EP3423605B1 - Copper alloy containing tin, method for producing same, and use of same - Google Patents

Description

The invention relates to a tin-containing copper alloy with excellent hot and cold formability, high resistance to abrasive wear, adhesive wear and fretting wear and improved corrosion resistance and stress relaxation resistance according to the preamble of one of claims 1 to 3, a method for their production according to the preamble of the claims 9 to 10 and their use according to the preamble of claims 16 to 18.

Due to the alloy component tin, copper-tin alloys are characterized by high strength and hardness. The copper-tin alloys are also considered to be corrosion-resistant and seawater-resistant.

This group of materials has a high level of resistance to abrasive wear. In addition, the copper-tin alloys ensure good sliding properties and high fatigue strength, which results in their excellent suitability for sliding elements and sliding surfaces in engine and vehicle construction as well as in general mechanical engineering. Often, an addition of lead is added to the copper-tin alloys for plain bearing applications to improve the emergency running properties and the machinability.

Copper-tin alloys are widely used in the electronics and telecommunications industries. They often have sufficient electrical conductivity and good to very good spring properties. The Adjustment of the spring properties requires sufficient cold formability of the materials.

In the music industry, percussion instruments are preferably made from copper-tin alloys because of their special sound properties. The manufacture of these cymbals, also known as cymbals in technical parlance, requires the materials to be very hot-formable. In particular, two types of copper-tin alloys with 8 and 20% by weight of tin are widespread.

In the first manufacturing step, casting, the copper-tin materials have a particularly strong tendency to absorb gas with subsequent pore formation and segregation phenomena due to their wide solidification interval. The Sn-rich segregations can only be removed to a very limited extent with a homogenization annealing following the casting process. The susceptibility of copper-tin alloys to pores and segregation increases with increasing Sn content.

The element phosphorus is added to the copper-tin alloys in order to sufficiently deoxidize the melt. However, phosphorus also extends the solidification interval of copper-tin alloys, which results in this group of materials being more susceptible to pores and segregation.

For this reason, in the publications DE 41 26 079 C2 and DE 197 56 815 C2 For the primary shaping of copper-tin alloys, thin strip casting is favored in addition to the spray compacting process. In this way, by means of precise adjustment of the solidification rate of the melt, a low-segregation preform with a fine and uniform distribution of the Sn-rich δ-phase can be produced for the subsequent hot forming.

In the pamphlet DE 581 507 A A basic indication is given of how pure copper-tin alloys with 14 to 32 wt.% Sn and alloys containing copper and tin with 10 to 32 wt.% Sn can be made hot-formable. It is suggested that the alloy be heated to a temperature of 820 to 970 ° C with subsequent, very slow cooling to 520 ° C. The cooling period should be at least 5 hours. After cooling to room temperature at normal cooling speed, the material can be hot-formed at 720 to 920 ° C.

From the pamphlet DE 704 398 A the description of a process for the production of shaped pieces from copper-tin alloys which contain 6 to 14% by weight of Sn, over 0.1% by weight of P, preferably 0.2 to 0.4% by weight of P , which can be replaced by silicon, boron or beryllium. Preferably, the copper-tin alloy has about 91.2% by weight Cu, about 8.5% by weight Sn and about 0.3% P. Accordingly, prior to final processing by cold forming or hot forming, the castings are homogenized at a temperature below 700 ° C. until the eutectoids enriched in tin and phosphorus dissolve.

The importance of crystallization nuclei for the formation of a fine-grain structure with a low proportion of Sn-rich segregations for the hot formability of Sn-containing copper alloys is explained in the publications U.S. 2,128,955 A and DE 25 36 166 A1 highlighted. Phosphidic compounds represent the nuclei of crystallization, which means that the cast structure is tempered and the formation of low-melting copper-phosphorus or copper-phosphorus-tin phases is reduced to a minimum. This is intended to significantly improve the hot formability.

As a result of increasing operating temperatures and pressures in modern engines, Machines, systems and aggregates have the most varied mechanisms of damage to the individual system elements. So there is an increasing need to take into account not only the types of sliding wear but also the mechanism of vibrational frictional wear damage, especially in the material-related and structural design of sliding elements and connectors.

Vibrational friction wear, also called fretting in technical terms, is frictional wear that occurs between oscillating contact surfaces. In addition to the geometrical and / or volume wear of the components, the reaction with the surrounding medium leads to fretting corrosion. The material damage can significantly lower the local strength in the wear zone, in particular the fatigue strength. Vibration cracks can originate from the damaged component surface, leading to fatigue fracture / frictional fatigue failure. With fretting corrosion, the fatigue strength of a component can drop well below the fatigue strength of the material.

The mechanism of vibratory frictional wear differs considerably from the types of sliding wear with unidirectional movement. In particular, the effects of corrosion are particularly pronounced during frictional wear.

From the pamphlet DE 10 2012 105 089 A1 the illustration of the damage consequences of frictional wear of plain bearings emerges. When the plain bearing is pressed into the bearing seat, a high level of tension is built up on the plain bearing, which is increased even further by the thermal expansion and dynamic shaft loads in modern engines. The changes in geometry of the plain bearing as a result of the excessive stress make micro-movements of the plain bearing possible relative to the bearing receptacle. The cyclical relative movements with less Oscillation widths at the contact surfaces between the bearing and the bearing mount lead to vibrational frictional wear / fretting / fretting of the plain bearing back. The result is the initiation of cracks and ultimately the frictional fatigue fracture of the plain bearing.

In motors and machines, electrical connectors are often arranged in an environment in which they are exposed to mechanical vibratory movements. If the elements of a connection arrangement are located on different assemblies which move relative to one another as a result of mechanical loads, a corresponding relative movement of the connection elements can occur. These relative movements lead to fretting wear and fretting of the contact zone of the connector. Microcracks form in this contact zone, which greatly reduces the fatigue strength of the connector material. This can result in failure of the connector due to fatigue failure. Furthermore, there is an increase in contact resistance due to fretting corrosion.

To reduce these forms of damage, the publication DE 10 2007 010 266 B3 proposed to equip each line connected to the connector constructively with a strain relief, so that the movements of the line can no longer reach the connector.

In the pamphlet DE 39 32 536 C1 contains a regulation on how the fretting corrosion behavior of connectors can be improved in terms of material. For example, a contact material made of a silver, palladium or palladium-silver alloy with a content of 20 to 50% by weight tin, indium and / or antimony is applied to a carrier made of bronze, for example. The silver and / or palladium content ensures corrosion resistance. The oxides of tin, indium and / or antimony increase the wear resistance. Thus, the Consequences of fretting corrosion are countered.

A combination of the material properties of wear resistance, ductility and corrosion resistance is therefore decisive for adequate resistance to fretting / fretting.

In the pamphlet DE 36 27 282 A1 the mechanisms of crystallization of a metallic melt are described. If there is only a small number of crystallization nuclei or if only a small number of nuclei are formed in the melt, a coarse-grained, segregated and often dendritic solidification structure is the result. A copper alloy with 0.1 to 25% by weight of calcium and 0.1 to 15% by weight of boron is named, which can be added to the grain refinement of the melt of copper materials. In this way, with the addition of crystallizers, a uniform and fine-grained solidification structure is created in copper alloys.

Alloying with metalloids such as boron, silicon and phosphorus achieves the lowering of the relatively high base melting temperature, which is important in terms of processing. In the coating and high-temperature materials of the Ni-Si-B and Ni-Cr-Si-B systems, the alloying elements boron and silicon in particular are responsible for the sharp reduction in the melting temperature of hard nickel-base alloys, which is why their use as self-fluxing hard nickel-base alloys is possible.

The lowering of the base melting temperature by the addition of boron is used for copper-tin materials that are used as build-up welding material. So is stated in the publication U.S. 3,392,017 A an alloy with up to 0.4 wt% Si, 0.02 to 0.5 wt% B, 0.1 to 1.0 wt% P, 4 to 25 wt% Sn and one Remainder Cu disclosed. The addition of boron and a very A high phosphorus content of greater than or equal to 0.1% by weight should improve the self-fluxing properties of the build-up welding alloy and the wettability of the substrate surface and make the use of additional flux superfluous. A particularly high P content of 0.2 to 0.6% by weight is specified with an Si content of the alloy of 0.05 to 0.15% by weight. This underlines the ostensible demand for the self-flowing properties of the material. With this high P content, however, the options for hot formability of the alloy will be severely limited.

In the pamphlet DE 102 08 635 B4 describes the processes in a diffusion solder joint in which intermetallic phases are present. Diffusion soldering is used to connect parts with different thermal expansion coefficients. In the event of thermomechanical stress on this soldering point or during the soldering process itself, great stresses occur at the interfaces, which can lead to cracks, especially in the vicinity of the intermetallic phases. As a remedy, mixing the solder components with particles is proposed, which compensate for the different expansion coefficients of the joint partners. For example, particles made of borosilicates or phosphorus silicates can minimize the thermomechanical stress in the soldered joint due to their advantageous thermal expansion coefficients. In addition, these particles hinder the cracks that have already been induced from spreading.

In the interpretative document DE 24 40 010 B2 the influence of the element boron in particular on the electrical conductivity of a silicon casting alloy with 0.1 to 2.0 wt.% boron and 4 to 14 wt.% iron is emphasized. In this Si-based alloy, a refractory Si-B phase precipitates, which is referred to as silicon boride.

