활용 용가재를 이용한 이종재료간의 신접합 기술 개발(Ⅱ)

배석천 啓明大學校 産業技術硏究所 1991 産業技術硏究所 論文報告集 Vol.14 No.1

The development of chemical technology, electronic device, auto indutry and aerospace has increased the demand of the advanced materials such as heat- and corrosion-resistant materials. These materials play important role as part of a large components which require heat-and corrosion-resistance. These materials are usually connected to order materials and hence it is required to development the solid state bonding technology such as brazing, because fusion welding is not suitable for the joining of ceramics and dissimilar materials. State of art brazing has been particularly developed and been applied for the joining of advanced materials due to its unlimited materials' application and the less mechanical defects at the joint interface, comparing to fusion welding Therefore, the present study was aimed to determine the optimum brazing conditions for the joining of ceramics and dissimilar materials which are widely used for many machine components and finally to develop the brazing technology for functionally advanced components. The effects of brazing parameters on the brazed joints performance were investigated. The results are as follows; -the optimum brazing temperature was 80-100℃ above melting temperature of filler metal -the strength of the brazed joins were slightly increased with increasing brazing time -the type of filler metals significantly affected the brazed joints performance. The results of the present study would be directly applied to the brazing technology for important parts of the automobiles and spacevehicles such as bearings, cylinders, nvalve seats and gas turbine blades, requiring excellent heat or wear resistance.

Ni base계 초내열 합금 접합용 극박 Insert Metal 개발

배석천 啓明大學校 産業技術硏究所 1997 産業技術硏究所 論文報告集 Vol.19 No.2

The purpose of this study is to develop new brazing insert metals for Ni-base superalloy 14 kinds of insert metals based on Ni-Zr-Cr system for Ni-base superalloy brazing were newly designed, manufactured by melt spinning process and tested on wettability, brazing conditions, microstructure of bonded area and bonding strength at high temperatures. Main results are as follows. For the brazing of Ni-base superalloys such as Inconel 718 and Rene' 41, insert metal of Ni-6Cr-3B-1Zr-1Al composition was newly developed and exhibited excellent brazeability. The bonding strength of Inconel 718 brazed joint was 98.6kgf/mm²at room temperature and 80-62 kgf /mm²at elevated temperature of 540-760℃, which were higher values than those of commercially producted insert metals. Another insert metal of Ni-11P-6Cr-1Zr-1Al compositions which has relatively low melting point was also manufactured under the form of amorphous foil. Two kinds of above insert metals represented good brazeability not only for Inconel alloy but for Rene' 41. The brazing temperature of Ni base superalloy with developed insert metals was 1150℃ for Rene' 41 alloy and 1120℃, for Inconel 718 alloy. However, the brazing temperature could be lower when the insert metal of amorphous structure applied. Some of developed insert metals possess better brazeability than commercially producted insert metals.

Al-Cr계 합금의 응고 조직에 관한 연구

배석천,조순형 대한용접접합학회 1995 대한용접·접합학회지 Vol.13 No.3

The structural changes of Al-Cr alloys due to the difference in the growth rates were investigated in the study using the water cooled copper chill apparatus, the levitation apparatus, and the melt spinner. Growth rate was evaluated by means of thermal analysis could measured the cooling rate up to 10$^{5}$ K/sec. The transformation from the cell structure to the massive transformed structure was obtained the Al-3.43wt%Cr alloy in the melt spinner method.

용융 아연 도금 강판의 Braze-Welding 기술 개발에 관한 연구

배석천 啓明大學校 産業技術硏究所 1996 産業技術硏究所 論文報告集 Vol.19 No.1

The final results of the study on applicability of braze-welding process to improve the characteristics of brazed joints of galvanized steel plate are summarized as follows; -At the Ar 96% and CO₂4% of gas mixture ratio for the most appropriate brazed joint formation of galvanized steel plate, the most ideal brazed seam was formed. -Also for the smooth outgasing of melted pool, the lower welding speed in a low current, compared to the welding condition in general, is required. -In case of applying MIG and TIG process, of the filler metal used, the Cusi₂Mn produced the excellent metallurgical trait of brazed joint. When CuAl8 filler metal was used, the formation of Fe-rich phase of FeAl system due to the familiarity between Fe and Al harmed the trait of brazed joint. However, in case of applying the optimal brazing condition for the two processes, the formation of Zn coating free zone between the brazed joint and the base material, coming out of the existing welding process using Oxygen-Acetilen and CO₂, was restrained, and at the same time, the brazed joint of good quality was obtained due to the low brazed temperature formed by the melting temperature of applied filler metal lower than the base material Fe.

