CN115584404B - Preparation method of high-strength high-conductivity 1-series aluminum alloy cathode plate base material - Google Patents

Abstract

The invention provides a preparation method of a high-strength high-conductivity 1-series aluminum alloy cathode plate substrate, which comprises the following preparation processes: casting, homogenizing, heat treating, hot rolling, cold rolling, transverse shearing and packaging; on one hand, defects such as shrinkage cavity, looseness and the like in an ingot are reduced by controlling the ratio of Fe to Si, the Fe-rich phase is refined by increasing the adding proportion of a grain refiner, and the morphology and the distribution of the Fe-rich phase in a matrix are changed by proper homogenization heat treatment, so that high conductivity and good corrosion resistance are realized; on the other hand, the strength of the hot rolled blank is improved by reducing the final rolling temperature of the hot rolled blank, the work hardening rate during cold rolling is improved by improving the thickness of the hot rolled blank, the high strength of the base material is realized, the strength of the finally prepared 1-series cathode plate base material is more than 135MPa, the conductivity of the 1-series cathode plate base material is more than 61.5 percent IACS, and the thickness of the 1-series cathode plate base material is 7.0mm, thereby realizing the comprehensive requirements of wet zinc hydrometallurgy on the cathode plate with high strength, high conductivity and long service life.

Description

Preparation method of high-strength high-conductivity 1-series aluminum alloy cathode plate base material

Technical Field

The invention belongs to the technical field of aluminum alloy processing, and particularly relates to a preparation method of a high-strength high-conductivity 1-series aluminum alloy cathode plate substrate.

Background

Since zinc hydrometallurgy was put into production industrially in the beginning of the 20 th century, technology of zinc hydrometallurgy is continuously developed, and more than 85% of total yield of zinc in the world is produced by adopting the process. However, the cathode plate has a plurality of defects in the zinc hydrometallurgy process, which often cause low efficiency and resource waste in the electro-deposition process. Under the condition that the energy source is increasingly tense and the price is continuously increased in the world, improving and improving the comprehensive performance of the cathode plate has important significance for improving the economic benefit and reducing the production cost.

In the wet-process zinc electrowinning process, a lead-silver alloy plate is often used as an anode plate, a rolled pure aluminum plate is used as a cathode, and the rolled pure aluminum plate is sequentially and alternately arranged in an electrolytic tank to be used as an electrolytic electrode. In the electro-deposition process, zinc ions in the electrolyte can be reduced into zinc precipitate on an aluminum cathode plate under the direct current effect, and the zinc precipitate is gathered to a certain thickness or deposited for a period of time, and then finished zinc is obtained through mechanical zinc stripping or manual zinc stripping. The following aspects are mainly focused on the production of the cathode plate from the aspect of improving the zinc hydrometallurgy efficiency and saving resources:

firstly, the cathode plate is aimed at improving the conductivity, and the cathode used as the electrodeposited zinc is naturally higher in conductivity, so that the electricity consumption is reduced, and the purpose of reducing consumption is realized;

secondly, in an effort to improve the life of the cathode plate, in this hydrometallurgical extraction, the selection of aluminum cathode plates is often made from its conductivity factors and life.

Obviously, on the one hand, the higher the conductivity of the cathode plate is, the better; on the other hand, the longer the service life of the cathode plate is, the better. Factors affecting the conductivity of the material are often related to the chemical composition and structure of the cathode plate material, but factors affecting the service life of the cathode plate are mainly related to the hardness and thickness of the cathode plate, because the existence of halogen elements such as F or Cl negative particles in the electrolyte in smelting can corrode the cathode aluminum plate, resulting in shortened service life of the cathode plate; meanwhile, the surface roughness of the cathode plate is increased, the bonding degree of a zinc deposition layer and the cathode is improved, and the cathode is difficult to strip, so that the service life of the cathode plate is shortened during stripping, and the tensile strength of the material is often improved in the service life industry, and the corrosion resistance and the thickness of the material are improved.

The Chinese patent with publication number of CN109022932B discloses a high-strength corrosion-resistant aluminum alloy cathode material for hydrometallurgical electrodeposited zinc and a preparation method thereof, and the aluminum alloy cathode material and the preparation method thereof are prepared by alloy batching, smelting, refining, deslagging, exhausting, filtering, ingot casting, face milling, degreasing, homogenizing annealing, hot rolling, cold rolling, finishing and fixed-length shearing. The aluminum alloy cathode material has the advantages of corrosion resistance, good electrochemical performance, high mechanical strength and excellent welding processability in an electrodeposited zinc system, and the corrosion resistance in fluorine-containing and chlorine-containing electrodeposited zinc melt is obviously superior to that of the traditional 1060 and 1070 electrodeposited zinc-aluminum cathode plate; although the aluminum alloy cathode material prepared by the method has excellent mechanical properties, the conductivity still cannot reach an ideal state in actual use, and the defect of low conductivity still exists.