The silicon borides, which are mostly in the form of the modifications SiB ₃ , SiB ₄ , SiB ₆ and / or SiB _{n, which} are determined by the boron content, differ significantly from silicon in their properties. These silicon borides have a metallic character, which is why they are electrically conductive. They have an extremely high temperature and oxidation resistance. _{The modification of SiB 6} , which is preferred for sintered products, is used, for example, in ceramic production and processing because of its very high hardness and high abrasive wear resistance.

The invention is based on the object of providing a copper-tin alloy which has excellent hot formability over the entire range of the tin content.

For hot forming, a starting material can be used that was produced by conventional casting processes without the need to carry out spray compacting or thin strip casting.

The copper-tin alloy should be free of gas and shrinkage pores as well as stress cracks and be characterized by a structure with a uniform distribution of the Sn-rich δ-phase that is present depending on the Sn content of the alloy. The as-cast state of the copper-tin alloy does not necessarily have to be homogenized by means of a suitable annealing treatment in order to be able to produce sufficient hot formability. Even the casting material should be characterized by high strength, high hardness and high corrosion resistance. A fine-grain structure with high strength, high hardness, high stress relaxation and corrosion resistance, high electrical conductivity and a high degree of complex wear resistance can be set by means of further processing that includes annealing or hot forming and / or cold forming with at least one annealing.

With regard to a copper-tin alloy, the invention is represented by the features of one of claims 1 to 3, with regard to a production method by the features of claims 9 to 10 and with regard to a use by the features of claims 16 to 18. The further claims referring back relate to advantageous designs and developments of the invention.

• 4,0 bis 23,0 % Sn,
• 0,5 bis 1,5 % Si,
• 0,005 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• wahlweise noch bis maximal 2,0 % Zn,
• wahlweise noch bis maximal 0,6 % Fe,
• wahlweise noch bis maximal 0,5 % Mg,
• wahlweise noch bis maximal 0,25 % Pb,
• Rest Kupfer und unvermeidbare Verunreinigungen,
• wobei das Verhältnis Si/B der Elementgehalte der Elemente Silicium und Bor zwischen 0,3 und 10 liegt.

The invention includes a high-strength tin-containing copper alloy with excellent hot 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):

• 4.0 to 23.0% Sn,
• 0.5 to 1.5% 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,
• Remainder copper and unavoidable impurities,
• the Si / B ratio of the element contents of the elements silicon and boron being between 0.3 and 10.

• 4,0 bis 23,0 % Sn,
• 0,05 bis 2,0 % Si,
• 0,005 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• wahlweise noch bis maximal 2,0 % Zn,
• wahlweise noch bis maximal 0,6 % Fe,
• wahlweise noch bis maximal 0,5 % Mg,
• wahlweise noch bis maximal 0,25 % Pb,
• Rest Kupfer und unvermeidbare Verunreinigungen,
• dadurch gekennzeichnet,
  • dass das Verhältnis Si/B der Elementgehalte der Elemente Silicium und Bor zwischen 0,3 und 10 liegt;
  • dass nach dem Gießen in der Legierung folgende Gefügebestandteile vorliegen:
    1. a) 1 bis zu 98 Volumen-% Sn-reiche δ-Phase,
    2. b) 1 bis zu 20 Volumen-% Si-haltige und B-haltige Phasen,
    3. c) Rest Kupfer-Mischkristall, bestehend aus zinnarmer α-Phase,
    wobei die Si-haltigen und B-haltigen Phasen von Zinn und/oder der Sn-reichen δ-Phase ummantelt sind;
  • dass beim Gießen die Si-haltigen und B-haltigen Phasen, welche als Siliciumboride ausgebildet sind, Keime für eine gleichmäßige Kristallisation während der Erstarrung/Abkühlung der Schmelze darstellen, so dass die Sn-reiche δ-Phase inselartig und/oder netzartig gleichmäßig im Gefüge verteilt ist;
  • dass die Si-haltigen und B-haltigen Phasen, welche als Borsilikate und/oder Borphosphorsilikate ausgebildet sind, zusammen mit den Phosphorsilikaten die Rolle eines verschleißschützenden und/oder korrosionsschützenden Überzuges auf den Halbzeugen und Bauteilen der Legierung übernehmen.

The invention also includes a high-strength tin-containing cast copper alloy with excellent hot 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):

• 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,
• Remainder copper and unavoidable impurities,
• characterized,
  • that the Si / B ratio of the element contents of the elements silicon and boron is between 0.3 and 10;
  • that the following structural components are present in the alloy after casting:
    1. a) 1 up to 98 volume% Sn-rich δ-phase,
    2. b) 1 up to 20% by volume Si-containing and B-containing phases,
    3. c) remainder of copper mixed crystal, consisting of low-tin α-phase,
    wherein the Si-containing and B-containing phases are coated by tin and / or the Sn-rich δ phase;
  • that during casting, the Si-containing and B-containing phases, which are designed as silicon borides, represent nuclei for uniform crystallization during the solidification / cooling of the melt, so that the Sn-rich δ phase is island-like and / or network-like evenly in the structure is distributed;
  • that the Si-containing and B-containing phases, which are designed as borosilicates and / or borophosphosilicates, together with the phosphorus silicates, take on the role of a wear-protecting and / or corrosion-protecting coating on the semi-finished products and components of the alloy.

Due to the uniform distribution of the Sn-rich δ-phase in island form and / or in network form, the structure is free from Sn-rich segregations. Among such Sn rich Segregation is understood to mean accumulations of the δ-phase in the cast structure, which are designed as so-called reverse block segregation and / or grain boundary segregation, which cause damage to the structure in the form of cracks when the casting is subjected to thermal and / or mechanical stress, which can lead to breakage. After casting, the structure is still free of gas pores and shrinkage pores as well as stress cracks.

In this variant, the alloy is in the as-cast state.

• 4,0 bis 23,0 % Sn,
• 0,05 bis 2,0 % Si,
• 0,005 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• wahlweise noch bis maximal 2,0 % Zn,
• wahlweise noch bis maximal 0,6 % Fe,
• wahlweise noch bis maximal 0,5 % Mg,
• wahlweise noch bis maximal 0,25 % Pb,
• Rest Kupfer und unvermeidbare Verunreinigungen,
• dadurch gekennzeichnet,
  • dass das Verhältnis Si/B der Elementgehalte der Elemente Silicium und Bor zwischen 0,3 und 10 liegt;
  • dass nach der Weiterverarbeitung der Legierung durch zumindest eine Glühung oder durch zumindest eine Warmumformung und/oder Kaltumformung nebst zumindest einer Glühung in der Legierung folgende Gefügebestandteile vorliegen:
    1. a) bis zu 75 Volumen-% Sn-reiche δ-Phase,
    2. b) 1 bis zu 20 Volumen-% Si-haltige und B-haltige Phasen,
    3. c) Rest Kupfer-Mischkristall, bestehend aus zinnarmer α-Phase,
    wobei die Si-haltigen und B-haltigen Phasen von Zinn und/oder der Sn-reichen δ-Phase ummantelt sind;
  • dass die enthaltenen Si-haltigen und B-haltigen Phasen, welche als Siliciumboride ausgebildet sind, Keime für eine statische und dynamische Rekristallisation des Gefüges während der Weiterverarbeitung der Legierung darstellen, wodurch die Einstellung eines gleichmäßigen und feinkörnigen Gefüges ermöglicht wird;
  • dass die Si-haltigen und B-haltigen Phasen, welche als Borsilikate und/oder Borphosphorsilikate ausgebildet sind, zusammen mit den Phosphorsilikaten die Rolle eines verschleißschützenden und/oder korrosionsschützenden Überzuges auf den Halbzeugen und Bauteilen der Legierung übernehmen.

Furthermore, the invention includes a high-strength tin-containing copper alloy in the further processed state, with excellent hot 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):

• 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,
• Remainder copper and unavoidable impurities,
• characterized,
  • that the Si / B ratio of the element contents of the elements silicon and boron is between 0.3 and 10;
  • that after further processing of the alloy through at least one annealing or at least one hot forming and / or cold forming in addition to at least one annealing in the alloy, the following structural components are present:
    1. a) up to 75% by volume Sn-rich δ-phase,
    2. b) 1 up to 20% by volume Si-containing and B-containing phases,
    3. c) remainder of copper mixed crystal, consisting of low-tin α-phase,
    wherein the Si-containing and B-containing phases are coated by tin and / or the Sn-rich δ phase;
  • that the contained Si-containing and B-containing phases, which are designed as silicon borides, represent nuclei for a static and dynamic recrystallization of the structure during the further processing of the alloy, whereby the setting of a uniform and fine-grain structure is made possible;
  • that the Si-containing and B-containing phases, which are designed as borosilicates and / or borophosphosilicates, together with the phosphorus silicates, take on the role of a wear-protecting and / or corrosion-protecting coating on the semi-finished products and components of the alloy.

The Sn-rich δ phase is preferably at least 1% by volume.

In the further processed state, the Sn-rich δ-phase is distributed evenly in the structure in an island-like and / or network-like and / or line-like stretched manner.
In this variant, the alloy is in a further processed state.

