• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1995년도 추계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.32-32
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• 1995

• Journal of Advanced Marine Engineering and Technology
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• 제36권8호
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• pp.1061-1068
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• 2012

오늘날 지구온난화, 환경오염 및 주요 에너지원인 화석연료의 고갈에 대한 우려가 높아지면서, 전세계적으로 신재생에너지 및 청정에너지에 대한 관심이 급격하게 증가하고 있다. 따라서 화석연료의 대체 및 SOX, NOX와 같은 오염물질을 적게 배출하는 청정에너지로써 LNG가 폭넓게 사용되고 있다. 그로인해 LNG의 소비는 급격하게 증가하고 있으며, 그것을 운반하기 위한 LNG선의 수요 또한 수십 년 동안 크게 증가하였다. 본 연구에서는 LNG선의 생산성을 향상시키기 위해 LNG선용 스테인리스강에 대한 용접에 고출력 파이버 레이저를 이용하였다. 사용된 재료는 탄소 함유량이 0.03% 이하의 STS316L이며 두께는 8mm이다. 최대출력 5kW의 파이버 레이저를 열원으로 사용하여 비초점거리, 겹치기 용접 그리고 맞대기 용접에 대한 실험을 진행하였다. 실험결과, 겹치기 용접의 경우 2.0m/min, 맞대기 용접의 경우 3.0m/min의 용접속도까지 접합이 가능하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권6호
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• pp.698-703
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• 2014

최근 기존 화석연료의 고갈로 인하여 대체에너지로써 천연액화가스의 수요 증가와 함께 LNG 운반선의 수요가 증가하고 있으며, 그로인해 극한의 환경에서 사용할 수 있는 LNG 선박용 벨로우즈의 수요 또한 증가할 것으로 예상된다. 현재 LNG 선박용 벨로우즈에 사용되는 재료는 저온취성과 해수부식에 강한 INCOLOY 825와 STS316L합금이다. 본 연구에서는 극저온에 사용되는 LNG용 벨로우즈 재질인 INCOLOY 825과 STS316L 합금에 대하여 최적의 용접조건을 설정하고, 에릭센 시험을 통하여 용접부의 성형성을 분석하였다. 최적 조건에서의 용접시 용접부의 인장강도는 모재에 비하여 90% 이상의 강도값을 나타내었다. 또한 에릭센 시험을 통한 성형성 분석의 결과, 용접부가 아닌 모재에서 파단이 발생하는 매우 양호한 용접부를 얻을 수 있었다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.373-378
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• 2000

The heat resistant material, in service, may experience static loading, cyclic loading, or a combination of two. An experimental study of crack growth behavior of STS 316L austenitic stainless steel under fatigue, and creep-fatigue loading conditions were carried out on compact tension specimens at various tensile hold times. In the crack growth experiments under hold times. In the crack growth experiments under hold time loading conditions, tensile hold times were ranged from 5 seconds to 100 seconds and its behavior was characterized using the $\Delta$K parameter. The crack growth rates generally increase with increasing hold times. However in this material, the trend of crack growth rates decreases with increasing hold times for short hold time range relatively. It is attributed to a decline in the cyclic crack growth rate as a result of blunting at the crack tip by creep deformation. The effect of grain size on the creep behavior of STS 316L was investigated. Specimens with grain size of 30, 65 and 125${\mu}{\textrm}{m}$ were prepared through various heat treatments and they were tested under various test conditions. The fracture mode of 316L changed from transgranular to intergranular with increasing grain size.

• 한국재료학회지
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• 제25권6호
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• pp.293-299
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• 2015

In this study, nitrogen ions were implanted into STS 316L austenitic stainless steel by plasma immersion ion implantation (PIII) to improve the corrosion resistance. The implantation of nitrogen ions was performed with bias voltages of -5, -10, -15, and -20 kV. The implantation time was 240 min and the implantation temperature was kept at room temperature. With nitrogen implantation, the corrosion resistance of 316 L improved in comparison with that of the bare steel. The effects of nitrogen ion implantation on the electrochemical corrosion behavior of the specimen were investigated by the potentiodynamic polarization test, which was conducted in a 0.5 M $H_2SO_4$ solution at $70^{\circ}C$. The phase evolution and texture caused by the nitrogen ion implantation were analyzed by an X-ray diffractometer. It was demonstrated that the samples implanted at lower bias voltages, i.e., 5 kV and 10 kV, showed an expanded austenite phase, ${\gamma}_N$, and strong (111) texture morphology. Those samples exhibited a better corrosion resistance.

