CN-122012982-A - High-uniformity superfine crystal brass alloy material and preparation method thereof

Abstract

The invention discloses a high-uniformity superfine crystal brass alloy material and a preparation method thereof, and belongs to the technical field of materials and preparation and processing. The alloy comprises, by mass, 28.5-31.5% of Zn, 0.005-0.25% of P, 0.002-0.1% of Ag, 0.001-0.1% of Ni, and the balance of Cu and unavoidable impurities. The preparation method sequentially comprises three steps of upward continuous casting, first-pass continuous extrusion and second-pass continuous extrusion. Wherein Zn and P are added in a form of intermediate alloy and are covered and protected by graphite flakes during smelting, the blank and the die are preheated before twice extrusion, and the rod is cooled after extrusion. The method can effectively control component segregation, and obtains the ultra-fine grain structure with average grain size not more than 1 micron and uniform structure through the synergistic effect of large plastic deformation and micro-alloying. The hardness of the obtained material is not lower than 150HV, the conductivity is not lower than 35% IACS, the comprehensive performance is good, and the material is suitable for the industrial field with high requirements on strength, conductivity and uniformity.

Inventors

• SONG HONGWU
• CHEN SHUAIFENG
• WANG SONGWEI
• ZHANG SHIHONG

Assignees

• 中国科学院金属研究所

Dates

Publication Date

20260512

Application Date

20260123

Claims (8)

1. 1. The high-uniformity superfine crystal brass alloy material is characterized by comprising, by mass, 28.5-31.5% of Zn, 0.005-0.25% of P, 0.002-0.1% of Ag, 0.001-0.1% of Ni, and the balance of Cu and unavoidable impurities.
2. 2. A method for preparing the high uniform ultra-fine grain brass alloy material in accordance with claim 1, comprising the steps of: (1) Smelting and casting raw materials configured according to a proportion to obtain a casting rod, wherein the casting temperature of the upper casting is 1120-1180 ℃ and the cooling water strength is 0.08-0.12MPa; (2) Continuously extruding the casting rod obtained in the step (1) for the first time to obtain a first extrusion rod material; (3) And (3) continuously extruding the first extrusion rod material obtained in the step (2) in a second pass to obtain an alloy rod material.
3. 3. The method for preparing the high-uniformity ultrafine-grained brass alloy material according to claim 2, wherein in the step (1), zn and P are added into a melt in a form of intermediate alloy, the surface of the melt is covered with graphite flakes during smelting, the intermediate alloy of Zn is Cu-Zn series, the Zn content is 40% -60%, the intermediate alloy of P is Cu-P series, and the P content is 10% -15%.
4. 4. The method for preparing a highly uniform ultra-fine grain brass alloy material according to claim 2, wherein in the step (1), the diameter of the cast rod obtained by the upward continuous casting is 8-16mm, the difference of Zn element contents at random three positions on the longitudinal section is not more than 1.5%, and the difference of P, ag and Ni element contents is not more than 0.003%.
5. 5. The method for preparing the high-uniformity ultrafine-grained brass alloy material according to claim 2, wherein in the step (2), the diameter of the rod obtained by the first-pass continuous extrusion is 8-16mm, and in the step (3), the diameter of the alloy rod obtained by the second-pass continuous extrusion is 12-28mm.
6. 6. The method for preparing a high uniform ultra-fine grain brass alloy material according to claim 2, wherein the preheating temperature of the billet is 450-680 ℃ and the preheating temperature of the die is 400-500 ℃ before the continuous extrusion in the step (2) and the step (3), wherein the preheating temperature of the first-pass billet is 450-550 ℃ and the preheating temperature of the second-pass billet is 600-680 ℃.
7. 7. The method for producing a highly uniform ultra-fine grain brass alloy material in accordance with claim 2, wherein in step (2) and step (3), the rotation speed of the extrusion wheel in the continuous extrusion process is 3.5-5.0rpm, and the working current of the extruder is 90-150A.
8. 8. The method for preparing a high-uniformity ultrafine-grained brass alloy material according to claim 2, wherein in the step (2) and the step (3), the extruded rod is cooled at the outlet of the cavity of the continuous extrusion equipment in a water-cooling or water mist cooling mode, and the temperature of cooling water is 15-25 ℃.

