급냉응고법에 의한 금속 섬유제조에 관한 연구

백남익,허성강,나형용 ( Nam Ik Baik,Sung Kang Hur,Hyung Yong Ra ) 한국주조공학회 1989 한국주조공학회지 Vol.9 No.5

N/A Metal fibers of Al and stainless steel were fabricated by the PDME method and the Taylor process. Tensile strength of metal fiber produced by both the PDME method and the Taylor process was much higher than that of conventionally solidified materials. Utilizing the PDME method, Al fiber with 100㎛ was fabricated under Ar gas atmosphere, and stainless steel fiber with 50㎛ was fabricated under 0.06 Torr vacuum. Continuous fiber of stainless steel was made by the Taylor process and the surface of this fiber was smother than that fabricated by the PDME method.

급랭응고한 Al-Fe 합금계 리본을 고온에 노출시킴에 따른 미세석출물의 성장거동

백남익 ( Nam Ik Baik ) 한국주조공학회 1995 한국주조공학회지 Vol.15 No.3

N/A The purposes of this study were to investigate the microstructural changes in alloy ribbons of Al-Fe-Mo-Si quarternary system at 450∼500℃, and to study the coarsening mechanism of fine precipitates. Using the hot stage in TEM, in situ microstructural changes in Al-4Fe-0.5Mo-1.5Si alloy ribbon and Al-8Fe-2Mo-1.5Si alloy ribbon have been examined successively up to 60 hours at 450℃ and 500℃. Cell structure in zone B of Al-4Fe-0.5Mo-1.5Si alloy ribbon was observed to collapse even in 10 minutes by in-situ heating at 450℃ and the size of precipitates in zone B increased twice in 60 hours. The precipitates in zone A of Al-4Fe-0.5Mo-1.5Si alloy ribbon showed slower coarsening rate than those in zone B by in-situ heating at 450℃. The precipitates in zone A of Al-8Fe-2Mo-1.5Si alloy ribbon increased 50% by in-situ heating at 500℃ in 50 hours compared to the initial precipitates while any microstructual change in zone B was not observed by in-situ heating at 500℃ up to 50 hours. Only the precipitates in zone A of Al-4Fe-0.5Mo-1.5Si alloy ribbon satisfied r³∝t relationship of coarsening mechanism.

Taylor 법의 Glass-Coated Melt Spinning 에 의한 Metal Fiber 제조특성

백남익 ( Nam Ik Baik ) 한국주조공학회 1998 한국주조공학회지 Vol.18 No.1

N/A The characteristics along with problems taken place in the fabrication of metal fiber using glass-coated melt spinning method was investigated. Specimens were heated to melt by simple melting apparatus equipped with high frequency generator. Appropriate temperature was confirmed. It ranged from annealing to working temperature of glass. To achieve steady production of metal fiber, both proper quantity of alloy metal and simultaneous heating of specimen and glass was required. Stainless steel fiber fabricated in this report was approximately 100 μm in diameter, and has higher tensile strength than conventional one. The strength of fiber is inversely proportional to diameter of stainless steel fiber. Particularly in case of aluminum alloy, specimens reacted easily in its melting state. Due to reduction of Si from SiO₂, glass lost its viscosity and fractured in its initial stage. (Received October 16, 1997)

쌍롤 주조법에 의해 제조한 알루미늄 합금의 미세조직

박종우,김희수,백남익 ( Jong Woo Park,Hee Soo Kim,Nam Ik Baik ) 한국주조공학회 1996 한국주조공학회지 Vol.16 No.2

N/A Several aluminum based alloys were fabricated by a twin roll strip casting mill. As-cast microstructures and microsegregations of these aluminum alloys were investigated by means of optical microscope, scanning electron microscope and electron probe micro analysis. Clear distinction on microsegregation among the alloy systems was observed, that is, Al235 and A8011 alloys showed diffused segregation in the middle of the strip, while A3003 and A5086 alloys revealed a centerline segregation consisted of lamellar structure. Above center line segregation was resulted from enrichment of the alloying elements such as Mn, Fe, Cu, Si and eutictic reaction in central region of the alloy strip.

Cr-Mo-V강과 2¼Cr-1Mo강의 피로균열전파에 있어 DCPD방법 적용에 관한 고찰

백남익,류선윤 선문대학교 첨단과학기술연구소 1999 첨단과학기술연구소 논문집 Vol.4 No.-

화력발전소용 turbine rotor 소재로 사용되는 두 가지 종류의 강에 대하여 피로균열 전파과정을 DCPD 법을 이용하여 조사하였다. 이를 위하여 새로운 실험장치를 고안하고 피로균열 전파실험을 실시하여 이 실험장치의 적용 가능성을 검토하였다. 본 연구에서는 피로 균열과정을 전압강하법과 동시에 육안으로 관찰하기 위해서 이동식 tele-microscope를 부착하여 전압강하법의 신뢰성을 확인하였다. 연구대상으로 Cr-Mo-V강과 21/4Cr-1Mo강을 택하였으며 전압강하법으로 측정한 피로균열 전파실험을 실시한 결과, 피로하중 조건에 다른 피로균열 전파길이는 전압강하와 전형적인 관계를 보이고 있었으며, 두 가지 재료에 대해 적용이 가능한 것으로 판단되었다. 피로균열 전파속도는 가한 피로 응력 세기가 커질수록 증가하였는데 이를 정량화하였고, 과로 주파수에 따른 피로균열 전파속도가 다르게 나타났다.

