결정립 미세화된 Cu-Zn-Al 형상기억합금의 열처리 조건에 따른 변태거동

강조원,장우양,양권승 ( J . W . Kang,W . Y . Jang,G . S . Yang ) 한국열처리공학회 1991 熱處理工學會誌 Vol.4 No.4

A small amount of misch metal and/or Zr was added as a dopant to 70.5wt%Cu-26wt%Zn-3.5wt%Al shape memory alloy in order to study the effect of grain refinement and heat treatments on the transformation behavior, stabilization of martensite, and shape memory ability. It was found that the addition of misch metal and Zr was very effective for reducing the grain size. The fracture mode has been changed from intergranular brittle fracture to ductile fracture with void formation and coalescence by the addition of misch metal and Zr. Aging of the β-phase decreases the M_5 temperature, but that of the martensite phase increases the A_s temperature. The hysteresis of transformation temperature ΔT(A_s-M_s) has an increasing tendancy by grain refinement. The crystal structure of martensite was identified as monoclinic structure. As the grain size decreased, martensite stabilization more easily occured and the shape, memory ability has been reduced by the grain size refined.

중간 및 최종크기의 지로카로이 피복관의 β-quenching에 의한 부식 및 기계적성질의 변화

강조원 조선대학교 생산기술연구소 1987 生産技術硏究 Vol.9 No.1

The mechanical properties and corrosion resistance of zircaloy-2 by using β-quenching in intermediate or final size were investigated. The results obtained in this paper are as follows; 1. β-quenching in intermediate or final size improved the 470 to 500℃ high-pressure steam corrosion resistance of zircaloy-2 cladding tubes. 2. β-quenching treatment prior to the final cold rolling leads to creep strength at 400℃ because of an effect of hardening by precipitation of small second-phase particles formed during β-quenching.

鑄型 및 中子의 乾燥에 관한 硏究

姜朝遠 조선대학교 생산기술연구소 1979 生産技術硏究 Vol.1979 No.-

In the drying of mold and core, the effects of drying temperature, humidity, thickness of mold, permeability, wind velocity, and wind direction on drying rate were investigated. The results obtained in this study were as follows; 1. The drying time of mold and core was decreased with the increase of drying temperature, that is, the drying time of mold and core at 240℃ and 400℃ were 50 minutes, 25 minutes respectively. 2. The effect of temperature in the second and tertiary period of drying(in Fig.2) was very weak. 3. The drying rate was independent of thickness of mold in the first period of drying-(in Fig.2)while in the tertiary period of drying it was inversely proportional to thickness of mold. 4. Drying time(T) of the mold and core coincided with T=Kd^(1·5-1·8). 5. The specimens of low permeability were more effected by drying temperature than those of high permeability were done. 6. The dryng time was decreased with the increase of wind velocity.

高速度鋼의 熱處理에 의한 硬度變化

강조원 朝鮮大學校 1977 綜合論文集 Vol.1977 No.-

本 實驗에서는 高速度鋼(SKH-2 SKH-3)을 사용하여 소정의 熱處理 溫度에서 熱處理한후 硬度와 ??을 조사하였다. 이때 最適의 熱處理 조건을 얻기위한 熱處理 溫度 및 維持時間은 SKH-2에 있어서는 quenching-temp 1290℃×5分 tempering-temp 580℃×20分 이였으며 이때 硬度 H??-64에 달했다. 그리고 SKH-3에 대해서는 quenching-temp 1310℃×5분 tempering-temp 570℃×20分 590℃×20分 이였으며 H??-63와 65를 각각 얻었으며 이들 硬度는 切削을 위한 공구로서 가장 理想的인 값을 얻었다. In this paper, investigated the hardness and metallurgical microscopic structure of the high speed steel (SKH2. SKH3) by Heatreatment. The best Conditions of heat treatment of SKH-2 and SKH.3 were 1290℃×5min. quenching, 580℃×20min. tempering and 1310℃×5min. quenching, 570℃×20min and 590℃×20min tempering. The results obtained were as follows, H??-64 in SKH-2 and H??-63, H??-65 in SKH-3, respectively.

