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Heavy Wall Thermo ‐ mechanically Rolled Plates for Offshore Construction Use
Author(s) -
Heigl Gemot,
Lengauer Harald,
Hodnik Peter
Publication year - 2008
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.200806223
Subject(s) - weldability , materials science , toughness , submarine pipeline , deformation (meteorology) , welding , slab , metallurgy , cracking , composite material , structural engineering , engineering , geotechnical engineering
The growing energy consumption of the world made the exploitation of many offshore oil & gas fields feasible. In order to have the benefit of high strength and toughness together with good weldability, thermo‐mechanical rolling has been developed. In the construction of offshore structures plate thicknesses in excess of 50 mm are common which could up to now only be manufactured with restricted mechanical properties and a loss of productivity. The necessary fine grain structure is obtained by a minimum of four times total deformation in the thermo‐mechanical rolling process with accelerated cooling. For a steel mill this means that a change to a higher slab thickness was obligatory. In the plate mill the main drives were replaced in order to increase the torque and as a consequence get better deformation in the centre of the slabs. The accelerated cooling unit was revamped to a higher water pressure to obtain higher cooling rates and additionally enlarged to reach lower cooling stop temperatures. The results obtained with this new concept are presented in terms of strength, toughness and weldability for a 75 mm plate. This together with fracture mechanical data on the plate and on the weld demonstrates the effectiveness of the new technical concept and set a new benchmark in steel properties.