Microstructure and Mechanical Properties in Hot-Rolled Extra High-Yield-Strength Steel Plates for Offshore Structure and
- PDF / 2,266,219 Bytes
- 13 Pages / 593.972 x 792 pts Page_size
- 26 Downloads / 179 Views
FOR highly stressed steel structures such as offshore platforms and ships, dead weight has a major influence on payload and, hence, economic performance. Oil exploration is moving into deeper sea areas, and the sizes of offshore structure are increasing. Distant transportation requires building very large container ships for improving transportation efficiency, leading to the increase of hull and associated components. Although plates produced via thermomechanically controlled processing (TMCP) with 355 MPa minimum yield stress are well accepted, the minimum thickness of such plates must be increased for large size members for offshore and ship building. To reduce the plate thickness, more advanced high-strength plates are required. Recently, heavy plates equivalent to the NV-E/F460 grades (minimum yield stress ReH = 460 MPa) and NV-D/E/F500 (minimum yield stress ReH = 500 MPa) grades (defined by Det Norske Veritas, i.e., Norway DONGSHENG LIU, Senior Researcher, and TOSHIHIKO EMI, Director, are with the Institute of Research of Iron and Steel, Shasteel, Jinfeng Town, Zhangjiagang City, Jiangsu Province, 215625, People’s Republic of China. Contact e-mail: [email protected] QINGLIANG LI, formerly Assistant Researcher, Institute of Research of Iron and Steel, Shasteel, is Production Engineer, Bekaert Binjiang Steel Cord Co. Ltd., Jiangyin City, Jiangsu Province 215625, People’s Republic of China. Manuscript submitted March 31, 2010. Article published online December 3, 2010 METALLURGICAL AND MATERIALS TRANSACTIONS A
Ship Classification Society) treated by TMCP were developed for the construction of ships and drilling platforms.[1–5] The adoption of the 60-mm-thick plates in 460 MPa yield strength class developed by JEF Steel Corporation (West Japan Steel Works, Fukuyama, Japan) has replaced conventional 80-mm-thick plates, leading to lighter weight and lower center of gravity of the superlarge container ship and with reduced construction cost and improved work efficiency.[2] In AG der Dillinger Hu¨ttenwerke (Dillingen, Germany),[3] steel plates in NV-D/E/F500 grades with maximum thickness of 75 mm were used for shipbuilding such as Mayflower Resolution. The extra high-strength steels reduced structural thickness, reduced the vessel’s deadweight, increased higher payload, and guaranteed ductility and toughness in cold waters. The production of heavy steel plates for shipbuilding requires advanced technologies covering clean steel and homogenous slab followed by TMCP and accelerated cooling process (AcC). Although the fundamentals of metallurgical phenomena during TMCP-AcC are well understood, optimizing integrated process specifications requires accurate descriptions of the entire microstructural evolution process and resultant mechanical properties of the steel plates in industrial production. Here, more data are required to reinforce databases that enable physical metallurgy knowledge to be translated into process parameter windows for industrial production. The production of NV-F460 class TMCP-treated heavythickness (e.g., up
Data Loading...
