• 한국해양공학회지
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• 제17권2호
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• pp.40-46
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• 2003

The corrosion resistance of super duplex stainless steel on both its fibrous and dispersed phase was investigated. These structures consist of various volume fraction and distribution of austenite structure, which were obtained by changing the heat treatment temperature and cycle. The fibrous phase had higher austenite volume fraction than that of the dispersed phase at the same temperature. Corrosion resistance of super duplex stainless steel was evaluated through an immersion test and an impingement test, using 35% HCI and sea water, respectively. Super duplex stainless steel was compared with STS316L and STS304. The corrosion resistance of super duplex stainless steel was superior to ST316L and STS304. The dispersed phase of super duplex stainless steel was more stabilized than the fibrous phase in corrosion. The magnitude of corrosion rate was in order STS304, STS316L, fibrous phase of super duplex stainless steel and dispersed phase of super duplex stainless steel.

• Corrosion Science and Technology
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• 제5권3호
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• pp.90-93
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• 2006

Prevention of crevice corrosion was studied for STS 304 stainless steel using a Mg-alloy galvanic anode in solutions with various specific resistivity. The crevice corrosion and corrosion protection characteristics of the steel was investigated by the electrochemical polarization and galvanic corrosion tests. Experimental results show that the crevice corrosion of STS 304 stainless steel does not occur in solutions of high specific resistivity, but it occurs in solutions of low specific resistivity like in solutions with resistivities of 30, 60 and $115{\Omega}{\cdot}m$. With decreasing specific resistivity of the solution, the electrode potential of STS 304 stainless steel in the crevice is lowered. The potential of STS 304 stainless steel in the crevice after coupling is cathodically polarized more by decreasing specific resistivity indicating that the crevice corrosion of STS 304 stainless steel is prevented by the Mg-alloy galvanic anode.

• 열처리공학회지
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• 제34권4호
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• pp.171-178
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• 2021

In the present study, we comparatively investigated the microstructures of two hot-rolled stainless steel clad plates; STS 304L - low carbon steel A516-70N and STS 316L - A516-70N. The STS 304L/A516-70N clad plate (Clad_304L_Ni) had a Ni-interlayer between stainless steel and carbon steel and a 90 ㎛ thick deformation band of unrecrystallized austenite grains on the stainless steel. The STS 316L/A516-70N clad plate (Clad_316L) had no interlayer and almost fully recrystallized austenite grains. Clad_304L_Ni exhibited the thinner a decarburized layer in carbon steel and a total carburized layer in stainless steel than Clad_316L. However, a severely carburized layer in stainless steel was thicker for Clad_304L_Ni than Clad_316L. Hardness profiles near the interface of clad plates matched well with microstructures at locations where the hardness values were measured.

• 열처리공학회지
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• 제23권5호
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• pp.269-276
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• 2010

This study has been carried out to the low temperature plasma nitriding treatment on the mechanical properties of stainless steel at temperature range between $400^{\circ}C$ and $500^{\circ}C$. It was found that there was precipitated to free CrN matrix below $400^{\circ}C$ and there was precipitated S-phase of STS 316L, ${\varepsilon}$-phase of STS 409L and ${\alpha}N$-phase of STS 420J2. STS 316L has formed relatively abundant CrN phase and ${\gamma}^{\prime}-Fe_4N$ phase at $500^{\circ}C$, alternatively STS 409L and STS 420J2 were more deeply nitrided than STS 316L at $500^{\circ}C$.

• 열처리공학회지
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• 제24권1호
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• pp.3-9
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• 2011

Plasma nitriding of stainless steels has been investigated over a range of temperature from 400 to $500^{\circ}C$ and time from 10 to 20 hours. Characterization of systematic materials was carried out in terms of mechanical properties and corrosion behaviors. The results showed that plasma nitriding conducted at low temperatures not only increased the surface hardness, but also improved the corrosion resistance of STS 316L, STS409L, and STS 420J2. It was found that plasma-nitriding treatment at $500^{\circ}C$ resulted in increasing the corrosion performance of STS 409L and STS 420J2, while STS 316L was observed with server and massive damage on surface due to the formation of CrN.

• 열처리공학회지
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• 제16권2호
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• pp.78-82
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• 2003

Nitrided compound layer and diffusion layer structure were observed by SEM. The compound layer and the constituent of nitrided surface of STS 304, STS 316, STS 410 and SACM 645 steel were analysed using EMPA and XRD respectively. The depth of nitriding layer that is obtained from similar nitriding condition decrease in the order of SACM 645 > STS 410 > STS 316 > STS 304. Result of phase transformation of the nitrided at $550^{\circ}C$ by XRD analysis were as follows; The austenitic stainless steel was mainly consist of $Cr_2N$ accompanying with $Fe_4N$ and $Fe_{2-3}N$ phase and martensitic stainless steel was mainly consist of present $Fe_{2-3}N+Cr_2N$ phase, but SACM 645 steel was $Fe_{2-3}N$ phase present only.

