• 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.

• The Journal of Advanced Prosthodontics
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• 제8권4호
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• pp.304-312
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• 2016

PURPOSE. The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS. Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS. The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION. 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla.

• 비파괴검사학회지
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• 제23권2호
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• pp.148-155
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• 2003

저방사화 페라이트강인 JLF는 핵융합로의 블랑켓과 같은 열교환기의 재료로써 유용한 재료이다. 이 재료의 광범위한 적용을 위해서는 JLF강과 다른 재료와의 접합기술의 개발이 중요하다. 최근 두 이종재료간의 접합에는 마찰용접이 많이 이용되고 있으며 본 연구에서도 JLF강과 STS304 간의 마찰용접에 의한 용접특성을 평가하였으며 특히 비파괴기법중의 하나인 음향방출 기법을 이용하여 두 이종재료간의 용접특성 및 최적의 용접조건을 평가하였다. 음향방출 파라미터중의 하나인 카운트와 사상수 등이 최적용접조건 및 용접품질을 평가하는데 유효한 파라미터들이었다.

• 동력기계공학회지
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• 제13권3호
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• pp.33-39
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• 2009

The aim of this study is to analyze the welds characteristics of the 205 stainless steel pipe for application of street pole material. The welds corrosion behavior of STS 205 pipe in 0.1 N sulphuric acid solution and 5% NaCl solution at room temperature was studied using both salt spray test and potentiodynamic polarization experiment. The morphology and components of corrosion products on surface of STS 205 pipe welds were investigated using SEM/EDX. The tensile strength and yield strength values of STS 205 plate were 715 MPa and 369 MPa respectively. The microvickers hardness values of STS 205 pipe welds were slightly increased than that of STS 304 pipe welds. Corrosion current density($I_{corr.}$) and critical current density($I_{crit.}$) values of STS 205 pipe welds in 3.5% NaCl solution were $1.89{\times}10^{-6}$ $A/cm^2$ and $15.8{\times}10 ^{-6}$ $A/cm^2$. The corrosion resistance of SIS 205 pipe welds was similar to its STS 304 pipe welds. The STS 205 and 304 pipe welds passive films were chromium oxide. Especially, the STS 205 pipe welds showed good corrosion resistance in 0.1 N sulphuric acid. This is attributed to the forming of protective chromium oxide on the surface of STS 205 pipe welds.