Clad stainless steels and high-Ni-alloys for welded tube application

Wickeder Westfalenstahl GmbH is cladding stainless steels and Ni-based alloys on different core materials. Strips are used for welded tubes. Final applications are tube heat exchangers and heating elements for example. Investigations have been carried out on clad 304 stainless, Alloy 316 Ti, Alloy 625, Alloy 800, Alloy 840 and Alloy 904L using Laser, Tig and Microplasma welding technique. Wall thicknesses of tubes are between 0.008” to 0.060”. Filler metals, when used, are Alloy 309L, Alloy 625, Alloy 82 and Alloy 80/20. Discussion of results includes metallography, hardness, tensile testing, corrosion testing, chemical analysis by EDX, segregation behaviour and crack origin by SEM as well as Schaeffler diagram. Comparisons between different welding processes will be discussed. A new technology of a welding-soldering process, which results in identical root chemical composition is reviewed. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.