In the case of the alloy variants, the invention is based on the consideration that a tin-containing copper alloy is provided in the cast state as well as in the further processed state with Si-containing and B-containing phases, which are produced by means of sand casting, shell mold casting, investment casting, full mold casting, Die casting and permanent mold casting process or with the help of the continuous or semi-continuous continuous casting process can be produced. The use of process engineering complex and cost-intensive primary forming techniques is possible, but is not an absolute necessity for the production of the tin-containing copper alloy according to the invention. For example, the use of spray compacting can be dispensed with. The casting formats of the Tin-containing copper alloys according to the invention can be hot-formed over the entire range of the Sn content, for example by hot rolling, extrusion or forging. This largely removes the processing restrictions that previously existed in the manufacture of semi-finished products and components made of copper-tin alloys and which led to this group of materials being subdivided into Cu-Sn wrought alloys and Cu-Sn cast alloys.

The matrix of the structure of the tin-containing copper alloy in the as-cast state consists of increasing proportions of δ-phase (Sn-rich) in otherwise α-phase (Sn-poor) with increasing Sn content of the alloy, depending on the casting process.

With an increasing Sn content of the alloy according to the invention, not only does the proportion of the δ phase in the structure increase, but the shape of the arrangement of the δ phase in the structure also changes. It has been found that in the Sn content range from 4.0 to 9.0% by weight, the δ phase is distributed uniformly in the structure with up to 40% by volume, predominantly in island form. If the Sn content of the alloy is between 9.0 and 13.0% by weight, the island shape of the δ phase, which is present in the structure with up to 60% by volume, changes into the network shape. This δ network is also distributed very evenly in the structure of the alloy. In the Sn content range from 13.0 to 17.0% by weight, the δ phase is almost exclusively in the form of a uniform network in the structure with up to 80% by volume. With an Sn content of the alloy of 17.0 to 23.0% by weight, the structural fraction of the δ-phase arranged as a dense network in the structure is up to 98% by volume.

By means of the combined content of boron, silicon and phosphorus, various processes are activated in the melt of the alloy according to the invention, which significantly change its solidification behavior compared to the copper-tin and copper-tin-phosphorus alloys.

The elements boron, silicon and phosphorus take on a deoxidizing function in the melt. This counteracts the formation of tin oxides in the tin-containing copper alloy. By adding boron and silicon, it is possible to reduce the phosphorus content without reducing the intensity of the deoxidation of the melt. This measure succeeds in suppressing the adverse effects of adequate deoxidation of the melt by means of an addition of phosphorus. A high P content would also extend the already very large solidification interval of the tin-containing copper alloy, which would result in an increase in the susceptibility to pores and segregation of this type of material. In addition, an increased formation of the copper-phosphorus phase would be the result. This type of phase is considered to be one of the reasons for the hot brittleness of tin-containing copper alloys. The disadvantageous effects of the addition of phosphorus are reduced by limiting the P content in the alloy according to the invention to the range from 0.001 to 0.08% by weight.

The elements boron and silicon are of particular importance in the tin-containing copper alloy according to the invention. The phases of the Si-B system already separate in the melt. These Si-B phases, known as silicon borides, can be present in the modifications SiB ₃ , SiB ₄ , SiB ₆ and SiB _n . The symbol "n" in the latter modification is based on the fact that boron has a high solubility in the silicon lattice.

The Si-containing and B-containing phases, which are designed as silicon borides, are referred to below as hard particles. In the melt of the alloy according to the invention, they take on the function of crystallization nuclei during solidification and cooling. As a result, there is no longer the need to add so-called foreign nuclei to the melt, the even distribution of which in the melt can only be inadequately guaranteed.

The lowering of the base melting temperature, especially due to the element boron, and the existence of the hard particles that act as crystallization nuclei lead to a significant reduction in the solidification interval of the alloy according to the invention. As a result, depending on the Sn content, the as-cast state of the invention has a very uniform structure with a fine distribution of the δ-phase in the form of evenly and densely arranged islands and / or in the form of a uniformly dense network. Accumulations of the Sn-rich δ-phase, which are formed as so-called reverse block segregation and / or as grain boundary segregation, cannot be observed in the cast structure of the invention.

In the melt of the alloy according to the invention, the elements boron, silicon and phosphorus cause a reduction in the metal oxides. The elements themselves are oxidized, rise to the surface of the castings and, as borosilicates, phosphorus silicates and / or borophosphosilicates, form a protective layer that protects the castings from gas absorption. Exceptionally smooth surfaces of the castings made of the alloy according to the invention were found, which indicate the formation of such a protective layer. The structure of the as-cast state of the invention was also free of gas pores over the entire cross-section of the cast parts.

A basic idea of the invention consists in the transfer of the effect of borosilicates and phosphorus silicates with regard to the adjustment of the different thermal expansion coefficients of the joining partners during diffusion soldering to the processes during casting, hot forming and thermal treatment of the copper-tin materials. Because of the wide solidification interval of these alloys, large mechanical stresses occur between the staggered crystallizing Sn-poor and Sn-rich structural areas, which can lead to cracks and pores. Furthermore, these damage features can also occur during hot forming and high-temperature annealing of the copper-tin alloys due to the different hot forming behavior and the different thermal expansion coefficients of the Sn-poor and Sn-rich structural components.

The combined addition of boron, silicon and phosphorus to the tin-containing copper alloy according to the invention causes, on the one hand, a uniform structure with a fine distribution of the structural components with different Sn content during the solidification of the melt by means of the action of the hard particles as crystallization nuclei. In addition to the hard particles, the borosilicates, phosphorosilicates and / or borophosphosilicates that form during the solidification of the melt ensure the necessary adjustment of the thermal expansion coefficients of the Sn-poor and Sn-rich phases. This prevents the formation of pores and stress cracks between the phases with different Sn contents.

Alternatively, the alloy according to the invention can be subjected to further processing by annealing or by hot forming and / or cold forming in addition to at least one annealing.

The effect of the hard particles as crystallization nuclei, which together with the borosilicates, phosphorus silicates and / or borophosphosilicates bring about an equalization of the thermal expansion coefficients of the Sn-poor and Sn-rich phases, could also be observed during the process of hot forming of the tin-containing copper alloy according to the invention. During hot forming, the hard particles serve as seeds for dynamic recrystallization. For this reason, the hard particles are to be made responsible for the fact that the dynamic recrystallization takes place favorably during the hot forming of the alloy according to the invention. This results in a further increase in the uniformity and fine-grainedness of the structure.

As after casting, an exceptionally smooth surface of the parts could also be determined after hot forming of the castings. This observation indicates the formation of borosilicates, phosphorus silicates and / or borophosphosilicates that takes place in the material during hot forming. The silicates and hard particles also cause the different thermal expansion coefficients of the Sn-poor and Sn-rich components to be matched during hot forming. Like after casting, the structure was free of cracks and pores even after hot forming.

The role of the hard particles as nuclei for the static recrystallization became apparent during the annealing treatment after cold forming. The outstanding function of the hard particles as nuclei for the static recrystallization manifested itself in the lowering of the necessary recrystallization temperature which has become possible, which additionally facilitates the establishment of a fine-grain structure of the alloy according to the invention.

_{This enables higher degrees of cold deformation} during the further processing of the alloy according to the invention, as a result of which particularly high values for the tensile strength R _m , the yield point R p0.2 and the hardness can be set. In particular, the level of the parameter R _p0.2 is important for the sliding elements and guide elements in internal combustion engines, valves, turbochargers, transmissions, exhaust gas aftertreatment systems, lever systems, brake systems and joint systems, hydraulic units or in machines and systems in general mechanical engineering. Furthermore, a high value of R _{p0.2 is} a prerequisite for the necessary spring properties of connectors in electronics and electrical engineering.

The Sn content of the invention ranges between 4.0 and 23.0 Wt%. A tin content of less than 4.0% by weight would result in too low strength values and hardness values. In addition, the running properties would be inadequate in the event of a sliding load. The resistance of the alloy to abrasive and adhesive wear would not meet the requirements. If the Sn content exceeds 23.0% by weight, the toughness properties of the alloy according to the invention would deteriorate rapidly, as a result of which the dynamic load-bearing capacity of the components made of the material is reduced.

Due to the precipitation of the hard particles, the alloy according to the invention has a hard phase component which, due to the high hardness of the silicon borides, contributes to an improvement in the material resistance to abrasive wear. In addition, the proportion of hard particles results in improved resistance to adhesive wear, since these phases show a low tendency to weld with a metallic counterpart when exposed to sliding stress. They thus serve as an important wear carrier in the tin-containing copper alloy according to the invention. Furthermore, the hard particles increase the heat resistance and the stress relaxation resistance of components from the invention. This represents an important prerequisite for the use of the alloy according to the invention, in particular for sliding elements and for components, line elements, guide elements and connecting elements in electronics / electrical engineering.

The formation of borosilicates, phosphorus silicates and / or borophosphosilicates in the alloy according to the invention not only leads to a significant reduction in the pores and cracks in the structure. These silicate phases also take on the role of a wear-protecting and / or corrosion-protecting coating on the components.

The alloy according to the invention thus ensures a combination of the properties of wear resistance and corrosion resistance. These The combination of properties leads to a high resistance to the mechanisms of sliding wear, as required, and to a high material resistance to fretting corrosion. In this way, the invention is excellently suited for use as a sliding element and plug connector, since it has a high degree of resistance to sliding wear and vibrational friction wear, known as fretting.

