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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 16, Issue 8 - Dec 2007
Volume 16, Issue 7 - Nov 2007
Volume 16, Issue 6 - Oct 2007
Volume 16, Issue 5 - Aug 2007
Volume 16, Issue 4 - Jul 2007
Volume 16, Issue 3 - Jun 2007
Volume 16, Issue 2 - Apr 2007
Volume 16, Issue 1 - Feb 2007
Selecting the target year
Wisdom and Essence Gained from the Research and Development of Steel Making Machine
Hayashi, K. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 419~425
DOI : 10.5228/KSPP.2007.16.6.419
Prediction for Forming Limit of Tube Warm Hydroforming Based on the Ductile Fracture Criteria
Yi, H.K. ; Moon, Y.H. ; Lee, J.H. ; Lee, Y.S. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 426~431
DOI : 10.5228/KSPP.2007.16.6.426
Hydroformability and fracture criteria of FE analysis based on ductile fracture were investigated in warm hydroforming of A16061 tube. To evaluate the hydroformability, uni-axial tensile test and bulge test were performed at room temperature and
. The measured flow stresses were used as input parameters for FE analysis. The damage values were calculated by FE analysis based on ductile fracture criteria at maximum radius of free bulged tubes. Damage values were compared of hexagonal shaped hydroformed parts. As a result, the formability by critical damage value for extruded tube is lower than that of full annealed tube up to 0.5.
Development of Prediction Model for Sidewall Curl in Sheet Metal Forming(I)-Analytical Model
Joo, B.D. ; Park, H.K. ; Kim, D.W. ; Moon, Y.H. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 432~437
DOI : 10.5228/KSPP.2007.16.6.432
Sidewall curl is the curvature that results from non-uniform through-thickness strain present in the sheet stamping process which involves material flow over a die radius. In order to understand and control sidewall curl for tight fit-up tolerances, an analytical model that can provide a reliable measure for the amount of curl would be very helpful. In this study, a model is developed based on the moment-curvature relationship during bending-under-tension operations. The analytical model includes the variables of applied tensile force, the yield strength, the elastic modulus, the bending radius, and the sheet thickness, which are the primary factors affecting sidewall curl during sheet stamping operations. For the accuracy of analytical model, six possible deformation patterns are proposed on the basis of material properties and bending geometries.
Development of Prediction Model for Sidewall Curl in Sheet Meta1 Forming(II)-Experimental Validation
Joo, B.D. ; Park, H.K. ; Kim, D.W. ; Moon, Y.H. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 438~442
DOI : 10.5228/KSPP.2007.16.6.438
Sidewall curl is the curvature that results from non-uniform through-thickness strain present in the sheet stamping process which involves material flow over a die radius. In order to understand and control curl for tight fit-up tolerances, an analytical model that can provide a reliable measure for the amount of curl would be very helpful. In this study, a model is developed based on the moment-curvature relationship during bending-under-tension operations. For the verification of analytical model, sidewall curl is experimentally measured after deformation of a strip using a bending-under-tension test system. The results show a consistent relationship between the theoretically predicted value and the experimentally obtained one, especially in regions of high curl.
Forging Process with Al6061 Alloy Rheology Material by Electromagnetic Stirring System
Kang, S.S. ; Oh, S.W. ; Kang, C.G. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 443~446
DOI : 10.5228/KSPP.2007.16.6.443
The semi-solid process has been developed near net-shape components for kinds of methods. Thixo-forming with reheating prepared billet and rheo-forming with cooled melt until semi-solid state. Material is applied electromagnetic stirring system to slurry with aluminum 6061 alloy. An experiment has variation factors which are pressure, solid-fraction, stirring current and stirring time. The mechanical properties are compared to forge sample with to apply heat treatment T6. This study is researched function a virtual pressure and fine shape zone. Optimum pressure is found to prevent defect of porosity.
Measurement of Springback of AZ31B Mg Alloy Sheet in OSU Draw/bend Test
Choi, J.G. ; Choi, S.C. ; Lee, M.G. ; Kim, H.Y. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 447~451
DOI : 10.5228/KSPP.2007.16.6.447
The springback characteristics of AZ31B magnesium alloy sheet was investigated in OSU draw/bend test Springback is the elastically-driven change of shape of a part after forming and it should be estimated and controlled to manufacture more precise products in sheet forming. Magnesium alloy sheets have unique mechanical properties such as high in-plane anisotropy/asymmetry of yield stress and hardening response. So, there will be a difference in the prediction of springback with symmetric mechanical properties for magnesium alloy sheets. In this work, the Strip draw/bend tests were conducted with various conditions - die radius, sheet thickness and controlled tensile force and the tendency of springback angle was observed from the tests.
