연속주조압연으로 제조한 Stainless 강판의 조직 및 기계적 성질

조성석 忠南大學校 産業技術硏究所 1986 산업기술연구논문집 Vol.1 No.1

Using the twin-roller type melt-quenching technique the effects of pouring temperatures on the microstructures and mechanical properties of stainless steel have been investigated. The melt-rolled stainless steel strips have the columnar(surface) and equiaxed grains(center) which became finer with increasing pouring temperature. But the hardness of these steels, which is about 295DPN, remains almost unchanged with grain size refinement. Hardness and ultimate tensile strength increased with increasing heat treatment temperature.

비정질 Co-B 합금의 기계적 성질 및 비전기저항의 조성의존성

조성석,김택기,김윤배,김영전 대한금속재료학회(대한금속학회) 1980 대한금속·재료학회지 Vol.18 No.4

비정질 Co_(100-)_xB_x 합금의 기계적 및 전기적 성질에 미치는 보론 함량의 영향을 조사하였다. 19≤x≤27at.% 범위에서 파괴응력, 특성계수, 인장인성, 경도 및 전기저항의 조성 의존성을 조사하였다. 실험 결과에 의하면 Co_(100-)_xB_x계 합금의 비정질 가능 조성 범위는 19≤x≤27at.%이고, 탄성계수는 1.3×10⁴∼1.9×10⁴㎏/㎟이었다. 파괴응력은 200∼260㎏/㎟이며 인장인성은 약 1.6∼1.8㎏-㎜/㎣이다. 경도는 Hv600∼900(200g하중)이다. 비정질 상태에서의 비전기저항은 약 1×10^(-4)∼1.2×10^(-4)Ω-㎝이고 열처리 후의 결정화 상태에서는 1×10^(-5)∼1.5×10^(-5)Ω-㎝로 변하였다. 결정화 온도의 농도 영향은 360∼430℃로 보론 함량이 증가함에 따라 증가하였다. The effect of composition on the mechanical and electrical properties of the amorphous Co_(100-)_xB_x in composition range x=19∼x=27 has been investigated systematically. The fracture stress, the Young's modulus, the toughness, the Vickers hardness and the electrical resistivity of amorphous Co_(100-)_xB_x showed tendency to increase with increasing boron content. The crystallization temperature of amorphous Co_(100-)_xB_x was raised with increasing boron content.

쌍롤법에 의해 제작된 고규소 강판의 자기적 특성

조성석,구자명,김학동 대한금속재료학회(대한금속학회) 1988 대한금속·재료학회지 Vol.26 No.9

The magnetic properties and the structure of high silicon steel sheets (3wt%-6.5wt%Si) prepared by the twin roller-quenching method were investigated. The columnar grains about 5-7㎛ in diameter were observed in the as-prepared sheets and the columnar grains grew from the surface to the center part of the sheet. In the as-prepared sheet, the coercive force was 1.05 Oe for the 6.5 wt%Si-Fe sheet, and the average mag netic iron loss W_(15/50) and W_(10/50) of the sheets having the coercive force of 1.05 Oe was 1.50 W/㎏ and 0.46W/㎏ respectively.

급속응고된 알루미늄합금 분말의 압출가공시 Cold compact 의 Preheating 에 관한 연구

조성석,이태행 대한금속재료학회(대한금속학회) 1991 대한금속·재료학회지 Vol.29 No.3

Preheating processes before the extrusion of rapidly solidified Al-7.9wt%Zn-2.4wt% Mg-1.5wt%Co-0.92wt%Ni alloy powders were studied. Cellular dendrite structures of aluminum alloy powders are found to be decomposed when cold compacted powders are preheated at the temperatures above 490℃. In an aluminum alloy preheated at 490℃ and hot extruded, the density of pores is lower than 0.1% and the maximum diameter of pores is less than 1㎛. The grain size of the aluminum alloy is less than 1㎛ and fine oxide particles are dispersed uniformly within grains and at grain boundaries. After solution (490㎛/1hr) and aging (120㎛/1hr) treatments, the room temperature yield, strength tensile strength and elongation of the aluminum alloy are 71.9㎏/㎟, 76㎏/㎟ and 5.0%, respectively.

Co, Ni 로 개량되어 급속응고된 P/M 7075 알루미늄 합금의 조직 및 기계적 성질

조성석,이태행,조성길 대한금속재료학회(대한금속학회) 1991 대한금속·재료학회지 Vol.29 No.3

The main objective aim of this study is to improve mechanical properties of a 7075 aluminum alloy. The alloy composition of a 7075 alloy was slightly modified. To enhance the precipitate hardening effect the content of zinc was increased by 2wt% also, 1wt% cobalt and 1wt% nickel were added to provide the dispersion hardening effect. These alloys were prepared by rapid soidification and hot extrusion. The experimental results suggest that newly developed P/M aluminum alloys exhibit much higher tensile strength than an I/M 7075 alloy. Especially, the alloys produced from fine powders show higher tensile strength and elongation compared to those from coarse powders. Improvements in tensile strength are attributed to suppression or elimination of coarse secondary phases, refinement of grain size and homogeneous distribution of fine precipitate particles, Co₂Al_9, Al₃Ni and oxide particles.

