Abstract
A condenser was built in Hastelloy B2 (UNS N10665) and has been in service since four years. The welds of the inletheader showed after this service time severe cracks. A failure analysis on cracks in Hastelloy B2 weldmetal was carried out. Results of this investigation showed that stress corrosion cracking is the reason for crackformation in the weldmetal. The main reason why this could happen is welding with too high heat input during manufacturing. A non-optimal chemical composition of the filler metal contributed to this failure.
The method of repair is discussed. The alloys B3 (UNS N10675) and B4 (UNS N10629) are preferred above alloy B2. In case one has to deal with B2 requirements on the "Fe" and "Cr"-content of the base and filler metal of B2 are advised (B2 with controlled chemistry). Above all keeping the interpass temperature low, by using wet rags is recommended.