Low-anisotropic-index high-intensity Cu-Ni-Si alloy and preparing process thereof

Abstract

The invention discloses a low-anisotropic-index high-intensity Cu-Ni-Si alloy and a preparing process thereof. The low-anisotropic-index high-intensity Cu-Ni-Si alloy and the preparing process are suitable for cold rolling copper-based thin panels for lead frames. The alloy comprises, by chemical mass percent, 2%-3% of Ni, 0.5%-1.0% of Si, 0.1%-0.5% of Sn, 0.05%-0.1% of Fe, 0.1%-0.3% of Mg, 0.05%-0.08% of Zn, 0.2%-0.5% of RE and the balance Cu. Yttrium-based heavy rare earth is added for purifying a copper solution, and Ni2Si precipitation is improved; meanwhile, harmful texture is effectively restrained through the process that low temperature annealing is combined with grading solid dissolving before solid dissolving; and by controlling the cold rolling reduction rate, a transverse shearing belt is obtained for a product, and anisotropism is greatly improved. The alloy has the beneficial effects that the strength of extension ranges from 650 MPa to 750 MPa, the elongation ranges from 13% to 18%, the in-plane anisotropy (IPA) of the intensity is smaller than 6%, the in-plane anisotropy (IPA) of the elongation is smaller than 8%, and defects of warping, deformation and cracking of the Cu-Ni-Si alloy in the blanking process can be effectively reduced.

Description

technical field [0001] The invention relates to a low-anisotropy index high-strength Cu-Ni-Si alloy and a preparation process thereof, which is especially suitable for cold-rolled sheet materials for lead frames and belongs to the technical field of high-performance copper alloy development and processing. Background technique [0002] Cu-Ni-Si series (C7025) alloy is a typical age-strengthened high-strength medium-conductivity alloy, which is widely used in lead frames, terminals and connectors due to its good weldability, corrosion resistance, oxidation resistance and plasticity and other electronic devices. In recent years, in order to meet the needs of the market and research and development, C7025 alloys of different alloy systems have been successfully developed in the laboratory. However, in the actual production process of C7025, the finished product rate is low, the product quality is unstable, downstream customers frequently object to the product, and the product’...

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Problems solved by technology

However, strength and deep processing performance are often a pair of contradictory performance indicators

Although the higher the precipitation of the second phase, the better the strength and electrical conductivity, but the excess of the second phase will lead to aggravation of the anisotropy behavior of the sheet and the decrease of the bending performance

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