(Fe, Co) 73.5 Nb3Cu1Si13.5B9 합금의 초미세결정립형성 및 연자기적 특성

조성석,김택기,권혁무,조용수,이갑호 대한금속재료학회(대한금속학회) 1992 대한금속·재료학회지 Vol.30 No.10

Ribbon-shaped amorphous Fe_(73.5-X),Co_XNb₃Cu₁Si_(13.5)B9(0≤X≤25, ΔX=5 at%) alloys prepared by rapidly quenching technique were annealed above their crystallization temperatures. The annealed Fe_(73.5-X)Co_XNb_₃Cu_₁,Si_(13.5)B_9 alloys tranformed into nanocrystalline in all range of X. Nanocrystalline Fe_(73.5-X)Co_XNb₃Cu_₁Si_(13.5)B_9 alloys annealed under optimum condition show the highest saturation magnetization and the lowest AC coercive force(f=1 ㎑, Ha=5 Oe) and core loss(f=100 ㎑, B_m0.5T) at X=5, But the initial permeability(f=1 ㎑, Ha=1 mOe) shows maximum value at X=0. An average grain size of α-Fe(Si) showing excellent soft magnetic properties is around 10 nm and increases with Co content. The degradation of soft magnetic properties during the intial crystallization process is due to the Fe-rich amorphous phase retained at grain boundary.

Ni基 超合金 Waspaloy의 再結晶에 미치는 初期 r' 크기의 영향(1)

조성석 충남대학교 공업교육연구소 1984 論文集 Vol.7 No.1

The effects of initial r'-size on the recrystallization behaviour of waspaloy have been studied by transmission electron microscopy. The deformed structure of I hour -aged specimen has more homogeneous and fine intersecting slip lines than that of 24 hour-aged specimen. These lead to the increase in sites of nucleation and the growth rate of the recrystallization front. Bypassing of migrating front due to high deformation accelerates the recrystallization of Waspaloy.

고강도 용접용 P/M Al-Mg-Cr 압출재의 미세조직 및 인장성질

조성석,강영곤,김득연 대한금속재료학회(대한금속학회) 1994 대한금속·재료학회지 Vol.32 No.7

A study has been performed on rapidly solidified Al-Mg-Cr alloy as a candidate for engineering applications requiring high strength and weldability. The objective of this work was to investigate the development of microstructure during extrusion snd tensile properties. This work has been achieved by employing a combination of X-ray diffraction, transmission electron microscopy, differential scanning calorimeter, and instron universal testing machine. The P/M Al-Mg-Cr alloy has a much finer grain and precipitates size than does I/M 5083. Through a combination of DSC and X-ray analysis obtained from Al-Mg-Cr powder and X-ray analysis from Al-Mg-Cr extrudate, the precipitate phase of being contributed to tensile strength of the extrudate is Cr₂Mg₃Al_(18).

정도관리를 위한 요침사의 화학적 보존방법

조성석,김명수,신경아 대한임상검사과학회 2017 대한임상검사과학회지(KJCLS) Vol.49 No.4

There is greater standardization of quality control for microscopic examination of urine than for physicochemical test. In this study, we investigated whether it is possible to control the sediment accuracy by microscopic examination through the real thing by preserving the essential sediment with glutaraldehyde, which is required for the rationality of sediment quality control. A urine specimen was prepared using 2.5% glutaraldehyde as a preservation solution. Samples treated with urine preservatives confirmed the morphological deformation of the cells for four weeks at intervals of one week and confirmed whether they should be preserved for 4 weeks thereafter. After preparing the required sediment slide, two more slides were produced; one was stored in a refrigerator for, and the other was stored at room temperature. The morphological deformation of the specimen was confirmed. Glutaraldehyde has the effect of preserving the refrigerated essential sediments and storing them for up to 8 weeks, refrigerated storage after slide production, stabilized by 3 days. Moreover, after treatment with preservatives, the production of the slide and comparison between the measured values between the laboratories and examiners showed a low consistency. In conclusion, we showed that the urine sediment components can be preserved, and it can be used for quality control and education through real objects. 요침사 검사는 물리화학적 검사보다 정도관리의 표준화가어려운 실정이다. 본 연구에서는 요침사 정도관리의 합리성을위해 요침사 보존제인 글루타르알데히드로 요침사를 보존하여실물을 통한 현미경 검사로 요침사 정도관리가 가능한지를 알아보고자 하였다. 2.5% 글루타르알데히드를 보존액으로 하여표본을 제작하였다. 보존제를 처리한 검체는 1주일 간격으로 4 주간 세포의 형태학적 변형을 확인하였고, 이후 4주간은 보존여부를 확인하였다. 요침사 슬라이드 제작 후 2개의 슬라이드를제작하였으며, 하나는 냉장보관, 다른 하나는 실온 보관하여 검체의 형태학적 변형을 확인하였다. 글루타르알데히드는 요침사를 냉장 보관하여 8주까지 보존하는 효과가 있었으며, 슬라이드 제작 후에는 냉장 보관하여 3일까지 안정한 것으로 나타났다. 또한 보존제 처리 후 슬라이드 제작하여 검사실간, 검사자간판독을 비교한 결과 낮은 일치도를 보였다. 결론적으로 본 연구를 통해 요침사 성분을 보존할 수 있으며, 실물을 통한 정도관리및 교육용으로 활용될 것으로 기대된다.

의료기관 평가와 의료의 질 향상 -진료지원 분야-

조성석,Jo, Seong-Seok 한국의료질향상학회 1995 한국의료질향상학회지 Vol.2 No.1