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ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering | 2013

Grade X65 and X70 Heavy Wall (up to 37mm in Thick) UOE Linepipe for Sour Service

Haruo Nakamichi; Nobuyuki Ishikawa; Shigeru Endo; Akihiko Tanizawa; Toru Kawanaka; Shinichi Kakihara; Noriaki Uchitomi

Based on the increasing demand for natural gas to be extracted under severe environmental conditions, requirements for thicker sour service pipe steels with high strength (X65 grades or more) are increasing. In order to achieve both a resistance to hydrogen induced cracking (HIC) and better mechanical properties, it is important to obtain a homogeneous microstructure. For this purpose, we manufactured API X65 and X70 heavy wall (up to 37mm in thick) UOE linepipe for sour service utilizing an advanced thermo mechanical control process (TMCP) employing the theoretical maximum cooling rate with water (the ‘ultimate cooling rate’) and homogeneous temperature distribution in accelerated cooling. For applications in deeper water, higher pipe thickness to diameter ratio (t/D) is required. However, during pipe forming, these high ratio pipes suffer higher plastic strain in the vicinity of the surface. This plastic strain causes increasing surface hardness and HIC resistance may deteriorate. It is important to evaluate the effect on strain systematically based on the difference of microstructure morphologies. Therefore, the effect of bending strain on HIC properties was investigated through a simulated laboratory bending test with a strain of up to 8.9%. It was found that homogeneous bainitic microstructure can prevent HIC even under a higher bending strain. On the other hand, crack area ratio (CAR) was almost doubled when 5% strain was applied near the surface area in the material in which inclusion morphologies were not optimized.Copyright


2012 9th International Pipeline Conference | 2012

Heavy Gauge UOE Pipe With Improved Compressive Strength for Offshore Pipeline

Nobuyuki Ishikawa; Hitoshi Sueyoshi; Kimihiro Nishimura; Osamu Yamamoto; Akihiko Tanizawa; Yasumitsu Kiyoto; Daisuke Naganuma

Offshore gas pipeline development has been expanding toward deeper water region that requires pipes to have strong resistance against collapse by external pressure. Collapse pressure is mainly dominated by pipe roundness and compressive strength. In order to improve compressive strength, it is quite important to understand the Bauschinger effect caused by cyclic deformation during pipe forming. Compressive strength is reduced by the Bauschinger effect since compression in the circumferential direction is applied after the pipe expansion. Therefore, prevention of Bauschinger effect is an important issue for improving compressive strength of pipes.In this paper, the effect of microstructure on the Bauschinger effect was investigated. It was proved that microstructure that consists of a hard second phase shows a large strength reduction in reverse loading, since a mixed microstructure with soft phase and hard phase enhances the Bauschinger effect. In order to obtain homogeneous bainitic microstructure, advanced plate production technology, where heat treatment on-line process (HOP) is applied after accelerated cooling, was developed. The steel produced by HOP process exhibits a fine bainitic microstructure with very low amount of hard second phase such as MA constituent. It was demonstrated that the trial produced pipe with HOP process has a higher compressive strength than conventional pipes.In addition to the fundamental study on compressive strength, further investigations were conducted to optimize other material properties for offshore linepipe, such as DWTT property, resistance to hydrogen induced cracking and HAZ toughness to comply with DNV requirements. Production tests of Grade X65 linepipe with the 38mm WT and 876mm OD was carried out. Material and mechanical properties of these heavy gauge linepipes were introduced.Copyright


Archive | 2010

Welded steel pipe for linepipe with superior compressive strength and superior toughness, and process for producing same

Nobuyuki Ishikawa; Akihiko Tanizawa; Hitoshi Sueyoshi; Masayuki Horie; Yasumitsu Kiyoto


Archive | 2010

Welded steel pipe for linepipe with superior compressive strength, and process for producing same

Kimihiro Nishimura; 西村公宏; Nobuyuki Ishikawa; 石川信行; Akihiko Tanizawa; 谷澤彰彦; Hitoshi Sueyoshi; 末吉仁; Masayuki Horie; 堀江正之; Yasumitsu Kiyoto; 清都泰光


Archive | 2010

Welded steel pipe for linepipe with superior compressive strength and excellent sour resistance, and process for producing same

Nobuyuki Ishikawa; Akihiko Tanizawa; Hitoshi Sueyoshi; Masayuki Horie; Yasumitsu Kiyoto; Nobuo Shikanai


Archive | 2010

Steel sheet for high strength steel pipe having high toughness and high deformability, and method for producing the same

Shinji Mitao; Mitsuhiro Okatsu; Nobuo Shikauchi; Akihiko Tanizawa; 眞司 三田尾; 光浩 岡津; 彰彦 谷澤; 伸夫 鹿内


Archive | 2013

THICK-WALLED HIGH-STRENGTH SOUR-RESISTANT LINE PIPE AND METHOD FOR PRODUCING SAME

Akihiko Tanizawa; Haruo Nakamichi; Toru Kawanaka; Noriaki Uchitomi; Takafumi Ozeki


Archive | 2010

WELDED STEEL PIPE FOR LINEPIPE HAVING HIGH COMPRESSIVE STRENGTH AND EXCELLENT SOUR GAS RESISTANCE AND MANUFACTURING METHOD THEREOF

Nobuyuki Ishikawa; Akihiko Tanizawa; Hitoshi Sueyoshi; Masayuki Horie; Yasumitsu Kiyoto; Nobuo Shikanai


Archive | 2008

Welded steel-pipe superior in crushing resistance and manufacturing method therefor

Shigeru Endo; Mitsuhiro Okatsu; Nobuo Shikauchi; Akihiko Tanizawa; 光浩 岡津; 彰彦 谷澤; 茂 遠藤; 伸夫 鹿内


Archive | 2008

Thick steel plate for high toughness line pipe in which lowering of yield stress caused by bauschinger effect is reduced and its production method

Shigeru Endo; Shinji Mitao; Mitsuhiro Okatsu; Nobuo Shikauchi; Akihiko Tanizawa; 眞司 三田尾; 光浩 岡津; 彰彦 谷澤; 茂 遠藤; 伸夫 鹿内

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Mitsuhiro Okatsu

Kawasaki Steel Corporation

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