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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of Materials Processing
Journal Basic Information
Journal DOI :
The Korean Society for Technology of Plasticity
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Volume & Issues
Volume 14, Issue 9 - Dec 2005
Volume 14, Issue 8 - Nov 2005
Volume 14, Issue 7 - Oct 2005
Volume 14, Issue 6 - Sep 2005
Volume 14, Issue 5 - Aug 2005
Volume 14, Issue 4 - Jul 2005
Volume 14, Issue 3 - Jun 2005
Volume 14, Issue 2 - Apr 2005
Volume 14, Issue 1 - Feb 2005
Selecting the target year
Intelligent Forging Technology Considering Microstructure Evolution
Lee You Hwan ; Lee Chong Soo ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 3~13
DOI : 10.5228/KSPP.2005.14.1.003
A Study on the Numerical Friction Model for Extrusion
Oh P. K. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 14~20
DOI : 10.5228/KSPP.2005.14.1.014
To carry out perfectly the forming analysis of the extruding products, it is necessary that the friction boundary condition between dies and blanks should be worked out the accurate numerical friction models. But, the existing numerical models of the extrusion may be large different from the actual conditions. In this study, accurate analysis of the extrusion forming for the variation of pressure and velocity should be subjected. It is to develop the accuracy of the numerical friction models and potentialize to apply for the high speed forming work in the extrusion. Therefore, the results should improve the accuracy, cause the energy saving for the extrusion and finally expand the applying areas of the results.
Study on Design Parameters in a Stamping Process of an Automotive Member with the Simulation-based Approach
Song J. H. ; Kim S. H. ; Kim S. H. ; Huh H. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 21~28
DOI : 10.5228/KSPP.2005.14.1.021
This paper is concerned with the quantitative effect of design parameters on a stamped part of the auto-body. The considered parameters in this paper are the blank holding force, the draw-bead force, the blank size which greatly affect the metal flow during stamping. The indicators of formability selected in this paper are failures such as tearing, wrinkling and the amount of springback. The stamping process of the front side inner member is simulated using the finite element analysis changing the design parameters. The numerical results demonstrate that the blank holding force cannot control the local metal flow during forming although it controls the overall metal flow. The modification of the initial blank size considering the punch opening line ensures the local wrinkling and reduces the amount of springback after forming. The restraining force of draw-bead controls the metal flow in the local area and reduces the amount of excess metal. It is noted that the parametric study of design parameters such as blank holding force, the blank size and the draw-bead are very important in the process design of the complicated member.
Finite Element Analysis of Orbital Forming Process in Bearing Manufacturing
Moon H. K. ; Lee M. C. ; Chung J. H. ; Joun M. S. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 29~36
DOI : 10.5228/KSPP.2005.14.1.029
In this paper, a useful rigid-plastic finite element method with various numerical schemes is presented for simulation of an orbital forming process. A new approach to reduce volume change during simulation is presented and an approximation method to reduce computational time is also presented. An actual orbital forming process found in a bearing making industry is simulated by the presented approach. The simulated results of the orbital forming process are compared with the experimental results.
Influence of Die Design Variables on the Sheared Surface in Shearing Process of Sandwich Sheet Metal
Kim J. Y. ; Chung W. J. ; Kim J. H. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 37~42
DOI : 10.5228/KSPP.2005.14.1.037
In order to invstigate the influence of die design variables on the quality of the sheared surface in cutting of sandwich sheet metals, the cut-off operation is carried out, which is the typical shearing process in sheet metal forming technology. For experiments we made the cut-off die which can be easily adjusted for die design variables such as blankholding force, pad force and clearance. The sandwich sheet metals considered are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results it is shown that the shearing mechanisms are different according the material of which sandwitch sheet metal is composed. The influence of die design variable is explored and we found optimal conditions for both sandwich sheet metals. It is expected that this investigation can be utilized to get the better sheared surface.
A Study on the Cross Rolling for Improvement of Flatness of Plate
Nam K. O. ; Seo K. S. ; Rho B. R. ; Hong S. I. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 43~48
DOI : 10.5228/KSPP.2005.14.1.043
The production of metal strip with uniform thickness and flatness are two important problems associated thin strip rolling. The thickness and flatness of strip are affected by the flattening of contact surface between strip and roll, the elastic recovery and the bending of roll. Especially, the flatness of the strip is greatly affected by bending deflection of roll. The roll must be designed considered the elastic deformation of roll. This study describes the measurement of thickness and flatness of strip and shows the crown roll for producing flat strip. But it is difficult to produce the crown roller. The cross rolling that is a simple method which can produce the flat strip is introduced and it is found the optimal cross angle for improvement of flatness of plate. These problems are solved by the MARC code on the basis of elastic-plastic material and the updated Lagrangian formulation.
