Metallurgical design basis, qualification testing, and production history of 50 ksi and 60 ksi steel plate for the MARS TLP deck fabrication
- Sumitomo Metal Industries, Ltd., Kashima (Japan)
- Shell Offshore, Inc., Houston, TX (United States)
The MARS TLP fast-track deck construction project required rapid qualification and production of 50 ksi and 60 ksi steel plate. This paper describes the development of high-performance 4 in. (101.6mm) 50 ksi and 3 in. (76.2mm) 60 ksi steels of a modified API 2W composition and presents the production history for the MARS deck steel order. The same base composition was used for both grades via innovative proprietary TMCP practice. Utilization of the mono-chemistry steel allowed for production of a wide range of thicknesses and grades in a very short time frame via a simplified melting schedule and made it possible to minimize the number of new welding procedures to be developed by the deck fabricator. Extremely low carbon equivalent allowed the implementation of low fabrication preheats, with resultant cost and fabrication schedule savings. The chemical composition of the steel was specifically designed for this project and qualification testing in accordance with API RP 2Z verified high heat-affected zone CTOD toughness free of local brittle zones over a wide range of heat input and interpass temperature. Strict production process control resulted in very tight production property histograms with all steel being verified to have Charpy V-notch transition temperatures below {minus}80 C ({minus}112 F) at the plate mid-width, mid-thickness position. The success of the MARS deck steel rapid qualification, production and delivery was enabled by close teamwork between deck design engineers, construction fabrication contractor, and steelmaker for this steel.
- OSTI ID:
- 205423
- Report Number(s):
- CONF-950695-; ISBN 0-7918-1309-6; TRN: IM9615%%203
- Resource Relation:
- Conference: International conference on offshore mechanics and arctic engineering, Copenhagen (Denmark), 18-22 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of OMAE 1995 -- Proceedings of the 14. international conference on offshore mechanics and arctic engineering. Volume 3: Materials engineering; Salama, M.M. [ed.] [Conoco, Inc., Ponca City, OK (United States)]; Toyoda, Masao [ed.] [Osaka Univ., Suita, Osaka (Japan)]; Liu, S. [ed.] [Colorado School of Mines, Golden, CO (United States)]; Santos, J.F. dos; Kocak, M. [eds.] [GKSS, Geesthacht (Germany)]; Patterson, E.A. [ed.] [Univ. of Sheffield (United Kingdom)]; Berge, S. [ed.] [Univ. of Trondheim (Norway)]; Stacey, A. [ed.] [Health and Safety Executive, London (United Kingdom). Offshore Safety Div.]; PB: 600 p.
- Country of Publication:
- United States
- Language:
- English
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