• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.405-410
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• 2011

The heat treatment of the steel is very important part on the forging industry. It is also effect to price competitiveness. The burner control system of the heat treating furnace is related LNG gas saving and fixed manufactured goods rate. This study show the burner control performance of the heat treating furnace. The result developed the performance of the heat treating furnace and show energy saving.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.1
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• pp.51-60
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• 2000

• Journal of the Korean Society for Heat Treatment
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• v.5 no.1
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• pp.32-40
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• 1992

This content is a part of the results of the study on the development of the vacuum carburizing technology. In this study the vacuum carburizing furnace being used was the furnace that developed through the joint project between KIMM and Kyung-Pook Heat Treating Co. from June 1988 to Nov. 1990. And the used carburizing gas was the propane gas and the introducing methods of the gas applied two methods such as pulse and constant pressure. By this study we established the basis of the furnace manufacturing technology and of the processing technology in the vacuum carburizing. Above all in this work there are notable meanings in a viewpoint of the foremost research in home. Hereafter, we are going to industrialize the vacuum carburizing technology by improving the results of the present work and by developing the process for the mass production.

• Clean Technology
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• v.4 no.2
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• pp.41-53
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• 1998

Most of flame furnace with uncontrolled atmosphere forms oxidation scales in the surface during heat treatment. In this case, shot blasting and pickling are commonly used for reduction of oxidation scales. These processes have many disadvantages, such as long process time, high operating cost and environmental problems due to polishing dust, etc. Hence, this study aimed to develop the advanced heat treating equipment which could make a controlled atmosphere using a heatresisting structure into the flame furnace. The analysis result with SEM, EPMA, and EDX revealed that the amount of scales formed is much less than that with the conventional flame furnace. A brightness of the sample treated with the advanced process is similar compared to the treatment with vacuum furnace. In the present work, it was recommended that the inside structure of the furnace and gas line system could made up of SBB410 and STS310, respectively. The operating cost with the advanced heat treatment system could be reduced annually by forty million won. As a result of this study, it may be possible to reduce the oxidation scales. The fundamental information obtained in this study will be useful not only for improving the heat treatment process(reduction of shot blast and cleaning process), but for promoting the manufacture of bright products.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.633-635
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• 2009

It is a quite quality concerning to control temperature of single crystalline growth as it does when you get most of heat treating products. It is also important factor to control temperature when you make the $Al_2O_3$(single crystalline) used to artificial jewels, glass of watches, heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while you are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system for the gas mixture to improve the quality of products.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.1
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• pp.142-147
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• 1998

Rotary bending fatigue tests were carried out on the nitrided titanium in order to investigate the effect of nitriding layer on fatigue limit. Main results obtained are as follows. (1) The fatigue limit of nitrided pure titanium is remarkably reduced because of enlargement of grain size at high heat treating temperature and high stress field created from the elastic interaction in the compound layer. (2) Further test using specimen which was removed nitrified layer gradually, were also conducted and it was found that by removing the compound layer the fatigue limit recovered as the level of basic material and rather increased by coming of a diffusion layer. Therefore it is concluded that the surface compound layer generated by nitriding treatment reduced the fatigue limit but diffusion layer increased it.

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.304-310
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• 1994

The use of thermally expanded core (TEe) fibers fabricated by thermal diffusion of dopants such as $GeO_{2}$ in hybrid fiber components has an advantage of eliminating lenses for collimation and focusing. An electric furnace is fabricated to heat the fibers locally for the core expansion. We observed an expansion of the mode size at $1.3\mu\textrm{m}$ wavelength by 27% after treating a section of single mode optical fiber at $1250^{\circ}C$ for 10 hours. hours.

• Journal of the Korean Society for Heat Treatment
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• v.6 no.1
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• pp.17-25
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• 1993

The Cu - $Nb_3Sn$ composites wire as a superconducting material was prepared by in situ method as follow: Cu - 15wt.% Nb alloys which were melted in a high -frequency induction furnace and casted in bar were cold-worked up to the final diameter of 0.24 mm, electroplated with Sn, pre-treated in two steps and then diffused at $550{\sim}650^{\circ}C$ for 24 ~ 96 hrs. The overall $J_c$ and $T_c$ of the specimens were measured by the four point-probe method at 10 K in the magnetic field of 0 Tesla. The overall $J_c$ of the composites wire which diffused at $550^{\circ}C$ after pre-treating in two steps were generally higher than those of the wire at either $600^{\circ}C$ or $650^{\circ}C$. For the specimens diffused at $550^{\circ}C$, the overall $J_c$ were increased until 72 hrs. of diffusion time and then decreased. However, in case of diffusion at $600^{\circ}C$ and $650^{\circ}C$, the overall $J_c$ were gradually decreased from the beginning. The maximum overall $J_c$ obtained in this experiment was $1.3{\times}10^4\;A/cm^2$, which was measured for the specimen diffused at $550^{\circ}C$ for 72 hrs. When the specimens were diffused at $550^{\circ}C$ for 72 hrs, after pre-treating, the measured critical temperature, $T_c$ was 16.19 K. Similar $T_c$ value were obtained in other specimens regardless of diffusion time and temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.207-211
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• 2007

It is a quite quality concerning to control the temperature of single crystalline growth as it does when we get most of heat treating products. It is also important factor to control the temperature when we make the $Al_2O_3$(single crystalline) used to artificial jewels, glass of watches, and heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while we are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system with DC-Motor for the gas mixture to improve the quality of products.

• Journal of the Korean Society for Heat Treatment
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• v.32 no.5
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• pp.201-211
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• 2019

Low carbon steel (S20C steel) and SPCC steel sheet have been austenitic nitrided at $700^{\circ}C$ in a closed pit type furnace by changing the flow rate of ammonia gas and heat treating time. When the flow rate of ammonia gas was low, the concentration of residual ammonia appeared low and the hardness value of transformed surface layer was high. The depth of the surface layer, however, was shallow. With increasing the concentration of residual ammonia by raising up the ammonia gas flow, both the depth of the surface layer and the pore depth increased, while the maximum hardness of the surface layer decreased. By introducing a large amount of ammonia gas in a short time, a deep surface layer with minimal pores on the outermost surface was obtained. In this experiment, while maintaining 10~12% of residual ammonia, the flow rate of inlet ammonia gas, 7 liter/min, was introduced at $700^{\circ}C$ for 1 hour. In this condition, the thickness of the surface layer without pores appeared about $60{\mu}m$ in S20C steel and $30{\mu}m$ in SPCC steel plate. Injecting additional methane gas (carburizing gas) to this condition played a deteriorating effect due to promoting the formation of vertical pores in the surface layer. For $1^{st}$ transformed surface layer for S20C steel, maintaining 10~12% residual ammonia condition via austenitic nitriding process resulted in ${\varepsilon}$ phase with relatively high nitrogen concentration (just below 4.23 wt.%N) among the mixed phases of ${\varepsilon}+{\gamma}$. The ${\varepsilon}$ phase was formed a specific orientation perpendicular to the surface. For $2^{nd}$ transformed layer for S20C steel, ${\gamma}$ phase was rather dominant (just above 2.63 wt.%N). For SPCC steel sheet, there appeared three phases, ${\gamma}$, ${\alpha}(M)$ and weak ${\varepsilon}$ phase. The nitrogen concentration would be approximately 2.6 wt.% in these phases condition.