Microstructures and properties of laser welded Super304 steel pipe joints using LNM304 filler wire as an additional material

Paper presents results of microstructure and mechanical tests of welded joints of new generation Super304 austenitic stainless steel using high power CO₂ laser (LBW method) with bifocal welding head. Super304 is modified 304 steel dedicated to energetic installation material, designed to replace currently used. High content of chromium and nickel with others alloying elements improve its resistance and strength characteristic. Use of Super304 steel for production of the superheaters, heating chambers and walls in steam boilers resulted in various weldability researches. In article are presented results of destructive and non-destructive tests. For destructive: static bending and Vickers hardness tests, and for non-destructive: VT, RT, UT, micro and macroscopic tests were performed.