9015-B9 is designed to weld equivalent ‘type T91’ T92 CrMo steels modified with small additions of vanadium and tungsten to give improved long term creep properties. These consumables are specifically intended for high integrity structural service at elevated temperature so the minor alloy additions responsible for its creep strength are kept above the minimum considered necessary to ensure satisfactory performance. In this case, weldments will be weakest in the softened (intercritical) HAZ region of parent material, as indicated by so-called ‘type IV’ failure in transverse weld creep tests.