The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform
Ryuichiro Ebara - One of the best experts on this subject based on the ideXlab platform.
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CORROSION FATIGUE BEHAVIOR OF SHIP HULL STRUCTURAL STEELS
2016Co-Authors: Ryuichiro EbaraAbstract:This paper seeks to describe on corrosion fatigue behavior of ship hull structural steels mainly based upon the author's recent experimental results. First it is described on general view of corrosion fatigue strength and corrosion fatigue crack propagation behavior of high strength steels. Then it is presented on corrosion fatigue strength of ship hull structural steel in ballast tank environment. It is demonstrated that tar epoxy resin coating effect on corrosion fatigue strength of KA32(TMCP) steel is observed in lower nominal stress range. Corrosion fatigue crack propagation behavior of ship hull structural steels in cargo Oil environment is also presented. Fatigue crack propagation rate for KA36(TMCP) and KAS steel is accelerated in the region where ⊿K is above about 16MPa m1/2 in the Sour Crude Oil containing 400ppm H2S. A couple of future problems on corrosion fatigue research of ship hull structural steels are also touched in brief
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effects of Sour Crude Oil on fatigue properties of steel plates for shipbuilding
International Journal of Fatigue, 1994Co-Authors: H Ouchi, Ryuichiro Ebara, J Kobayashi, T Ishikawa, H Takezawa, Yoshikazu YamadaAbstract:The concentration of diffusible hydrogen introduced into steel was measured, and fatigue crack growth tests and fatigue life tests were carried out in Sour Crude Oil containing a high concentration of hydrogen sulfide and under electrolytic hydrogen-charging conditions in neutral solution, using a high strength steel produced by the thermo-mechanical control process (TMCP) and a mild steel which are steels for hull plates. Comparison of the results demonstrated that a very small amount of hydrogen such as that introduced into steel from Sour Crude Oil under atmospheric pressure accelerated the fatigue crack growth in the high {Delta}K regime and shortened the fatigue life in the high stress range region, but did not shorten the fatigue life in the low stress region. The electrolytic hydrogen-charging condition appeared to be appropriate as a fatigue-crack-growth test environment to simulate Sour Crude Oil. The deterioration of fatigue characteristics of the TMCP high strength steel was similar with that of the mild steel.
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corrosion fatigue strength of ship structural steel plates and their welded joints in Sour Crude Oil
1994Co-Authors: Eiichi Watanabe, Ryuichiro Ebara, Hiroshi Yajima, Shigato Matsumoto, Yoshifumi Nakano, Eiji SugieAbstract:This presentation is mainly on the corrosion fatigue crack propagation behavior of the ship structural steels such as KA36 (TMCP) and KAS in a Sour Crude Oil environment, based on the corrosion fatigue crack propagation test and corrosion fatigue life test results in Sour Crude Oil containing 400 ppm H{sub 2}S and in air. The crack propagation rate of the base metals of these steels in the Sour Crude Oil was accelerated in the stress intensity factor range, {Delta}K higher than about 16 MPa/m. The ratio of acceleration of the crack propagation rate, da/dN, in the Sour Crude Oil with the {Delta}K of 30 MPa/m was 7 for KA36 (TMCP) and KA36 steels. The crack propagation rate of the heat affected zone and the weld metal of the KA36 (TMCP) in the Sour Crude Oil was also accelerated for the {Delta}K higher than about 20 to 25 MPA/m. In the higher stress range of S-N curves for the notched round bar specimens of the KA36 (TMCP), the influence of Sour Crude Oil containing 400 ppm H{sub 2}S on the fatigue life was obviously observed. The ratio of fatigue life in air to that in the Sour Crude Oil decreased withmore » decreasing stress to unity at the lower axial stress of about 200 MPa. It was found that brittle striations appeared predominantly in the accelerated crack propagation area of the fracture surface of the base metal and weldments in the Sour Crude Oil. The striation spacing per cycle, S, obtained from the measured striation spacing {Delta}S versus {Delta}K curve was well in agreement with the da/dN {approximately} {Delta}K curve in the accelerated crack propagation area. It can be concluded that the environment enhancement of the crack propagation rate in Sour Crude Oil is dependent on hydrogen evolved by the reaction between the ship structural steels and the hydrogen sulfide in Sour Crude Oil.« less
