Method for producing metal components and metal component produced in this way
The invention relates to a method for producing metal components, consisting at least partially of a copper alloy, comprising the following alloy components in wt. %: 0 wt. %<Sn≤8 wt. %; 0 wt. %<Zn≤6 wt. %; 0.1 wt. %≤S≤0.7 wt. %; optionally no more than 0.2 wt. % phosphorus; optionally no more than 0.1 wt. % antimony; and optionally iron, zirconium and/or boron alone or in a combination of two or more of said elements of no more than 0.3 wt. %; and unavoidable impurities, and the rest being copper. The method comprises the following stages: (a) melting the copper alloy: (b) producing press blanks from the copper alloy; and (c) pressing the press blanks at a suitable pressing temperature to form the metal components. The invention also relates to a metal component which has been produced according to a method of this type.
1. A method for producing a metal component which comprises a copper alloy that comprises the following alloy components in wt. %:
3.0 wt. %<Sn<8 wt. %;
1.3 wt. %<Zn<6 wt. %;
0.1 wt. %<S<0.7 wt. %;
no more than 0.2 wt. % phosphorus;
no more than 0.1 wt. % antimony; and
iron, zirconium and/or boron alone or in a combination of two or more of said elements no more than 0.3 wt. %; and unavoidable impurities, and copper for the remainder;
wherein the method comprises the following steps:
(a) melting the copper alloy;
(b) producing press blanks from the copper alloy; and
(c) pressing the press blanks at a suitable pressing temperature in a range of from 750° C. to 900° C. to form the metal component, and
wherein the pressing step reduces an average grain size of a structure of the copper alloy in the metal component from greater than 100 μm to less than 100 μm in a region up to 200 μm below the surface of the metal component, while leaving an average grain size of the structure as greater than 100 μm in another region more than 200 μm below the surface of the metal component.
2. The method according to claim 1 , characterized in that the proportion of sulfur in the alloy is 0.20 wt. %<S<0.65 wt. %.
3. The method according to claim 1 , characterized in that the proportion of zinc in the alloy is 1.3 wt. %<Zn<3.5 wt. %.
4. The method according to claim 1 , characterized in that the proportion of phosphorus in the alloy is 0.015 wt. %<P<0.1 wt. %.
5. The method according to claim 1 , characterized in that the content of the proportion of tin in the alloy is 3.0 wt. %<Sn<4.8 wt. %.
6. The method according to claim 1 , characterized in that copper is contained in the lead-free copper alloy in a quantity of greater than 90 wt. %.
7. The method according to claim 1 , characterized in that the pressing temperature in step (c) is in a range of from 800° C. to 880° C.
8. The method according to claim 1 , characterized in that the press blanks are heated to the pressing temperature before step (c) and are kept at the pressing temperature over a period of time of from 0.1 seconds to 60 minutes.