• 소성∙가공
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• 제20권3호
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• pp.193-205
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• 2011

Because of its rustproof property, stainless steel is widely used in kitchen appliances, building materials, electronics, chemical plants and automobile exhausts. In addition, the utilization of stainless steel for fuel cell application is growing. As the demand for this material increases, it is necessary to study the basic properties of stainless steel such as corrosion resistance, heat transfer, formability, cutting or shearing ability and weldability. In this article, the mechanical properties, formability and press forming performance of stainless steel are reviewed. Since temperature and strain rate affect the press forming performance of STS304(austenitic) stainless steel, the influence of these parameters on the plastic behavior should be investigated. Moreover, measures for the prevention of ridging of STS430(ferritic) and delayed fracture of STS430, which respectively appear during and after press forming, should be considered. Recently, stainless steel sheets with a thickness lower than 0.2 mm have been widely used in applications for mobile phone, digital camera and fuel cell separator. Therefore, there is a growing interest of studying the grain size effect and plasticity at the crystal scale in order to understand the anisotropic behavior and micro forming ability of thin sheets. This review paper was written with the objective of helping engineers and researchers to understand the forming characteristics of stainless steel and to establish standards in plastic forming techniques.

• Korean Journal of Acupuncture
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• 제24권1호
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• pp.59-63
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• 2007

Objectives : To discuss the biocompatibility of stainless steel for using acupuncture needles. Results and Conclusions : It is widely assumed that stainless steel is one of the good corrosion-resistant materials and is safe for human body, Most of metal acupuncture needles are made of STS304 and STS316 in light of human body safety: STS304 in more differences between STS304 and STS316 in light of human body safety: STS304 is more vulnerable to oxidation than STS316. A variety of literature survey showed that although STS316 is more corrosion-resistant than STS304 there is no evidence supporting the hypothesis that STS304 has the potential danger to human body, Further study would be necessary to draw more decisive conclusion.

• 한국융합학회논문지
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• 제10권11호
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• pp.241-246
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• 2019

STS 630에 이온질화를 통한 기계적 특성 및 세포독성을 고찰하여 의료기구용으로 활용중인 STS 420 소재의 대체 가능성을 융합적으로 고찰하고자 하였다. STS 630 합금을 $480^{\circ}C$에서 1시간 시효처리 후 온도, 시간, 압력, 질소투입량의 변화를 통하여 이온질화 최적조건을 선정하고, 미세조직, 경도, 인장강도 등 기계적 특성의 변화와 섬유아세포(IGF cell)를 이용한 MTT 세포독성 시험을 수행하였다. STS 630의 경도는 시험결과 $400^{\circ}C$에서 질화시간 3시간 이상일 때 시간에 따라 증가하며, 질소가스 투입량에 비례하여 질화층의 두께와 표면경도가 증가함을 알 수 있었다. STS 630의 인장강도는 시효처리와 이온질화에 의해 34%의 향상이 되었으며, 의료기구로서의 적합성을 확인하기 위하여 섬유아세포(IGF cell)를 이용한 MTT 세포독성 시험의 경우에는 대조군(STS 420)에서만 세포 독성이 관찰되고, STS 630의 경우에는 세포독성이 나타나지 않아 의료기구로서의 적합성은 있는 것으로 판단된다.

• 한국강구조학회 논문집
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• 제18권2호
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• pp.271-278
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• 2006

오스트나이트계 STS 304 스테인리스강의 응력도-변형도 곡선을 전 영역에 걸쳐 연구하는 것을 본 논문의 목적으로 한다. 실험적, 이론적 연구를 통하여 비교분석하였고, 개선된 곡선을 제안한다. 0.2% 강도까지 Ramberg-Osgood 곡선은 유용하지만, 이 영역을 초과하는 한계상태의 경우 그것은 원칙적으로 일치하지 않는다. Rasmussen 곡선은 Ramberg-Osgood 곡선의 원리에 기초하여 0.2% 강도를 초과하는 영역에 대하여 개발되었다. 실험과 비교한 결과 잘 일치하지 않기 때문에 실험결과를 분석하여 개선된 식을 제안하며 응력도-변형도 관계를 전 영역에 걸쳐 비교 평가한다.