大径厚比薄壁铝管1D弯曲半径成形方法
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摘要
为解决大径厚比薄壁铝管在1D极难弯曲成形的技术瓶颈,对比现有液压填充、钢珠、松香及低熔点合金填充推弯成形技术优劣,提出一种采用聚氨酯弹性填料分块填充进行内胀冷推弯的成形方法。首先利用有限元反推模拟技术得到优化的1D弯曲半径弯头下料尺寸;其次利用优化下料尺寸对规格为Φ50 mm×1 mm的LF2M大径厚比薄壁铝管进行1D弯曲半径内胀冷推弯成形试验,主要研究了球形芯轴进给量对成形的影响。结果表明:通过反推模拟技术获得优化管坯下料尺寸方法具有可行性;球形芯轴的进给量是内胀冷推成形工艺的关键,增大进给量能提高径向压应力,消除失稳起皱及减小截面畸变程度,而径向压应力过大则易造成成形不足;球形芯轴进给量为75°时,整体成形效果较好,外侧最大壁厚减薄率为6%,最大截面畸变率为2. 3%,成功实现大径厚比薄壁管的1D弯曲成形。
In order to solve the technical bottleneck of 1 D extremely difficult bending of thin-walled aluminum tubes with large ratio of diameter to thickness,a new inner-bulging and cold push bending method using polyurethanee elastic filler in block filling was proposed by comparing the advantages and disadvantages of push-bending filled with hydraulic filling,steel ball,rosin and low melting point alloy.Firstly,the optimized blanking size of 1 D bending radius elbow was obtained by finite element back-stepping simulation technology. Secondly,based on the optimized blanking size for Φ50 mm × 1 mm in thin-walled aluminum tube with the large ratio of diameter to thickness,the inner-bulging and cold push bending experiment of 1 D bending radius forming was conducted,and the influence of the spherical mandrel feeding on the forming process was studied. The results show that it is feasible to optimize the blanking size by back-stepping simulation technology,and the spherical mandrel feeding is the key to the inner-bulging and cold push bending process. Furthermore,increasing feeding can increase the radial compressive stress,eliminate wrinkling and reduce the distortion of cross-section,while the excessive radial compressive stress can easily lead to insufficient forming. When the spherical mandrel feeding is 75°,the overall forming effect is better,the maximum wall thickness thinning rate is 6%,and the maximum cross-section distortion rate is 2. 3%. Thus,the 1 D bending of thin-walled tube with large ratio of diameter to thickness is successfully realized.
In order to solve the technical bottleneck of 1 D extremely difficult bending of thin-walled aluminum tubes with large ratio of diameter to thickness,a new inner-bulging and cold push bending method using polyurethanee elastic filler in block filling was proposed by comparing the advantages and disadvantages of push-bending filled with hydraulic filling,steel ball,rosin and low melting point alloy.Firstly,the optimized blanking size of 1 D bending radius elbow was obtained by finite element back-stepping simulation technology. Secondly,based on the optimized blanking size for Φ50 mm × 1 mm in thin-walled aluminum tube with the large ratio of diameter to thickness,the inner-bulging and cold push bending experiment of 1 D bending radius forming was conducted,and the influence of the spherical mandrel feeding on the forming process was studied. The results show that it is feasible to optimize the blanking size by back-stepping simulation technology,and the spherical mandrel feeding is the key to the inner-bulging and cold push bending process. Furthermore,increasing feeding can increase the radial compressive stress,eliminate wrinkling and reduce the distortion of cross-section,while the excessive radial compressive stress can easily lead to insufficient forming. When the spherical mandrel feeding is 75°,the overall forming effect is better,the maximum wall thickness thinning rate is 6%,and the maximum cross-section distortion rate is 2. 3%. Thus,the 1 D bending of thin-walled tube with large ratio of diameter to thickness is successfully realized.
引文
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[10]陈清根,徐雪峰,马媛媛,等.采用小弯曲半径弯头反向推直与正向推弯的管坯设计方法[J].中国机械工程,2017,28(3):353-358.Chen Q G,Xu X F,Ma Y Y,et al. Design method of tube blankwith small bending radius elbow for reverse and forward push ben-ding[J]. China Mechanical Engineering, 2017, 28(3):353-358.
[11] Oh I Y,Han S W,Woo Y Y,et al. Tubular blank design to fabri-cate an elbow tube by a push-bending process[J]. Journal of Ma-terials Processing Technology,2018,260:112-122.
[12]杨雪.弯头冷推制工艺毛坯及工艺参数优化[D].秦皇岛:燕山大学,2013.Yang X. Process Blank and Process Parameter Optimization of El-bow Cold Pressing[D]. Qinhuangdao:Yanshan University,2013.
