MMA electrode – Basic metal powder type made on high-purity steel core wire manufactured to the requirements of AWS A5.5 E9015-B9 and BS EN ISO 3580-B.
Applications
These consumables are designed to weld equivalent ‘type 91’ P91 9CrMo steels modified with small additions of niobium, vanadium and nitrogen to give improved long-term creep properties. These consumables are specifically intended for high-integrity structural service at elevated temperatures 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 the parent material, as indicated by so-called ‘type IV’ failure in transverse weld creep tests. Modified 9CrMo steels are now widely used for components such as headers, main steam piping and turbine casings, in fossil-fuelled power-generating plants. They may also find future use in oil refineries and coal liquefaction and gasification plants.
Specification
AWS A5.5: E9015-B9
BS EN ISO 3580-A: E 6216-9C1MV