These consumables are designed to match similar
alloys, usually supplied as castings. The addition of
copper improves corrosion resistance in sulphuric
acid media and potentially increases strength and
wear resistance, but as-welded toughness and
pitting performance in chloride media are reduced
in comparison to alloys with <1%Cu. Although the
composition is controlled to ensure a minimum
Pitting Resistance Equivalent (PRE) of 40 to match
the superduplex alloys and maximize resistance to
pitting consumables with <1%Cu may be preferred
for non-sulphuric acid media unless PWHT is applied.
Applications include **pumps and valves, corrosion/
wear resisting parts, and process equipment for use
in offshore oil and gas industries, pulp, paper and
textile industries, and chemical and petrochemical
plant**.
Alloy type
25%Cr ferritic-austenitic superduplex stainless steels
with nominally 25%Cr-8%Ni-3.5%Mo-1.5%Cu-0.2%N.
Microstructure
In the as-welded, or solution annealed condition,
the microstructure is an austenite-ferrite duplex
with about 25-60% ferrite.