The effect of the hard particles as crystallization nuclei and recrystallization nuclei, as wear carriers and the effect of the silicate phases for the purpose of corrosion protection can only reach a technically significant level in the alloy according to the invention if the silicon content is at least 0.05% by weight and the boron Content is at least 0.005% by weight. On the other hand, if the Si content exceeds 2.0% by weight and / or the B content exceeds 0.6% by weight, this leads to a deterioration in the casting behavior. The excessively high content of hard particles would make the melt significantly more viscous. In addition, reduced toughness properties of the alloy according to the invention would be the result.

The range for the Si content within the limits from 0.05 to 1.5% by weight and in particular from 0.5 to 1.5% by weight is rated as advantageous. In the alloy according to claim 1, the Si content is within the limits of 0.5 to 1.5% by weight. For the element boron, a content of 0.01 to 0.6% by weight is considered to be advantageous. The boron content of 0.1 to 0.6% by weight has proven to be particularly advantageous.

To ensure a sufficient content of hard particles as well as borosilicates, phosphorus silicates and / or borophosphosilicates, the setting of a specific element ratio of the elements silicon and boron has proven to be important. For this reason, the Si / B ratio of the element contents (in% by weight) of the elements silicon and boron is the alloy according to the invention between 0.3 and 10. A Si / B ratio of 1 to 10 and furthermore from 1 to 6 has proven to be particularly advantageous.

The precipitation of hard particles influences the viscosity of the melt of the alloy according to the invention. This fact also underlines why the addition of phosphorus must not be dispensed with. Phosphorus has the effect that the melt is sufficiently thin despite the content of hard particles, which is of great importance for the castability of the invention. The phosphorus content of the alloy according to the invention is 0.001 to 0.08% by weight. A P content in the range from 0.001 to 0.05% by weight is advantageous.

The sum of the element contents of the elements silicon, boron and phosphorus is advantageously at least 0.5% by weight.

Machining of the semi-finished products and components made of conventional copper-tin and copper-tin-phosphorus wrought alloys, in particular with an Sn content of up to approx. 9% by weight, is only possible with great effort due to the inadequate machinability. The occurrence of long spiral chips in particular causes long machine downtimes, as the chips first have to be removed from the machining area of the machine by hand.

In the alloy according to the invention, on the other hand, the hard particles, in the regions of which, depending on the Sn content of the alloy, the element tin and / or the δ phase is crystallized or precipitated, serve as chip breakers. The resulting short crumbling chips and / or tangled chips facilitate the machinability, which is why the semi-finished products and components made of the alloy according to the invention have better machinability.

• 4,0 bis 9,0 % Sn,
• 0,05 bis 2,0 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In an advantageous embodiment of the invention, the tin-containing Copper alloys consist of (in% by weight):

• 4.0 to 9.0% Sn,
• 0.05 to 2.0% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.08% P,
• Remainder copper and unavoidable impurities.

• 4,0 bis 9,0 % Sn,
• 0,05 bis 0,3 % Si,
• 0,1 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a further advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 4.0 to 9.0% Sn,
• 0.05 to 0.3% Si,
• 0.1 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

• 4,0 bis 9,0 % Sn,
• 0,5 bis 1,5 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a particularly advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 4.0 to 9.0% Sn,
• 0.5 to 1.5% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

In the cast structure of these embodiments of the invention, the Sn-rich δ-phase is arranged uniformly in island form with up to 40% by volume. The element tin and / or the δ-phase is mostly crystallized and / or coated in the areas of the hard particles.

The castings of these embodiments have excellent hot formability at the working temperature in the range from 600 to 880 ° C. As a result Due to the dynamic recrystallization that has taken place, favored by the hard particles, the structure of the embodiments is very fine-grained after the hot forming. This results in very good cold formability with a degree of cold deformation ε of over 40%.

The hard particles precipitated in the structure act as recrystallization nuclei during the thermal treatment of the cold-formed material state at a temperature of 200 to 880 ° C for a period of 10 minutes to 6 hours. By means of this further processing step it is possible to set a structure with a grain size of up to 20 µm. The promotion of the recrystallization mechanisms by the hard particles allows the recrystallization temperature to be lowered so that a structure with a grain size of up to 10 µm can be created. By means of a multi-stage production process consisting of cold forming and annealing and / or by appropriately lowering the recrystallization temperature, it is even possible to set the size of the crystallites in the material structure to below 5 µm.

The mechanical properties of some embodiments are representative of the entire range of alloy compositions and production parameters. The results of the investigation of corresponding exemplary embodiments described below make it clear that values for the tensile strength R _m of over 700 to 800 MPa, values for the yield strength R _p0.2 of over 600 to 700 MPa can be achieved. At the same time, the toughness properties of the embodiments are at a very high level. This fact is expressed by the high values for the elongation at break A5.

• 9,0 bis 13,0 % Sn,
• 0,05 bis 2,0 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In an advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 9.0 to 13.0% Sn,
• 0.05 to 2.0% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.08% P,
• Remainder copper and unavoidable impurities.

• 9,0 bis 13,0 % Sn,
• 0,05 bis 0,3 % Si,
• 0,1 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a further advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 9.0 to 13.0% Sn,
• 0.05 to 0.3% Si,
• 0.1 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

• 9,0 bis 13,0 % Sn,
• 0,5 bis 1,5 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a particularly advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 9.0 to 13.0% Sn,
• 0.5 to 1.5% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

The structure of these embodiments of the invention is characterized by a content of the δ phase of up to 60% by volume, this type of phase being evenly distributed in the structure in island form and network form. Again, the element tin and / or the δ-phase is mostly crystallized and / or encased in the areas of hard particles.

The castings of these embodiments have excellent hot formability at the working temperature in the range from 600 to 880 ° C.

As a result of the dynamic recrystallization that has taken place, favored by the hard particles, the structure of the embodiments is very fine-grained after hot forming. This results in very good cold formability, which is achieved through accelerated cooling after hot forming in air or in water and / or through an annealing treatment after the hot forming process at a temperature of 200 to 880 ° C with a duration of 10 minutes to 6 hours can be further improved. After the hot forming process step, the structural feature of crystallization of the element tin and / or the δ-phase in the areas of the hard particles and / or the coating of these hard particles with the element tin and / or the δ-phase is more fully pronounced with regard to the as-cast state.

The hard particles precipitated in the structure act as recrystallization nuclei during the thermal treatment of the cold-formed material state at a temperature of 200 to 880 ° C for a period of 10 minutes to 6 hours. By means of this further processing step it is possible to set a finer-grain structure. The promotion of the recrystallization mechanisms by the hard particles allows the recrystallization temperature to be lowered so that a structure with a further reduced grain size can be produced. The fine-grain structure of the structure can be further optimized through a multi-stage production process consisting of cold forming and annealing.

• 13,0 bis 17,0 % Sn,
• 0,05 bis 2,0 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In an advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 13.0 to 17.0% Sn,
• 0.05 to 2.0% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.08% P,
• Remainder copper and unavoidable impurities.

• 13,0 bis 17,0 % Sn,
• 0,05 bis 0,3 % Si,
• 0,1 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a further advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 13.0 to 17.0% Sn,
• 0.05 to 0.3% Si,
• 0.1 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

• 13,0 bis 17,0 % Sn,
• 0,5 bis 1,5 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a particularly advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 13.0 to 17.0% Sn,
• 0.5 to 1.5% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

The δ-phase in the cast structure of these embodiments of the invention is in the form of a uniformly arranged network with up to 80% by volume. The element tin and / or the δ-phase is mostly crystallized and / or coated in the areas of the hard particles.

The castings of these embodiments also have excellent hot formability at the working temperature in the range from 600 to 880 ° C. It is precisely in this content range for the alloying element tin of 13.0 to 17.0% by weight that the conventional copper-tin alloys can only be thermoformed with great difficulty without the occurrence of hot cracks and hot fractures.

As a result of the dynamic recrystallization favored by the hard particles, the structure of the embodiments is in accordance with Hot forming very fine-grained. This results in very good cold formability, which results from the implementation of an accelerated cooling of the semi-finished products in air or in water after the hot forming and / or by an annealing treatment after the hot forming process at a temperature of 200 to 880 ° C with a duration of 10 minutes up to 6 hours can be further improved. After the hot forming process step, the structural feature of crystallization of the element tin and / or the δ-phase in the areas of the hard particles and / or the coating of these hard particles with the element tin and / or the δ-phase is more fully pronounced with regard to the as-cast state.

The hard particles precipitated in the structure act as recrystallization nuclei during the thermal treatment of the cold-formed material state at a temperature of 200 to 880 ° C for a period of 10 minutes to 6 hours. By means of this further processing step, it is possible to set a structure with a grain size of up to 30 µm. The promotion of the recrystallization mechanisms by the hard particles allows the recrystallization temperature to be lowered so that a structure with a grain size of up to 15 µm can be created. The network-like arrangement of the δ-phase in the structure is retained.

By means of a multi-stage production process consisting of cold forming and annealing and / or by appropriately lowering the recrystallization temperature, it is even possible to set the size of the crystallites in the material structure to below 5 µm.

• 17,0 bis 23,0 % Sn,
• 0,05 bis 2,0 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,08 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In an advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 17.0 to 23.0% Sn,
• 0.05 to 2.0% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.08% P,
• Remainder copper and unavoidable impurities.

