J. Phys. Colloques
Volume 48, Numéro C7, Décembre 19871st International Laser M2P Conference
|Page(s)||C7-167 - C7-170|
J. Phys. Colloques 48 (1987) C7-167-C7-170
EFFET DES TRAITEMENTS THERMIQUES SUR LES SOUDURES AU LASER D'ACIERS INOXIDABLES AUSTENITIQUESA. TIZIANI1, P. MATTEAZZI1, A. ZAMBON1 and A. MOLINARI2
1 Università di Padova, Via Gradenigo 6A, I-35100 Padova, Italy
2 Università di Trento, Povo, I-38050 Trento, Italy
It is well known that during stainless steels traditional welding delta ferrite can occur and that its amount varies depending on steel composition and welding parameters. Delta ferrite in laser welding has been observed too, though its amount was inferior to that in traditional welds. Previous studies have shown that in traditional welds ferrite transformation can occur, as a consequence of heat treatment, giving rise to sigma phase precipitation. This fact can cause brittleness occurence, depending on sigma phase morphology and amount. In this work sigma phase precipitation in laser welds has been examined, by means of soaking tests in air at temperatures ranging between 600 and 750 C, in order to identify its morphology and precipitation kinetics. Microstructural analysis has been performed by means of light microscopy, SEM and TEM observation. Different phases' relative amounts have been determined by means of Mossbauer Spettroscopy.