• Transactions of Materials Processing
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• v.6 no.6
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• pp.500-507
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• 1997

The conventional closed-die forgings had been applied to the forging of spur gears. But the forgings require high forging-pressure. In this paper, new precision forging technology have been developed. The developed technology is two steps forging process. Good shaped products are forged successfully with lower forging-pressure than those of conventional forging. The accuracy of the forged spur gear obtained by new precision forging technology is set nearly equal to that of cut spur gear of fourth and fifth class in Korean industrial standard.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.143-147
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• 2005

In this study, a die set for enclosed die forging is developed and it is applied to precision forging of bevel gears and spiders. The enclosed die forging die set is introduced in detail together with the enclosed die forging. A target mechanical press and a model product are selected and various engineering technologies are applied for detail design of the enclosed die forging die set. Several precision forgings are manufactured by the developed die set. The enclosed die forging die set as well as the precision forging processes are developed under intensive industry-university cooperation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.172-175
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• 1997

The conventional closed-die forgings had been applied to the forging of spur gears. But the forgings require high forging-pressure. In this paper, new precision forging technology have been developed. The developed technology is two steps forging process. Good shaped products are forged successfully with lower forging-pressure than those of conventional forging

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.166-173
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• 1999

Al forged parts are many cases with rib-web section which is difficult to manufacture precisely. Therefore, process conditions must be optimized for precision forging of Al alloys. In this study, various process parameters such as die design, lubricant, ram speed, forging temperature have been investigated using the experiment, upper bound theory and F.E.M. simulation to develop the precision forging technology for rib-web shape component. When lubricant is applied to both material and die, shear friction factor is 0.1 which shows best effect of lubricant. It is specific corner radius of die that minimized forging load regarding process conditions, especially according to the ratio of the width of rib and web. In conclusion, optimum corner radius is 2~3mm when the width of rib and web is 3mm and 20mm respectively.

• Transactions of Materials Processing
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• v.32 no.6
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• pp.335-343
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• 2023

Spur Gear parts for automobile actuators using existing former forging technology were produced in a total of three processes on a former forging machine. However, in order to improve cost increase due to frequent mold breakage, Spur Gear parts were designed and manufactured in the cold forging process after forming the preform through former forging. In other words, in the existing former forging mold, product seating defects occurred due to horizontal movement, resulting in many product defects and mold damage, so there was an urgent need to improve mold life and product defects. In order to improve this, we tried to improve the mold life by improving the existing 3 former forging processes to a former forging process and 2 cold forging processes. Therefore, We developed Spur Gear parts for automobile actuators were developed by applying precision cold forging technology through a former forging process and 2 cold forging processes to improve mold life.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.87-93
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• 2000

Powder Forging technology is being developed rapidly because of its economic merits and the possibility of lightening parts by replacing steel parts with aluminum ones especially in automotive parts manufacturing. Recently Powder Forging process is widely used for manufacturing primary mechanical parts as a combined technology of P/M and precision hot forging. This paper describes the process conditions for the powder forging of Aluminium alloy piston. For example powder alloy design preform design by FEM simulation cold of compaction of specimens and preform sintering of preform powder forging process. The characteristics of sintered compaction of specimens and preform sintering of preform powder forging process. The characteristics of sintered products and final forged piston ones are investigated with tensile strength hardness ductility and so on. Eventually its results prove the improve mechanical properties of the piston produced by powder forging.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.120-123
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• 1999

The precision cold forging process for steering yoke of automobile has been analysed by using rigid-plastic finite element analysis code DEFORM-3D Also the experiment has been performed through the optimized process. Until now steering yoke has been largely manufactured by hot forging or welding of forged head and shaft parts because of technical difficulty. the study has shown successful results of the precision cold forging through the proper selection of the process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.67-72
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• 2003

The cold precision forging of spur gears has been researched, and the effects of relief-hole shape and forging process on the spur gears forming has been analyzed. The results present that the forging load decreases when a suitability diameter of relief-hole is chosen, but the function is not obvious. The spur gears precision forging method with an adjustable movement of concave mould can benefit both the top and the bottom comers forming of the spur gears, full fill the tooth cavity, and decrease the forging load.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.354-357
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• 2005

When Ti-6Al-4V is used in long steam turbine blades, the main issues are how to improve the fatigue strength as a problem of internal quality and how to forge the thinnest possible blades as problem of dimensional precision. To assure an excellent fatigue strength, it is important to make the two phase fine and equiaxial structure by providing enough plastic deformation in the two phase$(\alpha\;phase/\beta\;phase)$ temperature region. Accordingly, it needs to predict that forging temperature, preform design and forging velocity in forging process. To achieve this end, the two steps forging process was suggested to forge the thin and twisted blades with a precision hammer considering die forces and metal flow. Two steps forging process consists of the flattening forging process and finishing forging process. Process in forging of a 1016mm long steam turbine blade is designed by the finite element method. This study attempts to derive systematic design procedures for process design in the forging. Forging parameters was analyzed in two-dimensional plane-strain simulation and two steps forging process carried out in three-dimensional simulation. Consequently, optimal forging process parameters of long steam turbine blades in Ti-6Al-4V with a high dimensional precision are selected in the hammer die forging.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.1-9
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• 2003

The precision forging developed very fast in recent years due to the development of the automobile industry in China. Several actual examples are given to show this development and the direction of the precision forging in China should move forward is pointed out.