JP2008516081A - Copper / zinc / silicon alloys, methods of use and methods of manufacture thereof - Google Patents

Abstract

  The present invention comprises 70-80 wt% copper, 1-5 wt% silicon, 0.0001-0.5 wt% boron, 0.2 wt% phosphorous and / or 0.2 wt%. The present invention relates to a copper-zinc-silicon alloy containing not more than 1% arsenic and the remaining zinc inevitably doped with impurities. Furthermore, the present invention relates to the use and production method of this alloy. The alloy is characterized by improved resistance to oxidation and homogeneous mechanical properties.

Description

  The present invention relates to copper-zinc-silicon alloys and methods of using and producing such copper-zinc-silicon alloys.

  A critical requirement for copper-zinc-silicon alloys is the resistance to dezincification and the ability to be machined. Here, the good mechanical properties of this kind of brass alloy are obtained by adding lead, for example as described in EP 1 045 041 A1. In recent years, however, lead-free brass alloys with good mechanical properties have been developed, as described for example in EP 1 038 981 A1 and DE 103 08 778 B3. Both lead-free copper-zinc-silicon alloys and lead-containing copper-zinc-silicon alloys are susceptible to oxidation and form scale layers at temperatures in the range of 300-800 ° C. This scale layer is further less adherent to the metal and can be easily separated from the metal. This disperses the product equipment and this layer severely contaminates the equipment. Product equipment is expensive to clean and increases manufacturing costs. A further problem with known copper-zinc-silicon alloys is that the mechanical properties of the material change along the long product being processed because the material is not homogeneous.

  In view of these facts, the present invention provides a copper-zinc-silicon alloy that has improved performance in terms of homogeneity and that is less prone to scale formation, as well as a brass alloy of this type. Based on the problem of providing a method of use and a method of manufacture.

  The primary purpose for the alloy is to make 70-80% copper, 1-5% silicon, 0.0001-0.5% boron, 0-0.2% phosphorus and / or Alternatively, the invention is achieved by an invention relating to a copper-zinc-silicon alloy containing arsenic and the remaining zinc to which impurities are inevitably added.

  The copper content is between 70 and 80% by weight. This is because if the copper content is less than 70% by mass or greater than 80% by mass, the mechanical properties of the alloy are adversely affected. The same applies if the silicon concentration is outside the range of 1-5% by weight as described above. The concentration of boron in the alloy is in the range of 0.0001 to 0.5% by weight. Surprisingly, adding boron within the claimed concentration range, on the one hand, prevents the formation of scale and on the other hand greatly increases the adhesion of the remaining scale to the material. I knew it was possible. More surprisingly, it has been found that the addition of boron can improve the homogeneity of the microstructure and thus suppress variations in mechanical properties. Phosphorus and arsenic may each be present in the alloy at a concentration of 0.2% by mass or less, and can be substituted for each other. Phosphorus and arsenic have a positive effect on the microstructure and corrosion performance of the initial casting, further improve melt flow performance and reduce the likelihood of stress corrosion cracking. The remaining major component in the alloy is zinc.

  In addition to the advantages mentioned above of suppressing easily separable scale layers that increase manufacturing costs and improving mechanical properties, a good machine combined with high resistance to corrosion Characteristics and molding performance are obtained. The resistance to dezincification and stress corrosion cracking is particularly evident in the present invention. A dezincification test carried out according to ISO 6509 gives a depth of only 26 μm or less due to the dezincification phenomenon.

  A second objective regarding the use of this type of copper-zinc-silicon alloy is to provide electrical engineering components, sanitary ware components, containers that carry or store liquids or gases, torsionally loaded components, Reusable components, drop cast components, semi-finished products, strips, sheets, contoured parts, usage as used on plates, or wrought, rolled or molded alloys This is achieved by the usage method.

  Copper-zinc-silicon alloys are used as contacts, pins, or fixing members in electrical engineering, for example, as fixed or attached contacts, including clamping and plug connections or plug-in contacts Is done.

  Alloys have a high resistance to corrosion with respect to liquid and gaseous media. Furthermore, the resistance to dezincification and stress corrosion cracking is particularly great. As a result, the alloy is particularly adapted for use in containers that carry or store liquids or gases, and in particular, containers and pipes used in freezers, water appliances, valve expanders, pipe connectors and sanitary ware Suitable for use with other valves.

