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- 검색키워드
- 주제어 : hydrogen embrittlement(HE) (검색결과 6 건)
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Hyung-Seop Shin(신형섭),Juho Yeo(여주호),Jaewon Cho(조재원),Eunsu Min(민은수),Un-Bong Baek(백운봉) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5
Recently, ANU group has established a simple screening technique for hydrogen embrittlement compatibility of steels, which is adopting an in-situ small-punch (SP) test method and corresponding to the ‘external hydrogen’ condition, and proposed a characterizing factor which is suitable for the SP test. The technique is based on the quantitative evaluation of the hydrogen embrittlement (HE) behaviors of various structural steels for hydrogen energy facilities. To investigate the HE compatibility of metallic materials, the in-situ SP tests were carried out under a high-pressure hydrogen gas environment and at the temperature ranges sensitive to HE. Through the measurement of the reduction of thickness (ROT) at the fractured part of the specimen after SP tests under both H2 and inert gas environments, the relative reduction of thickness (RRT) due to HE can be obtained. The RRT has a similar physical meaning to the relative reduction of area (RRA) obtained by the conventional slow strain-rate tensile test (SSRT), since both factors are based on the ductility induced under hydrogen environments. In this study, it is tried to investigate the hydrogen embrittlement (HE) behaviors of pipeline steels and welds by the in-situ SP test. The ductility-based RRT obtained by in-situ SP tests was used to quantify the HE sensitivity of the base metal and welds under various test conditions corresponding to practical use environments of hydrogen devices. This study will contribute to confirm the validity of in-situ SP tests as a simple test method for the quantitative evaluation of the HE susceptibility of pipeline steel welds.
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Hyung-Seop Shin(신형섭),Eunsu Min(민은수),Sungbeon Kang(강성범),Un-Bong Baek(백운봉) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.11
The introduction of hydrogen pipelines as a method for mass transportation of hydrogen is being considered. In the case of low pressure, it can be considered to use the current pipeline steels for natural gas supply. Quantitative evaluation of the hydrogen embrittlement (HE) sensitivity of pipeline steel welds is necessary in terms of securing stability. ANU group has been established simple screening techniques for HE compatibility of metallic materials, which is adopting both an in-situ small-punch (SP) test method and a simple SSRT using hollow tensile specimens corresponding to the ‘external hydrogen’ condition. Relative reduction of thickness (RRT), a characteristic factor suitable for the established in-situ SP test, was proposed, and the validity of RRT in screening HE susceptibility of various steels could be confirmed by comparison to RRA obtained by a simple SSRT. Practically, there are difficulties in performing SSRT and obtaining comparative data in a high-pressure hydrogen environment. There is a limitation to practically expand the in-situ SP test although it is a simple and effective test technique and to obtain the data validity. Therefore, in this study, for pipeline steel (API X70) welds, a simple SSRT test method using hollow tensile test pieces was newly established based on the similar test principle to the in-situ SP test. It was attempted to support the data reliability and validity of the in-situ SP test through the comparison of RRT to RRA obtained from SSRT tests in high pressure hydrogen environment.
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Changdong Yin,Dongdong Ye,Zhou Xu,Jianjun Chen,Yiwen Wu,Houli Liu,Xin Ge,Qiang Liu,Guiling Zeng 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.8
Understanding and solving the problem of hydrogen damage due to the degradation of service performance of high-strengthsteel caused by hydrogen penetration is a milestone for the reliability improvement of high-end hydrogen energy equipment. From the perspective of microscopic hydrogen movement behavior, this study investigated the permeability of hydrogenin base metal (BM) and welded metal (WM) of 2.25Cr–1Mo–0.25 V steel welded joint through electrochemical hydrogenpermeation test, and the analytical models of hydrogen penetration and hydrogen diffusion in the welding zone were established,and the effect of adding hydrogen-resistant coatings (HRCs) on hydrogen movement behavior in steel substrate wasstudied. The results showed that the diffusivity of hydrogen in WM of the welded joint was significantly lower than thatin BM, and the hydrogen concentration in BM was higher than that in WM at the beginning of hydrogenation without theaddition of HRCs protection, while it tended to be consistent at the later stage. However, the hydrogen concentration in WMwas lower than that in BM after adding HRCs and would be always higher than that in BM after a certain period of time,and the difference was directly related to the hydrogen resistance of the coatings. Additionally, the difference between theintermediate and outer layers for the welding zone steel substrate with and without HRCs presented a trend of rapid increasefollowed by a slow decrease. These findings could provide an important reference value for hydrogen damage protectionmeasures and related researches on HRCs.
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이규영,박광진,배동호 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.5
Sulfide stress corrosion cracking (SSCC) in crude oil field environment containing hydrogen sulfide (H2S) has been recognized as a material degradation and damage mechanism. Laboratory data and field experience have demonstrated that extremely low concentration of H2S may be sufficient to lead to SSCC failure of susceptible materials. In some cases, sulfides may act synergistically with chlorides to produce SSCC failures. SSCC mechanism is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weld of susceptible materials. In the heat-affected zones adjacent to the weld, there are often very narrow hard zones combined with regions of high residual stress that may become embrittled to such an extent by dissolved atomic hydrogen. On the basis of this understanding, SSCC tests were conducted with smooth specimens of the multi-pass welded ASTM A106 Gr B steel pipe used in the oil industries. And SSCC resistance according to the welding processes was evaluated. From the results, the weld by GTAW+FCAW showed the largest resistance against SSCC.
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Stress Corrosion Cracking Behavior of Al-Cu-Li-Mg-Zr(-Ag )Alloys
Lee, Chang-Soon,Choi, Yong,Park, In Gyu 대한금속학회 2002 METALS AND MATERIALS International Vol.8 No.2
The effect of aging on the stress corrosion cracking (SCC) behavior of Al-Cu-Li-Mg-Zr(-Ag) alloys such as Weldalite 049 and AA 8090 was studied by the constant elongation test method to investigate their SCC mechanism. The SCC resistance was not very sensitive under the strain rate of 2×10^-5/sec, whereas it was significantly decreased under the strain rate of 5×10^-6/sec. The SCC preferentially occurred in the intergranular crack mode. The relatively poor SCC resistance of Weldalite 049 in the under-aged condition was improved by aging. Considering the microstructural development during aging, it is related to the dissolution of the precipitation free zone as an anodic area and the strengthening by the coarsening of precipitation.
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