两侧的凹凸高度、凹凸高度与肺泡中心之间的距离、牙槽深度的应用, 研究了轧制速度对牙槽剖面的影响, 并通过试验验证, 可为冷轧辊的质量控制提供参考。形成。2冷滚打成型机构将实体材料功能面作为研究对象的冷弯辊成形, 局部动态加载采用不连续往复撞击的方式

56、, 通过强制局部流形成的金属材料积累, 逐渐需要形成的功能曲面。其工作原理见图 178 .图 1 高速冷辊跳动成形原理图3仿真分析3.1 仿真模型的建立在 abaqus 软件中建立了冷轧辊跳动动态模型, 模拟了 abaqus 的成形过程。在冷轧成型过程中, 轧辊与工件之间的接触时间短, 在滚子旋转的作用下摩擦力减小, 变形部分的温度变化缓慢, 因此应采用均匀的温度和摩擦力。由于轧辊和工件之间的轧制和碰撞产生的变形力,对滚子旋转对轧制力的影响为微不足道。工件材料可压缩和初始各向同性910 .为了缩短计算时间, 提高计算效率, 模型假设和适当简化。对于不影响仿真结果, 辊轴保存安装, 根据一定的运

57、动和空间关系, 对滚筒和工件模型进行了设置, 如图2所示。滚筒半径为72毫米, 工件长度为13毫米, 宽度为24毫米, 高度为8毫米. 轧制半径为73毫米, 深度为1毫米。选择分析刚性为滚筒材料, 工件材质为 LY12, 密度为2770千克/米3, 弹性模量为 73GPa, 泊松比为 0.33.图 2: 冷滚轧成形的有限元模型3.2 轧制速度对型材的影响当滚子命中空白时, 滚动齿轮的附录直接击中空白表面, 形成肺泡底部。和金属在滚筒两侧, 部分形成了由滚筒挤压的牙槽壁, 另一部分形成了牙槽两侧的凸起沿辊侧壁向上移动, 然后将凹凸流到部分阻力较小, 从而形成肺泡轮廓。形状, 如图3所示。肺泡宽度

58、为 B, 左侧的肺泡突起为 hL, 右侧为 hR ,肺泡中心与凹凸高度之间的距离为 L, 肺泡深度为 h.图 3: 齿槽轮廓示意图在冷辗压成形过程中, 轧辊转速是影响金属塑性流动的关键因素之一, 在不同轧制速度、热传导速率、变形温度、变形速率、流量金属不完全相同, 因此在肺泡轮廓的最终形成中存在较大的差异。当轧制模型保持不变时, 在其它参数不变的情况下, 改变轧制速度, 使齿槽剖面发生变化。如图4所示, 滚动速度的变化会影响牙槽剖面。当滚子转速从 500 r/分钟增加到 750 r/分钟时, 肺泡底部应力较大, 应力主要集中在根部。当滚子转速为 1000/分钟时, 肺泡变宽, 肺泡根部和肺泡两

59、侧的应力较大, 肺泡轮廓形状不规则, 牙槽形状与滚筒之间稍有偏差。转速增加到 2000 r/分钟, 减少应力, 分散到工件, 在根部和工件内的应力集中。当转速达到 3000/分钟时, 牙槽剖面表面应力没有明显的变化, 但两个牙槽凸度之间的应力较大, 工件内部不直接暴露在滚筒上, 但应力也较大。转速为 4000 r/分钟, 肺泡剖面相对完善, 肺泡根部和肺泡侧面和工件内应力适中, 分布均匀。(a) n = 500 ( b)n= 750 (c)n= 1000 (d) n = 2000 ( e)n= 3000 (f)n= 4000图 4: 不同轧制速度下的牙槽剖面在 ABAQUS 软件中, 在不同的

60、轧制速度下, 每个齿槽参数的测量和数据分析。观察肺泡参数的变化趋势;曲线如图5所示, 见图8。图 5: 通过轧制速度改变牙槽宽度曲线图 6: 牙槽两侧的凹凸高度曲线随轧制速度而变化图5为齿槽宽度曲线随轧制速度而改变, 滚子转速增加, 齿槽宽度先增大后减小到一定转速时大幅度改变。随着滚子转速的增加, 应变速率增大, 真正的应力变大, 肺泡宽度也增大。转速越高, 每一次轧辊行程毛坯金属的间隔时间越短。在一定的时间内, 轧辊命中齿轮坯的数量增加, 第一工件的材料作为塑料流动, 下一次再次撞击, 使材料的流动阻力在一定程度上降低, 轧制变形力也降低,应变速率减小, 空间宽度减小。图6为牙槽两侧的凹凸高

