EEMUA 218 : 2010

Defines all grades of duplex stainless steel and all components for both offshore (subsea and topsides) and onshore applications in the energy, chemical and other process industries.

This document covers all grades of duplex stainless steel and all components forboth offshore (subsea and topsides) and onshore applications in the energy,chemical and other process industries. It deals with duplex stainless steelcomponents purchased directly from the manufacturer or from stockists.Orders for duplex stainless steel components are often placed throughstockists and it is strongly recommended that stockists should adopt therequirements detailed in this EEMUA publication.There are many grades and designations of duplex stainless steel with threegeneric types principally used in the aforementioned industries. These aregenerally distinguished by their Pitting Resistance Equivalent Number (PREN): 22% chromium duplex stainless steels with a PREN generally > 35; 25% chromium duplex stainless steels with a PREN <40; and 25% chromium super duplex stainless steels with a PREN ≥ 40.In addition, there are further proprietary variations such as “lean” and “hyper”grades. Further information can be found in Table 1 (overleaf) and associatedfootnotes in EEMUA 1941.The more commonly used standards and grades are listed in NORSOK (Norwegianstandards authority) Standard M-6302 and in Table 1.The main manufacturing processes for duplex stainless steel are plate and piperolling, forging, casting, tube drawing, extrusion and hot isostatic pressing. Allthese processes are followed by solution annealing and water quenching.Typical components that are regularly manufactured in duplex stainless steel are: process vessels, pipework and pipelines (seamless and welded); flanges, hubs and fittings such as tees, elbows and bends; valve bodies and valve trim; pump casings; wellhead equipment and downhole tubing and accessories; hydraulic control and chemical injection tubing; plates and bars; bolts and fasteners; and heat exchanger tubes/tube plates.