A Study on the Design of Cold Forging Die with Parted Notch
Lee, H.Y. ; Yeo, H.T. ; Hur, K.D. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 452~456
DOI : 10.5228/KSPP.2007.16.6.452
Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to reduce the high pressure in die design of cold forging. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.
Study on the Characteristics of Drawbead Forces in Automotive Stamping Dies
Moon, S.J. ; Wagoner, R.H. ; Keum, Y.T. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 457~462
DOI : 10.5228/KSPP.2007.16.6.457
The drawbeads, which are used for controlling the flow of the sheet into die cavity by imposing the tension and for preventing the forming defects like wrinkling, springback, etc. during the sheet forming process, affect the formability strongly because of the differences in the restraint and opening forces according to the drawbead shapes and dimensions. In this study, the experimental device enabling to measure the drawbead restraining and opening forces is manufactured and the drawing forces of circular, square, and step drawbeads are measured. The drawbead restraining and opening forces of a circular drawbead are increased as its drawbead height is increased. Similarly, those of a square drawbead are increased as its height is increased and shoulder radii decreased. The drawbead forces obtained from the experiment were compared with those calculated in the numerical simulation of stamping process of automotive fender. Good agreement was found so that the experimental measurements can be used in the simulation of auto-body stamping process.
Prediction of Residual Stress in Straightening Process of SUS304 Wire
Kim, T.W. ; Ham, S.H. ; Moon, H.I. ; Kim, H.Y. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 463~466
DOI : 10.5228/KSPP.2007.16.6.463
Micro-wire made from straightening process invents high added value and it has been adopted many industrial fields. Therefore, many research activities about straightening process are advanced actively. It is known that fine straightness of micro-wire can be obtained by removing residual stress induced during the manufacturing processes. Generally, residual stress is removed or minimized through several drawing processes with heat treatment. In this study, the residual stress at each straightening process is calculated and monitored by finite element analyses and the main reason of stress change is investigated.
Effect of Initial Texture on the Twinning Formation of AZ31 Mg Alloy
Lee, Byoung-Ho ; Kim, Yong-Woo ; Park, Sung-Hyuk ; Lee, Chong-Soo ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 467~472
DOI : 10.5228/KSPP.2007.16.6.467
In this study, the effects of initial texture on the twinning formation of AZ31 Mg rolled sheet was investigated. Uniaxial compression tests were carried out on samples cut along the normal direction(ND) and roiling direction(RD), respectively, of rolled AZ31 Mg alloy sheet at various temperatures (RT, 200, 250, 300, 350,
) with the fixed strain rate(
). The results showed that deformation twining occurred actively only in the RD specimens, which promoted homogeneous deformation as compared to the ND specimens. The effect of temperature on the formation of deformation twins was also investigated, and the slip/twin transition temperature was found to be approximately
Deformation Mechanism Map of Nanocrystalline Metallic Materials
Yoon, S.C. ; Bok, C.H. ; Kwak, E.J. ; Kim, H.S. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 473~478
DOI : 10.5228/KSPP.2007.16.6.473
In this study, a deformation mechanism map of metallic nanocrystalline materials(NCMs) using the phase mixture model is proposed. It is based on recent modeling that appears to provide a conclusive description of the phenomenology and the mechanisms underlying the mechanical properties of NCMs. The proposed models adopted the concept of a 'phase mixture' in which the grain interior and the grain boundaries are treated as separate phases. The volume fraction of this grain boundary 'phase' may be quite appreciable in a NCM. Based on the theoretical model that provides an adequate description of the grain size dependence of plasticity covering all grain size range from coarse down to the nanoscale, the tensile deformation response of NCMs, especially focusing on the deformation mechanisms was investigated. The deformation mechanism map is newly proposed with axes of strain rate, grain size and temperature.
A Study on Life Estimation of a Forging Die
Choi, C.H. ; Kim, Y.J. ;
Transactions of Materials Processing, volume 16, issue 6, 2007, Pages 479~487
DOI : 10.5228/KSPP.2007.16.6.479
Die life is generally estimated taking failure life and wear amount into consideration. In this study, the forging die life was investigated considering both of these two factors. The fatigue life prediction for the die was performed using the stress-life method, i.e. Goodman's and Gerber's equations. The Archard's wear model was used in the wear life simulation. These die life prediction techniques were applied to the die used in the forging process of the socket ball joint of a transportation system. A rigid-plastic finite element analysis for the die forging process of the socket ball was carried out and also the elastic stress analysis for the die set was performed in order to get basic data for the die fatigue life prediction. The wear volume of the die was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.