61、度曲线随轧制速度而变化, 肺泡两侧的凹凸高度随转速的增加而增大。在一定范围内的轧制速度增加, 导致应变率变小, 材料硬化程度为凋落物, 肺泡两侧迅速增加。随着转速的不断提高, 材料硬化程度高, 金属流减小, 肺泡两侧减小。图 7: 通过轧制速度改变牙槽深度曲线图 8: 按轧制速度变化的凹凸槽中心距离曲线图7为齿槽深度曲线随轧制速度变化, 齿槽深度随辊轮转速的增加而增大。当辊道转速增大时, 齿槽底金属的数量随机组时间的推移而增加, 金属流速增加, 塑性应变增加, 肺泡深度增大。滚动速度越大, 动态冲击效应越强。塑性变形区集中、塑性变形区极限和弹性变形区变小, 弹性应变区减小, 肺泡深度减小。图8

62、是凸点和牙槽中心之间的距离曲线, 由轧制速度改变。随着滚子转速的增加, 凸点与牙槽中心之间的距离先增大后减小。凹凸和肺泡中心距离的变化趋势与凹凸和肺泡深度有关。变化规则大致相同的凹凸和肺泡深度。4冷轧辊跳动实验研究本实验的目的是根据冷轧辊跳动实验, 通过改变滚子转速来测量最终的牙槽成形轮廓, 然后比较分析实验结果和仿真结果。本实验采用自行研制的冷滚轧试验装置, 轧辊材料为 40Cr, 工件材料为 LY12 和红铜。4.1 实验装置本试验是在卧式铣床上进行的;刀具被特殊的冷辊跳动装置所取代。如图9所示, 是冷辊跳动装置的物理图像。4.2 实验结果分析本文对硬铝和红铜进行了冷轧辊跳动试验, 轧辊模

63、块为 2mm, 轧辊回转半径为 49mm, 旋转半径为24mm。如图10所示, 铝的冷轧辊跳动的结果, 滚筒转速是 1500 r/分钟。在图片中可以清楚地看到肺泡轮廓, 在局部放大图中可以明显观察到增编, 这是因为金属流的滚筒挤出了肺泡底部。同时, 中间牙槽两侧的凹凸高度大致相等, 轮廓均匀对称, 两者与以往的模拟结果一致。这是由于接近中牙槽侧的金属被两个滚筒挤压, 金属在一定程度上受限, 因此两侧的颠簸没有明显的差异。如图11所示的是铜的冷滚轧结果, 滚筒撞击工件的深度为 1mm, 工件的进料速度为60毫米/分, 辊轮转速为 1500/分钟。从图上看, 金属塑料的流动性比硬铝更大, 可以沿切

64、线清晰地看到;铜的硬度比硬铝小。当轧辊的深度撞到工件的同等杠杆和进料速度相同的工件时, 硬度越大, 金属塑料的流动性越小。该材料硬度较低, 塑性流动相对容易, 因此铜沿切线的金属塑性流动性大于硬铝。金属沿切线流动不仅影响材料的轮廓形状, 而且还应增加操作的去除。这不仅浪费了材料, 而且使加工时间更长, 降低了生产效率, 因此研究轧辊的齿槽剖面和工艺参数是提高冷轧辊跳动质量的关键。图 9: 冷打辊机图 10: 硬铝冷轧辊跳动试验结果图 11: 铜冷辊跳动试验结果5 结论 (1) 使用牙槽宽度、两侧肺泡肿块、肺泡中心与凹凸高度之间的距离、肺泡深度定量显示后形成的肺泡轮廓。建立了基于 ABAQUS 的冷滚轧动态仿真模型, 并对机架冷滚打模拟结果进行了仿真分析. (2) 通过改变滚筒转速, 分析金属流动规律, 进行单因素变量实验, 得出滚子转速对齿槽剖面的影响规律。在后一阶