Gerhard Schiroky & Gary Henrich, Swagelok Company, Solon, Ohio, USA

ABSTRACT

A study was performed to determine the corrosion behavior of welded tube samples of ultralow-manganese and low-manganese 316L alloys in corrosive gaseous environments. First, a weld-fume analysis was performed to determine which elements evaporate to a significant extent during orbital welding with 316L test samples containing different amounts of manganese. Second, welded tube sections were exposed to corrosive gases and the surfaces were characterized by scanning electron microscopy (SEM) both in the short term (24 h) and in the long term (28 days). It has been claimed that during welding, the manganese evaporates from the weld pool and redeposits in the heat-affected zone, primarily downstream of the weld pool, causing corrosion to occur.