강제 교반법에 의해 알루미늄 복합재료에 제조에 관한 연구

백남익 선문대학교 1998 공과대학논문집 Vol.1 No.1

본 연구는 알루미늄-실리콘 기지조직에 세라믹 강화재를 기계적 교반법으로 첨가하여 새로운 복합재료를 제조하기 위해 수행되었다. 알루미늄 기지 강화재로 BN과 알루미나와 같은 ceramic particle을 채택하였다. BN particle 강화재의 경우 알루미늄 기지에 대한 젖음성이 불량하여, 주어진 실험조건에서 알루미늄 기지 강화재로서 적합하지 못하다는 것을 발견하였다. BN 강화 복합재료를 제작하기 위해서는 BN입자를 coating 하는 등 표면처리가 필요한 것으로 판단되었다. Fabrication of aluminum-silicon alloy composite was conducted by adding the ceramic powder into aluminum alloy matrix during mechanical stirring for developing new composite material. In this study ceramic powders, such as BN and alumina were adopted and tested for strengthener of aluminum alloy composite materials. It was found that wettability of BN powder to the aluminum matrix was not appropriate as to compound stable composite during mechanical stirring. It was concluded that surface coating on BN particle could be necessary for better fabricating aluminum matrix composite material.

법랑 Panel의 변형해석에 관한 연구

전종균,백남익 선문대학교·중소기업기술지원연구소 1998 선문공대 연구/기술 논문집 Vol.3 No.1

법랑 Panel의 열처리 과정에서 수반되는 평면의 뒤틀림(warping)현상을 유한요소법을 이용하여 해석하였다 용접가공 대신 프레스가공으로 대치한 새로운 공정에 의한 변위에 대하여 연구하였다 결과적으로 프레스공정을 이용한 Panel의 최대변위가 용접가공에 의한 결과보다 반으로 줄어들었다. 뒤틀림현상면에서 볼 때 용접가공대신 프레스가공으로 대치한 새로운 공정이 기존의 공정보다 더 우수한 공정임을 입증하였다 Warping phenomenon during heat treatment of the porcelain enamel panel was investigated by Finite Element Analysis. The displacement pattern by the new process which replaces welding process with pressing was studied. Consequently, the maximum displacement of the panel using pressing process is reduced to half compared to welding process. As far as warping phenomenon concerns, it is proved that the new process is much better than old process.

비평형상을 형성하는 알루미늄-천이금속 합금의 특성평가

백남익 선문대학교 2000 공학계열 논총 Vol.3 No.-

Characterization of aluminium-transition alloys, Al_(100)_((x'Y))NixMm_(Y), prepared by splat cooling method was earned out to study their thermal stability with compositional change. Phase analysis by X-ray diffractometry showed that various phases such as aluminum with crystalline and amorphous stmcture and intermetallic compounds were obtained in the composition range of ((X+Y)≤20at%). Mixed phase of crystalline and amorphous structure was formed at the lower composition range of 6at36≤ (Ni+Mm) l0at%. Amorphous phase was mainly formed at the composition range of 10at%≤ Ni+Mm<20at%. Crystallization temperature of the amorphous Al_(100)-_((X+Y))NixMm with the composition of ((X+Y)≤20at%) was increased with the amount of (Ni+Mm). The amorphous phase tended to be thermally stabilized as the content of solute atoms increases at the composition range.

석유화학 Plant 에서 장시간 사용된 튜브형태 탄소강의 열화현상

백남익 한국열처리공학회 2000 熱處理工學會誌 Vol.13 No.1

There have been little reports on the degradation of medium-carbon steel tubes served at high temperature for a long period. The purpose of this research was to provide the information of the proper replacement span of the tubes with the new ones. We investigated the medium-carbon steel tubes which were used at petrochemical plant for about 50,000 hrs to examine their mechanical properties and microstructures. Experimental results showed that the tubes satisfied the specification of ASTM despite such a long period of service, but mechanical properties, especially charpy impact values, were reduced. It concludes that the tubes on service at the plants needs a periodical inspection.

Mn 강재 고압용기의 파단 원인 분석

백남익,이세종 한국열처리공학회 1998 熱處理工學會誌 Vol.11 No.4

This paper presents an investigation why Mn-steel high pressure gas cylinders have been failed in service. The fractured cylinders have been collected to identify the reason of the failure using various methods. The undamaged, new cylinder has also been tested for the base data. We examined the chemical compositions and fracture facets as well as the mechanical properties of the vessels. The microstructural observations of the fractured regions of the cylinder did not indicate the noticeable defects which might cause the failure. The experiments of cylinders on the compositinal and mechanical tests showed that the cylinder was in good shape according the standards of gas pressure vessel. The morphological analysis of the fracture surfaces concluded that the origin of the failure was the local weak segments induced by the external impact to the cylinder, which result in a sudden, fast fracture.