• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.489-495
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• 2015

Forging is a manufacturing process involving the shaping of metal using localized compressive forces and the process of deforming metal into a predetermined shape using certain tools and press according to the temperature. Forging provides stronger metal parts than that possible by casting or machining. Conventional clutch jaw parts have been developed through cold forging and precision machining; however, fabrication of integral clutch jaw parts for farm machinery has not been reported yet. These parts were developed by applying a complex forging technology combining cold and hot forging. The integrated forming technology proposed in this study will be useful for reducing the lead-time for manufacturing, improving the accuracy of products, and eliminating the welding process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.06a
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• pp.74-80
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• 1995

Forged aluminum lower arm has been developed to provide weight reduction of suspension parts. It was utilized FEM analysis in design of parts. Prototype parts were producted to two shape & different forging condition. Difference of forging condition was manufacturing process of stock, forging press, forging die, heat treatment condition. As a result, weight reduction of 44%, 38% was achived. Strength and fatigue endurance of forged aluminum lower arm was excellent.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.729-734
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• 2015

This research developed a new deep-bore, cup-shape, large forging process by combining die forging and free forging methods. In the proposed process, a preform for cup-shape large forging is produced by die forging, and a product with a deep bore is finally manufactured using an open die forging method, which is generally produced using a backward extrusion process. Finite element analysis results showed a higher effective strain distribution with a smaller forging load using the proposed method compared to the backward extrusion method. The production of a prototype with good internal quality using a small press capacity verified the proposed method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.756-759
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• 2003

Steam Generator is one of the most important structural part of nuclear power plant. It is manufactured by welding process of various steel forgings such as shell, head, torus and tube sheet. These steel forgings have been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced open die forging status and investigated forging method of the ultra large steel forgings which is used for the steam generator of 1000MW nuclear power plant. For the same thing. the type of steel forgings consisting steam generator is classified by shell, head, torus and tube sheet. And corresponding forging processes of the steel forgings have been investigated.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.77-83
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• 1996

This paper describes forging of trochoidal gears, which are being widely used in timing belt pulley, pump pulley etc., as a series of development of the simulator for non-axisymmetric elements. Kinematically admissible velocity fields for forging of trochoidal gear were proposed and the loads were calculated by numerical method. When the simulation was carried out, half pith of gear was divided into 6 deformation regions which have different velicity fields by assumptions and boundary conditions. The neutral surface was introduced into forging of trochoidal gears with flat punch and, for each step, it is assumed as a circle with its radius r$_{n}$. The experimental set-up was installed in 200 ton hydraulic press for forging. The billets, of A1 2218 aluminum alloy, were slightly phosphate-coated. It was shown that thd theoretical solutions, as upper bound, are useful to predict the forging load for forging of trochoidal gears, because thdt give estimates that are substantially higher than experimental loads.s.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.1
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• pp.1-6
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• 2001

This study is concerned with the cold forging of sintered preform by rotary forging process and direct powder compacting process. An experiment has been carried out using the rotary powder forging press (500kN) which had been designed and equipped with the rotational conical die inclined to the central axis of the press at certain angle The effect of process variables was observed and measured by several mechanical test, such as hardness distribution density, and microstructure of the specimens. It is found that the highly densified P/M parts can be obtained and this process is very effective for improving quality of the powder products.

• Transactions of Materials Processing
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• v.19 no.6
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• pp.329-336
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• 2010

Ring forging process is more appropriate for high-length and thin walled ring, because it utilizes the forging press and hence does not require heavy-duty ring rolling mill. Although ring forging process is very simple and economic for facilities, the process is not efficient because of multi-forging-step and low material utilization. An effective ring forging process is developed using a hollow ingot. When a hollow ingot is used with a workpiece, the ingot can be forged into a final ring without multi-stage pre-forging process, such as, cogging, upsetting, and piercing, etc.. Finally it has advantages of the material utilization and process improvement because a few reheating and forging process are not necessary to make workpiece for ring forging. The important design variables are the applied plastic deformation energy to eliminate cast structure and make uniform properties. In this study, the mechanical properties after forging of hollow cast ingot were investigated from the experiment using circumferential sectional model. Also, the effects of process variables were studied by FEM simulation on the basis of thermo-visco-plastic constitutive equation. Applied strain is different at each position in length direction because diameter of hollow ingot is different in length direction. The different strain distribution become into a narrow gap by additional plastic deformation during diameter extension process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.370-373
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• 2008

Small size gas turbine disk requires good mechanical strength and creep properties at high temperature. In this study, Waspaloy was used as a superalloy to satisfy these specifications. The control of microstructure was needed to satisfy material properties at high temperature. In order to do this, we studied forging conditions and material analysis. Therefore die and preform design conducted so that hot forged gas turbine disk could have a good microstructure. The die and preform shapes are designed with consideration of the predefined hydraulic press capacity and the microstructure of forging product. Also we carried out the hot compression test for Waspaloy in various test conditions. From these results, we obtained the forging conditions as material temperature, die velocity etc. To verify these forging conditions, we conducted FE simulations by means of the DEFORM 2D-HT. In this study, the hot closed die and preform designs were completed to offer high temperature material properties of a small size gas turbine.

• Transactions of Materials Processing
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• v.7 no.5
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• pp.426-431
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• 1998

This study is concerned with cold repressing of sintered preforms by the rotary forging process. An experiment has been carried out using the rotary powder forging press(500kN) which was designed and constructed in the authors' laboratory. The effect of process variables and aspect ration of sintered preform on the densification behavior during the rotary repressing was studied by several mechanical test such as working force hardness distribution density and microstructures of the specimens. Since a higher densification can be achieved by applying the rotary repressing on presinted preforms it was successively demonstrated that the cold rotary powder forging is an effective operation to improve quality of P/M parts.

• Transactions of Materials Processing
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• v.4 no.2
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• pp.141-150
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• 1995

The purpose of the open die press forging is to maximize the internal deformation for better structural homogeneity and center-line consolidation in case of the ingot. A two and three dimensional viscoplastic finite element analysis is carried out for the plate, cylinder and square forging with the flat die in order to study the forging effects during the process. Effect of width, height reduction, and die staggering are studied through simulation of the process. Thus favorable working conditions are suggested for better and more disirable product quality.