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Forming defects in aluminum alloy hot stamping of side-door impact beam 被引量:12
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作者 周靖 王宝雨 +2 位作者 林建国 傅垒 马闻宇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3611-3620,共10页
The forming defects, including thinning, rupture, wrinkling and springback, usually arising in producing a side-door impact beam, were investigated by trial and numerical simulation. A temperature-related constitutive... The forming defects, including thinning, rupture, wrinkling and springback, usually arising in producing a side-door impact beam, were investigated by trial and numerical simulation. A temperature-related constitutive model specific to the temperature range from 350 °C to 500 °C was established and used for the numerical simulation. The trial and numerical simulation were conducted to clarify the quantitative characteristics of forming defects and to analyze the effects of process parameters on the forming defects. Results show that the rupture situation is ameliorated and the springback is eliminated in the aluminum alloy hot stamping. The wrinkling severity decreases with increasing blank holder force (BHF), but the BHF greater than 15 kN causes the rupture at the deepest drawing position of workpiece. The forming defects are avoided with lubricant in the feasible ranges of process parameters: the BHF of 3 to 5 kN and the stamping speed of 50 to 200 mm/s. 展开更多
关键词 aluminum alloy hot stamping forming defects numerical simulation blank holder force
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Forming Mechanism of Gaseous Defect in Ti-48Al-2Cr-2Nb Exhaust Valves Formed with Permanent Mold Centrifugal Casting Method 被引量:2
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作者 Research Notes Wenbin SHENG, Jingjie GUO, Yanqing SU, Hongsheng DING and Jun JIA School of Materials Science and Engineering, Harbin Institute of Technology. Harbin 150001, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第5期569-571,共3页
A method combining theoretical analysis with experiment is adopted and the flowing process of Ti-48A1-2Cr-2Nb alloy melt poured in a permanent mould during the centrifugal casting process has been analyzed. A mathemat... A method combining theoretical analysis with experiment is adopted and the flowing process of Ti-48A1-2Cr-2Nb alloy melt poured in a permanent mould during the centrifugal casting process has been analyzed. A mathematical model of the filling process is established and the forming mechanism of internal gaseous defect is summarized. The results of calculation show that the melt fills the mould with varying cross-section area and inclined angle. The filling speed of the cross-section is a function of filling time. The cross-section area is directly proportional to the filling speed and the inclined angle is inversely proportional to the filling speed at a given rotating speed of the platform. Both of them changes more obvious near the mould entrance. The gaseous defect can be formed in several ways and the centrifugal field has an important influence on the formation of the defect. In addition, the filling process in centrifugal field has been verified by wax experiments and the theoretical analysis are consistent with experimental results. 展开更多
关键词 Forming Mechanism of Gaseous defect in Ti-48Al-2Cr-2Nb Exhaust Valves Formed with Permanent Mold Centrifugal Casting Method MOLD TI Al CR
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Reverse deep drawability of 5A06 aluminum alloy plate at elevated temperatures 被引量:3
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作者 张志超 徐永超 苑世剑 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第6期1538-1545,共8页
In order to avoid the occurrence of fracture at room temperature in reverse deep drawing of aluminum alloy plate, the warm reverse deep drawing method was proposed. The experiments were conducted at room temperature,... In order to avoid the occurrence of fracture at room temperature in reverse deep drawing of aluminum alloy plate, the warm reverse deep drawing method was proposed. The experiments were conducted at room temperature, 280 and 360 ℃ with a 4.5 mm thick 5A06 aluminum alloy plate. The effect of temperature, blank-holding force and gap on the fracture and wrinkle of the reverse deep drawing process was investigated. A fully coupled thermal-mechanical simulation was carried out to obtain the stress distribution through the commercial software of Abaqus/Explicit. The results show that the fracture is avoided at 280 ℃ since the bending-induced stress gradient in the transient area between the inside corner and the straight wall decreases from 505 MPa at RT to 72 MPa at 280 ° C. Although the fracture is avoided as the temperature increases, the wrinkle occurs at the outside die corner at temperature over 280 ° C, where the circumferential compressive stress becomes larger than that at the inside. As the temperature increases to 360 ℃, the fracture occurs due to the excessive softening, the tensile stress in the straight wall reaches rapidly to the tensile strength at the beginning of reverse deep drawing. When 1.5t (t=4.5 mm) blank holding gap is applied at 280 ℃, both the fracture and wrinkle can be avoided, and 420 mm deep cups are drawn successfully. 展开更多
