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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of Materials Processing
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Journal DOI :
The Korean Society for Technology of Plasticity
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Volume & Issues
Volume 3, Issue 4 - Dec 1994
Volume 3, Issue 3 - Sep 1994
Volume 3, Issue 2 - Jun 1994
Volume 3, Issue 1 - Mar 1994
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Fabrication of Semi-solid Materials and Components forming Processes
Kang, Chung-Gil ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 3~17
The semi-solid metal forming for vigorously agitated semi-solid alloys has been widely studied over the last decade. Metal forming processes are now being developed using alloys in the semi-solid state, among them are rolling, forging, extrusion, and die casting. Some of these are now employed commercially to produce a components and are also used to fabricate metal matrix composites. The semi-solid materials can be processed either directly during solidification and for this purpose mechanical stirring was demonstrated to produce a highly solidification. This paper is concerned with the influence of processing parameters on limitations of semi-solid forming.
생산기술연구원의 소성가공 연구
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 18~22
A Study on the Piping Defect at The Final Stage of Axisymmetric Extrusion by Upper Bound Element Technique
Choi, Jae-Chan ; Choi, In-Keun ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 23~37
The upper bound element technique(UBET) is used to analyze the final stage of the axisymmetric forward extrusion. Kinematically admissible velocity field involving curved surface of velocity discontinuity is assumed. The required power to arise the piping defect is obtained and is compared with Aviture's solution a the same condition. Conditions for inception of the cavity and development of the pipe are predicted. The internal radius of the pipe and critical length of billet are also determined. Experiments are carried out for extrusion with lead specimens to investigate the piping phenomena. The theoretically predicted results showed reasonably good agreement with the experimental observation.
Press Formability of Austenitic AISI304 Stainless Steel
Nam, J.B. ; Ryoo, D.Y. ; Kim, Y.S. ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 38~50
Fundamental deformation mechanism and plastic behavior of AISI304 austenitic stainless steel were investigated to evaluate press formability. Local and uniform deformation capacity of AISI304 steel were compared to those of ferritic AISI430 steel and Al killed low carbon steel. Nine kinds of austenitic stainless steels having different austenite stabilities were made in laboratory scale to examine the transformation behavior in various deformation mode and variation of mechanical properties. Deformation path and strain distributions along edge corner of commercial sink die were illustrated and effect of austenite stability on press forming of sink die was clarified with experiments using square cup drawing tools.
Comparison of Friction Coefficients of Sheet Materials in Various Deformation Modes
Kim, Young-Suk ; Kim, Ki-Soo ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 51~62
Cup drawing test and U-bending test were performed to evaluate the friction characteristics of sheet materials for the different deformation modes involved in stamping process. The coefficient of friction calculated from the each test was compared to that obtained from the draw bead friction test. It was clarified that the cup drawing test could be simply used for evaluating the friction characteristic of sheet material in deep drawing process with high contacting pressure. However the U-bending test is suitable to evaluate the frictional characteristic of sheet material in bending process with low contacting pressure.
An Analysis of Hot-Rolling in the Twin-Roll Strip Casting Process by using the Slab Method
Shim, Hyun-Bo ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 63~83
In this paper, the slab method have been applied to investigate the strip casting process in which hot coil is produced from molten steel directly. In the twin roll strip casting process, molten steel supplied by the nozzle cools and solidifies due to the heat extraction effect of the rolls and hot rolling of the solidified shell takes place simultaneously. The analysis of hot rolling has been carried out by using the existing results of solidification analysis for the twin roll strip casting process. The current slab method provides basic design data such as roll separation force, rolling torque, rolling power as well as end dam separation force which are required to design strip caster. The effect of friction on the basic process parameters are investigated also. It is shown that the use of appropriate friction coefficient is important and that the characteristics of hot rolling in the twin-roll strip casting process is quite different from the conventional hot rolling processes.
Prediction of Spring Back and Formability in 3-D Stamping by An Explicit Code
Kim, Heon-Young ; Kim, Joong-Jae ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 84~96
Simulation of 3 dimensional large irregularly shaped stamping process by a dynamic approach, based on an explicit time integration scheme, has been shown to be highly efficient and robust in comparison to traditional, implicit, quasi-static ones. The objective of the work is to evaluate the results from explicit code in application to deep drawing of rectangular cup and stamping of automotive front fender, in which deformation, force, thickness distribution are calculated. The method of predicting spring back and formability by and explicit code are suggested and applied to the processes.
An Upper-Bound Analysis for Closed-Die Forging of the Involute Spur Gears with Circular Arc Fillet
Choi, J.C. ; Hur, K.D. ; Kim, C.H. ; Choi, Y. ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 97~109
Closed-die forging of the spur gears with circular are fillet has been analyses by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, the tooth profile consists of the involute curve and the circular arc fillet. In the analysis, the deformation regions have been divided into eight zones. A constant frictional stress has been assumed on the contacting surfaces Utilizing the formulated velocity field, numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth, addendum modification coefficient and friction factor, on the relative forging pressure of spur gears. As the result of numerical calculations, the relative forging pressure does not change so much against the variation of module. On the other hand, the relative forging pressure increases at the final filling stage as the addendum modification coefficient increases.
An Experimental Study of Forming Process Development in Large Nozzle-Shaped Product Using the Incremental Forging Method for Expanding
Park, C.Y. ; Yang, D.Y. ; Lee, K.H. ; Eun, I.S. ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 110~119
In this paper, a new forming process of large-size forgings of converged nozzle-shape is developed by the experimental study using the incremental forging method and combined forming method. The development of the forming process is focused on the manufacturing of large-size forgings by the press with medium load capacity. Various related processes are proposed and modelling experiments using plasticine are carried out. Thus, the incremental forging method for expanding is recommanded from the study of formability and forming load, etc. The selected process is then subjected to modelling experiments of lead and the design parameters such as preform for final process, die-width of the upper die and reduction amount of each stroke are determined. In order to verify the effectiveness of the selected process, 1/7 scale prototype experiment of the real material is carried out. Forgings of converged nozzle shape can be produced by the developed process within the limit loads and with the simple tools.
Finite Element Analysis of Strip Drawing Including the Evolution of Material Damage
Hahm, Seung-Yeun ; Lee, Yong-Shin ;
Transactions of Materials Processing, volume 3, issue 1, 1994, Pages 120~132
Strip drawing of strain-hardening, viscoplastic materials with damage is analyzed by a rigid plastic finite element method. A process model is formulated using two state variables, one for strain hardening from slip dominated plastic distortion and the other for damage from growth of microvoids. Application of the model to aluminum strip drawing is given via implementation in a consistent penalty finite element formulation. The predicted density changes as a result of void growth are compared to those from experiments reported in the literature. The effects of drawing conditions such as drawing speed and die angle on the mechanical property chages are studied.