Marine Link
Friday, October 28, 2016

ClassNK Issues New Welding Guidelines

January 14, 2014

Classification society ClassNK (Chairman and President: Noboru Ueda) announced that it has released new Guidelines on the Welding of Duplex Stainless Steels. The guidelines have been developed to help shipyards safely and effectively make use of new duplex steels that are increasingly being used in the construction of cargo tanks for chemical carriers. As part of its work to support the safe construction of ships, ClassNK has released the guidelines for free via its website.

Duplex stainless steel has a two-phase microstructure containing grains of both ferritic and austenitic phase, giving it a combination of excellent corrosion resistance and high strength with a lower nickel content than austenitic stainless steels such as SUS304 and SUS316L.

The vast majority of the world’s chemical tankers with stainless steel cargo tanks are built at Japanese shipyards, which have traditionally used austenitic steels for cargo tank construction. Recently however these shipyards are increasingly using duplex stainless steels as an alternative to austenitic stainless steels for their corrosion resistance and high strength properties.

Before shipyards or builders can use duplex stainless steel in the construction of vessels, however, they must first obtain approval for the Welding Procedure Specification (WPS) that will be used when welding duplex stainless steel. It was in order to simplify this process and support the widespread use of these new materials at shipyards around the world that ClassNK released its new Guidelines on the Welding of Duplex Stainless Steels on 14 January 2014.

The new guidelines, which conform to ClassNK rules, provide a comprehensive summary of the requirements for welding procedure specification certification and welding procedure qualification tests, including relevant precautionary measures for the welding of duplex stainless steels.

Maritime Reporter Magazine Cover Oct 2016 - Marine Design Annual

Maritime Reporter and Engineering News’ first edition was published in New York City in 1883 and became our flagship publication in 1939. It is the world’s largest audited circulation magazine serving the global maritime industry, delivering more insightful editorial and news to more industry decision makers than any other source.

Maritime Reporter E-News subscription

Maritime Reporter E-News is the subsea industry's largest circulation and most authoritative ENews Service, delivered to your Email three times per week

Subscribe for Maritime Reporter E-News