https://bura.brunel.ac.uk/bitstream/2438/13497/1/Fulltext.pdf

Material properties and compressive local buckling response of high strength steel square and rectangular hollow sections

Offshore wind has been identified as one of the emerging sustainable energy sources in the United Kingdom. Offshore wind turbine support structures are mainly fabricated of welded tubular members, similar to structures used for oil and gas applications, and are exposed to highly dynamic, harsh marine environments. However, their structural details and design requirements are significantly different due to the magnitude and frequency of operational and environmental loadings acting on the support structures. These conditions would significantly affect their structural dynamic response characteristics due to the magnitude of the applied load. This may therefore have some significant effects on the crack growth behaviour and the extent to which corrosion can be associated with damage to the support structures. However, the magnitude of the applied load might depend on turbine size, water depth, soil conditions and type of support structures. It is therefore essential to design wind turbine support structures against prescribed limit states to ensure economical and safe operation. This paper presents a review of corrosion fatigue in offshore structures as regards the effects of seawater, environment and mechanical loading. Existing literature which documents results from previous campaigns is presented, including works referring to oil and gas structures, highlighting the significant difference in the aspects of loading and use of modern fabrication processes, with a view to illustrating the requirements for an update to the existing corrosion fatigue database that will suit offshore wind structures׳ design requirements.

Review of corrosion fatigue in offshore structures: Present status and challenges in the offshore wind sector

Mechanical properties and design recommendations of very high strength steel S960 in fire

Some of the major manufacturing processes and corresponding mechanical properties of titanium clad steel plates were analyzed, and the consequences of research, manufacturing, and application of titanium clad steel plates in both markets of China and overseas were also summarized. As an economical and environmentally friendly technology, the roll bonding process is expected to become the next-generation mainstream process for the manufacturing of titanium clad steel plate. Some of the crucial and most important technical problems of this particular process, including vacuum sealing technology, surface treatment process technology, application of a transition layer, and rolling process, were discussed along with the advantageous mechanical properties and life-cycle economy of these plates processed by this technology. Finally, the market needs, application trends, and requirements of titanium clad steel plate were also considered from industries of petrochemical, shipbuilding, marine, and electric power.

Manufacturing Technology and Application Trends of Titanium Clad Steel Plates

Coatings have been widely used in the corrosion protection of metallic materials in marine environments. In this work, the corrosion and tribocorrosion behavior of three potential coatings employed in offshore applications has been evaluated. The coatings studied were a Thermally Sprayed Carbide coating with an organic sealant (C1), a Thermally Sprayed Aluminum with an organic sealant (C2), and an epoxydic organic coating reinforced with ceramic platelets (C3). Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization techniques have been employed to assess the corrosion performance of the coatings in synthetic seawater. Furthermore, unidirectional ball-on-disc tribocorrosion tests were performed to study the response of the coatings subjected to simultaneous action of wear and corrosion. The coatings were found to provide to the steel substrate with enhanced corrosion resistance, both in absence and during wear process, and to improve in the tribological properties with lower coefficients of friction in seawater. The coating less affected by sliding in terms of corrosion resistance was C2 coating, which also showed the lowest coefficient of friction.

Evaluation of protective coatings for offshore applications. Corrosion and tribocorrosion behavior in synthetic seawater

High strength steels (yield strength > 500MPa to typically 700MPa) are increasingly being used in offshore structural applications including production jack-ups with demanding requirements. They offer a number of advantages over conventional steels, particularly where weight is important. This review considers the types of steel used offshore, their mechanical properties, their weldability and their suitability for safe usage offshore in terms of fracture, fatigue, static strength, cathodic protection and hydrogen embrittlement performance. It also addresses the performance of high strength steels at high temperatures and at high strain rates and outlines the difficulties in working with the very limited published codes and standards discussing performance in the field. Current design restrictions such as limits on yield ratios, susceptibility to hydrogen cracking including the influence of sulphate reducing bacteria (SRBs) and the management of the behaviour of such steels in seawater undercathodic protection conditions are discussed. Makes recommendations to encourage the wider use of high strength steels in the future and identifies areas where further study is required. (author)

J Billingham

Papers

Review of the performance of high strength steels used offshore