자동차 바디용 강판의 열처리 특성에 관한 연구

김순경,김문경,전언찬 東亞大學校 1998 東亞論叢 Vol.35 No.-

As demand for various kinds and small lot products has been increasing, batch annealing has been appreciated for its small restriction for the operation. The cold spot of the coil is very important in the BAF(Batch annealing furnace) annealing process. Because of the annealing cycle time in the BAF, annealing was decided on the cold spot of the coil Development on the mechanical properties of steel sheet for the automobile body panel is very important in the BAF annealing process. Because of the heat treatment method in the BAF, mechanical properties was decided on the heat treatment method of the coil. So, we tested on the development of mechanical properties according to heat treatment method at the annealing furnace using the Ax atmospheric gas and the HNx atmospheric gas. As a result of several investigations. We confirmed the following characteristics mechanical properties was changed under the influence of the annealing cycle and the atmospheric gas. The cold spot of coil was the mid point of the B coil in the Ax atmospheric gas. And, atmospheric gas is very important in the high convection annealing furnaces. And so, we tested the effect, variation of cold spot, for hydrogen contents of atmosphric gas at the annealing furnace. As a result of several investigations. We confirmed the following characteristics after the heating and soaking, the cold spot of coil moved to 1/3 of coil thickness in the HNx atmospheric gas, but the mid point of the coil thickness is the cold spot in the Ax or H2 atmospheric gas. Therefore, the use of hydrogen instead of nitrogen as the protective gas, combined with high convection in batch annealing furnaces, has shown that considerable increases n furnace output and material quality are attaninable. Owing to the low density, high diffusion and reducing character of hydrogen, a better transfer resulting in uniform material temperatures and improved coil surfaces can be achieved.

작업롤의 파손과 크롬함량에 따른 마멸특성

김순경,전언찬,이승수,김문경 동아대학교 공과대학부설 생산기술연구소 1996 生産技術硏究所硏究論文集 Vol.1 No.2

Work rolls used in cold rolling mills must have outstanding wear resistance and very little plastic deformation. Thus, these rolls require a higher surface hardness and hardening to a greater depth. To meet these requrements, the rolls, in general, have basic chemical composition of 0.7 to 1.0% carbon and 1.0 to 5.0% chromium(Cr), plus a small amounts of special elements, and are subjected to intensive water quenching and tempering at low temperature to provide a surface hardness of over 90 shore. This test results are as follows. Deflection and fracture load of 5% Cr material are than those of 3% Cr material and show flat curve from surface to subsurface. It will be clear that 5% Cr work roll has a superior resistibility against wear and abrasion comparing with 3% Cr work roll. The improvement of wear and abration in 5% Cr work roll will be achieved by the large amount of spheroidal carbide. In grindability and polish, 5% Cr work roll will be a little inferior comparing with 3% Cr work roll.

프리셉터 경험이 간호업무수행과 직무만족에 미치는 영향 연구

류언나,송혜숙,장은희,서효신,추연화,김인선,나명주,지성애,박경숙 중앙대학교 간호과학연구소 2001 중앙간호논문집 Vol.5 No.2

The purpose of this study was to investigate how preceptor experience has an effect upon preceptor nurses. This study was so designed that it could compare the difference between clinical performance and Job satisfaction of preceptor nurses and those of nonpreceptor nurses. Study subjects were sampled out from those nurses who worked with two university hospitals where preceptor programs were implemented. The number of subjects totaled to 134, including 69 preceptor nurses and 70 nonpreceptor nurses. The score of preceptor nurses' clinical performance and job satisfaction revealed a higher value than that of nonpreceptor nurses. A similar result was also shown in the subdomains. However these difference were not statistically significant. Among all of the preceptor nurses, the highest number of preceptor experience was just one time. Except for five times in preceptor experience, the more the number of times of preceptor experience, the higher score in clinical performance. It was manifested that the number of preceptor experience was not related to job satisfaction. The score of preceptor nurses' clinica1 performance and job satisfaction revealed a higher value than that of nonpreceptor nurses. A similar result was also shown in the subdomains. However these difference were not statistically significant. The reward that preceptor nurses wished most was a reduction of the work load assigned to them. Currently preceptor nurses are only receiving a small quantity of financial reward related with their preceptor role. Most of preceptor nurses (96.8%) were not satisfied with their existing reward. Almost half of the preceptor nurses(43.5%) did not want to play a role as preceptor again. The reason why the scores of clinical performance and job satisfaction were low might be attributed to the inadequate preceptor training program and reward system. Appropriate knowledge and clinical skill are expected to enhance the level of preceptor nurses' clinical performance and appropriate internal and external reward to elevate the level of preceptor nurses' Job satisfaction. Therefore, it is needed for us to develop more effective preceptor education program, financial reward, support of colleague nurses and nursing managers, and adjust workload for the purpose of more effective preceptor programs.

