微量元素를 添加한 Al-Zn-Mg 合金에 관한 硏究(Ⅱ)

白勝男,高濟晩 조선대학교 동력자원연구소 1986 動力資源硏究所誌 Vol.8 No.1

The investigated results of the trace additional elements which is affected in precipitation phenomena of Al-Zn-Mg alloys by the hardness or electrical resistivity measurements related with vacancies, dislocations and lattice defects of grains boundary was as follows. 1. The precipitation hardening of Al-Zn-Mg alloys was reduced remarkably due to the addition of Cr, Zr, Mn and the crystal defects of increased dislocation, sub-boundary, grain boundary and insoluble compounds was acted as sinks which has decreased the concentration of quenched-in vacance by these additional elements. 2. The addition of copper and the pre-aging at low temperature has affected greatly in the precipitation hardening increased of Al-Zn-Mg alloys ; and these phenomena are resulted from the increased number of G.P Zone which is capable of acting as the heterogeneous nucleation of precipitates.

國産成形 코크스를 燃料로한 Cupola의 熱精算

白勝男 조선대학교 생산기술연구소 1978 生産技術硏究 Vol.1978 No.-

國産成形 코크스를 燃料로 操業한 Cupola(이하 本爐라함)에서 얻은 測定値를 가지고 熱精算한 結果를 無煙炭을 燃料로 操業한 Cupola(이하 無煙炭爐라함)의 熱精算과 比較하여 다음과 같은 結果를 얻었다. 1) 같은 熱風溫度에서 送風으로부터 오는 熱量은 無煙炭爐의 경우 全入熱中의 6.35% 였으나 本爐에서는 8.74%였다. 2) 金屬의 酸化熱은 Mn과 Fe는 거의 같았으나 Si에 依한 酸化熱은 無煙炭爐에서는 3.94%였고 本爐에서는 1.51%였다. 3) 熔湯이 가져가는 熱은 無煙炭爐의 경우 15.22%였으나 本爐에서는 15.19%였다. 4) 石灰石 分解에 依한 熱損失은 無煙炭爐가 1.68%, 本爐에서는 1.60%였다. 5) Slag가 가져가는 熱은 無煙炭爐가 3.03%였고 本爐에서는 3.42% 였다. 6) 爐頂gas中 co의 煙燒熱은 無煙炭爐가 39.63% 本爐가 5.83%였다. 7) 放射傳熱,爐體蓋熱,造倖 기타의 경우 熱損失은 無煙炭爐가 34.49%였으며 本爐가 33.75% 였다. 8) 溶解效率은 無煙炭爐가 17.09%. 本爐가 17.86%였다. 9) 燃燒效率은 無煙炭爐가 55.5%. 木爐가 57.79% 였다. The results of heat balance both by data from cupola operation using domestic sintered coke as fuel and by those of cupola operation using anthracite was compared with each other and investigated. The results obtained are summarized as follows : 1) The calory from hot blasts of the same temp. was 8. 74% in sintered coke-cupola operation but 6.35% in anthracite-cupola. 2) The heat of oxidation was the same in Mn and Fe, but the heat of oxidation by silicon was 3.94% and 1.51 % in anthracite-cupola, and sintered coke-cupola, respectively. 3) The heat taken away by molten metal was 15.22% in anthractite-cupola, while 15.91% in sintered coke-cupola. 4) The heat loss by the decomposition of limestone was 1.68% III anthracite -cupola but 1.60% in sintered coke-cupola. 5) The heat taken away by slag was 3.03% in anthracite-cupola, but 3.42% in sintered coke-cupola. 6) The combustion heat of carbon monoxide of furanace top gas was 39.63% in anthracite-cupola but 35.83% in sintered coke-cupola. 7) The heat of emission and conduction, furnace body and slagging, etc. was 34.49% and 33.75% in anthracite-cupola and sintered coke-cupola respectively. 8) The efficiency of melting was 17.09% and 17.86% in anthracite-cupola and sintered coke-cupola. respectively. 9) The efficiency of combustion was 55.5% and 57.79% in anthracite-cupola and sintered coke-cupola, respectively.

