Abstract
This paper was intended to investigate the influence of the welded heat input on the polarization behavior and the susceptibility to stress corrosion cracking (SCC) of the welded joint of commercial SUS 316 type austenitic stainless steel in 42% boiling MgCl2 solution. The measurements of the polarization curves and the potentiostatic constant load SCC tests were carried out under the applied stress of 25kgf/mm2 on the specimens welded with various heat inputs from 14 to 46kJ/cm, and the crack distribution in the cross section of specimens was observed by an optical microscope.
The pitting potential in the polarization curve of the deposited metal zone shifted remarkably toward less noble potential with the increase of heat input, while those of the base metal zone and the heat affected zone shifted toward the other way.
The SCC susceptibility of the welded specimens depended remarkably on the applied potential irrespective of the amount of heat input.
The susceptibility to SCC of each part of the welded joint was influenced by the heat input, and this agreed with the SCC susceptibility estimated from its polarization behavior.
