WO2019023818A1

WO2019023818A1 - Readily cold-formable deformable zinc alloy material, preparation method therefor, and application thereof

Info

Publication number: WO2019023818A1
Application number: PCT/CN2017/000522
Authority: WO
Inventors: 孙文声; 郭俊; 冯振仙; 唐宁; 郜晓彬
Original assignee: 宁波博威合金材料股份有限公司
Priority date: 2017-08-02
Filing date: 2017-08-14
Publication date: 2019-02-07
Also published as: CN107385278A; CN107385278B

Abstract

A readily cold-formable deformable zinc alloy, having the following composition in percentage by weight: 1.0-3.5 wt% of Cu, 0.05-0.5 wt% of Mn, and ≤ 0.05 wt% of Al, the balance being Zn and unavoidable impurities. The phase composition of the deformable zinc alloy material comprises a Cu-substituted Zn solid solution with Zn as a matrix, a second phase of Zn5Cu, and a second phase of a zinc-manganese-copper intermetallic compound. The deformable zinc alloy material has a tensile strength of 260-320 MPa, an elongation of 25-35%, and an HV5 hardness of 90-100. The deformable zinc alloy material has medium strength, high elongation, and good dimensional stability, and its total processing rate can reach 80-90%.

Description

Deformed zinc alloy material which is easy to be cold-formed and preparation method and application thereof

Technical field

The invention relates to the field of deformed zinc alloy and its application technology, in particular to a deformed zinc alloy material which is easy to be cold-formed and a preparation method and application thereof.

Background technique

Cold working technology is the processing method of quickly processing blanks into various complicated structures through various molds, such as cold heading, cold forging, spinning, riveting and so on. Compared with the traditional turning technology, cold working can improve the utilization rate of materials, reduce the loss, improve the production efficiency of the products, and the cold-processed products are evenly organized and compact. They can be widely used in various standard parts. Cold processing has become a processing of metal materials. Important means. However, the cold working has a large amount of deformation to the metal, and the general metal belongs to the work hardening material. Therefore, for some cryogenic processing such as deep freezing and deep cold forging, the metal generally has difficulty in processing or even processing. In the case, it is necessary to repeat the annealing treatment to eliminate the stress before processing. Unlike ordinary metals, zinc alloys are not work hardened materials. Zinc alloys have obvious advantages in certain cold processing areas.

Conventional cast and die-cast zinc alloys have low strength and high brittleness and are generally used as low-end structural members. The processable deformed zinc alloy has the advantages of high strength, good plasticity and low cost. Some of its properties are obviously superior to copper alloys, and can be used to replace copper alloys in some fields. Therefore, the deformed zinc alloy has gradually attracted people's attention in recent years. .

CN104073686B discloses a rivetable deformed low copper alloy material composed of Al, Cu, M, Zn and unavoidable impurities, and M is Ni, V, Ti, Zr, La, Ce At least one of Pr, Nd, Mo, Si, Be, Cr, Mn, Co, and Mg, the impurities including at least one of Fe, Pb, Sn, Sb, and Cd; the weight of the low copper alloy material In the percentage composition: the content of Al x = 0.1 - 6.0 wt%, the content of Cu y = 0.1 - 4.0 wt%, the content of M z=0.001-1.0wt%, the total amount of impurities is ≤0.1wt%, the balance is Zn; the sum of the contents of Al and Cu satisfies: 0.5wt%≤x+y≤9.0wt%, the ratio of Al to Cu Satisfied: 1 ≤ x / y ≤ 4. When the low copper alloy material is subjected to large deformation cold working, there are many problems of cracking after cold rolling.

Summary of the invention

The technical problem to be solved by the present invention is that, in view of the deficiencies of the prior art, a deformed zinc alloy material which is easy to be cold-formed and a preparation method and application thereof are provided, and the deformed zinc alloy material can be applied to cold heading, cold forging and spinning. Cold-working deformation such as riveting and deep drawing, widely used in zippers, hardware, and electronic and electrical parts.

The technical solution adopted by the present invention to solve the above technical problem is: a deformed zinc alloy material which is easy to be cold-formed, and the weight percentage composition of the deformed zinc alloy material includes: Cu: 1.0-3.5 wt%, Mn: 0.05-0.5 wt% , Al ≤ 0.05 wt%, the balance is Zn and unavoidable impurities, and the phase composition of the deformed zinc alloy material comprises a solid solution of Zn-based Cu-substituted Zn, a Zn ₅ Cu second phase, and a zinc-manganese-copper intermetallic compound. The second phase.