[13]刘琪,徐雪峰,付春林,等.带长直管的小弯曲半径薄壁弯头推弯成形实验研究[J].锻压技术,2018,43(5):62-67.Liu Q,Xu X F,Fu C L,et al. Push bending experiments of thin-walled elbows with small bending radius and long straight tubes[J]. Forging&stamping Technology,2018,43(5):62-67.
[14]牟菊,门向南,陈清根,等.基于ABAQUS有限元模拟铝合金小弯曲半径内压推弯成形[J].热加工工艺,2015,27(13):109-112.Mou J,Men X N,Chen Q G,et al. Based on ABAQUS finite ele-ment simulation of aluminum alloy small bending radius internalpressure push bending forming[J]. Hot Working Technology,2015,27(13):109-112.
[2] Lovric M. Press-bending of thin-walled tubes/Increasing the pro-ductivity of internal high pressure forming processes[A]. Pro-ceedings of the 4th International Conference on Hydroforming[C]. Fellbach,2005:365-386.
[3]曾元松,李志强.铝合金小弯曲半径管内压推弯成形过程的数值模拟[J].塑性工程学报,2003,10(2):14-17.Zeng Y S,Li Z Q. Numerical simulation of pressure push-bendingprocess in small bending radius tube of aluminum alloy[J]. Jour-nal of Plastic Engineering,2003,10(2):14-17.
[4] Zeng Y S,Li Z Q. Experimental research on the tube push-ben-ding process[J]. Journal of Materials Processing Techonlogy,2002,122:237-240.
[5]宋鹏,王小松,徐永超,等.内压对薄壁铝合金管材充液压弯过程的影响[J].中国有色金属学报,2011,21(2):311-317.Song P,Wang X S,Xu Y C,et al. Effect of internal pressure onhydrostatic bending process of thin-walled aluminum alloy pipes[J]. Chinese Journal of Nonferrous Metals,2011,21(2):311-317.
[6]郎利辉,罗璇,程鹏志,等.薄壁小半径弯头弯胀成形数值模拟技术研究[J].锻压技术,2014,39(12):45-52.Lang L H,Luo X,Cheng P Z,et al. Research on numerical simu-lation technology of bending and bulging of thin-walled elbow withsmall radius[J]. Forging&Stamping Technology,2014,39(12):45-52.
[7]张兴华.不锈钢薄壁管材推弯成形工艺研究[D].沈阳:沈阳理工大学,2012.Zhang X H. Study on Push Bending Process of Stainless SteelThin-walled Pipe[D]. Shenyang:Shenyang University of Tech-nology,2012.
[8]王继荣.用灌注松香法弯制铝合金管[J].设备管理与维修,1998,(4):20-21.Wang J R. Bending of aluminum alloy pipes by casting rosin[J].Equipment Management and Maintenance,1998,(4):20-21.
[9]郭训忠,陶杰,王文涛,等.芯棒形式对纯铝-316L不锈钢复合管冷推弯成形的影响研究[A].第3届层压金属复合材料开发与应用学术研讨会[C].北京,2012.Guo X Z,Tao J,Wang W T,et al. Study on the influence of man-drel form on cold push bending of pure aluminium-316L stainlesssteel composite pipe[A]. The 3rd Seminar on the Developmentand Application of Laminated Metal Composite Materials[C].Beijing,2012.
[10]陈清根,徐雪峰,马媛媛,等.采用小弯曲半径弯头反向推直与正向推弯的管坯设计方法[J].中国机械工程,2017,28(3):353-358.Chen Q G,Xu X F,Ma Y Y,et al. Design method of tube blankwith small bending radius elbow for reverse and forward push ben-ding[J]. China Mechanical Engineering, 2017, 28(3):353-358.
[11] Oh I Y,Han S W,Woo Y Y,et al. Tubular blank design to fabri-cate an elbow tube by a push-bending process[J]. Journal of Ma-terials Processing Technology,2018,260:112-122.
[12]杨雪.弯头冷推制工艺毛坯及工艺参数优化[D].秦皇岛:燕山大学,2013.Yang X. Process Blank and Process Parameter Optimization of El-bow Cold Pressing[D]. Qinhuangdao:Yanshan University,2013.
[13]刘琪,徐雪峰,付春林,等.带长直管的小弯曲半径薄壁弯头推弯成形实验研究[J].锻压技术,2018,43(5):62-67.Liu Q,Xu X F,Fu C L,et al. Push bending experiments of thin-walled elbows with small bending radius and long straight tubes[J]. Forging&stamping Technology,2018,43(5):62-67.
[14]牟菊,门向南,陈清根,等.基于ABAQUS有限元模拟铝合金小弯曲半径内压推弯成形[J].热加工工艺,2015,27(13):109-112.Mou J,Men X N,Chen Q G,et al. Based on ABAQUS finite ele-ment simulation of aluminum alloy small bending radius internalpressure push bending forming[J]. Hot Working Technology,2015,27(13):109-112.