• Proceedings of the KWS Conference
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• 2006.05a
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• pp.124-126
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• 2006

• Steel and Composite Structures
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• v.7 no.4
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• pp.321-337
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• 2007

The investigation on the behaviour of cold-formed stainless steel non-slender circular hollow section columns is presented in this paper. The normal strength austenitic stainless steel type 304 and the high strength duplex materials (austenitic-ferritic approximately equivalent to EN 1.4462 and UNS S31803) were considered in this study. The finite element method has been used to carry out the investigation. The columns were compressed between fixed ends at different column lengths. The geometric and material nonlinearities have been included in the finite element analysis. The column strengths and failure modes were predicted. An extensive parametric study was carried out to study the effects of normal and high strength materials on cold-formed stainless steel non-slender circular hollow section columns. The column strengths predicted from the finite element analysis were compared with the design strengths calculated using the American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. The numerical results showed that the design rules specified in the American, Australian/New Zealand and European specifications are generally unconservative for the cold-formed stainless steel non-slender circular hollow section columns of normal and high strength materials, except for the short columns and some of the high strength stainless steel columns. Therefore, different values of the imperfection factor and limiting slenderness in the European Code design rules were proposed for cold-formed stainless steel non-slender circular hollow section columns.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.366-372
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• 1999

The deformation behavior of commercial stainless steels under hot rolling conditions was investigated by means of hot compression tests performed in the temperature range 800$^{\circ}C$ to 1200$^{\circ}C$. The measured flow stress-strain curves were analyzed by using a simple flow stress model. It was found that the reference strength of stainless steels are much higher than that of carbon steel and that nitrogen and molybdenum alloying greatly increases flow stress of austenitic stainless steel. Ferritic and duplex stainless steel showed comparatively low flow stresses. The flow stress model, which correlates the flow stress with temperature and strain rate, was applied to predict roll forces during hot-plate rolling of stainless steels.

• Transactions of Materials Processing
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• v.20 no.3
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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.

• Corrosion Science and Technology
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• v.17 no.4
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• pp.183-192
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• 2018

Stainless steel can be classified into three categories depending on the microstructure as austenitic stainless steel, ferritic stainless steel and martensitic stainless steel. Generally, stainless steel is extremely resistant to corrosion as the name implies. However, under specific environments, susceptibility to localized corrosion such as pitting, intergranular corrosion and stress corrosion cracking increases. This paper reviewed the state of arts on intergranular corrosion mechanisms, countermeasures on intergranular corrosion and intergranular corrosion test methods. Intergranular corrosion is mostly related with chromium depletion at the grain boundary and sometimes with segregation of electroactive elements in solution annealed stainless steel. Countermeasures on intergranular corrosion include avoiding chromium depletion by heat treatment and the addition of alloying elements. Sensitization evaluation of stainless steel was performed either through acid immersion test or electrochemical test. The methods were standardized in (Japanese Industrial Standards). Even though are useful in evaluating the degree of sensitization for industrial purpose but do not provide detailed information about sensitization mechanism, cause and chromium profile.

• Proceedings of the KWS Conference
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• v.43
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• pp.133-134
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• 2004

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.208-209
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• 2001

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03a
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• pp.149-152
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• 1999

The effect of initial orientation on the microstructure and texture evolution of two ferritic stainless steels was investigated. the columnar and equiaxed crystal specimens which were prepared from continuous casting slab were hot rolled annealed cold rolled and annealed respectively. The rolling and recrystallization textures at each process stage were examined by orientation distribution function (ODF) and electron back-scattered diffraction (EBSD); The observation showed that the orientation density of the $\alpha$-fibre of hot rolled band of columnar crystal specimen was more pronounced than that of the equaxed one at the center layer. Nevertheless the cold rolled textures of Type 430 steel have demonstrated a rather similar development . Compared to Type 430 steel the development of the $\alpha$-fibre in the center layer of Type 409L steel was much more pronounced. The relation between texture evolution and ridging behaviour has been discussed.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.140-142
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• 2006

The bend ductility of Type 410S ferritic stainless steel overlay weld on carbon steel was investigated. Overlay weld that was stabilized with Nb had large columnar ferrite grain and Nb precipitate on grain boundary. And that caused fracture when bend test without concern of PWHT condition. Proper bend ductility at as-welded condition was achieved by refining ferrite grain with addition of $0.04{\sim}0.09%$ Al and $0.2{\sim}0.5%$ Ti that make oxide, carbide and nitride at high temperature.

• Corrosion Science and Technology
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• v.2 no.3
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• pp.127-134
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• 2003

In order to explain the effect of alloying Cu on the corrosion resistance of stainless steels in chloride media for both ferritic and austenitic stainless steels, the corrosion behavior of Cu-bearing stainless steels was investigated. Alloying Cu showed beneficial effect in an active potential range and harmful effect in a noble potential range. The beneficial effect of alloying Cu was explained by the stability of deposited Cu on an anodic surface. Difference in the effect of alloying Cu between the ferritic and austenitic steels was ascribed by the differences in their corrosion potentials and the morphology of the deposited Cu.