1985 Volume 3 Issue 4 Pages 722-729
It was found out that the first layer overlay weld metal with the austenite/martensite duplex microstructure provided the overlay welds with better hydrogen-induced disbonding resistance than that with the conventional austenitic microstructure containing several percents ferrite as previously reported.
The purpose of the present study is to determine the mechanical properties of the overlay welds with the duplex weld metal. The main results obtained in this study are as follows:
1) The ductility of the overlay weld was not decreased by the regular post-wled heat treatment (PWHT), and almost equal to that of the conventional overlay weld.
2) The absorbed energy values both in the weld metal and at the bond were almost equal to those of the conventional overlay weld before and after PWHT.
3) The fracture position and fracture mode of the Charpy impact test specimens altered by PWHT.
4) As the martensite content of the 1st layer weld metal was increased, the values of the residual stress in through-thickness direction of the bond between the duplex weld metal and the base metal were decleased.
5) This low residual stress was one of the main reasons to provide the overlay weld with good dis-bonding resistance.
