DS EN 10253-4:2008 Butt-Welding Pipe Fittings - Part 4: Wrought Austenitic And Austenitic-Ferritic (Duplex) Stainless Steels With Specific Inspection Requirements Defines the technical delivery requirements for seamless and welded butt-welding fittings (elbows, concentric and eccentric reducers, equal and reducing tees, caps) made of austenitic and austenitic-f