关键词 5A06 aluminum alloy PLATE warm reverse deep drawing forming defect
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Multi-Point Forming Technology for Sheet Metal 被引量:10
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作者 LI Ming-zhe, CAI Zhong-yi, SUI Zhen, YAN Qing-guang (Roll Forging Institute, Jilin University of Technology, Changchun 130025, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期17-,共1页
Multi-point forming (MPF) is an advanced manufacturing technology for three-dimensional sheet metal parts. In this paper, the MPF integrated system is described that can form a variety of part shapes without the need ... Multi-point forming (MPF) is an advanced manufacturing technology for three-dimensional sheet metal parts. In this paper, the MPF integrated system is described that can form a variety of part shapes without the need for solid dies, and given only geometry and material information about the desired part. The central component of this system is a pair of matrices of punches, and the desired discrete die surface is constructed by changing the positions of punches though the CAD and control system. The basic MPF process is introduced and the typical application examples show the applicability of the MPF technology. Wrinkle and dimple are the major forming defects in MPF process, numerical simulation is a feasible way to predict forming defects in MPF. In conventional stamping, the mode to form sheet metal with blankholder is an effective way to suppress wrinkling; the same is true in MPF. A MPF press with flexible blankholder was developed, and the forming results indicated the forming stability of this technique. Based on the flexibility of MPF, varying deformation path MPF and sectional MPF were explored that cannot be realized in conventional stamping. By controlling each punch in real-time, a sheet part can be manufactured along a specific forming path. When the path of deformation in MPF is designed properly, forming defects will be avoided completely and lager deformation is achieved. A work piece can be formed section by section though the sectional MPF, and this technique makes it possible to manufacture large size parts in a small MPF press. Some critical experiments were performed that confirmed the validity of two special MPF techniques. 展开更多
关键词 sheet metal multi-point forming flexible forming forming path WRINKLING forming defects
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Numerical simulation and experimental study for rheo-forged component using direct and indirect die system 被引量:2
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作者 H.H.KIM C.G.KANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1799-1804,共6页
Sand casting and die casting processes have been used widely for complex automotive products such as knuckle, arm, etc.Usually, a part fabricated by casting has limited strength due to manufacturing defects such as th... Sand casting and die casting processes have been used widely for complex automotive products such as knuckle, arm, etc.Usually, a part fabricated by casting has limited strength due to manufacturing defects such as the dendrite structure, segregation and porosities.As an attempt to offer a solution to these problems, forging has been used as an alternative process.However, the forging process provides limited formability for complex shape products.Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes.In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of molten metal.The results of an A356 aluminum alloy sample, which are obtained by experiment and by simulation using DEFORM 3D, are present. 展开更多
关键词 rheo-forging A356 alloy FORMABILITY forming defects
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Hot spinning of cylindrical workpieces of TA15 titanium alloy 被引量:1
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作者 XU Wenchen,SHAN Debin,YANG Guoping,CHEN Yu,LU Yan,and KANG Dachang School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China 《Rare Metals》 SCIE EI CAS CSCD 2007年第S1期255-261,共7页
In order to form large-diameter thin-wall cylindrical workpieces of TA15 titanium alloy,tube hot spinning experiments of the alloy were conducted on a CNC hot spinning machine.The causes of some forming defects occuri... In order to form large-diameter thin-wall cylindrical workpieces of TA15 titanium alloy,tube hot spinning experiments of the alloy were conducted on a CNC hot spinning machine.The causes of some forming defects occuring in hot spinning,such as crack,pileup,bulge and corrugation,were analyzed and the corresponding measures were put forward to avoid spinning defects,based on which a proper process scheme of hot spinning of TA15 alloy was obtained and the large-diameter and thin-walled cylindrical workpieces were formed with good quality.The results show that spinning temperature