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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Transactions of Materials Processing
Journal Basic Information
Journal DOI :
The Korean Society for Technology of Plasticity
Editor in Chief :
Volume & Issues
Volume 23, Issue 8 - Dec 2014
Volume 23, Issue 7 - Nov 2014
Volume 23, Issue 6 - Oct 2014
Volume 23, Issue 5 - Aug 2014
Volume 23, Issue 4 - Jul 2014
Volume 23, Issue 3 - Jun 2014
Volume 23, Issue 2 - Apr 2014
Volume 23, Issue 1 - Feb 2014
Selecting the target year
A Study on the Complex Automation Die Manufacturing Technology for an Automotive Seat Cushion Panel
Park, D.H. ; Jung, C.S. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 75~81
DOI : 10.5228/KSTP.2014.23.2.75
Progressive dies are used for metal stamping during which multiple operations are performed in a sequence. Material is fed automatically from a coil into the press and advances from one die station to the next with each press stroke. Transfer dies are used in high-volume manufacturing for round, deep-drawn, and medium-to-large parts. Several different operations may be incorporated within a transfer die such as blanking, bending, piercing, trimming, and deep drawing. The main challenge in the current study is how to deform a seat cushion panel meeting the design specifications without any defects. A complex automation die manufacturing technology for the automotive seat cushion panel, mixing both semi-progressive die and transfer die for continuous production, was developed.
Texture and Plastic Strain Ratio Changes during a 2 Step Asymmetric Rolling and Annealing of AA5083 Al Alloy Sheet
Jeong, H.B. ; Lee, J.H. ; Kim, G.H. ; Nam, S.K. ; Kim, I. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 82~87
DOI : 10.5228/KSTP.2014.23.2.82
The plastic strain ratio is one of the factors that affect the deep drawability of Al alloy sheet. The deep drawability of Al alloy sheet is limited because of its low plastic strain ratio. Therefore an increase in the plastic strain ratio to improve the deep drawability of Al alloy sheet is needed. The current study investigated the increase of the plastic strain ratio and the change in texture of AA5083 Al alloy sheet after a 2 step asymmetric rolling with heat treatments. The average plastic strain ratio of initial AA5083 Al alloy sheets was 0.83. After the first asymmetric rolling step of 88% deformation and subsequent heat treatment at
for 10 minutes the value was still 0.83. After the second asymmetric rolling of 14% reduction and subsequent heat treatment at
for 10 minutes the plastic strain ratio rose to 1.01. The average plastic strain ratio after the 2 step asymmetric rolling and heat treatment is 1.2 times higher than that of initial AA5083 Al alloy sheet. This result is related to the development of ND/<111> texture component after the second asymmetric rolling and heat treatment.
Plate Forging Process Design for an Under-drive Brake Piston in Automatic Transmission
Jeon, H.W. ; Yoon, J.H. ; Lee, J.H. ; Kim, B.M. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 88~94
DOI : 10.5228/KSTP.2014.23.2.88
The under-drive brake piston is an essential part in the automatic transmissions of automobiles. This component is manufactured by forging after blanking from S55C plate with a thickness of 6mm. It is difficult to design the plate forging process using a thick plate approach since there will be limited material flow as well as large press loads. Furthermore, the under-drive brake piston has a complex shape with a right angle step, which often results in die unfill and abrupt increase in press load. To overcome these obstacles, a separate die for filling material sufficiently to the corner of the right angle step is proposed. However, this approach induces an uncontrolled workpiece surface between the dies, resulting in flash. This excess flash degrades the tool life in the final machining after cold forging as well as increases the cycle time to obtain the net-shape of the part. In the current study, we propose an optimum process design using a conventional die shaped with the benefit of finite element analysis. This approach enhanced the process efficiency without sacrificing the dimensional accuracy in the forged part. As the result, the optimum plate forging process was done with a two stage die, which reduces weight of by 6% compared with previous process for the under-drive brake piston.
Finite Element Analysis for Optimizing the Initial Thickness of an Under-drive Brake Piston used in a Automatic Transmission
Lee, J.S. ; Yoon, J.H. ; Lee, J.H. ; Kim, S.H. ; Hong, E.C. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 95~102
DOI : 10.5228/KSTP.2014.23.2.95
The under-drive brake piston is an important component in automotive transmissions. It changes the velocity by controlling the gear ratio. It has been traditionally manufactured by hot forging. Recently, there has been an effort to replace this traditional manufacturing method with cold forging in order to improve the dimensional accuracy and decrease the surface roughness. Cold forging uses a smaller amount of initial material and also has a shorter cycle time since the forged surface can be the final surface without the need of post-processing such as machining or grinding. In the current study, finite element analysis was conducted to evaluate a process design using an initial plate with reduced thickness. This smaller thickness decreases the amount of material needed for the part as well as the machining to produce the final product.
Effect of Shape Design Variables on Flexibly-Reconfigurable Roll Forming of Multi-curved Sheet Metal
Son, S.E. ; Yoon, J.S. ; Kim, J. ; Kang, B.S. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 103~109
DOI : 10.5228/KSTP.2014.23.2.103
Flexibly-reconfigurable roll forming (FRRF), which is a sheet forming process for multi-curved sheet metal, may solve both the economic and technical problems incurred in using a conventional die forming process. In the FRRF process, the multi-curved sheet metal is formed by different strain distributions on the sheet metal, and the reconfigurable rollers are used as tools during the forming. Therefore, a thorough investigation focused on the reconfigurable rollers is required for the realization of the FRRF process prior to the fabrication of FRRF machine. In the current study, a series of finite element simulations were conducted to study the load distributions experienced by the reconfigurable roller. In order to verify the shape design variables, the effect of the metal thickness on the curvatures of sheet is also presented.
A Study on the Relationship between Tensile and Low Cycle Fatigue Properties of High Strength Material
Park, M.K. ; Suh, C.H. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 110~115
DOI : 10.5228/KSTP.2014.23.2.110
Low cycle fatigue characteristics are very important in the development of automobile suspension parts. Fatigue properties using the strain life approach are usually obtained from low cycle fatigue tests. However, low cycle fatigue testing requires a lot of time and cost. In the current study, an attempt to estimate low cycle fatigue properties of high strength steel sheet from tensile test and tensile simulations is performed. In addition, low cycle fatigue testing was conducted to compare the fatigue properties obtained from tensile testing and simulations. In conclusion, the results effectively predict the low cycle fatigue properties. However, some deviations still exist.
A Study on Flow Forming Process of Magnesium Road Wheel
Kim, J.H. ; Park, S.M. ; Lee, J.J. ; Yoon, H.S. ;
Transactions of Materials Processing, volume 23, issue 2, 2014, Pages 116~121
DOI : 10.5228/KSTP.2014.23.2.116
Low pressure die casting and flow forming have been successfully used to produce sound road wheels from magnesium alloy AM80. In the current study, high speed compression testing was initially conducted to simulate the flow forming of a Mg wheel. Subsequently the flow forming was simulated with "Forge
", an FEM software package. On the basis of flow forming simulations, the flow forming of the Mg wheel was performed under different conditions. For the flow forming experiments, the preform castings were made by low pressure die casting from AM80, a commercial magnesium alloy. In flow forming of the magnesium preform wheel, the flow forming of the Mg wheel was successfully accomplished when the feed rate was less than half that for the forming of an aluminum road wheel. The reduction in feed rate was 52%. Finally, a comparison with the flow forming simulations was made.