Al-Li 합금의 시효석출에 미치는 Cu, Mg 및 Zr 첨가의 영향

백승남,김종원 조선대학교 생산기술연구소 1995 生産技術硏究 Vol.17 No.2

The purpose of this study is to improve the low toughness of Al-Li binary alloy which is expected to be widely used for the structural materials of the aircraft and light industry. For the sake of improvement addition Cu, Mg and Zr were together added. The kind of shape and variation of precipitation phase formed by age precipitation in alloy with addition element and the mechanism of nucleation were closely examined. The above were carried out through investigation of the variation of mechanical properties such as tensile strength, yield strength, hardness and elongation, microstructure by TEM, and the formation and dissolution of precipitate by thermo analysis. 1. For Al-Li-Cu-Mg-Zr porynary alloy at 170℃, the strength is at the highest at 72hr aging, but elongation is at the lowest at 65hr aging. 2. There are various precipitates of δ', α', S' and T1 at 170℃ aging. It is assumed that these mixed structures have an effect on the strength and elongation in the under aging. This is attributed to multipicative mutual supplement action by coexistence of composite phase rather than δ'single phase. 3. The resurt of thermo analysis of as-quenched shows that endothermic range regarded as dissolution of G. P. zone appeared at 130℃ lower by about 70℃ than predictable on the phase diagram.

Cupola와 side-blown converter를 組合한 二重熔解에 依한 鑄鋼製造에 關한 硏究

白勝男,趙煥從,李吉弘 조선대학교 생산기술연구소 1980 生産技術硏究 Vol.1980 No.-

cupola에서 나온 熔湯을 side-blown converter에서 refining할때 溶揚中의 珪素含量이 精鍊操業에 미치는 영향을 조사한 결과는 마음과 같았다. (1)場中의 珪素含量은 鋼材의 成分파 機械的 性質에 영향을 끼치지 않았고 거의 같았다. (2) Si를 2.2% 含有한 熔湯은 珪素가 充分히 低下되 지 않는한 軟鋼製造가 어려웠다. (3) 珪素를 2.2% 含有한 熔湯의 精練時間은 O.9%Si의 熔湯보다 37.5% (6分) 길었다. (4) O.9%Si의 熔湯과 1.2%Si의 熔湯은 珪素의 산화가 빨랐고 짧은 시간에 低炭素鋼을 얻을 수 있었다. 또한 精練完了期를 정확히 알 수 있었다. (5) O.9%Si의 熔湯에서는 脫炭作用이 Si, Mn이 최저인 상태에서 일어났으며 가장 合理的이였고 生산效率도 가장 좋았다. This paper aims to compare and investigate which of high, medium and low-silicon process is most resonable and efficient in side-blown converter. The effect of Si on the refining of molten pig iron in the side-blown converter was investigated. The results obtained in this experiment were summarized as follows: 1) The mechanical properties and components of steel were not effected by the amount of Si in molten metal. 2) The refining time of the molten metal with 2.2%Si was longer than that with 0.9% Si by 6 minutes. 3) In the molten metal with 2.2%Si mild steel was difficult to yield unless the content of Si decreased in full. 4) In the refining of the molten metal each with O.9%Si and 1.2%Si, the oxidation of Si was fast and the low carbon steel was able to be obtained in short time. And the finishing period of the operation could be distinctly judged. 5) The refining of the molten metal with O.9% Si was most reasonable and the efficiency of production was also best. In this process decarburization occurred in the state of the lowest content of Si and Mn.

Al-Zn-Mg-Cu 合金의 時效析出에 관한 熱分析的 硏究

白勝男,姜朝遠,高濟晩 조선대학교 생산기술연구소 1987 生産技術硏究 Vol.9 No.2

The relations between the aging process and various compositions in Al-Zn-Mg, Al-Zn-Mg-Cu alloys were studied by specific heat measurements. The specimens were solution treated at 465℃ for 1hr., quenched into ice-water, and finally aged at 50℃ and 180℃. The result obtained were as follows: 1. There were observed two sorts of endothermic change and exothermic change on the specific heat-temperature curve (S-T curve) of specimens aged at low temperatures were observed. The detailed shapes of S-T curves varied according to the compositions of specimens. 2. The amount of G. P. Zones formed during aging was much large in the specimens of higher Zinc content, and complicated shape was observed in the exothermic part of 8-T curves in Zinc rich specimens. 3. Two sorts of precipitation processes were exist in Al-Zn-Mg-Cu alloys. One process was that observed in Al-Zn-Mg alloys and the other Al-Cu-Mg alloys.