  The low corrosion rate inherently ensures that the properties of the alloy components lost due to metal scrubbing, i.e. the operation of the liquid or gaseous medium, are inherently low. In this respect, the material is suitable for application fields that require reduced pollutant emissions to protect the environment. This allows the alloys according to the invention to be used in the field of recyclable materials.

  Less resistance to stress corrosion cracking means that alloys are preferred for use in screws or clamped connections for technical reasons that high elastic energy is stored. For this reason, the alloy is compatible with all components, in particular nuts and bolts, which are particularly subjected to tensile and / or torsional loads. After cold forming, the material has a large value of yield strength. As a result, a larger tightening torque can be used in screw connections that are not necessarily deformed like plastic. The yield strength ratio of the copper-zinc-silicon alloy is lower than that of free-cutting brass. Screw connections that are tightened only once in the process become intentionally overexpanded, and a particularly high holding force is obtained.

  The possible use of the copper-zinc-silicon alloy results in starting materials both in the form of tubes and strips. The alloy is also very suitable for rolled or perforated strips, sheets and plates, especially keys, wood blocks, for decorative purposes or for leadframe applications.

  A third object of the method for producing a copper-zinc-silicon alloy of this kind is to perform normal continuous casting and hot rolling at a temperature in the range of 600 to 760 ° C., followed by deformation. In particular, it is achieved by a production method which performs cold rolling and preferably additionally performs annealing and deformation steps.

  The purpose for the production of this kind of copper-zinc-silicon alloy is to carry out normal continuous casting and injection at temperatures below 760 ° C., preferably in the range 650-680 ° C. It is also achieved by a manufacturing method such as cooling in

  More advantageous improvements in the copper-zinc-silicon alloy are 75-77 wt% copper, 2.8-4 wt% silicon, 0.001-0.1 wt% boron, Phosphorus and / or arsenic is 0.03 to 0.1% by mass, and the rest is zinc inevitably added with impurities.

  In another preferred embodiment, the copper-zinc-silicon alloy comprises 0.01-2.5 wt% lead, 0.01-2 wt% tin, and 0.01-0.3 wt% iron. And at least one selected from the group consisting of 0.01 to 0.3% by weight cobalt, 0.01 to 0.3% by weight nickel, and 0.01 to 0.3% by weight manganese. Contains one additional element. Adding lead has a positive effect on the mechanical properties.

  In this case, the alloy contains 0.01 to 0.1% by weight of lead, 0.01 to 0.2% by weight of tin, 0.01 to 0.1% by weight of iron, 0% It is more advantageous to comprise 0.01 to 0.1% by weight of cobalt, 0.01 to 0.1% by weight of nickel, and 0.01 to 0.1% by weight of manganese.

  In a preferred improvement, the copper-zinc-silicon alloy comprises 0.5 wt% or less silver, 0.5 wt% or less aluminum, 0.5 wt% or less magnesium, and 0.5 wt% or less. It further includes at least one element selected from the group consisting of antimony, 0.5% by mass or less of titanium, and 0.5% by mass or less of zirconium, and more preferably 0.01-0. 1% by weight silver, 0.01-0.1% by weight aluminum, 0.01-0.1% by weight magnesium, 0.01-0.1% by weight antimony, 0.01-0.1% by weight It additionally includes at least one element selected from the group consisting of 0.1% by weight titanium and 0.01-0.1% by weight zirconium.

  In another preferred embodiment, the copper-zinc-silicon alloy comprises 0.3 mass% or less cadmium, 0.3 mass% or less chromium, 0.3 mass% or less selenium, and 0.3 mass%. And further comprising at least one element selected from the group consisting of the following tellurium and 0.3% by weight or less bismuth, more preferably 0.01 to 0.3% by weight cadmium, and 0 0.01-0.3 wt% chromium, 0.01-0.3 wt% selenium, 0.01-0.3 wt% tellurium, 0.01-0.3 wt% bismuth, , At least one element selected from the group consisting of:

  Exemplary embodiments will be described in more detail with reference to the drawings and the following description.