Further, the state requirements of the cathode plate for hydrometallurgical zinc electrodeposition are specified in the standard of non-ferrous metal industry of the people's republic of China (YS/T1088-2015) as H18 state, namely, the strength of the cathode plate is improved by a work hardening method, but the thicker the thickness of the cathode plate is, the more difficult the obtaining of the H18 state is, especially when the thickness is 7.0mm, because of the limitation of the blank thickness, because the inlet thickness of the aluminum cold rolling mill in the world is more than 12.0mm at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a high-strength high-conductivity 1-series aluminum alloy cathode plate substrate with the thickness of 7.0 mm.

The technical scheme of the invention is as follows:

the preparation method of the high-strength high-conductivity 1-series aluminum alloy cathode plate base material comprises the following preparation processes:

s1, preparing raw materials according to the following weight percentage: less than 0.10% of Si, 0.10% -0.15% of Fe=0.002%, less than 0.005% of Cu, less than 0.005% of Mn, less than 0.005% of Mg, less than 0.005% of Cr, less than 0.005% of Zn, 0.045% -0.065% of Ti=99.70% of Al, and less than or equal to 0.03% of other unavoidable single elements;

s2, smelting and casting, namely placing the raw materials in the step S1 into a smelting furnace for smelting, guiding the melt into a refining furnace for refining, and casting into an aluminum alloy cast ingot after degassing and deslagging;

s3, homogenizing heat treatment, namely placing the aluminum alloy cast ingot obtained in the step S2 into a heating furnace for homogenizing heat treatment after sawing and milling, controlling the metal temperature to be 605+/-10 ℃, and preserving heat for 12 hours; the spheroidization rate of the Fe eutectic phase after homogenization reaches more than 80 percent;

s4, hot rolling, namely carrying out multi-pass hot rolling on the aluminum alloy ingot subjected to the homogenization heat treatment, and stopping hot rolling before carrying out the last-pass hot rolling, wherein the thickness of the hot rolled blank is 14.0mm after carrying out the last-pass hot rolling when the temperature of the hot rolled blank is reduced to 220-230 ℃;

s5, cold rolling, namely cold rolling the blank with the thickness of 14.0mm obtained in the S4 twice to obtain a cold-rolled blank with the thickness of 7.0 mm;

s6, performing transverse shearing cleaning, straightening and cutting on the cold-rolled blank obtained in the step S5 to obtain the aluminum alloy substrate.

Further, in the step S2, after the degassing and deslagging are finished, the launder is added with an online grain refiner Al-5Ti-1B wire.

Further, in S4, the final hot rolling temperature of the hot rolled blank is 200 ℃ to 220 ℃.

Further, in S5, the first cold rolling has a working rate of 20% and an uncoiling tension of not more than 5N/mm ^2’ The second pass is rolled to a cold rolled stock of 7.0mm thickness.

Further, the tensile strength of the aluminum alloy base material is 135-150MPa, and the electric conductivity is more than 61.5% IACS.

Compared with the prior art, the invention has the following beneficial effects:

1. when the material is prepared, the addition amount of Fe is controlled to be larger than that of Si, so that the fluidity of a melt is facilitated, the material is useful for preventing hot cracks and micro shrinkage porosity of cast ingots, the material is easy to form, and the metallurgical and casting quality is convenient to improve;

the principle is as follows: the main impurity elements in the industrial pure aluminum are Fe and Si, which have great difference with the properties of the matrix as impurity phases, so that the material directly affects the subsequent mechanical property, surface property and the like in the processing process, and the industrial pure aluminum can be regarded as aluminum-iron-silicon with very low iron-silicon contentAlloy is adopted; the impurity phase is dissolved in the Al matrix to form alpha solid solution, and also forms intermetallic compounds with aluminum to be separated out from aluminum melt or aluminum solid solution; in addition, fe and Al in the impurity phase can form needle-shaped hard and brittle phases and block-shaped hard and brittle siliceous points, and can also form two ternary phases; when Fe > Si, alpha iron (Fe ₂ SiAl ₈ ) The primary crystal is in an amorphous flake shape, the eutectic crystal is in a skeleton shape, and is a hexagonal crystal system; when Si < Fe, beta (FeSiAl is formed ₅ ) The phase is monoclinic system; both are brittle compounds, which have a greater risk of plasticity;