Austenitic Stainless Steel의 粒界腐蝕에 關한 硏究

白勝男 朝鮮大學校 1977 綜合論文集 Vol.1977 No.-

This study aimed to investigate an intergranular corrosion by measuring a degree of corrosion of SUS304, SUS316, and SUS321, in copper sulfate-sulfuric acid and sulfuric acid by condition of heat treatment. 1) The corrosion resistance of SUS321 in stabilization was strongest in any solution. 2) In copper sulfate-sulfuric acid, the corrosion of SUS316 containing Mo by sensitizing was more intensive than that of SUS304 stabilized. 3) In sulfuric acid the corrosion of SUS304 sensitized was greater than that SUS316 stabilized.

球狀黑鉛鑄鐵의 脫硫法

白勝男 朝鮮大學校 工科大學 1972 論文集 Vol.1 No.-

Al-Li합금의 시효석출에 미치는 Be첨가의 영향

白勝男,金鍾源 조선대학교 생산기술연구소 1992 生産技術硏究 Vol.14 No.2

The purpose of the present study is to improve the low toughness of Al-Li binary alloy which is expected to be widely used for the structural materials of the aircraft and light industry. To improve the low toughness Be was added in Al-Li binary alloy. The kind, shape and variation of precipitate phase formed by age-precipitation in alloy with addition element and the mechanism of nucleation were closely examined. Moreover the correlation between precipitate phase and mechanical property and the formation and grouth of discontinuous precipitate were studied. The above were carried out through investigation of the variation of mechanical properties such as tensile strength, yield strength and elongation, microstructure by TEM. 1. Al-Li binary alloy with addition of 0.05wt% and 0.43wt% Be has been promoted by about 2~4hrs in precipitation rate at 190℃ ageing. 2. It is assumed to be the effect of δ' phase and α-Be particle that the hardness and strength of Al-Li binary. alloy with addition of Be have been increased with increase of Be content. 3. The shape of δ' phase, Spheroidite precipitated in Al-Li binary alloy has not been changed with addition of Be but the coarsening rate has been increased. 4. For Al-Li binary alloy with addition of 0.43wt% Be, a discontinuous precipitate has occurred at grain boundary and its growing orientation has no relation with interfacial energy with increasing ageing time.

Fe-Ni-C 합금의 Ausforming처리에 의한 기계적성질의 변화

백승남,강조원 조선대학교 동력자원연구소 1987 動力資源硏究所誌 Vol.9 No.1

The ausformed martensite obtained from austenite with various deformation degrees in Fe-30% Ni-0.25% C alloy was transformed to reversed austenite at 500℃ by cyclic reverse martensitic transformation. The effects of prior deformation and number of cyclic transformation on the microstructure, mechanical properties of reversed austenite were investigated. The results obtained are summarized as follows : 1) Prior deformation degrees applied below A_d point raises A_f point.A_f points of ausformed martensites in this alloy are from 475 C to 486 C with prior deformation degrees. 2) The strength of reversed austenite is higher than that of original austenite without prior deformation. This is considered to be due to the higher dislocation density and grain size refinement. 3) The yield strength of reversed austenite below 25% prior deformation is higher than that of deformed austenite, but above 25% prior deformation, the yield strength of the reversed austenite is lower than that of the deformed austenite. 4) The strength of reversed austenite is more increased with the number of cyclic transformation, especially it is principally strengthened at the first cyclic transformation and the strengthening effect is more remarkable in yield strength than in ultimate tensile strength.

Hot Wall Epitaxy(HWE)에 의한 CdGa₂Se₄/GaAs epilayer 성장과 광전기적 특성

백승남,홍광준 조선대학교 에너지.자원신기술연구소 2002 에너지·자원신기술연구소 논문지 Vol.24 No.1

The stochiometric mix of evaporating materials for the CdGa₂Se₄single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CdGa₂Se₄mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 630℃ and 420℃, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of CdGa₂Se₄single crystal thin films measured from Hall effect by van der Pauw method are 8.27×10^(17) ㎤, 345 ㎠/V ·s at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuInSe₂ single crystal thin film. We have found that the values of spin orbit splitting △So and the crystal field splitting △Cr were 106.5 meV and 418.9 meV at 10 K, respectively. From the photoluminescence measurement on CdGa₂Se₄single crystal thin film, we observed free excition (Ex) existing only high quality crystal and neutral bound exicition (D^(0) ,X) having very stron peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy of neutral donor bound excition were 8 meV and 13.7 meV, respectivity. By Haynes rule, an activation energy of impurity was 137 meV.