Circumferential welds of stainless steels (SS) are frequently sites of preferred corrosion for several reasons. The paper deals with 3 different SS (AISI 321, 316 Ti, 317L) and their matching filler materials as well as overalloyed filler materials. The objective of this paper is to investigate whether overalloyed filler metals can resolve the observed corrosion
problems. The corrosion behavior of these alloys in welded and unwelded condition was tested in numerous inorganic acids, sodium hydroxide and also with chemical and electrochemical test methods with regard to pitting resista nce. From a corrosion point of view overalloyed filler materials additions to 321, 316Ti and 317LN welds cannot solve
the practical problems that the corrosion resistance of the weld material is not fully equivalent to that of the base metal for nearly all media regardless which type of corrosion is considered. Metallurgical reasons like segregation or micro-segregations are responsible for this corrosion behavior as verified by XPS-Line Scan. These analyses also showed that in TIG-welds with 4 and 4.5% No filler material, No-gradients down to 1.6% Mo were found, clearly below the lower limit of the material's composition specification of 316-type of SS. Keywords: weld, welding, corrosion, pitting, stress corrosion cracking, selective corrosion, stainless steels, delta-ferrite, sigma-phase, and martensite, MIC, filler metals