熱處理의 缺陷과 그 對策 : Especially on oxidation and decarburization Quenching crack temper brittleness

姜朝遠 朝鮮大學校 工科大學 1972 論文集 Vol.1 No.-

表面硬化鋼의 Cas-Carburinzing에 關한 硏究

姜朝遠 조선대학교 생산기술연구소 1978 生産技術硏究 Vol.1978 No.-

表面硬化鋼에 Gas-Carburizing을 행한후 Carbon-Potential에 의한 硬度의 變化와 Carburizing-time에 의한 硬度의 변화 Carburizing-temperature에 의한 硬度 변화를 조사 硏究하였다. 본 實驗으로 부터 얻어진 結果는 다음과 같다. 1) Carbon-Potential이 높은 경우 Carburinzing-layer도 깊고 表面 硬化도 높은 것을 얻었다. 2) Carburizing-time이 길고 Carburizing-temperature가 높은 경우에 우수한 表面 硬度가 얻어졌다. 가장 理想的인 Carburizing-time과 Carburizing-temperature는 930℃×16h 였다. 3) 결국 Gas-Carburizing에 의한 硬度變化는 Carburizing-time과 Carburizing-temperature에 의해 크게 좌우 되었다. In this paper after Gas-Carburizing Several kinds of case Hardening steel by using Gas-Carburizing furnace. The change of the Relation between hardness and carbon-potential, carburizing time, and carburizing temperature was investigated. The important results are as follows. 1) Deep carburizing and High-surface Hardness were formed in the case of High-carbon Potential. 2) Excellent Surface Hardness was obtained in the case of High-carburizing temperature and long carburizing time. The Best ideal carburizing was in case of 930℃ X 16hrs. 3. It is concluded that the change of Hardness by Gas-Carburizing depends on the carburizing time and temperatare.

Cu-Zn-Al 형상기억합금의 변태특성 및 기계적 성질에 미치는 Misch Metal 첨가효과

강조원,장우양,양권승 조선대학교 동력자원연구소 1989 動力資源硏究所誌 Vol.11 No.2

Misch metal was added as dopant to a Cu-26.5 wt% Zn-3.5 wt% Al shape memory alloy in order to study its effect on grain refinement, transformation characteristics, mechanical properties and shape memory effect. It was founded that misch metal is very effective in reducing grain size. The coarse grains with size above 1000㎛ were refined up to the size of 40㎛ by only 0.8wt% misch metal addition. The grain growth rate was also decreased with the increasing misch metal content. Influence of grain size on the mechanical properties was investigated by tensile testing. The ultimate tensile strength and elongation below Mf temperature were increased with the decreasing grain size. The SEM observation of the tensile fracture surface revealed that fracture mode changed from the intergranular fracture to the transgranular fracture by the grain refinement. Transformation temperatures decreased with the increasing misch metal content. And the addition of misch metal had a little influence on the recovery rate of shape.

Cu-Al-Ni-Ti-Mn 합금의 변태특성 및 기계적 성질에 미치는 가공열처리의 영향

강조원,장우양,양권승,이영수,곽사호,김춘동,백승남 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The distribution of the second phase, the change of transformation temperature and mechanical properties with thermomechanical treatment conditions were investigated by metallography, calorimetry, EDS, tensile test and fractography in a Cu-Al-Ni-Ti-Mn alloy. The cast structure revealed Ti-rich precipitates(X_L phase) between dendrite arms, which have been identified as (Cu,Ni)₂TiAl intermetallic compounds. By homogenizing above 900℃, the X_L phase was melted in the matrix, while the X_s phase was precipitated in matrix and the volume fraction of it was increased. When hot-rolled specimen was betatized below 750℃, recrystallization could not be observed. However, the specimen betatized above 800℃ was recrystallized and the grain size was about 50㎛, while X_s phase was precipitated in matrix. With raising betatizing temperature, M_s and A_s temperatures were fallen and transformation hysteresis became larger. The strain of the specimen betatized at 800℃ was 8.2% as maximum value. The maximum shape recovery rate could be obtained in the specimen betatized at 800℃ but it was decreased due to the presence of X_s phase with increasing betatizing temperature.

새로운 진공침탄 기술

강조원,장우양 한국열처리공학회 2003 熱處理工學會誌 Vol.16 No.1

超硬質用 WO₃의 焙燒에 있어서의 不純物이 미치는 影響과 製造條件에 따르는 粒度의 影響

趙煥從,郭士濩,姜朝遠 朝鮮大學校 工科大學 1973 論文集 Vol.2 No.-

It is very difficult to control quality or recovery in chemical metallurgy industry. It is compararatively easy to contrel it if we can find out various factors that have effects on the quality by experiments, but there will be difficult and complex things in actual experiments. So we must find out the variety and the mutual actions of all the processes, though the result of experiment and plant and plant productions do not always coincide with each other, With such aims we executed the following experiments.