Copper alloy containing tin, method for producing same, and use of same

A tin-containing copper alloy consisting of (in % by weight):

• 4.0% to 23.0% Sn,
• 0.05% to 2.0% Si,
• 0.005% to 0.6% B,
• 0.001% to 0.08% P,
• optionally up to a maximum of 2.0% Zn,
• optionally up to a maximum of 0.6% Fe,
• optionally up to a maximum of 0.5% Mg,
• optionally up to a maximum of 0.25% Pb,
• the balance being copper and unavoidable impurities,
• wherein
• the Si/B ratio of the element contents of the elements silicon and boron is between 0.3 and 10;
• after casting, the following microstructure constituents are present in the alloy:
• a) 1% to 98% by volume of Sn-rich δ phase (1),
• b) 1% to 20% by volume of Si-containing and B-containing phases (2),
• c) the balance being a solid solution of copper, consisting of low-tin α phase (3),
• wherein the Si-containing and B-containing phases (2) are ensheathed by tin and/or the Sn-rich δ phase (1);
• in the casting, the Si-containing and B-containing phases (2) which are in the form of silicon borides constitute seeds for homogeneous crystallization during the solidification/cooling of the melt, such that the Sn-rich δ phase (1) is distributed homogeneously in the microstructure in the form of islands and/or a network;
• the Si-containing and B-containing phases (2) which are in the form of boron silicates and/or boron phosphorus silicates, together with phosphorus silicates, assume the role of a wear-protective and/or corrosion-protective coating on semifinished products and components of the alloy.

A tin-containing copper alloy consisting of (in % by weight):

• 4.0% to 23.0% Sn,
• 0.05% to 2.0% Si,
• 0.005% to 0.6% B,
• 0.001% to 0.08% P,
• optionally up to a maximum of 2.0% Zn,
• optionally up to a maximum of 0.6% Fe,
• optionally up to a maximum of 0.5% Mg,
• optionally up to a maximum of 0.25% Pb,
• the balance being copper and unavoidable impurities,
• wherein
• the Si/B ratio of the element contents of the elements silicon and boron is between 0.3 and 10;
• after a further processing of the alloy by at least one annealing operation or by at least one hot forming operation and/or cold forming operation in addition to at least one annealing operation, the following microstructure constituents are present in the alloy:
• a) up to 75% by volume of Sn-rich δ phase (1),
• b) 1% to 20% by volume of Si-containing and B-containing phases (2),
• c) the balance being a solid solution of copper, consisting of low-tin α phase (3),
• wherein the Si-containing and B-containing phases (2) are ensheathed by tin and/or the Sn-rich δ phase (1);
• the Si-containing and B-containing phases (2) present, which are in the form of silicon borides, constitute seeds for static and dynamic recrystallization of the microstructure during the further processing of the alloy, which enables the establishment of a homogeneous and fine-grain microstructure;
• the Si-containing and B-containing phases (2) which are in the form of boron silicates and/or boron phosphorus silicates, together with phosphorus silicates, assume the role of a wear-protective and/or corrosion-protective coating on the semifinished products and components of the alloy.