  The CuZn21Si3P alloy (copper-zinc 21-silicon 3-phosphorous alloy) in the exemplary embodiment has variations in the component concentrations. The amount of copper is in the range of 75.8 to 76.1% by mass, the amount of silicon is in the range of 3.2 to 3.4% by mass, and the amount of phosphorus is 0.07 to 0.1% by mass. %, And the remainder is zinc inevitably added with impurities. Various samples of the alloy contain different amounts of boron, 0 wt%, 0.004 wt% and 0.009 wt%. The alloy is produced by continuous casting, followed by injection at a temperature below 760 ° C., preferably in the range of 650-680 ° C., followed by rapid cooling.

  All alloys have excellent resistance to the dezincing phenomenon. A dezincification test carried out according to ISO 6509 reveals a dezincification depth less than just 26 μm.

  If the CuZn21Si3P alloy is exposed at a temperature in the range of 300 to 800 ° C., for example, in hot working, a scale (a thin oxide film) is formed. This scale is easily separated and can contaminate the product equipment. The extensive scaled surface of a boron free CuZn21Si3P alloy is shown in FIG. 1a. The surface of the object to be inspected is represented as gray, which accounts for the majority in FIG. 1a. This gray color indicates the surface on which the scale is formed in the CuZn21Si3P alloy. A few individual bright spots that are not regularly distributed are observed on the surface of the alloy. In contrast, a CuZn21Si3P alloy containing 0.0004 wt% boron as shown in FIG. 1b has much more white spots on the surface than an alloy containing no boron. These white dots indicate areas of shiny metal in the alloy. These bright metal areas, i.e. unscaled areas, are unevenly distributed on the surface of the alloy. The proportion of the surface on which the scale is formed is greatly reduced and the remaining scale adheres more firmly to the metal than in the case of an alloy without boron. FIG. 1c shows a CuZn21Si3P alloy containing 0.009 wt% boron. This figure clearly shows that the number of shining metal surfaces, ie the number of white dots, is further increased. In some areas there is a relatively large continuous area of shiny metallic material, and this figure shows a very regular distribution on the surface of the alloy. The proportion of the surface on which the scale is formed further decreases and the remaining scale adheres firmly to the metal. For this reason, low concentrations of boron in the range of 0.0001-0.5% by weight limit the scale formation of the copper-zinc-silicon alloy, while at the same time the adhesion of the scale to the metal is greatly increased. As a result, it has surprisingly been found to prevent unwanted contamination of the product equipment.

  Similar results are seen with copper-zinc-silicon-phosphorous alloys with different lead content, for example 0.01%, 0.05%, 0.1% or 2.5% by weight. It was.

  In addition to reducing the ease of scale formation of copper-zinc-silicon alloys, boron has a positive effect on mechanical identification. This is because boron makes the microstructure of the alloy more homogeneous. Such a change in the microstructure of the alloy is shown in FIG. 2 as a function of the concentration of boron. The CuZn21Si3P alloy without boron has a coarse and inhomogeneous microstructure (FIG. 2a), whereas the CuZn21Si3P alloy with 0.0004% by weight boron already has a very uniform grain size. It has a fine structure (FIG. 2b). When boron is further increased to 0.009 mass%, a more homogeneous and more uniform CuZn21Si3P alloy is obtained. In this case, the finely structured particles can no longer be seen with the naked eye (FIG. 2c).

In addition to visual changes in the microstructure, the increase in boron has a positive effect on the mechanical properties. This is particularly evident in rods extruded from copper-zinc-silicon alloys. In measuring the mechanical properties, samples were taken at the tips and ends of such rods. Regarding the tensile strength of the rod formed from the CuZn21Si3P alloy containing no boron, there was a difference exceeding 60 N / mm ² at the end of the rod compared to the end of the rod. In contrast, in a similar alloy containing 0.0004 wt% boron, the difference in tensile strength between the tip and end of the rod was less than 40 N / mm ² . If the 0.009 wt% boron when added to CuZn21Si3P alloy, the strength difference tension between the tip and the end of the rod was less than 5N / mm ^2.