Description

High-uniformity superfine crystal brass alloy material and preparation method thereof Technical Field The invention belongs to the technical field of materials and preparation processing, and particularly relates to a high-uniformity superfine crystal brass alloy material and a preparation method thereof. Background Brass (copper zinc alloy) is widely used in the fields of electric connection, fasteners, heat dissipation devices, load-bearing structural members and the like due to its good electrical conductivity, thermal conductivity, corrosion resistance and processability. With the development of high-end equipment manufacturing, precision electronics and other industries, the market puts higher demands on the comprehensive performance of brass materials, namely, the strength, hardness and wear resistance of the brass materials are greatly improved while good conductivity and processability are maintained. According to the theory of strengthening metal materials, grain refinement is an effective way to improve the strength and toughness of the materials at the same time. Currently, the technical approaches for realizing brass grain refinement are mainly divided into two categories: The first type is large plastic deformation methods such as equal channel angular Extrusion (ECAP), high Pressure Torsion (HPT), etc. The method can obtain ultrafine grain or even nanocrystalline structure, but has the inherent defects of intermittent process, incapability of continuous production, large equipment investment, high energy consumption, limited product size and the like, and is difficult to meet the requirement of industrialized mass production. More importantly, the severe plastic deformation process is easy to generate uneven strain distribution and texture in the material, so that the microstructure uniformity of the final product is poor, and the mechanical property and the physical property show fluctuation on a long-size product, thereby influencing the reliability of use. The second type is microalloying, i.e., the inhibition of grain growth by the addition of trace alloying elements. However, in brass systems, the major alloying element zinc, as well as commonly used grain refiners (such as phosphorus), is relatively low melting and volatile to oxidize. In conventional smelting and casting processes, particularly in large-scale production, severe component segregation and element burn-out are liable to occur, making it difficult to accurately control the alloy composition. By simply relying on microalloying, grain refinement can be realized only locally, and uniform and stable submicron superfine grain structure is difficult to obtain on the whole section of the cast ingot. Meanwhile, excessive addition of certain alloying elements seriously impairs the conductivity of the material, resulting in a contradiction between strength and conductivity. Even if large plastic deformation is combined with micro-alloying, the problems are still difficult to effectively solve if the adopted preparation process is improper. For example, the traditional semicontinuous casting is adopted to prepare large-size cast ingots, the cooling speed is low, macrosegregation is easy to form, even if extrusion with large deformation is carried out later, the initial non-uniformity is difficult to eliminate thoroughly, and the tissue and performance consistency of the final product are poor. In addition, the conventional process has insufficient protection to the easily oxidized elements such as zinc, phosphorus and the like, and aggravates the difficulty of component control. Accordingly, there is a lack of a brass alloy preparation solution in the prior art that effectively synergistically addresses the series of interrelated problems of composition uniformity, tissue uniformity, high strength and good electrical conductivity from the beginning of smelting and casting. In particular, a complete technical scheme which can adapt to continuous and large-scale industrial production, can stably obtain a short flow of high-uniformity ultrafine grain tissue, has low cost and is accurate in process control is lacking. This limits the application of brass in fields where high-end connectors, lead frames, high-performance electromagnetic shields, etc. have extremely high requirements for material integrity and consistency. Disclosure of Invention The invention aims to provide a high-uniformity superfine crystal brass alloy material and a preparation method thereof. In order to achieve the above object, the present invention provides the following technical solutions: The high-uniformity superfine crystal brass alloy material comprises, by mass, 28.5-31.5% of Zn, 0.005-0.25% of P, 0.002-0.1% of Ag, 0.001-0.1% of Ni, and the balance of Cu and unavoidable impurities. The preparation method of the high-uniformity superfine crystal brass alloy material comprises the following steps: (1) Smelting and casting raw materials configured according to