Abstract: A copper based alloy, which when employed in a marine environment with a cathodic protection system or when galvanically coupled to a dissimilar metal, is resistant to hydrogen embrittlement, copper being present in an amount of about 70% to 80% by weight, and the alloy having in addition, (by weight):______________________________________ nickel 13.5% to 20.0% aluminium 1.4% to 2.0% manganese 3.4% to 9.3% iron 0.5% to 1.5% chromium 0.3% to 1.0% niobium 0.5% to 1.0% ______________________________________and wherein the constituent elements are so controlled that:A Cu/(Mn+Ni) is less than 4.9 in terms of weight %;B Cu/(Mn+Ni) is greater than 3 in terms of weight %;C Al+Nb is at least 2.1 in terms of weight %; andD Ni/(Al+Nb) is at least 6.0 in terms of weight %.

Abstract: A high chromium, copper containing, duplex steel alloy having a microstructure in which 40% to 60% is a ferritic matrix, the matrix having austenite grains embedded therein, the structure being substantially free of precipitated particles of other phases, and the steel consisting of a balance iron together with the following elements in proportion by weight;______________________________________ Chromium 23-27% Nickel 4-7% Molybdenum 2-4% Silicon 0.2-2% Carbon 0.08% maximum; ______________________________________and the invention being characterized by controlled additions of:manganese in an amount of 5% and 7% by weight;copper in an amount of 1.1% to 3% by weight; tonitrogen in an amount of 0.1% to 0.4% by weight; and the percentage of chromium, plus three timesthe percentage of molybdenum, being greater than 32%.

Abstract: The invention provides a corrosion resistant high strength steel, which has a ferritic/austenitic microstructure consisting of 40 to 60% austenite grains embedded in a ferrite matrix being substantially free of precipitated particles of other phases, the steel consisting of the following elements in proportion by weight:______________________________________ Chromium 26.5% - 30% by weight Nickel 7.4% - 14% by weight Molybdenum 2.0% - 5% by weight Copper 0.5% - 5% by weight Silicon 0.2% - 2% by weight Manganese 0.2% - 4% by weight Carbon 0.01% - 0.1% by weight Nitrogen 0.1% - 0.