COPPER-ZINC ALLOY AND USE THEREOF

Abstract

A copper-zinc alloy contains 59.0 to 65.0% Cu, 2.5 to 4.0% Mn, 1.2 to 2.5% Al, 0.5 to 2.0% Si, 0.2 to 1.0% Fe, 0 to 1.0% Pb, 0 to 1.5% Ni, 0 to 0.2% Sn, balance Zn and unavoidable impurities. The zinc alloy has excellent temperature resistance and surfaces produced by machining have a considerably reduced surface roughness.

Claims

1. A copper-zinc alloy, comprising: 59.0 to 65.0% wt. Cu; 2.5 to 4.0% wt. Mn; 1.2 to 2.5% wt. Al; 0.5 to 2.0% wt. Si; 0.2 to 1.0% wt. Fe; 0 to 1.0% wt. Pb; 0 to 1.5% wt. Ni; 0 to 0.2% wt. Sn; and balance Zn and unavoidable impurities.

2. The copper-zinc alloy according to claim 1, wherein: 62.5 to 64.5% wt. of said Cu; 2.7 to 3.5% wt. of said Mn; 1.3 to 1.9% wt. of said Al; 0.8 to 1.2% wt. of said Si; 0.3 to 0.6% wt. of said Fe; 0 to 1.0% wt. of said Pb; 0 to 1.5% wt. of said Ni; 0 to 0.2% wt. of said Sn; and balance said Zn and said unavoidable impurities.

3. The copper-zinc alloy according to claim 1, wherein: 63.0 to 64.0% wt. of said Cu; 2.9 to 3.2% wt. of said Mn; 1.4 to 1.9% wt. of said Al; 0.8 to 1.2% wt. of said Si; 0.3 to 0.6% wt. of said Fe; 0 to 1.0% wt. of said Pb; 0.5 to 0.7% wt. of said Ni; 0 to 0.2% wt. of said Sn; and balance said Zn and said unavoidable impurities.

4. The copper-zinc alloy according to claim 1, wherein the copper-zinc alloy has an electrical conductivity of more than 9.0 m/ohm mm.sup.2.

5. The copper-zinc alloy according to claim 1, wherein cast state intermetallic compounds present in a microstructure have a size of not more than 150 μm.

6. A bearing bushing, comprising: a bearing bushing body, containing: 59.0 to 65.0% wt. Cu; 2.5 to 4.0% wt. Mn; 1.2 to 2.5% wt. Al; 0.5 to 2.0% wt. Si; 0.2 to 1.0% wt. Fe; 0 to 1.0% wt. Pb; 0 to 1.5% wt. Ni; 0 to 0.2% wt. Sn; and balance Zn and unavoidable impurities.

7. The bearing bush according to claim 6, wherein the bearing bushing is a turbocharger bearing bushing.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0023] FIG. 1 is an illustration showing a microstructure of a copper-zinc alloy according to the invention;

[0024] FIG. 2 is a cross-sectional view of a machined surface of the copper-zinc alloy; and

[0025] FIG. 3 is a cross-sectional view of a machined surface of a conventional copper-zinc alloy.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a microstructure image of a copper-zinc alloy according to the invention. It is apparent therefrom that a maximum size of the intermetallic compounds (dark crystals) in a longitudinal direction of the crystals is not more than 150 mm.

[0027] FIG. 2 shows a cross-sectional view through a surface of a component made of the copper-zinc alloy, wherein the surface has been machined. As is apparent from FIG. 2 deviations occur on the surface in the region of intermetallic compounds. The deviations have a maximum depth of about 2.55 μm.

[0028] For comparison FIG. 3 shows a cross-sectional view through a machined surface of a component produced from a conventional copper-zinc alloy (70.5% Cu, 7.8% Mn, 5.2% Al, 2.0% Si, 1.0% Fe, balance Zn and avoidable impurities). Deviations having a depth of more than 20 μm occur on the surface here.

[0029] With the copper-zinc alloy according to the invention it is thus possible to produce components which, upon machining, exhibit markedly smaller deviations on the surface than components produced from a conventional copper-zinc alloy. With the copper-zinc alloy according to the invention bearing bushings having an improved surface quality, in particular upon machining, can be produced. Owing to its excellent thermal properties the copper-zinc alloy according to the invention is particularly suitable for producing bearing bushings for turbochargers.