The Cu added in the present invention is mostly dissolved in a solid solution of Zn-based Cu-substituted Zn, and a small amount of Cu is precipitated as an ε phase (i.e., a Zn ₅ Cu second phase). Cu improves the strength, hardness, corrosion resistance and flow properties of the alloy, and reduces the intergranular corrosion sensitivity of the alloy. The maximum solid solubility of copper in zinc is 2.7 wt%, and the ε phase precipitates as the temperature decreases. In the case of a low copper content, the amount of ε phase precipitated is small and the size is small. When the alloy maintains a small strength increase, the elongation increases and the hardness remains substantially unchanged. Properly increasing the copper content is beneficial to refining the zinc matrix structure, increasing the density of the alloy, and reducing the tendency of shrinkage and shrinkage. In order to meet the requirements of cold forming, cold forging and other large deformation cold processing, the alloy needs to have good plasticity while ensuring the necessary strength. If the copper content is too low, the strength of the alloy is not enough to meet the strength requirements of the part; if the copper content is too high, a large amount of ε phase will be precipitated. Although the strength and hardness of the alloy are increased, the elongation will be greatly reduced. Influencing the plasticity of the alloy, the cold processing requirement of the large deformation amount cannot be satisfied, and the copper content in the deformed zinc alloy material of the present invention is controlled to be 1.0-3.5 wt% in order to balance the strength and plasticity of the alloy.

Mn plays a metamorphism in the zinc alloy of the present invention, and Mn reacts with Zn to form a fine second phase compound of zinc manganese copper intermetallic compound, and the second phase compound of zinc manganese copper intermetallic compound can refine grains and improve zinc alloy. Organizational stability. Because zinc alloy is inferior to other alloys, the zinc alloy is easily deformed after being left at room temperature for a long time, and the dimensional stability is poor, which affects the normal use of the processed parts. Therefore, the dimensional stability of the zinc alloy is improved. Sex is very important. The second phase of the zinc manganese copper intermetallic compound in the phase composition of the deformed zinc alloy material of the present invention belongs to a high melting point particulate matter, and the presence of the second phase of the zinc manganese copper intermetallic compound increases the recrystallization temperature and the structural stability of the alloy, In the later processing and use of the alloy, the dimensional stability is good, which is beneficial to ensure the precision of the processed parts and ensure the performance of the parts. Although Mn is beneficial to improve the strength and hardness of the zinc alloy of the present invention, too high Mn may reduce the plasticity of the alloy, and the manganese content in the deformed zinc alloy material of the present invention is controlled at 0.05-0.5 wt under the premise of ensuring the stability of the alloy structure. %. In the present invention, Al is controlled as an impurity element.

Al is solid-solubilized in the zinc matrix, although the strength and hardness can be improved, the Applicant has found that in the subsequent electroplating process of the product, a higher Al content hinders the growth of the plating layer, and the plating performance of the alloy deteriorates, therefore, Al Controlled as an impurity at ≤ 0.05 wt%.

Preferably, the volume fraction of the Zn ₅ Cu second phase in the microstructure of the deformed zinc alloy material is 10-30%, and the second phase of the zinc manganese copper intermetallic compound is in the deformed zinc alloy material. The volume fraction in the microstructure is 5-10%.

Preferably, the Zn ₅ Cu second phase has an average particle diameter of ≤ 5 μm, the zinc manganese copper intermetallic compound second phase has an average particle diameter of ≤ 5 μm, and the matrix has an average particle diameter of ≤ 10 Micron. The fine second phase and the matrix particles have an equiaxed crystal distribution, so that the performance of the zinc alloy of the present invention in the parallel processing direction and the vertical processing direction is uniform, and there is no anisotropy, thereby further improving the performance stability of the alloy. The fine second phase particle distribution increases the strength without affecting the elongation, ensuring that the zinc alloy of the present invention achieves a combination of medium strength and high plasticity to meet the cold processing requirements of large deformation.