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the quantitative analysis of fatigue fracture surfaces of ht 50 tmcp and mild steel in Sour Crude Oil
Journal of The Society of Materials Science Japan, 1994Co-Authors: Ryuichiro Ebara, Yoshikazu YamadaAbstract:Corrosion fatigue crack propagation tests of HT50 (TMCP) and mild steel and corrosion fatigue life test of HT50 (TMCP) were conducted in Sour Crude Oil containing 400ppm H2S. The detailed SEM observations were carried out on these fracture surfaces obtained. The crack propagation rate of these steels in the Sour Crude Oil was accelerated in the stress intensity factor range, ΔK higher than about 16MPa√m. The ratio of acceleration of the crack propagation rate, da/dN in the Sour Crude Oil in the ΔK of 30MPa√m was 7 for HT50 (TMCP) and mild steel.In the higher stress range of S-N curve for the round notched bar specimens of HT50 (TMCP), the influence of Sour Crude Oil containing 400ppm H2S on the fatigue life was observed obviously. The fatigue life ratio decreased with decreasing the stress to unity at the lower axial stress.It was found that the crack propagated predominantly on the cleavage fracture surface in association with brittle striation in the accelerated crack propagation area of fracture surface in the Sour Crude Oil.The striation spacing per cycle, S obtained from the measured striation spacing ΔS versus ΔK curve was well coincident with the da/dN-ΔK curve in the accelerated crack propagation area.It might be concluded that the environmental enhancement of the fatigue crack propagation rate in Sour Crude Oil is dependent on hydrogen evolved by reaction between the structural steels and hydrogen sulfide in the Sour Crude Oil.
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corrosion fatigue strength of ship structural steel plates in Sour Crude Oil
Journal of the Society of Naval Architects of Japan, 1993Co-Authors: Ryuichiro Ebara, Yoshikazu Yamada, Akira Fushimi, Daisuke Sakai, Eiichi Watanabe, Hiroshi YajimaAbstract:There have been no tests carried out on the fatigue strength of ship's hull structural members in large Oil tankers because of the difficulty of conducting tests in the Crude Oil which contains H2S gas which is toxic to the human body. The authors manufactured Sour Crude Oil corrosion fatigue testing apparatus for trials and then conducted corrosion fatigue crack propagation tests and corrosion fatigue life tests for KA 36 (TMCP) and KAS steel in Sour Crude Oil containing 400 ppm of H2S gas. Consequently, it was found that corrosion fatigue cracks propagated on cleavage facets associated with brittle striation and corrosion fatigue crack propagation rages for the KA 36 (TMCP) and KAS steel are accelerated in the region where K is relatively large in Sour Crude Oil containing 400 ppm of H2S. The corrosion fatigue crack propagation mechanism is also discussed for these steels in a Sour Crude Oil environment.
Yoshikazu Yamada - One of the best experts on this subject based on the ideXlab platform.
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effects of Sour Crude Oil on fatigue properties of steel plates for shipbuilding
International Journal of Fatigue, 1994Co-Authors: H Ouchi, Ryuichiro Ebara, J Kobayashi, T Ishikawa, H Takezawa, Yoshikazu YamadaAbstract:The concentration of diffusible hydrogen introduced into steel was measured, and fatigue crack growth tests and fatigue life tests were carried out in Sour Crude Oil containing a high concentration of hydrogen sulfide and under electrolytic hydrogen-charging conditions in neutral solution, using a high strength steel produced by the thermo-mechanical control process (TMCP) and a mild steel which are steels for hull plates. Comparison of the results demonstrated that a very small amount of hydrogen such as that introduced into steel from Sour Crude Oil under atmospheric pressure accelerated the fatigue crack growth in the high {Delta}K regime and shortened the fatigue life in the high stress range region, but did not shorten the fatigue life in the low stress region. The electrolytic hydrogen-charging condition appeared to be appropriate as a fatigue-crack-growth test environment to simulate Sour Crude Oil. The deterioration of fatigue characteristics of the TMCP high strength steel was similar with that of the mild steel.