2. for the homogenization heat treatment process, the relatively high iron-silicon content in the cathode plate enables industrial pure aluminum to form relatively coarse iron-silicon phases in the smelting and casting process, and on the one hand, cracks can be generated in the aluminum ingot in the subsequent cold rolling deformation process; on the other hand, the existence of impurity phases can lead to the generation of primary cell effect in the soaking process of the aluminum cathode plate in ZnSO4 electrolyte, thereby generating pitting corrosion; the microstructure and refined grains of the aluminum cathode plate can be improved by heat treatment, so that the mechanical property, corrosion performance and forming performance of the aluminum alloy thin plate are improved, the corrosion is generated on the surface of the aluminum cathode plate due to the fact that Fe and Si contents in the aluminum cathode plate are higher and the distribution of Fe and Si is uneven, and in the homogenization process, atoms in a high concentration area are diffused to a low concentration area through high temperature, so that the segregation of an ingot is reduced, and an unbalanced phase is completely dissolved; the morphology of the iron-containing compound changes with increasing temperature; the Fe content of impurities after high-temperature homogenization enables needle-shaped and flake-shaped iron phases in the alloy to be spheroidized and dispersed more, and the metal temperature is controlled to be 605+/-10 ℃ in the homogenization heat treatment process, so that the distribution of pure aluminum iron phases can be effectively improved, and the corrosion resistance of the material is further improved;

3. according to the invention, the online grain refiner Al-5Ti-1B wire is added according to the titanium content of 0.045-0.065%, the boron can improve the conductivity of iron-containing aluminum, meanwhile, the improvement of the refiner content is beneficial to refining grains of cast ingots, and meanwhile, the higher refiner content can refine Fe-rich phases and serve as nucleation cores of the Fe-rich phases, so that the Fe-rich phases are effectively refined; in addition, the material strength can be improved to a certain extent;

4. in the hot rolling process, after the temperature of the hot rolled blank is reduced to 220-230 ℃, the final hot rolling is carried out, so that the strength of the hot rolled blank can be effectively improved, the microstructure of the base material is a long-strip fibrous structure, and meanwhile, the lower finishing temperature does not cause coarse grains of the hot rolled blank due to higher finishing temperature;

5. the thickness of the blank after hot rolling is controlled to be 14.0mm, so that the total processing rate in the subsequent cold rolling process is ensured to reach 50%, and the strength of the aluminum base material with the thickness of 7.0mm after cold rolling is further effectively improved;

6. in the preparation stage, the impurity content except Fe, si, ti, cu is controlled to be less than 0.005%, so that the conductivity of the aluminum alloy base material is improved by reducing the impurity content;

in a word, the 1-series aluminum alloy base material prepared by the method provided by the invention has good mechanical strength and higher conductivity.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

The preparation method of the high-strength high-conductivity 1-series aluminum alloy cathode plate base material comprises the following preparation processes:

s1, preparing raw materials according to the following weight percentage: si=0.01%, fe=0.15%, cu < 0.002%, mn < 0.005%, mg < 0.005%, cr < 0.005%, zn < 0.005%, ti=0.045%, al=99.74%, and other unavoidable elements add up to 0.05%;

s2, smelting and casting, namely placing the raw materials in the step S1 into a smelting furnace for smelting, introducing the melt into the refining furnace for refining, and then adding an online grain refiner Al-5Ti-1B wire into a launder after degassing and deslagging, and casting into an aluminum alloy ingot, wherein the addition of the online grain refiner Al-5Ti-1B wire is carried out according to the titanium content of 0.045-0.065% in a base material;

s3, homogenizing heat treatment, namely placing the aluminum alloy cast ingot obtained in the step S2 into a heating furnace for homogenizing heat treatment after sawing and milling, controlling the metal temperature to be 605+/-10 ℃, and preserving heat for 12 hours;

s4, hot rolling, namely carrying out multi-pass hot rolling on the aluminum alloy cast ingot subjected to the homogenization heat treatment, stopping hot rolling before carrying out the last-pass hot rolling, carrying out the last-pass hot rolling when the temperature of a hot rolled blank is reduced to 220 ℃, wherein the thickness of the hot rolled blank is 14.0mm, and the final temperature of hot rolled blank hot rolling is 200 ℃;

s5, cold rolling, namely cold rolling the blank with the thickness of 14.0mm obtained in the S4 twice to obtain a cold-rolled blank, wherein the processing rate of the first cold rolling is 20%, and the uncoiling tension is not more than 5N/mm ² ；

S6, performing transverse shearing cleaning, straightening and cutting on the cold-rolled blank obtained in the step S5 to obtain the aluminum alloy substrate.