• 한국주조공학회지
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• 제43권5호
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• pp.223-229
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• 2023

In this study, STS316L produced by a double-melting process involving vacuum induction melting (VIM) and vacuum arc remelting (VAR) was subjected to extrusion and drawing to form a tube and was subsequently electrolytic polished (EP). The grain size of the obtained STS316L without EP was approximately 55 ㎛, with no difference found after EP. The thickness of the EP layer was measured by AES and TEM, showing values of approximately 10 nm and 15 nm, respectively. After EP, the Cr/Fe and CrO/FeO ratios of the passive layer increased from 1.48 to 1.62 and from 2.15 to 2.26, respectively, while the surface roughness decreased significantly from 0.255 to 0.024 ㎛. Consequently, the corrosion rate decreased in both NaCl and HCl solutions after the EP process. Additionally, the amounts of eluted Cr and Fe ions were reduced from 1.2 to 0.8 ppb and 10.3 to 0.8 ppb, respectively. Furthermore, polarization tests revealed that STS316L treated with EP required a lower current density to reach a passive state, indicating that corrosion behavior was retarded.

• 한국재료학회지
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• 제13권9호
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• pp.587-592
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• 2003

The thin films of 316L stainless steel were made on glass and S45C substrate by Ion beam assisted deposition with reactive atmosphere of argon and nitrogen. The films were deposited at the various conditions of ion beam power and the ratios of Ar/$N_2$gas. Properties of these films were analyzed by glancing x-ray diffraction method(GXRD), AES, potentiodynamic test, and salt spray test. The results of GXRD showed that austenite phase could be appeared by $N_2$ion beam treatment and the amount of austenite phase increased with the amount of nitrogen gas. The films without plasma ion source treatment had the weak diffraction peak of ferrite phase. But under the Ar plasma ion beam treatment, the strong diffraction peaks of ferrite phase were appeared and the grain size was increased from 12 to 16 nm. Potentiodynamic polarization test and salt spray test indicated that the corrosion properties of the STS 316L films with nitrogen ion source treatment were better than bulk STS 316L steel and STS 316L films with Ar ion source treatment.

• 한국분말재료학회지
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• 제27권3호
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• pp.219-225
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• 2020

The directed energy deposition (DED) process of metal 3D printing technologies has been treated as an effective method for welding, repairing, and even 3-dimensional building of machinery parts. In this study, stainless steel 316L (STS316L) and Inconel 625 (IN625) alloy powders are additively manufactured using the DED process, and the microstructure of the fabricated STS316L/IN625 sample is investigated. In particular, there are no secondary phases in the interface between STS316L and the IN625 alloy. The EDS and Vickers hardness results clearly show compositionally and mechanically transient layers a few tens of micrometers in thickness. Interestingly, several cracks are only observed in the STS 316L rather than in the IN625 alloy near the interface. In addition, small-sized voids 200-400 nm in diameter that look like trapped pores are present in both materials. The cracks present near the interface are formed by tensile stress in STS316L caused by the difference in the CTE (coefficient of thermal expansion) between the two materials during the DED process. These results can provide fundamental information for the fabrication of machinery parts that require joining of two materials, such as valves.

• Tribology and Lubricants
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• 제34권6호
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• pp.270-278
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• 2018

STS 316L prepared by additive manufacturing (AM) exhibits deterioration of mechanical properties and wear resistance due to the presence of defects such as black-of-fusion defects, internal porosity, residual stress, and anisotropy. In addition, high surface roughness (integrity) of AM products remains an issue. This study aimed to apply ultrasonic nanocrystal surface modification (UNSM) technology to STS 316L prepared by AM to increase the surface hardness, to reduce the surface roughness, and to improve the friction and wear behavior to the level achieved by bulk material manufactured using traditional processes. Herein, the as-received and polished specimens were treated by UNSM technology and their resulting properties were compared and discussed. The results showed that UNSM technology increased the surface hardness and reduced the surface roughness of the as-received and polished specimens. These results can be attributed to grain size refinement and pore elimination from the surface. Moreover, the friction of the as-received and polished specimens after UNSM technology was lower compared to those of the as-received and polished specimens, but no significant differences in wear resistance were found.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.192-192
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• 2013

하이브리드 표면처리는 다른 표면처리법을 동시 또는 연속적으로 행하여 단일표면처리에 비해 더욱 우수한 특성을 부여시키기 위한 표면처리법이다. 본 연구는 붕소와 질소 원소를 이용한 하이브리드 표면처리를 오스테나이트계 스테인리스강인 STS 316L 소재에 적용하여 변화된 특성을 평가하였다. 본 실험에 사용된 하이브리드 표면처리법으로는 붕소분말을 이용한 보로나이징처리와 활성스크린을 이용한 이온질화처리법을 적용하였다. 하이브리드 표면처리된 STS 316L시편은 FE-SEM을 이용하여 표면형상 및 단면조직을 관찰하였으며 GDS와 XRD를 이용하여 깊이에 따른 원소 및 상분석을 실시하였다. 또한 마이크로비커스 경도계와 마모시험기를 이용하여 경도와 마모특성을 측정하였고, 염수분무시험을 통하여 해수환경에서 부식거동을 평가하였다.