• 17,0 bis 23,0 % Sn,
• 0,05 bis 0,3 % Si,
• 0,1 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a further advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 17.0 to 23.0% Sn,
• 0.05 to 0.3% Si,
• 0.1 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

• 17,0 bis 23,0 % Sn,
• 0,5 bis 1,5 % Si,
• 0,01 bis 0,6 % B,
• 0,001 bis 0,05 % P,
• Rest Kupfer und unvermeidbare Verunreinigungen.

In a particularly advantageous embodiment of the invention, the tin-containing copper alloy can consist of (in% by weight):

• 17.0 to 23.0% Sn,
• 0.5 to 1.5% Si,
• 0.01 to 0.6% B,
• 0.001 to 0.05% P,
• Remainder copper and unavoidable impurities.

A very dense network of the δ phase, which is evenly arranged with up to 98% by volume in the structure, is a feature of these embodiments of the invention. The element tin and / or the δ-phase is mostly crystallized and / or coated in the areas of the hard particles.

As a result of the uniformity of the dense δ network, the castings of these embodiments also have excellent hot formability at the working temperature in the range from 600 to 880 ° C.

During the adhesive wear and tear on a component from the According to the invention, tin-containing copper alloy, the alloy element tin contributes in particular to the formation of a so-called tribo-layer between the sliding partners. This mechanism is particularly important under mixed friction conditions, when the emergency running properties of a material come to the fore. The tribo-layer leads to a reduction in the size of the purely metallic contact area between the sliding partners, which prevents the elements from welding or seizing.

Due to the increase in the efficiency of modern engines, machines and units, operating pressures and temperatures are increasing. This is particularly noticeable in the newly developed internal combustion engines, which are working towards more and more complete combustion of the fuel. In addition to the increased temperatures in the area of the internal combustion engine, there is also the generation of heat that occurs during operation of the plain bearing systems. As a result of the high temperatures during storage operations, borosilicates, phosphorus silicates and / or borophosphosilicates are formed in the parts made of the alloy according to the invention, similar to casting and hot forming. These compounds further strengthen the tribo-layer, which results in increased adhesive wear resistance of the sliding elements made from the alloy according to the invention.

Already during the casting process of the invention, the hard particles precipitate in the structure. These hard phases protect the material from the consequences of abrasive wear and tear, that is, from material removal due to corrugation wear. Furthermore, the hard particles have a low tendency to weld with the metallic sliding partner, which is why, together with the complex tribo-layer, they ensure a high adhesive wear resistance of the invention.

In addition to their function as wear carriers, the hard particles bring about a higher temperature stability of the structure of the copper alloy according to the invention. This results in a high heat resistance and an improvement in the resistance of the material to stress relaxation.

The cast variant and the further processed variant of the alloy according to the invention can contain the following optional elements:
The element zinc can be added to the tin-containing copper alloy according to the invention in a content of 0.1 to 2.0% by weight. It was found that, depending on the Sn content of the alloy, the alloy element zinc increases the proportion of Sn-rich phases in the invention, thereby increasing strength and hardness. However, no indications could be found that the addition of zinc has a positive effect on the uniformity of the structure and on the further reduction of the content of pores and cracks in the structure. Obviously, the influence of the combined alloy content of boron, silicon and phosphorus predominates. A strength- and hardness-increasing effect could not be observed below 0.1% by weight of Zn. At Zn contents above 2.0% by weight, the toughness properties of the alloy were reduced to a lower level. In addition, the tin-containing copper alloy of the present invention deteriorated in corrosion resistance. A zinc content in the range from 0.5 to 1.5% by weight can advantageously be added to the invention.

To further improve the mechanical material properties of strength and hardness as well as the stress relaxation resistance at elevated temperatures, the alloying elements iron and magnesium can be added individually or in combination.

The alloy according to the invention can contain 0.01 to 0.6% by weight of iron. in the Structures are thus up to 10 vol .-% Fe borides, Fe phosphides and Fe silicides and / or Fe-rich particles. Furthermore, there is the formation of addition compounds and / or mixed compounds of the Fe-containing phases and the Si-containing and B-containing phases in the structure. These phases and compounds contribute to increasing the strength, hardness, heat resistance, stress relaxation resistance, electrical conductivity and improving the resistance to abrasive and adhesive wear of the alloy. This improvement in properties is not achieved with an Fe content of less than 0.01% by weight. If the Fe content exceeds 0.6% by weight, there is a risk of the iron clustering in the structure. This would be associated with a significant deterioration in the processing properties and performance properties.

Furthermore, the element magnesium can be added to the alloy according to the invention in an amount of from 0.01 to 0.5% by weight. In this case, up to 15% by volume of Mg borides, Mg phosphides as well as Cu-Mg phases and Cu-Sn-Mg phases are present in the structure. In addition, addition compounds and / or mixed compounds of the Mg-containing phases and the Si-containing and B-containing phases are formed in the structure. These phases and compounds also contribute to increasing the strength, hardness, heat resistance, stress relaxation resistance, electrical conductivity and improving the resistance to abrasive and adhesive wear of the alloy. If the Mg content is below 0.01% by weight, this improvement in properties is not achieved. If the Mg content exceeds 0.5% by weight, the castability of the alloy in particular deteriorates. In addition, the excessively high content of Mg-containing compounds would significantly impair the toughness properties of the alloy according to the invention.

The tin-containing copper alloy can optionally contain a small amount of lead. Lead contents of up to a maximum of 0.25% by weight are still just acceptable and above the contamination limit. In a particularly preferred advantageous embodiment of the invention, the tin-containing copper alloy is free of lead except for any unavoidable impurities. In this context, lead contents of up to a maximum of 0.1% by weight of Pb are envisaged.

The extensive freedom of the structure from gas pores and shrinkage pores, voids, segregations and cracks in the as-cast state is regarded as a particular advantage of the invention. This results in the particular suitability of the alloy according to the invention as a wear protection layer which is melted, for example, onto a base body made of steel. With the alloy composition according to the invention, in particular the formation of open porosity can be suppressed during the melting process, as a result of which the compressive strength of the sliding layer is increased.

Another particular advantage of the invention is the elimination of the imperative to carry out a special primary molding technique such as spray compacting or thin strip casting to provide a uniform, largely pore-free and segregation-free structure. To establish such a structure, conventional casting processes can be used for the primary shaping process of the alloy according to the invention. Thus, one aspect of the invention includes a method for producing end products or components with a shape close to the end product from the tin-containing copper alloy according to the invention with the aid of the sand casting process, shell mold casting process, investment casting process, full mold casting process, die casting process or lost foam Procedure.

In addition, one aspect of the invention includes a method for the production of strips, sheets, plates, bolts, round wires, profile wires, round bars, profile bars, hollow bars, tubes and profiles from a material according to the invention tin-containing copper alloy with the help of the permanent mold casting process or the continuous or semi-continuous continuous casting process.

It is noteworthy that after chill casting or continuous casting of the formats made of the alloy according to the invention, no complex forging processes and / or upsetting processes have to be carried out at elevated temperature in order to weld, i.e. close, pores and cracks in the material.

In addition, in order to ensure sufficient hot formability, the invention no longer has the imperative to distribute or dissolve and thus eliminate the Sn-rich δ phase in the structure by means of homogenization annealing or solution annealing, depending on the Sn content. The δ phase, which is evenly and finely distributed in the cast structure of the alloy according to the invention with a corresponding Sn content, assumes an essential function for the performance properties of the alloy.

In a preferred embodiment of the invention, the further processing of the as-cast state can include performing at least one hot forming in the temperature range from 600 to 880.degree.

Advantageously, the semi-finished products and components can be cooled after hot forming in calmed or accelerated air or with water.

Advantageously, at least one annealing treatment of the as-cast state and / or the hot-formed state of the invention in the temperature range from 200 to 880 ° C with a duration of 10 minutes to 6 hours, alternatively with cooling in calm or accelerated air or with water, can be carried out.

One aspect of the invention relates to an advantageous method for further processing the as-cast state or the hot-formed state or the annealed cast state or the annealed hot-formed state, which comprises performing at least one cold forming.

Preferably, at least one annealing treatment of the cold-formed state of the invention can be carried out in the temperature range from 200 to 880 ° C. for a duration of 10 minutes to 6 hours.

Stress relief annealing / aging annealing can advantageously be carried out in the temperature range from 200 to 650 ° C. for a period of 0.5 to 6 hours.

The matrix of the uniform structure of the invention consists of a ductile α-phase with proportions of the δ-phase depending on the Sn content of the alloy. Due to its high strength and hardness, the δ phase leads to the alloy's high resistance to abrasive wear. In addition, due to its high Sn content, which results in its tendency to form a tribo-layer, the δ phase increases the resistance of the material to adhesive wear. The hard particles are embedded in the metallic matrix. In further embodiments of the invention, Fe and / or Mg-containing phases precipitated in the metallic base material are added.

This heterogeneous structure, consisting of a metallic base mass of α- and δ-phase, in which precipitates of great hardness are embedded, gives the subject matter of the invention an outstanding combination of properties. In this context, the following should be mentioned: high strength values and hardness values combined with very good toughness, excellent hot formability, sufficient cold formability, high temperature resistance of the structure with the resulting high heat resistance and high stress relaxation resistance, electrical conductivity sufficient for many applications, high corrosion resistance and high resistance to the wear mechanisms of abrasion, adhesion and surface disruption as well as to the so-called fretting.