In this example, the tensile strength of the aluminum alloy base material was 150MPa, and the electrical conductivity was 61.9% iacs.

Example 2

The preparation method of the high-strength high-conductivity 1-series aluminum alloy cathode plate base material comprises the following preparation processes:

s1, preparing raw materials according to the following weight percentage: si=0.01%, fe=0.1%, cu < 0.002%, mn < 0.005%, mg < 0.005%, cr < 0.005%, zn < 0.005%, zn=0.003%, ti=0.065%, al=99.8%, and the total of other unavoidable elements is 0.01%;

s2, smelting and casting, namely placing the raw materials in the step S1 into a smelting furnace for smelting, introducing the melt into the refining furnace for refining, and then adding an online grain refiner Al-5Ti-1B wire into a launder after degassing and deslagging, and casting into an aluminum alloy ingot, wherein the addition of the online grain refiner Al-5Ti-1B wire is carried out according to the titanium content of 0.045-0.065% in a base material;

s3, homogenizing heat treatment, namely placing the aluminum alloy cast ingot obtained in the step S2 into a heating furnace for homogenizing heat treatment after sawing and milling, controlling the metal temperature to be 605+/-10 ℃, and preserving heat for 12 hours;

s4, hot rolling, namely carrying out multi-pass hot rolling on the aluminum alloy cast ingot subjected to the homogenization heat treatment, stopping hot rolling before carrying out the last-pass hot rolling, carrying out the last-pass hot rolling when the temperature of a hot rolled blank is reduced to 230 ℃, wherein the thickness of the hot rolled blank is 14.0mm, and the final temperature of hot rolled blank hot rolling is 220 ℃;

s5, cold rolling, namely cold rolling the blank with the thickness of 14.0mm obtained in the S4 twice to obtain a cold-rolled blank, wherein the processing rate of the first cold rolling is 20%, and the uncoiling tension is not more than 5N/mm ² ；

S6, performing transverse shearing cleaning, straightening and cutting on the cold-rolled blank obtained in the step S5 to obtain the aluminum alloy substrate.

In this example, the tensile strength of the aluminum alloy base material was 135MPa, and the electrical conductivity was 62.2% iacs.

Example 3

The preparation method of the high-strength high-conductivity 1-series aluminum alloy cathode plate base material comprises the following preparation processes:

s1, preparing raw materials according to the following weight percentage: si=0.03%, fe=0.11%, cu < 0.002%, mn < 0.005%, mg < 0.005%, cr < 0.005%, zn < 0.005%, ti=0.05%, al=99.73%, and other unavoidable elements add up to 0.07%;

s2, smelting and casting, namely placing the raw materials in the step S1 into a smelting furnace for smelting, introducing the melt into the refining furnace for refining, and then adding an online grain refiner Al-5Ti-1B wire into a launder after degassing and deslagging, and casting into an aluminum alloy ingot, wherein the addition of the online grain refiner Al-5Ti-1B wire is carried out according to the titanium content of 0.045-0.065% in a base material;

s3, homogenizing heat treatment, namely placing the aluminum alloy cast ingot obtained in the step S2 into a heating furnace for homogenizing heat treatment after sawing and milling, controlling the metal temperature to be 605+/-10 ℃, and preserving heat for 12 hours;

s4, hot rolling, namely carrying out multi-pass hot rolling on the aluminum alloy ingot subjected to the homogenization heat treatment, stopping hot rolling before carrying out the last-pass hot rolling, carrying out the last-pass hot rolling when the temperature of a hot rolled blank is reduced to 225 ℃, wherein the thickness of the hot rolled blank is 14.0mm, and the final temperature of hot rolled blank hot rolling is 210 ℃;

s5, cold rolling, namely cold rolling the blank with the thickness of 14.0mm obtained in the S4 twice to obtain a cold-rolled blank, wherein the processing rate of the first cold rolling is 20%, and the uncoiling tension is not more than 5N/mm ² ；

S6, performing transverse shearing cleaning, straightening and cutting on the cold-rolled blank obtained in the step S5 to obtain the aluminum alloy substrate.