Further, the deformed zinc alloy material further includes one or more of Mg: 0.001-0.1 wt%, Zr: 0.001-0.1 wt%, Ti: 0.001-0.1 wt%, and Cr: 0.001-0.1 wt%. Mg has a small amount of solid solubility in zinc, which has the effect of increasing the strength of the alloy, and can improve the intergranular corrosion resistance of the alloy. However, as the content increases, the strength and hardness of the alloy increase, and the plasticity decreases, which increases. The heat cracking and cold cracking properties deteriorate the riveting and punching properties, and therefore, the content of Mg in the alloy of the present invention is controlled to be 0.001 to 0.1% by weight. The solubility of Zr and Ti in the zinc alloy is very low, and it will combine with Zn and Cu to form fine dispersed particles, which can refine the grain of the alloy and improve the strength. For example, TiZn ₃ formed by Ti and Zn can refine the alloy. The grain, thereby improving the mechanical properties and recrystallization temperature of the alloy, but the excessive content of Zr and Ti tends to cause the brittleness of the alloy, which is not conducive to the subsequent riveting process. Therefore, the addition amount of Zr and Ti in the alloy of the present invention is controlled to 0.001, respectively. -0.1 wt%. The addition amount of Cr is controlled to be 0.001 to 0.1% by weight, and Cr forms a second phase with zinc and is uniformly dispersed in the zinc matrix to exert a second phase strengthening effect on the alloy of the present invention.

Preferably, the deformed zinc alloy material has a tensile strength of 260 to 320 MPa, an elongation of 25 to 35%, and a hardness HV5 of 90 to 100. The alloy of the invention belongs to a medium-strength, high-plastic zinc alloy, and the medium strength can meet the requirements for strength in the cold processing of large deformation. If the strength is too low, the size and accuracy of the part during processing are difficult to guarantee; if the elongation is too low, the alloy is susceptible to cracking during cold processing of large deformation.

The above preparation method of the deformed zinc alloy material which is easy to be cold-formed comprises the following steps:

1) accurately weigh each raw material required for preparing the deformed zinc alloy material according to the ratio;

2) Producing ingots by hot-top casting, semi-continuous casting or horizontal continuous casting. In the casting process, 80% of the zinc blocks are first put into place, and after complete melting, the temperature is raised to 650-900 ° C, and then the remaining 20% of the zinc blocks are added. Other raw materials, the temperature is raised to 500-650 ° C, then add deaerator and modifier, completely melted, stirred, slag, sampled for component analysis, qualified after casting and sawing, to obtain a length of 400-700mm

Ingot

3) will

The ingot is heated to 200-300 ° C and then extruded on a reverse extruder

Circle line

4) Right

The coiling line is subjected to multiple stretching, and the processing rate of the pass is 10-30%. During the stretching process, heat treatment is performed 1-3 times, the heat treatment temperature is 200-330 ° C, the heat treatment time is 0.5-2 h, and the drawing is extended to the design. specification.

The above-mentioned wrought zinc alloy material which is easy to be cold-formed is applied to zippers, hardware, and electronic and electrical parts.

The advantages of the present invention over the prior art are:

(1) The present invention obtains a deformed zinc alloy material which is easy to be cold-formed by controlling the content ratio of Cu, Zn, Mn, Al and the phase composition of the alloy;

(2) The microstructure of the deformed zinc alloy material of the present invention is composed of a plurality of phases, including a solid solution of Cu-substituted Zn based on Zn, a second phase of Zn ₅ Cu second phase and a zinc-manganese-copper intermetallic compound, and no anisotropy And work hardening to ensure the strength, plasticity and structural stability of the alloy;

(3) The deformed zinc alloy material of the present invention has a tensile strength of 260-320 MPa, an elongation of 25-35%, and a hardness HV5 of 90-100, has moderate strength, high elongation, and good dimensional stability, and its total The processing rate can reach 80-90%, and can be applied to cold forming deformation of large deformation such as cold heading, cold forging, spinning, riveting and deep drawing, repeated cold heading, repeated cold forging and deep drawing processing in large deformation. It can be widely used in zippers, hardware, and electronic and electrical components such as plugs and terminals.

DRAWINGS

Figure 1 is a metallographic photograph (x 1000) of the microstructure of the extruded compact of Example 1;

Figure 2 is a SEM photograph (x 10000) of the microstructure of the extruded compact of Example 1;

3 is a result of energy spectrum analysis of the second phase of Zn ₅ Cu shown at A in FIG. 2;

Figure 4 is a SEM photograph (x 10000) of the microstructure of the extruded compact of Example 2;

5 is a result of energy spectrum analysis of a solid solution of Zn-based Cu-substituted Zn shown in B of FIG. 4;

Figure 6 is a SEM photograph (x 10000) of another microstructure of the extruded compact of Example 2;

Fig. 7 is a graph showing the results of energy spectrum analysis of the second phase of the zinc manganese copper intermetallic compound shown at C in Fig. 6.

