• 한국표면공학회지
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• 제39권5호
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• pp.199-205
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• 2006

Titanium nitride (TiN) coatings were produced on AISI 420 stainless steel by DC magnetron sputtering of a Ti target changing the processing variables, such as the flow rate of $N_2/Ar$, substrate temperature and the existence of Ti interlayer between TiN coatings and substrates. The hardness and residual stress in the films were investigated using nanoindentation and a laser scanning device, respectively. The stoichiometry and surface morphology were investigated using X-Ray Diffraction and SEM. The corrosion property of the films was also studied using a polarization method in NaCl (0.9%) solution. Mechanical properties including hardness and residual stress were related to the ratio of $N_2/Ar$ flow rate. The corrosion resistance also was related to the processing variables.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.269-270
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• 2013

• 소성∙가공
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• 제20권8호
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• pp.588-594
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• 2011

A new manufacturing process is presented for automotive drive plate using a boron-containing carbon steel sheet, which is hot-formed and press quenched. Particular attention was given to the capability of the process in minimizing dimensional change.

• Journal of Computational Design and Engineering
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• 제3권1호
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• pp.71-90
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• 2016

Steel nitriding is a thermo-chemical process leading to surface hardening and improvement in fatigue properties. The process is strongly influenced by many different variables such as steel composition, nitrogen potential, temperature, time, and quenching media. In the present study, the influence of such parameters affecting physic-chemical and mechanical properties of nitride steels was evaluated. The aim was to streamline the process by numerical-experimental analysis allowing defining the optimal conditions for the success of the process. Input parameters-output results correlations were calculated through the employment of a multi-objective optimization software, modeFRONTIER (Esteco). The mechanical and microstructural results belonging to the nitriding process, performed with different processing conditions for various steels, are presented. The data were employed to obtain the analytical equations describing nitriding behavior as a function of nitriding parameters and steel composition. The obtained model was validated, through control designs, and optimized by taking into account physical and processing conditions.

• 한국레이저가공학회지
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• 제2권1호
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• pp.22-29
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• 1999

This work was carried out as a fundamental experiment to fabricate a Graded-Boundary Ni/Steel material using a laser beam. A Ni sheet was placed on a steel substrate, and then a series of high power $CO_2$ laser beams were irradiated on the surface in order to produce a homogeneous alloyed layer. The processing parameters were : 4 ㎾ laser power, 2m/min traverse speeds, -2mm defocuing, 17 l/min sheiding gas flow rates. The sequential repetition of the laser surface alloying treatment up to 4 times, resulted in about 5mm thick of fair compositional gradient systems. In order to determine the microstructure, phase and compositional profiles in this material, optical microscopy, XRD and EDS were used. The compositions varied from 66% to 0% for Ni and 34% to 100% for Fe in this material The microstructures were typical morphologies of rapid solidification and solid-state cooling. Since compressive stress was formed in the heat affected region due to martensitic transformation, while relative tensile stress was developed in the alloyed region, cracks were formed between the alloyed region and the substrate region.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.121-126
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• 2003

Steel frame construction is divided into subsidiary materials with column, beam, girder and bracing. After these are processed in factory for using installing in construction field. These prefabricated furniture is very important in accordance with design drawing about processing and prefabricating. In the case of design process using information transmission in blueprint, omission of material number, processing measure and finishing material, or discordance of each structure drawing and selecting incongruent structural material generated an error in the process of design. These error caused delaying tine and increasing cost and increasing safety accident in the steel-structure work operating process. therefore, design process should consider problem of operating process.

• 한국건축시공학회지
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• 제3권2호
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• pp.111-118
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• 2003

Steel frame construction is divided into subsidiary materials with column, beam, girder and bracing. After these are processed in factory for using installing in construction field. These prefabricated furniture is very important in accordance with design drawing about processing and prefabricating. In the case of design process using information transmission in blueprint, omission of material number, processing measure and finishing material, or discordance of each structure drawing and selecting incongruent structural material generated an error in the process of design. These error caused delaying time and increasing cost and increasing safety accident in the steel-structure work operating process. therefore, design process should consider problem of operating process.

• Advances in materials Research
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• 제3권1호
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• pp.283-295
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• 2014

In this paper, the microstructure, hardness, tensile deformation and fracture behavior of high strength alloy steel X2M is presented anddiscussed. The influence of both composition and processing on microstructure of the as-provided material and resultant influence of microstructure, as a function of orientation, on hardness, tensile properties and final fracture behavior is highlighted. The macroscopic mode and intrinsic microscopic features that result from fracture of the steel specimens machined from the two orientations, longitudinal and transverse is discussed. The intrinsic microscopic mechanisms governing quasi-static deformation and final fracture behavior of this high strength steel are outlined in light of the effects oftest specimen orientation, intrinsic microstructural effects and nature of loading.

• 한국강구조학회 논문집
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• 제11권1호통권38호
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• pp.1-11
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• 1999

본 논문에서는 강구조물의 제작 및 시공에서 용접이음부의 고품질을 확보하기 위하여 강구조물 용접이음부 외부결함의 자동검출에 관한 화상처리 알고리즘을 개발한다. 개발 알고리즘은 광학계의 적절한 배치에 의해 얻어지는 4매의 입력화상을 이용하여 기존의 기법에서 검출할 수 없었던 용접이음부 외부결함을 검출할 수 있음을 보인다. 용접 외부결함이 존재하는 시험편을 제작하고 실험을 통하여 개발 알고리즘의 유용성을 확인하였다. 또한 검출된 용접외부결함의 분류 결과를 육안검사 결과와 비교하였다.

• 한국주조공학회지
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• 제18권3호
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• pp.240-245
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• 1998

In the view point of the environmental conservation and the energy reduction, the recycling of metal scrap is coming as one of the global subjects in the world. In this study, the movement of intermetallics with electromagnetic force in a melt of a scrap of Al-Si-Cu alloy (JIS ADC12), which was widely used in diecasting process, was investigated in order to eliminate the Fe element, which was usually accumulated in a scrap. In this study, we applied electromagnetic method to eliminate Fe element in ADC12 aluminum alloy scrap which contains 1.64wt.% Fe and the effects of electromagnetic force on the particle movement was visualized and confirmed by water modeling and experiment. As a result, the Fe intermetallic compounds are moved to the direction opposite to that of the electromagnetic force as the force applies, thus eliminated from the bulk metal. Therefore, the content of Fe in matrix decreased from 1.64wt.% to 0.45wt.%.