Due to the uniform and fine-grain structure with an extensive absence of pores, freedom from cracks and segregation and the content of hard particles, the alloy according to the invention has a high degree of strength, hardness, ductility, complex wear resistance and corrosion resistance even in the as-cast state. For this reason, the alloy according to the invention has a wide range of uses even in the as-cast state.

This results in the particular suitability of the alloy according to the invention as a wear protection layer, which is melted, for example, onto a base body made of steel. In this regard, it should be emphasized that the treatment temperatures for quenched and tempered steels (hardening 820 to 860 ° C., tempering 540 to 660 ° C.; DIN EN 10083-1) are in the heat treatment range of the invention. This means that after the tin-containing copper alloy has been melted onto a base body made of heat-treated steel, the mechanical properties of both composite partners can be optimized in just one treatment step. Another advantage is that the formation of open porosity is suppressed during the melting process, which increases the compressive strength of the wear protection layer.

In addition to melting, other joining processes can also be considered. In this context, a composite production by means of forging, soldering or welding with the optional implementation of at least one annealing in the temperature range from 200 to 880 ° C. would also be conceivable. Likewise, for example, composite bearing shells or composite bearing bushings can be produced by roll cladding, inductive or conductive roll cladding or by laser roll cladding getting produced.

Sliding elements and guide elements in internal combustion engines, valves, turbochargers, transmissions, exhaust gas aftertreatment systems, lever systems, brake systems and joint systems, hydraulic units or in machines and systems in general can already be made from casting formats in strip form, sheet metal form, plate form, bolt form, wire form, rod form, tube form or profile form Mechanical engineering are produced. By means of further processing of the as-cast state, semi-finished products and components with complicated geometry and increased mechanical properties and optimized wear properties can be produced for these purposes. This takes into account the increased component requirements in the event of dynamic loading.

Another aspect of the invention includes a use of the tin-containing copper alloy according to the invention for components, line elements, guide elements and connecting elements in electronics / electrical engineering.

Due to the excellent strength properties and the wear resistance and corrosion resistance of the tin-containing copper alloy according to the invention, another possible application is possible. Thus, the invention is suitable for the metal objects in structures for the rearing of organisms living in seawater (aquaculture). Another aspect of the invention includes a use of the tin-containing copper alloy according to the invention for propellers, blades, propellers and hubs for shipbuilding, for housings of water pumps, oil pumps and fuel pumps, for idlers, impellers and paddle wheels for pumps and water turbines, for gears, worm wheels, helical gears as well as for pressure nuts and spindle nuts as well as for pipes, seals and Connecting bolts in the maritime and chemical industry.

The material is of great importance for the use of the alloy according to the invention for the production of percussion instruments. Basins in particular, so-called cymbals, of high quality are made from tin-containing copper alloys by means of hot forming and at least one annealing before they are usually brought into their final shape by means of a bell or a bowl. The basins are then annealed again before they are finally machined. The production of the different variants of the pools, for example ride pools, hi-hats, crash pools, china pools, splash pools and effect pools, therefore requires a particularly advantageous hot formability of the material, which is ensured by the alloy according to the invention. Different structural proportions for the δ phase and for the hard particles can be set within a very wide range within the range limits of the chemical composition of the invention. In this way, it is already possible on the alloy side to influence the sound of the cymbals.

Further important exemplary embodiments of the invention are explained with reference to Tables 1 to 11. Ingots of the tin-containing copper alloy according to the invention were produced by permanent mold casting. The chemical composition of the casts is shown in Tables 1 and 3.

Table 1 shows the chemical composition of alloy variants 1 and 2. These materials are characterized by an Sn content of approx. 7% by weight, a P content of 0.015% by weight and a different element ratio of the elements silicon and boron and the remainder copper. <b><u> Table 1: </u></b> Chemical composition of working examples 1 and 2 Cu Sn P. Si B. 1 rest 7.18 0.015 0.66 0.26 2 rest 7.08 0.015 0.19 0.40

After casting, the structure of exemplary embodiments 1 and 2 is characterized by a very uniform, mostly island-shaped distribution of a relatively small proportion of the δ phase (approx. 15 to 20% by volume) and the hard particles. The structure of the as-cast state of alloy 1 is in Fig. 1 shown (200x magnification). The Sn-rich δ-phase 1 can be seen, which is arranged uniformly like an island in the copper mixed crystal 3, which consists of the low-tin α-phase. In addition, the hard particles 2 can be seen, which are encased in tin and / or the Sn-rich δ phase.

The hardness of these types of alloys is 105 HB for the leg. 1 and at 98 HB for alloy 2 (Tab. 2). <b><u> Table 2: </u></b> Hardness of the chill cast blocks from exemplary embodiments 1 and 2 alloy hardness HB 2.5 / 62.5 1 105 2 98

Tab. 3 shows the chemical composition of a further alloy variant 3. In addition to approx. 15% by weight Sn and 0.024% by weight P, this material contains the other elements Si (0.77% by weight) and boron (0.20% by weight). <b><u> Table 3: </u></b> Chemical composition of embodiment 3 Cu Sn P. Si B. 3 rest 15.03 0.024 0.77 0.20

The invention is characterized, inter alia, in that the structure in the as-cast state consists of increasing proportions of δ-phase with increasing Sn content of the alloy, depending on the casting / cooling process. The The arrangement of this Sn-rich δ-phase changes from a finely distributed island shape with an increase in the Sn content of the alloy into a dense network shape. In the cast structure of alloy type 3, the δ phase is present with a significantly higher content (up to approx. 70% by volume). This structure goes out Fig. 3 in 200 times and off Fig. 4 in 500x magnification. The reference numeral 1 is in Fig. 4 the Sn-rich δ-phase, which is arranged like a network in the structure, is characterized. Furthermore, the hard particles 2, which are coated by tin and / or the Sn-rich δ phase, can be seen. The structural component of the copper mixed crystal is labeled with the reference number 3.

The increase in the hardness of the material with increasing Sn content is expressed by the significantly higher value of 190 HB for alloy 3 (Tab. 4). <b><u> Table 4: </u></b> hardness of the chill cast blocks from embodiment 3 alloy hardness HB 2.5 / 62.5 3 190

One aspect of the invention relates to a method for producing strips, sheets, plates, bolts, wires, rods, tubes and profiles from the tin-containing copper alloy according to the invention with the aid of the permanent mold casting process or the continuous or semi-continuous continuous casting process.

The alloy according to the invention can also be subjected to further processing. On the one hand, this enables the production of specific and often complex geometries. On the other hand, in this way the demand for an improvement of the complex operating properties of the materials, especially for components subject to wear and for structural and connecting elements in electronics / electrical engineering, is met, since it is a one in the corresponding machines, motors, gears, assemblies, constructions and systems strongly increasing stress on the system elements comes. In the course of this further processing, a significant improvement in the toughness properties and / or a substantial increase in tensile strength R _m , yield strength R _p0.2 and hardness is achieved.

Due to the excellent hot formability of the alloy according to the invention, the further processing of the as-cast state can advantageously include carrying out at least one hot forming in the temperature range from 600 to 880.degree. Plates, sheets and strips can be produced using hot rolling. Extrusion enables the production of wires, bars, tubes and profiles. Finally, forging processes are suitable for producing near-net-shape components with sometimes complex geometry.

A further advantageous possibility of further processing the as-cast state or the hot-formed state or the annealed cast state or the annealed hot-formed state comprises carrying out at least one cold forming. With this process step, in particular the material _{parameters R m} , R p0.2 and the hardness are significantly increased. This is important for applications in which there is mechanical stress and / or intensive abrasive and adhesive wear and tear on the components. Furthermore, the spring properties of the components made of the alloy according to the invention are significantly improved as a result of cold forming.

For the corresponding recrystallization of the structure of the invention after cold forming, at least one annealing treatment can be carried out in a temperature range from 200 to 880 ° C. with a duration of 10 minutes to 6 hours. The resulting very fine-grained structure is an important prerequisite for producing the combination of properties of high strength and hardness and sufficient toughness of the material.

In order to lower the internal stresses of the components, an additional stress relief / aging anneal can advantageously be carried out in a temperature range from 200 to 650 ° C. with a duration of 0.5 to 6 hours.

For areas of application with particularly high, complex component stress, further processing can be selected that includes at least cold forming or a combination of at least one hot forming and at least one cold forming in connection with at least one annealing in a temperature range of 200 to 880 ° C with a duration of 10 Minutes to 6 hours and leads to a recrystallized structure of the alloy according to the invention. The fine-grain structure of the alloy adjusted in this way ensures a combination of high strength, high hardness and good toughness properties. In addition, a stress relief annealing treatment in the temperature range from 200 to 650 ° C with a duration of 0.5 to 6 hours can be carried out to reduce the internal stresses of the components.

