• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.103-108
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• 2000

Since the ceramic/metal joint material is made at a high temperature, the residual stress development when it is cooled from bonding temperature to room temperature due to remarkable difference of thermal expansion coefficient between ceramic and metal. As residual stress at ceramic/metal joints influences the strength of joints, it is important to estimate residual stress quantitatively. In this study, it is attempted to estimate joint residual stress of $Si_3N_4/STS304$ joints quantitatively and to compare the strength of Joints. The difference of residual stress is measured when repeated thermal cycle is loaded under the conditions of the practical use of the ceramic/metal joint. And 4-point bending test is performed to examine the influence of residual stress on fracture strength. As a residual it is known that the stress of joint decreases as the number of thermal cycle increases.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.39-44
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• 2002

As laser cutting process is widely used in industry, an automated on-line process control system has become very important. In this paper, development of a laser cutting monitoring system, which is regarded as the fundamental step toward automation of the process, is presented. Acoustic emission and an artificial neural network were used for the monitoring system. With given process Parameters including laser power and scanning speed the system can predict the suitability of laser beam for the cutting or a stainless steel (STS304) plate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.193-198
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• 2001

The feasibility of the acoustic emission technique in predicting the residual fatigue life of STS304 stainless steel is presented. Acoustic emission was continuously monitored during the fatigue tests. Considerable acoustic emission occurred during the first few cycles. Acoustic Emission increased rapidly at about 90% of the fatigue life, clear and ample warning of impending fatigue failure was observed. Fatigue damage accumulation was evaluated in terms of an AE cumulative counts. The AE cumulative counts may be taken as an indicator of fatigue cumulative damage. Fatigue damages corresponding to 20, 40, 60 and 80% of the total life were induced at a cyclic stress amplitude. The specimens with and without fatigue damage were subjected to tensile tests. In tensile tests, the total cumulative counts were reduced with increasing fatigue damage. It was observed that the residual tensile strength of material did not change significantly with prior cyclic loading damages.

• 한국기계가공학회지
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• 제16권4호
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• pp.24-29
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• 2017

This paper provides an experimental analysis on the breakage of the coated tool using the face-milling cutter of the machining center due to changes in the cutting speed and the feed rate. The experimental studies were conducted using STS 304 materials and the damage to the tool was analyzed according to the change in machining time. The experiments confirmed that the cutting speed and feed rate affected the tool damage and the mechanical impact and thermal shock were determined to severely damage the tool. From the production engineering point of view, it has been experimentally investigated that the increased feed rate significantly influences the material removal rate more than the increased cutting speed.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.205-207
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• 2009

아크이온플래이팅 기술과 스퍼터링 기술이 결합된 하이브리드 코팅 시스템을 이용하여 STS 304와 Si 기판에 4성분계 Cr-Al-Mo-N 코팅을 증착하였다. $N_2$/Ar 혼합가스 분위기하에 아크 타겟은 Cr을 사용하였고 스퍼터링 타겟은 Al과 Mo를 사용하였으며 합성된 Cr-Al-Mo-N 코팅은 주로 치환고용된 (Cr, Al, Mo)N으로 구성되었다. 최고 경도값은 Mo 함량이 24.2 at.%일 때 35 GPa을 나타냈으며 마찰계수는 Mo의 함량이 0에서 33.2 at.%로 증가함에 따라 0.9에서 0.48로 감소하였다. 이는 $MoO_3$가 코팅면과 스틸볼 계면에서 고체 윤활제로 작용한 것으로 사료된다. 그러나 Cr-Al-Mo-N 코팅은 MoN의 낮은 내산화온도로 인하여 Cr-Al-N에 비하여 더 낮은 온도에서 산화되었다.

• 소성∙가공
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• 제4권4호
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• pp.345-352
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• 1995

Warm deep drawing for optimum forming conditions to give the maximum drawing depth is investigated and compared with the results from experiments performed at room temperature. Experiments which draw square cups of STS 304 stainless steel sheet under the constant lubrication condition of teflon film are made both in a crank and hydraulic press for two kinds of specimens. The maximum drawing depth at warm forming condition reaches 1.4 times the drawing depth at room temperature in a crank press, whereas 1.6 times in a hydraulic press, and also more uniform distribution of thickness in case of warm deep drawn cup is observed. The effects of other factors on formability, such as forming temperature, speed of press and cooling of punch are examined and discussed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.597-601
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• 1994

In this paper, we have describes about the reationships between a core gap and a feeding velocity, an amplitude and the core gap by the exciting forc, the parts movement and a bowl materials, and the feeding veocity and the parts in the parts feeder. The main results as compared with the stainless and the aluminum materials are as follow : 1) The mean feeding velocity by bowl material shown more relative proportion in the STS304 to the exciting voltage than the C%AV 2) IN the exciting voltage, the response time for the aluminum material is slow, but the stainless is sensibility. 3) An exciting voltage is rised by an increase of the weight, but an amplitude has been in the range between 23 .mu.m through 40 .mu. m.

• 한국생산제조학회지
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• 제7권3호
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• pp.68-78
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• 1998

Welding structure contains residual stress due to thermal-plastic strain during welding process, and its magnitude and distribution depend on welding conditions. Cracks initiate from various defects of the weldment, propagate and lead to final fracture, The crack initiation and propagation processes are affected by the magnitude and distribution. Therefore, the magnitude and distribution of weldment residual stress should be considered for safety design and service of welding structures. Also it is very important that more accurate assessment method of fatigue crack growth must take into account the redistributing the residual stress quantitively. because the residual stress in weldment has characteristics of its redistribution with loading magnitude, number of cycles and fatigue crack propagation. In this study fatigue crack behavior of STS-304 weldment was investigated during crack propagation into tensile residual stress region or compressive residual stress region. Crack growth rates were predicted and compared with experimental results.

• 한국생산제조학회지
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• 제7권5호
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• pp.29-37
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• 1998

In recent years, grinding techniques for precision machining of stainless steel used in shaft, screw parts and clear value have been improved by using the superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasive wheel makes possible the effective precision grinding of stainless steel. However, the present dressing system cannot have control of optimum dressing of the superabrasive wheel. In this study, a new system and the grinding mechanism of optimum in-process dressing of superabrasive wheel. Therefore, the optimum in-process electrolytic dressing is a good method to obtain the efficiency and mirror-like grinding of stainless steel (STS304)

• 열처리공학회지
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• 제17권5호
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• pp.278-282
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• 2004

Effect of pre-treatment on the gas nitriding process of austenitic stainless steels has been investigated and the following results were obtained. Minimum pre-treatment time was decreased to 5min with increasing treatment temperature from $200^{\circ}C$ to $600^{\circ}C$. Surface activation effect by the pre-treatment was maintained in the air up to holding time of 64hr, judging from the analysis result of gas nitrided specimens. The Depth of nitrided layer of STS 304 and 316 stainless steels were ranged from $5{\mu}m$ to $90{\mu}m$ at $440^{\circ}C{\sim}600^{\circ}C$. The X-ray diffraction intensity for austenitic stainless steels were increases as nitriding temperature from $440^{\circ}C$ to $600^{\circ}C$.