  Thus, the material has the same mechanical properties from the tip to the end. For this reason, uniform strength can be obtained over the entire length of the extrusion. The reason is due to the effect of boron atomization.

  The table shows the relationship between the boron content of the copper-zinc-silicon alloy and the increase in the microstructure homogeneity of the alloy, ie the decrease in the difference in strength in the extruded processed product.

(A) CuZn21Si3P alloy without boron, (b) CuZn21Si3P alloy containing 0.0004 mass% boron, and (c) CuZn21Si3P alloy containing 0.009 mass% boron at 600 ° C. Fig. 3 shows the morphology of the scale layer after time annealing. (A) CuZn21Si3P alloy without boron added, (b) CuZn21Si3P alloy containing 0.0004 mass% boron, and (c) CuZn21Si3P alloy containing 0.009 mass% boron, respectively. Shows the form of the microstructure.

Claims (9)

70-80 mass% copper,
1 to 5 mass% silicon,
0.0001-0.5 mass% boron,
0-0.2% by weight of phosphorus and / or arsenic;
With the remaining zinc unavoidably added,
Copper-zinc-silicon alloy containing Copper is 75-77 mass%,
Silicon is 2.8-4% by weight,
Boron is 0.0001-0.01 mass%,
2. The copper-zinc-silicon alloy according to claim 1, wherein phosphorus and / or arsenic is 0.03 to 0.1% by mass. 0.01 to 2.5 mass% lead,
0.01-2 mass% tin,
0.01-0.3 mass% iron,
0.01-0.3 mass% cobalt,
0.01 to 0.3 mass% nickel,
0.01-0.3 mass% manganese,
The copper-zinc-silicon alloy according to claim 1 or 2, further comprising at least one element selected from the group consisting of: The group is
0.01 to 0.1% by weight of lead;
0.01-0.2 mass% tin,
0.01-0.1% by mass of iron;
0.01-0.1% by weight of cobalt,
0.01-0.1% by weight of nickel;
0.01-0.1% by weight of manganese,
4. The copper-zinc-silicon alloy according to claim 3, wherein 0.5% by mass or less of silver,
0.5 mass% or less of aluminum,
0.5% by weight or less of magnesium,
0.5% by mass or less of antimony,
Less than or equal to 0.5 wt% titanium,
0.5 mass% or less of zirconium,
Additionally comprising at least one element selected from the group consisting of:
0.01 to 0.1% by weight of silver,
0.01 to 0.1% by weight of aluminum;
0.01-0.1% by weight of magnesium,
0.01-0.1% by weight of antimony;
0.01-0.1% by mass of titanium,
0.01-0.1% by weight of zirconium,
The copper-zinc-silicon alloy according to claim 1, further comprising at least one element selected from the group consisting of: Less than 0.3% by weight of cadmium;
0.3% by mass or less of chromium,
0.3% by mass or less of selenium,
Less than 0.3% by weight tellurium;
Less than 0.3% by weight of bismuth,
Additionally comprising at least one element selected from the group consisting of:
0.01-0.3 mass% cadmium;
0.01-0.3 mass% chromium,
0.01 to 0.3% by weight of selenium;
0.01-0.3% by weight tellurium;
0.01-0.3 mass% bismuth,
The copper-zinc-silicon alloy according to claim 1, further comprising at least one element selected from the group consisting of: A method of using a copper-zinc-silicon alloy according to any one of claims 1 to 6,
Electrical engineering components, sanitary ware components, containers that carry or store liquids or gases, torsionally loaded components, reusable components, drop cast components, semi-finished products, strips, sheets, Usage for contoured parts, plates, or as a wrought, rolled or molded alloy. A method for producing a copper-zinc-silicon alloy according to any one of claims 1 to 6,
Normal continuous casting and hot rolling at temperatures in the range of 600-760 ° C. followed by deformation, in particular cold rolling, preferably additionally with annealing and deformation steps. Such a manufacturing method. A method for producing a copper-zinc-silicon alloy according to any one of claims 1 to 6,
A manufacturing method in which normal continuous casting and injection at a temperature of 760 ° C. or lower, preferably at a temperature in the range of 650 to 680 ° C., followed by cooling in air.

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