Copper alloy and fabrication method thereof

Abstract

The invention relates to the field of a metal alloy, in particular to a Cu-Ni-Si alloy. A fabrication method of a copper alloy comprises the steps as follows: A) casting, B) hot rolling, C) face milling and D) cold rolling and annealing. The copper alloy comprises the following chemical components by mass percent: 1.8-2.1% of nickel, 0.4-0.68% of silicon, 0-0.2% of iron, 0-0.1% of manganese, 0-0.2% of zinc, 0-0.005% of cadmium, 0-0.02% of lead, 0-0.3% of other impurities and the balance of cooper, wherein iron, manganese, zinc, cadmium and lead are all impurities; the tensile strength Rm of the copper alloy is greater than or equal to 600MPa; the broken elongation A11.3 is greater than or equal to 8%; the Vickers hardness HV is greater than or equal to 180; and the electrical conductivity is greater than or equal to 46% IACS (International Annealed Copper Standard). The ideal performance of a copper alloy material for a lead frame can be obtained by the fabrication method for the copper alloy.

Description

technical field [0001] The invention relates to the field of metal alloys, in particular to Cu-Ni-Si alloys. Background technique [0002] With the rapid development of electronic chips, the requirements for the tensile strength and hardness of the copper alloy material used in the lead frame of the chip are getting higher and higher. At present, the desired tensile strength Rm of the copper alloy for the lead frame is ≥ 600MPa , Elongation after breaking A11.3 ≥ 8%, Vickers hardness HV ≥ 180 (Vickers hardness value, no unit). [0003] At present, the main materials used for lead frames in China are Cu-Fe-P alloys (C19400, C19210) and Cu-Ni-Si alloys (C7025). The existing problems of copper alloys for lead frames are: 1. The tensile strength of existing Cu-Fe-P alloy products (C19400, C19210) is 420-500 MPa, which cannot meet the technical requirements of high-grade lead frames. 2. Some alloys have low elongation and poor plasticity during stamping, and are not easy to fo...

AI Technical Summary

Problems solved by technology

The existing problems of copper alloys for lead frames are: 1. The tensile strength of existing Cu-Fe-P alloy products (C19400, C19210) is 420-500 MPa, which cannot meet the technical requirements of high-grade lead frames

2. Some alloys have low elongation, poor plasticity, and are not easy to form when stamping, and there is a risk of cracking and large residual stress during stamping

3. The mold bears a large load during stamping, and the mold is easily damaged

4. Due to the high nickel content of the existing Cu-Ni-Si alloy (C7025), casting and hot rolling production is difficult, the yield rate is low, and the material cost is too high