In this example, the tensile strength of the aluminum alloy base material was 145MPa, and the electrical conductivity was 61.7% iacs.

Comparative example 1

Comparative example 1 was substantially the same as the production method of example 1 except that the metal temperature was controlled at 430℃and the heat was kept for 12 hours at the time of the homogenization heat treatment in the step S3.

Comparative example 2

Comparative example 2 is substantially the same as the production method of example 1 except that in the step S4, before the last hot rolling is performed, the hot rolling is suspended, the last hot rolling is performed when the temperature of the hot rolled slab is lowered to 300 to 350 ℃, the thickness of the hot rolled slab is 14.0mm, and the final hot rolling temperature of the hot rolled slab is 290 to 300 ℃.

Comparative example 3

Comparative example 3 is substantially the same as the production method of example 1 except that in the step S4, before the last hot rolling, the hot rolling is suspended, the last hot rolling is performed when the temperature of the hot rolled slab is reduced to 220 to 230 ℃, the thickness of the hot rolled slab is 9.0mm, and the final hot rolling temperature of the hot rolled slab is less than 220 ℃.

The results of conducting property measurements on the aluminum alloy substrates prepared in examples 1 to 3 and comparative examples 1 to 3 are shown in the following table:

	example 1	Example 2	Example 3
				Tensile strength MPa	145	135	150
Yield strength MPa	124	117	131
				Elongation percentage%	16.5％	18.2％	16.0％
Conductivity 20 ℃ (% IACS)	61.9％	62.6％	61.7％

From the comparison, it is found that the material conductivity is lower in comparative example 1 due to the lower homogenization temperature; comparative example 2 has lower final strength due to higher hot rolling final temperature; comparative example 3 has lower strength after cold rolling due to the thinner thickness of the hot rolled stock.

Although the present invention has been described with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements and changes may be made without departing from the spirit and principles of the present invention.

Claims (2)

1. The preparation method of the high-strength high-conductivity 1-series aluminum alloy cathode plate base material is characterized by comprising the following preparation processes:

s1, preparing raw materials according to the following weight percentage: less than 0.10% of Si, 0.10% -0.15% of Fe=0.002%, less than 0.005% of Cu, less than 0.005% of Mn, less than 0.005% of Mg, less than 0.005% of Cr, less than 0.005% of Zn, 0.045% -0.065% of Ti=99.70% of Al, and less than or equal to 0.03% of other unavoidable single elements;

s2, smelting and casting, namely putting the raw materials in the step S1 into a smelting furnace for smelting, guiding the melt into the refining furnace for refining, and adding an online grain refiner Al-5Ti-1B wire into a launder after degassing and deslagging, so as to cast an aluminum alloy cast ingot;

s3, homogenizing heat treatment, namely placing the aluminum alloy cast ingot obtained in the step S2 into a heating furnace for homogenizing heat treatment after sawing and milling, controlling the metal temperature to be 605+/-10 ℃, and preserving heat for 12 hours; the spheroidization rate of the Fe eutectic phase after homogenization reaches more than 80 percent;

s4, hot rolling, namely carrying out multi-pass hot rolling on the aluminum alloy cast ingot subjected to the homogenization heat treatment, stopping hot rolling before carrying out the last-pass hot rolling, carrying out the last-pass hot rolling when the temperature of a hot rolled blank is reduced to 220-230 ℃, wherein the thickness of the hot rolled blank is 14.0mm, and the final temperature of the hot rolled blank is 200-220 ℃;

s5, cold rolling, namely cold rolling the blank with the thickness of 14.0mm obtained in the S4 twice to obtain a cold-rolled blank with the thickness of 7.0mm, wherein the processing rate of the first cold rolling is 20%, and the uncoiling tension is not more than 5N/mm ² Rolling to a cold-rolled blank with the thickness of 7.0mm in the second pass;

s6, performing transverse shearing cleaning, straightening and cutting on the cold-rolled blank obtained in the step S5 to obtain the aluminum alloy substrate.

2. The method for preparing a high-strength high-conductivity 1-series aluminum alloy cathode plate substrate according to claim 1, wherein the method comprises the following steps: the tensile strength of the aluminum alloy substrate is 135-150MPa, and the electric conductivity is more than 61.5% IACS.