조기 정상임신 태낭발육의 초음파 단층상

배석천,정윤조,이용선,노영철 대한산부인과학회 1976 대한산부인과학회 학술대회 Vol.38 No.-

열교환기용 AIMgSi1.0 합금의 접합부 강도 특성 개선에 관한 연구

배석천 啓明大學校 産業技術硏究所 1996 産業技術硏究所 論文報告集 Vol.19 No.1

The application of aluminum alloy has been gradually increased as the variety of industrial structures, anti-pollution, low fuel cost and recycling of used material are required to modern society. Especially, the application of the brazing process as a new joining technology has been increasing in the case of a complicated product like heat exchange facility. To serve the need, this investigation introduces the comparison of torch brazing process was furnace brazing process where AlSil2, ZnAl5 filler metal and flux(F600), flux(F400M) were applied to the base material, AlMgSil.0. The result of the experiment showed that the specimen in which furnace brazing process was applied with AlSil2 filler metal and flux(F600) had more excellent mechanical and metallurgical properties. According to our result, the most important factor of brazed seam characteristics of AlMgSi1.0 alloy was the effect of flux. The ZnAl5 filler metal, when compared to AlSi12, had an excellent strength property which was as strong as AlSi12 filler metal at 200℃. However, the application problem has occurred due to the low fatigue strength.

Inconel 600 접합용 적정용가재 성분계 설정에 관한 연구

배석천 啓明大學校 産業技術硏究所 1997 産業技術硏究所 論文報告集 Vol.19 No.2

The main objective of this study is to develope the insert metal foil for joining Ni-base heat-resistant alloys. As the purpose of the project, joining the materials such as Inconel 600, a studied by using commercial brazing insert metals. The brazed interface was analyzed and the effect of alloying elements on spreadability and strength was investigated. The suitable components of insert metals for joining Inconel 600 were selected by evaluating these properties. These properties including microstructures were compared with the developing insert metals of Ni-Zr-Cr for Inconel 600 and which were produced experimentally in the laboratory.

비정질 용가재를 이용한 Ti 및 TiAl6V4 합금의 고온 브레이징 접합부 특성에 관한 연구

배석천 啓明大學校 産業技術硏究所 1992 産業技術硏究所 論文報告集 Vol.15 No.1

A simple process for the brazing of Titanium materials has been developed by using an amorphous filler metal at high temperature brazing process. The filler matal is used in form of a metallic glass. The surfaces treatment, which is necessary for existing brazing procedure, is no more needed. In addition to that, diffusion annealing and aging of specimen at elevated temperatures is no more necessary after brazing is completed. The brazed joionts chow excellent mechanical and electrochemical properties. The developed method not only simplifies and improves the brazing process for Titanium and Titanium alloys, but also saves 80 to 90% of time and expenses compared with the conventional processes.

AlZnMgCu0.5 합금의 Electron Beam 용접성에 관한 연구

배석천 대한용접접합학회 1997 대한용접·접합학회지 Vol.15 No.4

The high strength AlZnMgCu0.5 alloy is a light metal with good age hardenability, and has a high tensile and yielding strength. Therefore, it can be used for structures requiring high speciple strength. Even though high strength AlZnMgCu alloy has good mechanical properties, it has a lot of problems in TIG and MIG welding processes. Since lots of high heat absorption is introduced into the weldment during TIG and MIG processes, the microstructural variation and hot cracks take place in heat affected zone. Therefore, the mechanical properties of high strength AlZnMgCu0.5 alloy can be degraded in weldment and heat affected zone. Welding process utilizing high density heat source such as electron beam should be developed to reduce pore and hot cracking, whichare usually accompanied by MIG and TIG welding processes. In this work, electron beam welding process were used with or without AlMg4.5Mn as filler material to avoid the degradation of mechanical properties. Mechanical and metallurgical characteristics were also studied in electron beam weldment and heat affected zone. Moreover hot cracking mechanism was also investigated.

자연피임법으로서의 배란법의 피임효과

배석천,정윤조,나종구,오원섭,김승조,Bae, S.C.,Chung, Y.J.,Rha, J.G.,Oh, W.S.,Kim, S.J. 대한생식의학회 1976 Clinical and Experimental Reproductive Medicine Vol.3 No.1

In recent years, explosive increase in population has been damaging mankind in terms of deprivation of natural resources and more of economical demands. Therefore, we have thought about problems as to counter-balance the increasing population, and reached a resolution of artificial methods of controlling birth. In the past, though now used in some of contraceptive methods, extravaginal ejaculation, condom were commonly used. But recently, pills, IUD and several kinds of operative procedures are quite popular. Though the recent methods are known to be effective compared with the traditional methods, a certain unwanted side effects as well as limited value of usages now must be discussed. On this aspect, we are trying to research for a ideal methods such as symptom free, more of natural way of family planning and try to zero the failure rate. And also it has been suggested that only if those scientific methods of controlling birth can be base on religious concepts of moral being, it will be enlightened. At the Happy Family Planning Clinic of St. Mary's Hospital, we apply Billing's ovulation method to out-patients who want contraception and usually advise them to use it on a self-care basis. For a retrospective study of the presurvey data analysis and use-effectiveness of the ovulation method from April 1, 1975 to Nov., 30, 1975, we have dealt with a total of 1,383 women (urban areas 465, rural areas 918). The results of preliminary survey were as follows; 1) Among 465 women in Seoul areas, the failure rate was 10.3, which signified unplanned pregnancies of 32 women. 27 of the 32 women were pregnant due to the users own failure and the remaing 5 due to the failure of the method. Therefore, the failure of the method accounted for 1.6. 2) Among 918 women in rural areas, the failure rate was 15.2 signifing unplanned pregnancies in 93 women. The cause of the failure in 81 of the 93 women was attributable to the user's own mistake and that in the remaing 12 to the default of the method. Therefore, the failure attributable to the method accounted for 2.0.