Detailed ways

The invention will be further described in detail below with reference to the embodiments of the drawings.

Twenty example alloys and two comparative alloys were selected and prepared by the method of the present invention:

Ingot

3) will

The ingot is heated to 200-300 ° C and then extruded on a reverse extruder

Circle line

4) Right

The coiling line is subjected to multiple stretching, and the processing rate of the pass is 10-30%. During the stretching process, heat treatment is performed 1-3 times, the heat treatment temperature is 200-330 ° C, the heat treatment time is 0.5-2 h, and the stretching is Φ 4 Finish the .6mm round wire and then straighten it.

The deaerator used in the above preparation method is hexachloroethane, and the modifier is potassium fluorotitanate and/or potassium fluoroborate.

The composition and performance test results of the respective examples and comparative examples are shown in Table 1. The metallographic photograph of the microstructure of the extruded billet of Example 1 is shown in Fig. 1, and the SEM photograph is shown in Fig. 2; the SEM photograph of the microstructure of the extruded billet of Example 2 is shown in Figs. 4 and 6.

Claims

A deformed zinc alloy material which is easy to be cold-formed, characterized in that the weight percentage composition of the deformed zinc alloy material comprises: Cu: 1.0-3.5 wt%, Mn: 0.05-0.5 wt%, Al ≤ 0.05 wt%, balance As a Zn and an unavoidable impurity, the phase composition of the deformed zinc alloy material includes a Cu-substituted Zn solid solution of Zn as a matrix, a Zn 5 Cu second phase, and a second phase of a zinc-manganese-copper intermetallic compound.
A deformed zinc alloy material which is easy to be cold-formed according to claim 1, wherein the volume fraction of the Zn 5 Cu second phase in the microstructure of the deformed zinc alloy material is 10-30%. The volume fraction of the second phase of the zinc manganese copper intermetallic compound in the microstructure of the deformed zinc alloy material is 5-10%.
A deformed zinc alloy material which is easy to be cold-formed according to claim 1, wherein said Zn 5 Cu second phase has an average particle diameter of ≤ 5 μm, and said zinc manganese copper intermetallic compound second phase The average particle size is ≤ 5 microns and the average particle size of the substrate is ≤ 10 microns.
A deformed zinc alloy material which is easily cold-formed according to any one of claims 1 to 3, which further comprises Mg: 0.001 - 0.1 wt%, Zr: 0.001 - 0.1 wt%, Ti: 0.001 - 0.1 One or more of wt% and Cr: 0.001-0.1 wt%.
A deformed zinc alloy material which is easy to be cold-formed according to any one of claims 1 to 3, wherein the deformed zinc alloy material has a tensile strength of 260-320 MPa, an elongation of 25-35%, and a hardness. The HV5 is 90-100.
A method for preparing a deformed zinc alloy material which is easy to be cold-formed according to any one of claims 1 to 5, which comprises the following steps:

1) accurately weigh each raw material required for preparing the deformed zinc alloy material according to the ratio;

2) Producing ingots by hot-top casting, semi-continuous casting or horizontal continuous casting. In the casting process, 80% of the zinc blocks are first put into place, and after complete melting, the temperature is raised to 650-900 ° C, and then the remaining 20% of the zinc blocks are added. Other raw materials, the temperature is raised to 500-650 ° C, then add deaerator and modifier, completely melted, stirred, slag, sampled for component analysis, qualified after casting and sawing, to obtain a length of 400-700mm
Ingots of 150-230;

3) will
The 150-230mm ingot is heated to 200-300 ° C and then extruded on a reverse extruder
6-20mm circle;

4) Right
The 6-20mm loop wire is multi-stretched, the pass processing rate is 10-30%, and during the stretching process, 1-3 heat treatments are performed, the heat treatment temperature is 200-330 ° C, and the heat treatment time is 0.5-2 h. Reach to the design specifications.
The method for preparing a deformed zinc alloy material which is easy to be cold-formed according to claim 6, wherein the getter is hexachloroethane, and the modifier is potassium fluorotitanate and/or fluorine. Potassium borate.
The use of a deformed zinc alloy material which is easily cold-formed according to any one of claims 1 to 5 in zippers, hardware, and electronic and electrical parts.