• Journal of the Korean Society for Heat Treatment
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• v.34 no.1
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• pp.25-30
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• 2021

The differential gear system is a device designed to distribute the driving force of both vehicle wheels and control the rotational speed when the vehicle turns on a curve. The differential device consists of a differential gear case, a ring gear, and a pressure ring. A differential pinion gear and side gear are mounted on the differential pinion shaft inside the differential gear case. In this study, a pin press-fitting device that mounts the pinier gear and side gear to the differential pinion shaft in the differential gear case was designed, and a jig device for pin press-fitting using servo press was developed. In addition, by precisely measuring the pin press-in load and press-in distance according to the pin hole diameter of the differential gear shaft, the optimization of the pin pressin process was established.

• Transactions of Materials Processing
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• v.20 no.8
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• pp.588-594
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• 2011

A new manufacturing process is presented for automotive drive plate using a boron-containing carbon steel sheet, which is hot-formed and press quenched. Particular attention was given to the capability of the process in minimizing dimensional change.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.86-91
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• 2006

Magnesium alloys have been widely used for many structural components of automobiles and aircraft because of high specific strength and good castability in spite of hexgonal closed-packed crystal structure of pure magnesium. In this paper, FE analysis was executed about the formability of AZ3l magnesium alloy on press forging process. For this, the variation of sheet temperature, distribution of punch force and the effect of heat transfer and friction between punch and sheet on the forming characteristics during press forging of AZ31 has been analyzed by finite element analysis. In order to obtain temperature dependence of material characteristics, uniaxial tension tests at elevated temperature were done under temperature of $100^{\circ}C\~ 500^{\circ}C$.

• Advances in aircraft and spacecraft science
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• v.9 no.6
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• pp.493-506
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• 2022

The study presents the results of the research of heat and heat exchange processes on the heat-stressed elements of the structure of an advanced TsAGI descent vehicle. The studies were carried out using a mathematical model based on solving discrete analogs of continuum mechanics equations. Conclusions were drawn about the correctness of the model and the dependence of the intensity of heat and mass transfer processes on the most heat-stressed sections of the apparatus surface on its geometry and the catalytic activity of the surface.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.37-45
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• 2011

Purpose: Heat pressed ceramics, used for all ceramic restorations, have the additional advantage of being technically less change through using of the lost-wax technique. Conceptually, combining the ceramic with the clinically proven reinforcing ability of a metal framework would be advantageous; however, cause of mismatching of fusion between ceramics and metal frameworks which from differences of casting temperature and coefficient of thermal expansion, pressed ceramics could not be used with a metal framework. The purpose of this study was to compare shear bond strength of press-to metal ceramic to porcelain fused non precious metal and feldspatic porcelain fused non precious metal. Methods: The 30 metal specimens were casted in a porcelain fused non precious metal nickel-chromium alloy. They were divided into 3 groups by surface treatment and applied ceramic: $125{\mu}m$ aluminium oxide sandblasting and veneered feldspatic porcelain (group FP), $125{\mu}m$ aluminium oxide sandblasting and had press-to-metal ceramic applied (group PC), porcelain bonder (gold bonder) fused on surface of metal specimens and had press-to-metal ceramic applied (group PCG). In each group 10 metal specimens were used. The press-to-metal ceramic applied 20 specimens had ash-free wax pattern applied, the metal-wax complexes invested, and were pressed with heat press ceramic. All specimens were subjected to shear bond strength test at a crosshead speed of 1.0 mm/min. Results: The results of measured in Mean SD and data were analyzed by one-way AVOVA (p= .05) and Tukey HSD test (p= .05).: group FP $16.090{\pm}1.841$ MPa, group PC $12.620{\pm}1.8256$ MPa, group PCG $10.920{\pm}0.9283$, significant differences between all groups (p < .05). Significant differences were found in each between group FP and group PC, group FP and group PCG (p < .05). Conclusion: The shear bond strength of press-to-metal ceramic to porcelain fused non precious metal was described higher in unused gold bonder group than used gold bonder groups.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.4
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• pp.241-247
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• 2004

• Journal of the Korean Society for Heat Treatment
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• v.23 no.5
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• pp.257-262
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• 2010

Recently, metal molding has become essential not only for automobile parts, but also mass production, and has greatly influenced production costs as well as the quality of products. Its surface has been treated by carburizing, nitriding and induction hardening, but these existing treatments cause considerable deformation and increase the expense of postprocessing after treatment; furthermore, these treatments cannot be easily applied to parts that requiring the hardening of only a certain section. This is because the treatment cannot heat the material homogeneously, nor can it heat all of it. Laser surface treatment was developed to overcome these disadvantages, and, when the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.6
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• pp.339-344
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• 2009

Recently, Laser surface treatment technologies have been used to improve wear charactenitics and fatigue resistance of metal molding. When the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source. To estimate this, microstructural changes and hardness characteristics of three parts (the surface treatment part, heat affect zone, and parental material) are observed with the change of laser beam speed and surface temperature. Moreover, the depth of the hardened area is observed with the change of the laser beam speed and temperature. From the results of the experiments, it has been shown that the maximum hardness is approximately 788Hv when the heat treatment temperature and the travel speed are $1150^{\circ}$ and 2 mm/sec, respectively.

• Journal of the Korea Furniture Society
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• v.18 no.2
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• pp.143-146
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• 2007

This study was carried out to assess the dimensional stability of wood material treated by plastic processing for bentwood and compression wood. The evaluation method was different between two wood materials, but the treatments for them were very similar to each other. One of the main methods is heat treatment with sufficient water vapor. In bentwood, the used species were painted maple (Acer mono), bitter wood (Picrasma quassioides) and birch (Betula schmidtii). Steaming was the worst treatment method for dimensional stabilization of bentwood. The best results could be attained with PEG treatment for dimensional stabilization of bentwood. Dimensional stability of bitter wood was found to be conspicuous. However the steaming treatment at lower temperatures, i.e., about $130^{\circ}C$ was not suitable for dimensional stability of bentwood. In compression wood, the used specimen was Italian poplar wood (Populus euramericana). Two heat compressive pressing conditions, an open-press system and an air-tighten closed-press system, were used. The recovery rate was measured after boiling and/or absorbing in water to estimate the dimensional stability of heat compressed wood. The best dimensional stability of compressed wood in the air-tighten closed-press system was found to be better at $200^{\circ}C$ than $180^{\circ}C$. The best compression rate for dimensional stability was 73 percent.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.303-310
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• 2011

The mechanical properties of heat-compressed Radiata pine (Pinus radiata D.Don) by compression temperature and time were investigated. The compressive strength and bending strength of heat-compressed wood increased with increasing compression temperature and time. But the compressive strength and bending strength decreased with press temperature $220^{\circ}C$. It was considered due to thermal degradation during high temperature conditions. The surface hardness of heat-compressed wood increased with increasing compression temperature. However, the effect of compression time was negligible. The nail holding power was not affected by compression temperature and time.