• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.19 no.2
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• pp.102-108
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• 2023

A Chloride-induced stress corrosion cracking (CISCC) of austenite stainless steel in dry cask storage system (DCSS) can occur with extending service time than originally designed. Cold spray coating (CSC) not only form a very dense microstructure that can protect from corrosive environments, but also can generate compressive stress on the surface. This characteristic of CSC process is very helpful to increase the resistance for CISCC. CSC with several powders, such as 304L, 316L and Ni can be optimized to form very dense coating layer. In addition, the impact energy generated as the CSC powder collides with the surface of base metal at a speed of Mach 2 or more can remove the residual tensile stress of welding area and serve the compress stress. CSC layers include no oxidation and no contamination with under 0.2% porosity, which is enough to protect from the penetration of corrosive chloride. Therefore, the CSC coating layer can be accompanied by a function that can be disconnected from the corrosive environment and an effect of improving the residual stress that causes CISCC, so the canister's CISCC resistance can be increased.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.232-233
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• 2005

Stainless steel has been stably used closed by passivity oxidation films($Cr_2O_3$) is made by neutral atmospheric environment. However, passivity oxidation films of the surface of stainless steel occasionally comes to be destroyed in seawater which is influenced by an environment having halogen ion like $Cl^-$, then, localization corrosion comes to occur. Stainless steel 304 for shaft system material of the small-size FRP fishing boat on seawater environments made an experiment on simulation of sacrifical anode(Al, Zn). Through these experiment and study, following results have been obtained ; According to the field inspection and corrosion simulation, the corrosion on the 2nd class stainless steel shaft(STS 304) in FRP fishing boat has been verified to occur by crevice corrosion and galvanic corrosion etc.. According to the comparison and analysis of Stainless steel 304 shaft materials after simulation leaving unprotected and applying cathodic protection, unprotected shaft specimen of stainless steel 304 was severely corroded, but, protected shaft specimen was not totally corroded. This result is assumed to be made by the facts that anodic reaction, $Fe{\rightarrow}Fe^{2+}$ + $2e^-$, has been restricted by the cathodic protection current of sacrificial anode material.

• Journal of Surface Science and Engineering
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• v.53 no.5
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• pp.257-264
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• 2020

Anodization of Fe and Fe alloys is one of the most promising techniques to obtain iron oxide films applying to the various electrochemical devices due to their electrochemical catalytic properties. In this study, we investigate on the preparation of anodic iron oxide composite incorporated with WO₃ through a single-step anodization of stainless steel type-304 (STS304) as a substrate. The effects of applied voltage and tungsten precursor on the structural characteristics of iron oxide composite with different amount of incorporated WO₃ were observed. It is demonstrated that when the voltage of 60 V applied with 20 mM of Na₂WO₄ as a precursor, anodic iron oxide composite with a large pore diameter and a thick oxide length in which WO₃ is uniformly incorporated is obtained.

• 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.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.5
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• pp.727-733
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• 2020

Recently, reciprocating cryogenic pumps are mainly developed for small-and-mid sized fuel supply systems. Centrifugal type pumps are not actively developed. Most cryogenic submerged pumps are imported. For transportation, cryogenic liquefied natural gas requires the liquid pump technology that can works in extreme evironments. In order to transport liquefied natural gas, it is necessary to apply pump technology. This is the fundamental research for developing the submerged pump technology applicable to the transportation and storage system equipment of cryogenic liquefied system. It tries to secure basic design materials through reverse-engineering in the cryogenic submerged pump development. Regarding materials, STS-304 and STS-431 which are stainless materials widely used in the cryogenic area are applied. Aluminum alloy is applied to impeller and upper manifolder and the pump rotates at the high speed of 6,000rpm.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.12-19
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• 2000

In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also development of in-process real-time weld quality(such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve(SUH3-SUH35 dissimilar steels of 12.3mm, 16mm, 20mm and 24mm in diameters) were performed, comparing with the other FRW matches of materials such as SUH3 to SUH31, SUH3 to STS303 and SUH3 to STS304. As an important result, the techniques for dissimilar friction welding optimization of engine heat resisting steels SUH3 and SUH35( 12.3mm, 16mm, 20mm, 24mm) and its real-time weld quality evaluation by AE were developed, considering on both diameter and carbon equivalent effects.

• Transactions on Electrical and Electronic Materials
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• v.6 no.3
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• pp.128-132
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• 2005

In this paper, we have investigated the characteristics of the magnetic abrasive using sludge on polishing of internal finishing of seamless stainless steel (STS304) tube applying magnetic abrasive polishing. Either white alumina (WA) or green carborundum (GC) grain was used to resin sludge at a low temperature, and the sludge of magnetic abrasive powder was synthesized and crushed into 200 meshes. Surface roughness was measured before and after polishing, and more than $40\%$ of improvement of surface roughness was achieved when WA grain was used under a specific condition. Even though some degree of surface roughness due to deeper scratches still exist, but the result showed a prospective magnetic abrasive polishing using sludge with WA or GC grains.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.79-87
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• 2001

In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also the development of in-process real-time weld quality (such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve (SUH3-SUH35 dissimilar steels of 12.3mm, 16mm, 20mm, and 24mm in diameters) were performed, comparing with the other FRW matches of materials such as SUH3 to SUH31, STS303 and SUH3 to STS304. As an important result, the techniques for dissimilar friction welding optimization of engine heat resisting steels SUH3 and SUH35 (12.3mm, 16mm, 20mm, and 24mm) and its real-time weld quality evaluation by AE was developed, considering on both diameter and carbon equivalent effects.

• Journal of Applied Reliability
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• v.6 no.1
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• pp.51-61
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• 2006

Failure analyses were conducted on a crank shaft and a chock liner by using X-ray diffraction, optical microscopy and SEM/EDS techniques. In the crank shaft, a crack developed where a maximum tensile stress coincided with band structure formed by hot forging. The maximum tensile stress was observed to originate from volume expansion during high frequency induction heat treatment and the band structure to develop between upper and lower dies during hot forging. In the chock liner, the wear mechanism varied with the chemical affinity and hardness of liner material relative to friction pair of housing liner. Brass of low chemical affinity and hardness compared to housing liner showed uniform adhesive wear. STS 304 and STS 420J2 of high chemical affinity showed galling and scoring respectively.

• Journal of Surface Science and Engineering
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• v.22 no.3
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• pp.135-144
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• 1989

Aluminium Oxide was deposited with a C.V.D.-technique on various substrates. The effects of various treating condition such as temperature, time, heat resistance and composition of substrates were investigated in order to understand the relationship of structure, property and process. Grain size depends upon the activity of adsorption siite and coarsened with increasing temperature and time. Deposition rate decreases in order of electrolytic iron, carbon steel STS430 and STS304, since the active site for adsorption of reactant was more decreased for Cr and Ni than Fe. Oxidation resistance of alumina coated specimens improved markedely and that of stainless steel was prominent.