has distinct influence on forming quality of spun workpieces.The range of spinning temperature determines the spinnability of titanium alloy and the ununiformity of temperature distribution near the deformation zone leads to the formation of bulge.The reasonable heating method is that the deforming region is heated to the optimum temperature range of 600-700 ℃,the deformed region is heated continuously and a certain length of undeformed region is preheated.With the thickness-to-diameter ratio(t/D) of spun workpiece reducing to certain value(t/D<1%),surface bulge and corrugation is rather easier to come into being,which could be controlled through restraining diameter growth and employing smaller reduction rate and lower temperature in the optimum spinning temperature range. 展开更多
关键词 TA15 titanium alloy hot spinning cylindrical workpiece forming defect thickness-to-diameter ratio
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Three Dimensional Numerical Simulation of Cup-Shaped Thin-Walled Inner Gear Spin-Forming 被引量:1
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作者 SUN Ling-yan YE Bang-yan HAO Shao-hua XIA Qin-xiang 《Computer Aided Drafting,Design and Manufacturing》 2009年第2期21-26,共6页
The cyclic symmetry and local fine-mesh technology were adopted in the establishment of numerical simulation model for inner gear spin-forming. And the processing experiment was proceeded to verify the reliability of ... The cyclic symmetry and local fine-mesh technology were adopted in the establishment of numerical simulation model for inner gear spin-forming. And the processing experiment was proceeded to verify the reliability of the established model. The simulation result indicates that besides radial and axial flows, there also exists rather large tangential flow, which results in an increase of forming force in tangential direction. Furthermore, the un-uniform deformation of metal during spin-forming would cause forming defects, such as underfill in tooth fillet region and indentation on the outside spun part. 展开更多
关键词 inner gear spin-forming numerical simulation forming defect spinning force
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Effect of film types on thermal response,cellular structure,forming defects and mechanical properties of combined in-mold decoration and microcellular injection molding parts 被引量:1
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作者 Wei Guo Zhihui Yu +3 位作者 Wenting Wei Zhenghua Meng Huajie Mao Lin Hua 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第33期98-108,共11页
Different types of polymer films were used in the combined in-mold decoration and microcellular injection molding(IMD/MIM)process.The multiphase fluid-solid coupled heat transfer model was established to study the the... Different types of polymer films were used in the combined in-mold decoration and microcellular injection molding(IMD/MIM)process.The multiphase fluid-solid coupled heat transfer model was established to study the thermal response at the melt filling stage in the IMD/MIM process.It was found that the temperature distributed asymmetrically along the thickness direction due to the changed heat transfer coefficient of the melt on the film side.When polyethylene terephthalate(PET)films were applied,the temperature of the melt-film interface increased faster and to be higher at the end of melt filling stage in comparison with the application of polycarbonate(PC)and thermoplastic polyurethane(TPU)films.And the effects of film types on the cellular structure,forming defects and mechanical properties of IMD/MIM parts were also studied experimentally.The results showed that the film types had no obvious effect on the cells size in the transition layer and the mechanical properties of the parts.Under certain film thickness,the offset distance of core layer was the largest with PET film used,while the offset distance was the smallest with TPU film used.And similar results were found for the warpage of the parts.However,an exactly opposite change occurred for the thickness of film-side transition layer and the bubble marks on the surface of the parts. 展开更多
关键词 Microcellular injection molding In-mold decoration Thermal response Cellular structure Forming defects Mechanical properties
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Improving the process forming limit considering forming defects in the transitional region in local loading forming of Ti-alloy rib-web components 被引量:2
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作者 Pengfei GAO Xiaodi LI +2 位作者 He YANG Xiaoguang FAN Zhenni LEI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2017年第3期1270-1280,共11页
The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by... The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element(FE) simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology(RSM).The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components. 展开更多
关键词 defect Large-scale rib-web component Local loading forming Process forming limit Transitional region
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