Copper-nickel-tin alloy, method for the production and use thereof

A high-strength copper-nickel-tin alloy having excellent castability, hot formability and cold formability, high resistance to abrasive wear, adhesive wear and fretting wear, and improved corrosion resistance and stress relaxation resistance, consisting of (in % by weight):

• 2.0% to 10.0% Ni,
• 2.0% to 10.0% Sn,
• 0.01% to 1.0% Fe,
• 0.01% to 0.8% Mg,
• 0.01% to 1.5% Si,
• 0.002% to 0.45% B,
• 0.004% to 0.3% P,
• optionally up to a maximum of 2.0% Co,
• optionally up to a maximum of 0.25% Pb,
• balance:
• copper and unavoidable impurities,
• characterized in that
• the Si/B ratio of the element contents in % by weight of the elements silicon and boron is a minimum of 0.4 and a maximum of 8;
• the following microstructure constituents are present in the alloy after casting:
• a) an Si-containing and P-containing metallic base composition having, based on the overall microstructure,
• a1) up to 30% by volume of first phase constituents that can be reported by the empirical formula CuhNikSnm and have an (h+k)/m ratio of the element contents in atom % of 2 to 6,
• a2) up to 20% by volume of second phase constituents that can be reported by the empirical formula CupNirSns and have a (p+r)/s ratio of the element contents in atom % of 10 to 15 and
• a3) a balance of solid copper solution;
• b) phases which, based on the overall microstructure, are present
• b1) at 0.01% to 10% by volume as Si-containing and B-containing phases,
• b2) at 1% to 15% by volume as Ni—Si borides having the empirical formula NixSi2B with x=4 to 6,
• b3) at 1% to 15% by volume as Ni borides,
• b4) at 0.1% to 5% by volume as Fe borides,
• b5) at 1% to 5% by volume as Ni phosphides,
• b6) at 0.1% to 5% by volume as Fe phosphides,
• b7) at 0.1% to 5% by volume as Mg phosphides,
• b8) at 1% to 5% by volume as Ni silicides,
• b9) at 0.1% to 5% by volume as Fe silicides and/or Fe-rich particles,
• b10) at 0.1% to 5% by volume as Mg silicides,
• b11) at 0.1% to 5% by volume as Cu-containing and Mg-containing phases and/or Cu-containing and Sn-containing and Mg-containing phases in the microstructure, which are present individually and/or as addition compounds and/or mixed compounds and are ensheathed by tin and/or the first phase constituents and/or the second phase constituents;
• in the course of casting the Si-containing and B-containing phases in the form of silicon borides, the Ni—Si borides, Ni borides, Fe borides, Ni phosphides, Fe phosphides, Mg phosphides, Ni silicides, Fe silicides and/or Fe-rich particles, Mg silicides and the Cu-containing and Mg-containing phases and/or Cu-containing and Sn-containing and Mg-containing phases that are present individually and/or as addition compounds and/or mixed compounds constitute seeds for uniform crystallization during the solidification/cooling of the melt, such that the first phase constituents and/or the second phase constituents are distributed uniformly in the microstructure like islands and/or like a mesh;
• the Si-containing and B-containing phases that are in the form of boron silicates and/or boron phosphorus silicates, together with the phosphorus silicates and Mg oxides, assume the role of a wear-protecting and corrosion-protecting coating on the semifinished materials and components of the alloy.

A high-strength copper-nickel-tin alloy having excellent castability, hot formability and cold formability, high resistance to abrasive wear, adhesive wear and fretting wear, and improved corrosion resistance and stress relaxation resistance, consisting of (in % by weight):

• 2.0% to 10.0% Ni,
• 2.0% to 10.0% Sn,
• 0.01% to 1.0% Fe,
• 0.01% to 0.8% Mg,
• 0.01% to 1.5% Si,
• 0.002% to 0.45% B,
• 0.004% to 0.3% P,
• optionally up to a maximum of 2.0% Co,
• optionally up to a maximum of 0.25% Pb,
• balance:
• copper and unavoidable impurities,
• characterized in that
• the Si/B ratio of the element contents in % by weight of the elements silicon and boron is a minimum of 0.4 and a maximum of 8;
• after the further processing of the alloy by at least one annealing operation or by at least one hot forming operation and/or cold forming operation, as well as at least one annealing operation in the alloy, the following microstructure constituents are present:
• A) a metallic base composition having, based on the overall microstructure,
• A1) up to 15% by volume of first phase constituents that can be reported by the empirical formula CuhNikSnm and have an (h+k)/m ratio of the element contents in atom % of 2 to 6,
• A2) up to 10% by volume of second phase constituents that can be reported by the empirical formula CupNirSns and have a (p+r)/s ratio of the element contents in atom % of 10 to 15 and
• A3) a balance of solid copper solution;
• B) phases which, based on the overall microstructure, are present
• B1) at 2% to 40% by volume as Si-containing and B-containing phases, Ni—Si borides having the empirical formula NixSi2B with x=4 to 6, as Ni borides, Fe borides, Ni phosphides, Fe phosphides, Mg phosphides, Ni silicides, Fe silicides and/or Fe-rich particles, Mg silicides and as Cu-containing and Mg-containing phases and/or Cu-containing and Sn-containing and Mg-containing phases in the microstructure, which are present individually and/or as addition compounds and/or mixed compounds and are ensheathed by precipitates of the (Cu, Ni)—Sn system,
• B2) at up to 80% by volume as continuous precipitates of the (Cu, Ni)—Sn system in the microstructure,
• B3) at 2% to 35% by volume as Ni phosphides, Fe phosphides, Mg phosphides, Ni silicides, Fe silicides and/or Fe-rich particles, Mg silicides and as Cu-containing and Mg-containing phases and/or Cu-containing and Sn-containing and Mg-containing phases in the microstructure that are present individually and/or as addition compounds and/or mixed compounds, are ensheathed by precipitates of the (Cu, Ni)—Sn system and have a size of less than 3 μm;
• the Si-containing and B-containing phases that are in the form of silicon borides, the Ni—Si borides, Ni borides, Fe borides, Ni phosphides, Fe phosphides, Mg phosphides, Ni silicides, Fe silicides and/or Fe-rich particles, Mg silicides and the Cu-containing and Mg-containing phases and/or Cu-containing and Sn-containing and Mg-containing phases that are present individually and/or as addition compounds and/or mixed compounds constitute seeds for static and dynamic recrystallization of the microstructure during the further processing of the alloy, which enables the establishment of a uniform and fine-grain microstructure;
• the Si-containing and B-containing phases that are in the form of boron silicates and/or boron phosphorus silicates, together with the phosphorus silicates and Mg oxides, assume the role of a wear-protecting and corrosion-protecting coating on the semifinished materials and components of the alloy.