BAF Annealing에서 저온점의 온도변화에 관한 연구

김순경,이승수,김문경,전언찬 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.2

As demand for various kinds and small lot products has been increasing, batch annealing has been appreciated for its small restriction for the operation. The cold spot of the coil is very inportant in the BAF(Batch annealing furnace) annealing process. Because of the annealing cycle time in the BAF, annealing was decided on the cold spot of the coil. So, we tested the effect, variation of cold spot, for hydrogen contents of atmospheric gas at the annealing furnace. As a result of several investigations. We confirmed the following characteristics ; after the heating and soaking, the cold spot of coil moved to 1/3 of coil thickness in the HNx atmospheric gas, but the mid point of the coil thickness is the cold spot in the Ax or H₂atmospheric gas. Therefore, the use of hydrogen instead of nitrogen as the protective gas, combined with high convection in batch annealing furnaces, has shown that considerable increases in furnace output and material quality are attainable. Owing to the low density, high diffusion and reducing character of hydrogen, a better transfer resulting in uniform material temperatures and improved coil surfaces can be achieved.

냉간 압연용 작업롤의 제조 기술에 따른 특성

전언찬,김문경,김순경,이충엽 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1

75% H₂BAF의 소둔특성에 관한 연구

김순경,전언찬 동아대학교 공과대학 부설 한국자원개발연구소 1995 硏究報告 Vol.19 No.2

A cold spot temperature control system for the BAF(batch annealing furnace)has been established in order to reduce energy consumption to improve productivity and stabilize the properties of products. Therefore we confirmed for the improving of material quality (eq. even and consistent tempering, high surface cleanliness, reduced carbon depositing etc.), increasing of output, comparison of annealing cycle time, reducting of annealing cost and distrubition of cold spot temperature according to BAF type. The use of hydrogen instead of the protective gas, combined with high convection in batch annealing furnaces, has shown that considerable increases in furnace output and material quality are attainable. Owing to the low density, high diffusion and reducing character of hydrogen, a better transfer resulting in uniform material temperatures and improved coil surfaces can be achieved.

분위기 가스가 냉연강판의 성형성에 미치는 영향

김순경,이승수,전언찬 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.1

Development on the mechanical properties of steel for the automobile body panel is very important in the BAF(Batch annealing furnace) annealing process. Because of the heat treatment in the BAF, mechanical properties was decided on the heat treatment method of the coil. So, we tested on the development of mechanical properties according to heat treatment method at the annealing furnace using the Ax atmospheric gas and the HNx atmospheric gas. As a result of several investigation. We confirmed the following characteristics ; mechanical properties was changed under the influence of the annealing cycle and the atmospheric gas. And, We have some result according to heat treatment method. 1. elongation one of the mechanical properties was good NHx BAF than Ax BAF. 2. The cost of heat treatment was expensive HNx BAF than Ax BAF. We will arrange a annealing cycle in order to gain a good quality of CQ and DDQ Sheet. Because Even if we save a cast, mechanical properties were no better.

자동차 차체용 Galvalume 강판의 용접성에 관한 연구

김순경,김민주,전언찬 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.1

An extensive corrosion study was initiated by galvalume steel sheet manufacturing company to clarify the corrosion behavior of zinc and zinc-alloy coated automotive sheet steel in out panel and electrical application. Since the early 1980's the use of zinc and aluminum alloy coated steel for vehicular corrosion protection has increased dractically. Car and electonic products makers, however, are not consistent in their choice of specific galvalume types or coating weights. This paper presents an overview of the program and some initial test results on the of weldability, lifetime on the electode tip shape of spot welder and corrosion protection.

저탄소강의 풀림 사이클에 대한 예측 프로그램 개발

김순경,이승수,김문경,전언찬 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.2

The cold spot of the coil is very important in the BAF(Batch annealing furnace) annealing process. Because of the annealing cycle time in the BAF, annealing was decided on the cold spot of the coil. So, we tested the temperature variation of cold spot and the correctness of computer simulation at the annealing furnace using the Ax atmospheric gas. As a result of several investigations. We confirmed the following characteristics ; Annealing cycle was changed under the influence of the strip surface condition and the strip tension. The cold spot of coil was the mid point of the B coil in the Ax atmospheric gas. And, the power of recirculation fan is very important in the high convection annealing furnaces.

冷間壓延用 作業 롤의 Spalling 發生原因에 관한 硏究

全彦燦,全泰玉,金舜經 동아대학교 공과대학 부설 한국자원개발연구소 1995 硏究報告 Vol.19 No.2

A study on the spalling causes of work roll for cold rolling was performed in the cold rolling mill. Performance of work roll is dependent to a great extent on spalling so that both roll manufacturers and users show great interest in spalling. So this paper shows that spalling phenomena were investigated and causes determined because of more than 85% of spalling has its origin on the roll surface. As being well known, spalling mostly occurred due to developing fatigue fracture originated a crack on a roll. But such spalling can be prevented by proper roll maintenance. The spalling accidents have sharply decreased since 1981 because of the use of ultrasonic test to detect cracks on a roll.