The Effect of the Gate Shape on the Microstructure of the Grain Size Controlled Material
Jung Y.S. ; Seo P. K. ; Kang C. G. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 49~56
DOI : 10.5228/KSPP.2005.14.1.049
In the semi-solid die casting process, an important thing is the flow behavior of semi-solid materials. The flow patterns of the semi-solid material can make the defects during die filling. To control the flow patterns is very important and difficult. In this paper, the flow behavior of the semi-solid A356 alloy material during die filing at various die gate shapes has been observed with the grain size controlled material. The effect of the gate shape on the die filling characteristics was investigated. The filling tests in each plunger stroke were experimented, and also simulated on the semi-solid material die casting process by MAGMAsoft. According to the filling tests and computer simulation, the effect of the gate shape on liquid segregation has been investigated.
Process Design of Shaft Considering Effect of Preform and Eccentric Load on Cold Forging Product in Multistage Former of Horizontal Type
Park S. S. ; Lee J. M. ; Kim B. M. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 57~64
DOI : 10.5228/KSPP.2005.14.1.057
This study deals with the cold forging process design for shaft in the main part of automobile motors with rectangular deep groove. In forging process, the accuracy and die lift is very important because it have influence on reduction of the production cost and the increase of the production rate. Therefore, it is necessary to develop the manufacturing process of shaft by cold forging., process variables are the cropped face angle of billet and the eccentric load of punch. The former is derived from cropping test, the latter is occurred by clearance between container and preform. Also, grooved preform select the process variable for decrease in punch deflection. We investigate that a deflection of punch and a deformation of preform to every process variables. Through this investigation, we suggest the optimal preform and process design, expect to be improved the tool life in forging process.
Strain Rate Dependence of Plastic Deformation Properties of Nanostructured Materials
Yoon Seung Chae ; Kim Hyoung Seop ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 65~70
DOI : 10.5228/KSPP.2005.14.1.065
A phase mixture model was employed to simulate the deformation behaviour of metallic materials covering a wide grain size range from micrometer to nanometer scale. In this model a polycrystalline material is treated as a mixture of two phases: grain interior phase whose plastic deformation is governed by dislocation and diffusion mechanisms and grain boundary `phase` whose plastic flow is controlled by a boundary diffusion mechanism. The main target of this study was the effect of grain size on stress and its strain rate sensitivity as well as on the strain hardening. Conventional Hall-Petch behaviour in coarse grained materials at high strain rates governed by the dislocation glide mechanism was shown to be replaced with inverse Hall-Petch behaviour in ultrafine grained materials at low strain rates, when both phases deform predominantly by diffusion controlled mechanisms. The model predictions are illustrated by examples from literature.
Thermal Stability and Dry Sliding Wear Behavior of Ultra-Fine Grained 6061 Al Alloy Processed by the Accumulative Roll-Bonding Process
Kim Y.S. ;
Transactions of Materials Processing, volume 14, issue 1, 2005, Pages 71~77
DOI : 10.5228/KSPP.2005.14.1.071
Thermal stability and dry sliding wear behavior of ultra-fine grained 6061 Al alloy fabricated by an accumulative roll-bonding (ARB) process have been investigated. After 4 ARB cycles, an ultra-fine grained microstructure of the 6061 Al alloy composed of grains with average size of 500nm, and separated mostly by high-angle boundaries was obtained. Though hardness and tensile strength of the ARB processed Al alloy increased with ARB cycles up to 4 cycles, the processed alloy exhibited decreased ductility and little strain hardening. Thermal stability of the ARB-processed microstructure was studied by annealing of the severely deformed alloy at
. The refined microstructure of the alloy remained stable up to 473K, and the peak aging treatment of the alloy at 450K for 8 hrs increased the thermal stability of the alloy. Sliding-wear rates of the alloy increased with the number of ARB cycles in spite of the increased hardness with the cycles. Wear mechanisms of the ultra-fine grained alloy were investigated by examining worn surfaces, wear debris, and cross-sections by a scanning electron microscopy (SEM).