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the quantitative analysis of fatigue fracture surfaces of ht 50 tmcp and mild steel in Sour Crude Oil
Journal of The Society of Materials Science Japan, 1994Co-Authors: Ryuichiro Ebara, Yoshikazu YamadaAbstract:Corrosion fatigue crack propagation tests of HT50 (TMCP) and mild steel and corrosion fatigue life test of HT50 (TMCP) were conducted in Sour Crude Oil containing 400ppm H2S. The detailed SEM observations were carried out on these fracture surfaces obtained. The crack propagation rate of these steels in the Sour Crude Oil was accelerated in the stress intensity factor range, ΔK higher than about 16MPa√m. The ratio of acceleration of the crack propagation rate, da/dN in the Sour Crude Oil in the ΔK of 30MPa√m was 7 for HT50 (TMCP) and mild steel.In the higher stress range of S-N curve for the round notched bar specimens of HT50 (TMCP), the influence of Sour Crude Oil containing 400ppm H2S on the fatigue life was observed obviously. The fatigue life ratio decreased with decreasing the stress to unity at the lower axial stress.It was found that the crack propagated predominantly on the cleavage fracture surface in association with brittle striation in the accelerated crack propagation area of fracture surface in the Sour Crude Oil.The striation spacing per cycle, S obtained from the measured striation spacing ΔS versus ΔK curve was well coincident with the da/dN-ΔK curve in the accelerated crack propagation area.It might be concluded that the environmental enhancement of the fatigue crack propagation rate in Sour Crude Oil is dependent on hydrogen evolved by reaction between the structural steels and hydrogen sulfide in the Sour Crude Oil.
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corrosion fatigue strength of ship structural steel plates in Sour Crude Oil
Journal of the Society of Naval Architects of Japan, 1993Co-Authors: Ryuichiro Ebara, Yoshikazu Yamada, Akira Fushimi, Daisuke Sakai, Eiichi Watanabe, Hiroshi YajimaAbstract:There have been no tests carried out on the fatigue strength of ship's hull structural members in large Oil tankers because of the difficulty of conducting tests in the Crude Oil which contains H2S gas which is toxic to the human body. The authors manufactured Sour Crude Oil corrosion fatigue testing apparatus for trials and then conducted corrosion fatigue crack propagation tests and corrosion fatigue life tests for KA 36 (TMCP) and KAS steel in Sour Crude Oil containing 400 ppm of H2S gas. Consequently, it was found that corrosion fatigue cracks propagated on cleavage facets associated with brittle striation and corrosion fatigue crack propagation rages for the KA 36 (TMCP) and KAS steel are accelerated in the region where K is relatively large in Sour Crude Oil containing 400 ppm of H2S. The corrosion fatigue crack propagation mechanism is also discussed for these steels in a Sour Crude Oil environment.
Christopher M Saffron - One of the best experts on this subject based on the ideXlab platform.
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hydrogen network optimization by integrating impurity distributions of a fluid catalytic cracker and hydrogenation reaction kinetics
Journal of Cleaner Production, 2018Co-Authors: Xiaoqiang Liang, Lixia Kang, Yongzhong Liu, Christopher M SaffronAbstract:Abstract Minimizing hydrogen consumption in hydrotreating (HDT) units is increasingly important as more heavy and Sour Crude Oil are processed in refineries. A fluid catalytic cracking (FCC) unit commonly links the vacuum gas Oil HDT unit with the cracked diesel and the cracked gasoline HDT units. In the course of processing, undesired impurities, such as sulfur, nitrogen and aromatics, pass from the upstream HDT unit, to the FCC unit where they are cracked, and then to the downstream HDT units. As impurity removal can be accomplished in the upstream and downstream HDT units, it is important to understand how the interconnecting FCC unit affects impurity distributions of the adjacent HDT units when minimizing the hydrogen consumption of the whole hydrogen network. A stepwise optimization strategy, using three mathematical models (designated M1, M2 and M3), is proposed to minimize the hydrogen consumption considering impurity distributions within the FCC unit and hydrogenation reaction kinetics. By integrating the FCC unit, M1 is used to investigate the effects of the FCC unit on the upstream and downstream HDT units’ purification degrees and their hydrogen consumption. Based on the hydrogenation reaction kinetics, M2 is used to optimize the operating conditions and to minimize hydrogen consumption within the HDT units according to optimal purification degrees as established by M1. M3 is a hydrogen network optimization model, which is used to obtain the optimal structure of the hydrogen network. Eco-indicator 99 was employed to evaluate the environmental impacts of the hydrogen network. Results show that the hydrogen consumption, the total annual cost (TAC) and the environmental impacts of the hydrogen network are reduced by 44.5%, 34.4% and 38.6%, respectively, compared to the original operation. Optimization without considering the FCC unit and the hydrogenation reaction kinetics only reduced by 32.6%, 19.1% and 28.2% in the hydrogen consumption, TAC and the environmental impacts. Consequently, the effects of the FCC unit and the hydrogenation reaction kinetics should be considered when optimizing the hydrogen network in a refinery.