Three different production sequences were selected for the production of strip-shaped semifinished products from the exemplary embodiments 1 and 2 (Tab. 1). They mainly differ in the number of cold forming / annealing cycles as well as in the level of the applied cold forming degrees and annealing temperatures (Tab. 5). <b><u> Table 5: </u></b> Production programs for exemplary embodiments 1 and 2 No. Manufacturing 1 Manufacturing 2 Manufacturing 3 1 chill casting 2 Hot rolling at 780 ° C + water quenching 3 Cold rolling: 1: from 7.39 to 2.1 mm (ε≈ 72%) 2: from 7.34 to 2.1 mm (ε≈ 71%) 4th Stress relief annealing at 280 ° C / 2 h Annealing Annealing 680 ° C / 3 h 450 ° C / 3 h 5 Cold rolling (ε≈ 60%): Cold rolling (ε≈ 30%): 1: from 2.1 to 0.84 mm 1: from 2.1 to 1.47 mm - 2: from 2.1 to 0.84 mm 2: from 2.1 to 1.47 mm 6th Stress relief annealing Stress relief annealing - 280-400 ° C / 2-4 h 240-360 ° C / 2 h

After chill casting and hot rolling, the corresponding blocks or semi-finished products were characterized by an exceptionally smooth surface. As a result of the dynamic recrystallization of the structure that took place during the hot rolling process, the hot-formed state of both alloy variants 1 and 2 exhibited excellent cold formability. The hot-rolled plates could be cold-rolled crack-free with a cold deformation ε of approx. 70%.

In the course of production 1, the cold-rolled strips were annealed at the temperature of 280 ° C. for a period of 2 hours. The characteristic values of the ligaments thus relaxed are shown in Table 6. Despite high strength and hardness values, the strips of both alloys have extremely good toughness properties, for which the high values for the elongation at break A5 represent the measure. <b><u> Table 6: </u></b> Characteristic structural data and mechanical characteristic values of the strips of exemplary embodiments 1 and 2 in the final state <b> (production 1) </b> Leg. Electrical conductivity [% IACS] R _m [MPa] R _p0.2 [MPa] A5 [%] Hardness HB 1.0 / 10 1 9.8 820 767 12.9 244 2 12.6 757 660 14.1 256

An indication of the importance of the element ratio Si / B of the elements silicon and boron is provided by the comparison of the individual data for the strips from alloys 1 and 2. Due to the higher Si / B ratio of alloy 1 of approx during the casting and during the thermal and thermomechanical manufacturing steps reinforces the borosilicates, Phosphorosilicates and / or borophosphosilicates. For this reason, the superiority of alloy 1 with regard to corrosion resistance compared to alloy 2 was found in various tests. In addition, the values for R _m and R _{p0.2 of} the strips made of alloy 1 are at a significantly higher level. As a result of the Si / B ratio, which is about 0.5 smaller, a higher Si content was bound in the hard particles in the structure of alloy 2. This results in a higher electrical conductivity and an increased elongation at break A5, which results in better ductility of alloy 2. The results of production 1 already show that the properties can be adapted exactly to the respective fields of application by varying the chemical composition of the invention.

As part of production 2, the strips of alloy variants 1 and 2 were annealed at 680 ° C. for 3 hours after the first cold rolling. The strips were then cold-rolled with a cold deformation ε of approx. 60%. At the end of production, the strips were thermally relaxed at various temperatures between 280 and 400 ° C. The characteristic values of the resulting material conditions are listed in Tab. 7.

As after completion of production 1, the states of embodiment 1 show the higher strength values, whereas embodiment 2 is characterized by higher values for the electrical conductivity and for the elongation at break A5. Furthermore, from Table 7 it can be seen that the structure of the strips relaxed at 280 ° C contain deformation features, which is why no value could be given for the grain size. At approx. 340 ° C, the structure begins to recrystallize, which leads to a sharp drop in strength and hardness. <b><u> Table 7: </u></b> Characteristic structural data and mechanical characteristic values of the strips of exemplary embodiments 1 and 2 in the final state <b> (production 2) </b> Leg. Stress relief annealing temperature [° C] Grain size [µm] Electr. Conductive [% IACS] R _m [MPa] R _p0.2 [MPa] A5 [%] Hardness HB 1.0 / 10 1 280 ° C / 2 h - 9.9 790 752 9.5 249 280 ° C / 4 h - 10.0 780 730 9.9 266 340 ° C / 2 h 2 10.0 571 430 45.6 173 340 ° C / 4 h 2 9.9 565 417 43.0 168 400 ° C / 2 h 4-5 9.8 529 342 54.5 143 400 ° C / 4 h 4-5 9.9 523 327 56.8 143 2 280 ° C / 2 h - 12.7 739 694 17.8 248 280 ° C / 4 h - 12.9 733 678 21.3 242 340 ° C / 2 h 2-3 13.0 500 371 51.0 150 340 ° C / 4 h 2-3 12.5 490 353 52.2 143 400 ° C / 2 h 5-6 12.8 466 200 59.0 127 400 ° C / 4 h 5-6 12.3 475 296 57.0 124

For this reason, the annealing temperature after the first cold forming was reduced to 450 ° C. in production 3. After the three-hour annealing at this temperature, the strips were cold-rolled with a cold deformation ε of about 30%. The final two-hour stress-relieving annealing at temperatures between 240 and 360 ° C led to the characteristic values shown in Table 8.

The structure at 500-fold magnification of the final state of the strip of exemplary embodiment 1, relaxed at 240 ° C./2 h, is shown in FIG Fig. 2 shown. The fine-grain structure with the hard particles 2, which are embedded in the copper mixed crystal 3, can be seen. The hard particles are coated with tin and / or the Sn-rich δ-phase 1.

The results indicate a completely recrystallized structure with extremely high values for strength and hardness. Nevertheless, the high values for the elongation at break A5 indicate the excellent ductility of the material conditions. Even after production 3, the strength values of the states of alloy 1 are above those of alloy 2. In contrast, the states of alloy 2 offer advantages in terms of elongation at break A5 and electrical conductivity. <b><u> Table 8: </u></b> Characteristic structural data and mechanical characteristic values of the strips of exemplary embodiments 1 and 2 in the final state <b> (production 3) </b> Leg. Stress relief annealing temperature [° C] Grain size [µm] Electr. Conductive [% IACS] R _m [MPa] R _p0.2 [MPa] A5 [%] HB 1.0 / 10 1 240 ° C / 2 h 5-10 9.9 739 653 25.3 228 280 ° C / 2 h 5-10 9.9 723 648 27.1 219 320 ° C / 2 h 5-10 9.9 708 582 28.3 213 360 ° C / 2 h 5-10 10.0 570 400 47.0 153 2 240 ° C / 2 h 5-10 12.8 668 598 26.7 204 280 ° C / 2 h 5-10 12.9 653 557 32.4 197 320 ° C / 2 h 5-10 12.7 636 544 34.3 189 360 ° C / 2 h 5-10 12.9 536 390 43.6 149

The tapes of embodiment 3 of the invention, the chemical composition of which can be found in Tab. 3, were produced according to the production program that emerges from Tab. 9. The hot-rolling of the chill casting formats took place at a temperature of 750 ° C with subsequent cooling in calm air and in water. The advantage of accelerated cooling of the hot-formed semi-finished product in water is expressed in the better cold formability. The hot-rolled and water-quenched strip can then be cold-rolled with a cold deformation ε of 24%. In contrast, the strip that was cooled in air after hot rolling only allows cold rolling with a cold deformation ε of approx. 5%. <b><u> Table 9: </u></b> Production program for embodiment 3 No. production 1 Permanent mold casting 2 3-A, 3-B 3-C Hot rolling Hot rolling at 750 ° C + water quenching at 750 ° C + air cooling 3 Cold rolling Cold rolling 3-A / B: from 7.20 to 5.50 mm (ε≈ 24%) 3-C: from 7.38 to 7.04 mm (ε≈ 5%) 4th 3-A and 3-C Annealing: 500 ° C / 3h, 550 ° C / 3h, 600 ° C / 3h + air cooling 3-B Annealing: 600 ° C / 4h + air cooling 5 Cold rolling 3-B: from 5.50 to 3.67mm (ε≈ 33%) 6th 3-B Annealing: 550 ° C / 4h + air cooling 7th Cold rolling 3-B: from 3.67 to 2.05mm (ε≈ 44%) 3-B 8th Annealing: 500 ° C / 3h + air cooling Cold rolling 9 3-B: from 2.05 to 1.40mm (ε≈ 32%) 3-B 10 Stress relief annealing: 200 ° C / 2h, 240 ° C / 2h, 280 ° C / 2h, 320 ° C / 2h

The grain size and the hardness of the cold-rolled condition as well as the cold-rolled and annealed condition are shown in Table 10. As a result of the annealing treatment, the structural properties equalize at a high level with increasing annealing temperatures. <b><u> Table 10: </u></b> Grain size and hardness of the cold-rolled (after production step 4 in Table 8) and subsequently annealed strips from embodiment 3 Alloy / condition Heat treatment Grain size [µm] Hardness HB 2.5 / 62.5 3-A cold rolled 15-20 247 (hot rolled with water quenching + cold rolled from 7.2 to 5.5 mm) 500 ° C / 3h + air 5-10 188 550 ° C / 3h + air 10-15 178 600 ° C / 3h + air 15-20 170 3-C cold rolled 15-20 210 (hot rolled with air cooling + cold rolled from 7.38 to 7.04 mm) 500 ° C / 3h + air 15-20 182 550 ° C / 3h + air 20-25 174 600 ° C / 3h + air 20-25 174

The structure of the tape 3-A was finally heat-treated with the parameters 500 ° C / 3h + air and 600 ° C / 3h + air and is in FIGS. 5 and 6 shown. After annealing at 500 ° C / 3h ( Fig. 5 ), in addition to the Sn-rich δ-phase 1, coarser and very fine hard particles 2 are present in the structure, which are coated by tin and / or the Sn-rich δ-phase 1. In addition, the copper mixed crystal 3, which consists of a low-tin α phase, can be seen. After annealing at the higher temperature of 600 ° C, the structure of the strip 3-A is coarse-grained ( Fig. 6 ). The Sn-rich δ phase 1 and the hard particles 2 are embedded in the copper mixed crystal 3.