H Ouchi - One of the best experts on this subject based on the ideXlab platform.
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effects of Sour Crude Oil on fatigue properties of steel plates for shipbuilding
International Journal of Fatigue, 1994Co-Authors: H Ouchi, Ryuichiro Ebara, J Kobayashi, T Ishikawa, H Takezawa, Yoshikazu YamadaAbstract:The concentration of diffusible hydrogen introduced into steel was measured, and fatigue crack growth tests and fatigue life tests were carried out in Sour Crude Oil containing a high concentration of hydrogen sulfide and under electrolytic hydrogen-charging conditions in neutral solution, using a high strength steel produced by the thermo-mechanical control process (TMCP) and a mild steel which are steels for hull plates. Comparison of the results demonstrated that a very small amount of hydrogen such as that introduced into steel from Sour Crude Oil under atmospheric pressure accelerated the fatigue crack growth in the high {Delta}K regime and shortened the fatigue life in the high stress range region, but did not shorten the fatigue life in the low stress region. The electrolytic hydrogen-charging condition appeared to be appropriate as a fatigue-crack-growth test environment to simulate Sour Crude Oil. The deterioration of fatigue characteristics of the TMCP high strength steel was similar with that of the mild steel.
Hiroshi Yajima - One of the best experts on this subject based on the ideXlab platform.
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corrosion fatigue strength of ship structural steel plates and their welded joints in Sour Crude Oil
1994Co-Authors: Eiichi Watanabe, Ryuichiro Ebara, Hiroshi Yajima, Shigato Matsumoto, Yoshifumi Nakano, Eiji SugieAbstract:This presentation is mainly on the corrosion fatigue crack propagation behavior of the ship structural steels such as KA36 (TMCP) and KAS in a Sour Crude Oil environment, based on the corrosion fatigue crack propagation test and corrosion fatigue life test results in Sour Crude Oil containing 400 ppm H{sub 2}S and in air. The crack propagation rate of the base metals of these steels in the Sour Crude Oil was accelerated in the stress intensity factor range, {Delta}K higher than about 16 MPa/m. The ratio of acceleration of the crack propagation rate, da/dN, in the Sour Crude Oil with the {Delta}K of 30 MPa/m was 7 for KA36 (TMCP) and KA36 steels. The crack propagation rate of the heat affected zone and the weld metal of the KA36 (TMCP) in the Sour Crude Oil was also accelerated for the {Delta}K higher than about 20 to 25 MPA/m. In the higher stress range of S-N curves for the notched round bar specimens of the KA36 (TMCP), the influence of Sour Crude Oil containing 400 ppm H{sub 2}S on the fatigue life was obviously observed. The ratio of fatigue life in air to that in the Sour Crude Oil decreased withmore » decreasing stress to unity at the lower axial stress of about 200 MPa. It was found that brittle striations appeared predominantly in the accelerated crack propagation area of the fracture surface of the base metal and weldments in the Sour Crude Oil. The striation spacing per cycle, S, obtained from the measured striation spacing {Delta}S versus {Delta}K curve was well in agreement with the da/dN {approximately} {Delta}K curve in the accelerated crack propagation area. It can be concluded that the environment enhancement of the crack propagation rate in Sour Crude Oil is dependent on hydrogen evolved by the reaction between the ship structural steels and the hydrogen sulfide in Sour Crude Oil.« less
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corrosion fatigue strength of ship structural steel plates in Sour Crude Oil
Journal of the Society of Naval Architects of Japan, 1993Co-Authors: Ryuichiro Ebara, Yoshikazu Yamada, Akira Fushimi, Daisuke Sakai, Eiichi Watanabe, Hiroshi YajimaAbstract:There have been no tests carried out on the fatigue strength of ship's hull structural members in large Oil tankers because of the difficulty of conducting tests in the Crude Oil which contains H2S gas which is toxic to the human body. The authors manufactured Sour Crude Oil corrosion fatigue testing apparatus for trials and then conducted corrosion fatigue crack propagation tests and corrosion fatigue life tests for KA 36 (TMCP) and KAS steel in Sour Crude Oil containing 400 ppm of H2S gas. Consequently, it was found that corrosion fatigue cracks propagated on cleavage facets associated with brittle striation and corrosion fatigue crack propagation rages for the KA 36 (TMCP) and KAS steel are accelerated in the region where K is relatively large in Sour Crude Oil containing 400 ppm of H2S. The corrosion fatigue crack propagation mechanism is also discussed for these steels in a Sour Crude Oil environment.