The strip 3-B was subjected to further processing with several cold rolling / annealing cycles. The characteristic values of the final states relaxed at different temperatures are listed in Tab. 11.

With each cycle, which consists of a cold rolling step and an annealing treatment, the structure of embodiment 3 of the invention is progressively stretched in lines. The line-like arrangement of the very high δ component due to the high Sn content of the alloy leads to high hardness values close to 300 HV1. At the same time the brittle character of the alloy increases, which is expressed by the very low values for the elongation at break A11.3. <b><u> Table </u> 11: </b> Characteristic structural data and mechanical characteristic values of the strips from embodiment 3 in the final state Leg / condition Stress relief annealing temperature [° C] Grain size [µm] Electr. Conductive [% IACS] R _m [MPa] R _p0.2 [MPa] A11.3 [%] HV1 3-B cold rolled 2-3 6.3 574 477 0.4 282 200 ° C / 2h 3-4 6.5 734 693 0.3 294 240 ° C / 2h 3-4 6.5 731 658 0.6 283 280 ° C / 2h 2-3 6.5 702 621 0.7 281 320 ° C / 2h 2-3 6.7 703 628 0.7 275

As a result, it can be concluded that the alloy according to the invention has excellent castability and hot formability over the entire range of Sn content from 4 to 23% Sn. The cold formability is also at a high level. However, due to the increasing δ component of the structure, the ductility of the invention naturally deteriorates with increasing Sn content.

List of reference symbols

1

Sn-rich δ-phase

2

Hard particles that are coated by tin and / or the Sn-rich δ phase

3

Copper mixed crystal, consisting of a low-tin α phase

Claims (18)

1. High-strength tin-containing copper alloy with excellent hot-formability and cold-formability, high resistance with respect to abrasive wear, adhesive wear and fretting wear and improved corrosion-resistance and ageing relaxation resistance, comprising (in % by weight):

   from 4.0 to 23.0% Sn,

   from 0.5 to 1.5% Si,

   from 0.005 to 0.6% B,

   from 0.001 to 0.08% P,

   optionally also up to a maximum of 2.0% Zn,

   optionally also up to a maximum of 0.6% Fe,

   optionally also up to a maximum of 0.5% Mg,

   optionally also up to a maximum of 0.25% Pb,

   the balance being copper and inevitable impurities,

   characterised in that

   - the ratio Si/B of the element contents of the elements silicon and boron is between 0.3 and 10.
2. High-strength tin-containing cast copper alloy with excellent hot-formability and cold-formability, high resistance with respect to abrasive wear, adhesive wear and fretting wear and improved corrosion-resistance and ageing relaxation resistance, comprising (in % by weight):

   from 4.0 to 23.0% Sn,

   from 0.05 to 2.0% Si,

   from 0.005 to 0.6% B,

   from 0.001 to 0.08% P,

   optionally also up to a maximum of 2.0% Zn,

   optionally also up to a maximum of 0.6% Fe,

   optionally also up to a maximum of 0.5% Mg,

   optionally also up to a maximum of 0.25% Pb,

   the balance being copper and inevitable impurities,

   characterised in that

   - the ratio Si/B of the element contents of the elements silicon and boron is between 0.3 and 10,

   - in that after the casting the following structural components are present in the alloy:

   a) from 1 to 98% by volume Sn-rich δ-phase (1),

   b) from 1 to 20% by volume Si-containing and B-containing phases (2),

   c) the balance being copper mixed crystal, comprising tin-poor α-phase (3), wherein the Si-containing and B-containing phases (2) are surrounded by tin and/or the Sn-rich δ-phase (1) ;

   - in that during casting the Si-containing and B-containing phases (2) which are formed as silicon borides constitute nuclei for a uniform crystallisation during the solidification/cooling of the melt so that the Sn-rich δ-phase (1) is distributed in an insular and/or reticular manner uniformly in the structure;

   - in that the Si-containing and B-containing phases (2) which are formed as boron silicates and/or boron phosphorus silicates, together with the phosphorus silicates act as a wear-protection and/or corrosion-protection coating on the semi-finished products and components of the alloy.
3. High-strength tin-containing copper alloy in the further processed state with excellent hot-formability and cold-formability, high resistance with respect to abrasive wear, adhesive wear and fretting wear and improved corrosion resistance and ageing relaxation resistance, comprising (in % by weight):

   from 4.0 to 23.0% Sn,

   from 0.05 to 2.0% Si,

   from 0.005 to 0.6% B,

   from 0.001 to 0.08% P,

   optionally also up to a maximum of 2.0% Zn,

   optionally also up to a maximum of 0.6% Fe,

   optionally also up to a maximum of 0.5% Mg,

   optionally also up to a maximum of 0.25% Pb,

   the balance being copper and inevitable impurities,

   characterised in that

   - the ratio Si/B of the element contents of the elements silicon and boron is between 0.3 and 10,

   - in that after the further processing of the alloy by means of at least one annealing operation or by means of at least one hot-forming and/or cold-forming operation together with at least one annealing operation the following structural components are present in the alloy:

   a) up to 75% by volume Sn-rich δ-phase (1),

   b) from 1 to 20% by volume Si-containing and B-containing phases (2),

   c) the balance being copper mixed crystal, comprising tin-poor α-phase (3), wherein the Si-containing and B-containing phases (2) are surrounded by tin and/or the Sn-rich δ-phase (1) ;

   - in that the contained Si-containing phases and B-containing phases (2) which are formed as silicon borides constitute nuclei for a static and dynamic recrystallisation of the structure during the further processing of the alloy, whereby the production of a uniform and fine-grained structure is present;

   - in that the Si-containing and B-containing phases (2) which are formed as boron silicates and/or boron phosphorus silicates, together with the phosphorus silicates act as a wear-protection and/or corrosion-protection coating on the semi-finished products and components of the alloy.
4. Tin-containing copper alloy according to either claim 2 or claim 3, characterised in that the element silicon is contained at from 0.05 to 1.5%.
5. Tin-containing copper alloy according to any one of claims 2 to 4, characterised in that the element silicon is contained at from 0.5 to 1.5%.
6. Tin-containing copper alloy according to any one of claims 1 to 5, characterised in that the element boron is contained at from 0.01 to 0.6%.
7. Tin-containing copper alloy according to any one of claims 1 to 6, characterised in that the element phosphorus is contained at from 0.001 to 0.05%.
8. Tin-containing copper alloy according to any one of claims 1 to 7, characterised in that the alloy is free from lead with the exception of any inevitable impurities.
9. Method for producing end products and components with a form close to an end product comprising a tin-containing copper alloy according to any one of claims 1 to 8 using the sand-casting method, shell-mould casting method, fine-casting method, full-mould casting method, die-casting method or the lost-foam method.
10. Method for producing strips, metal sheets, plates, pins, round wires, profiled wires, round rods, profiled rods, hollow rods, pipes and profiles from a tin-containing copper alloy according to any one of claims 1 to 8, using the chill casting method or the continuous or semi-continuous strand casting method.
11. Method according to claim 10, characterised in that the further processing of the cast state involves carrying out at least one hot-forming in the temperature range from 600 to 880°C.
12. Method according to any one of claims 9 to 11, characterised in that at least one annealing processing operation is carried out in the temperature range from 200 to 880°C with a duration of from 10 minutes to 6 hours.
13. Method according to any one of claims 10 to 12, characterised in that the further processing of the cast state or the hot-formed state or the annealed cast state or the annealed hot-formed state involves carrying out at least one cold-forming operation.
14. Method according to claim 13, characterised in that at least one annealing processing operation is carried out in the temperature range from 200 to 880°C with a duration of from 10 minutes to 6 hours.
15. Method according to claim 13 or 14, characterised in that a stress-relieving annealing operation/ageing annealing operation is carried out in the temperature range from 200 to 650°C with a duration of from 0.5 to 6 hours.
16. Use of the tin-containing copper alloy according to any one of claims 1 to 8 for gibs and sliding rails, for friction rings and friction discs, for plain bearing surfaces in composite components, for sliding elements and guiding elements in internal combustion engines, valves, turbochargers, gear mechanisms, exhaust gas reprocessing systems, lever systems, braking systems and articulation systems, hydraulic units or in machines and installations of general mechanical engineering.
17. Use of the tin-containing copper alloy according to any one of claims 1 to 8 for structural elements, conduction elements, guiding elements and connection elements in electronics/electrical engineering.
18. Use of the tin-containing copper alloy according to any one of claims 1 to 8 for metal objects in the breeding of organisms which live in seawater, for percussion instruments, for propellers, wings, ship propellers and hubs for ship construction, for housings of water pumps, oil pumps and fuel pumps, for guide wheels, impellers and paddle wheels for pumps and water turbines, for gears, worm gears, helical gears and for pressure nuts and spindle nuts and for pipes, seals and connection bolts in the maritime and chemical industry.

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