CN108559889A - Strong Alcoa and preparation method thereof in a kind of microalloying - Google Patents

Abstract

The invention discloses strong Alcoa in a kind of microalloy, each component and its weight percent are：Mg constituent contents are 0.4~0.8%, Si constituent contents are 0.5~1.0%, Cu constituent contents are 0.3~0.6%, it be 0.15~0.35%, Zr constituent contents is 0.10~0.25% that Mn constituent contents, which are 0.2~0.4%, Er constituent contents, B element content is 0.01~0.06%, Fe constituent content≤0.15%, the total content≤0.15%, Al of other impurity elements is balance-element.The aluminium alloy has high corrosion resisting property and good mechanical property, and preparation method is also simple and practicable, and cost is relatively low.There are prodigious application potentials in fields such as automobile, high ferro, ship, extra large work engineerings for heretofore described aluminium alloy.

Description

A kind of micro-alloyed medium-strength corrosion-resistant aluminum alloy and its preparation method

technical field

The invention belongs to the technical field of nonferrous metals, in particular to a microalloyed medium-strong corrosion-resistant aluminum alloy and a preparation method thereof.

Background technique

Al~Mg~Si series aluminum alloys have the characteristics of light weight, high strength, and excellent formability, and are widely used in industrial structural components, such as automobile body panels, ship decks, and hulls. The working environment of these industrial structural components requires Al-Mg-Si aluminum alloys to have high strength, plasticity, corrosion resistance and weldability. However, these properties of aluminum alloys are often contradictory, and it is usually difficult to obtain them at the same time. Excellent corrosion resistance, strength and plasticity. In order to improve the strength of Al～Mg～Si aluminum alloys, the content of Mg and Si elements is usually increased, but the Mg5Al8 phase is continuously precipitated along the grain boundary, which reduces the corrosion resistance of the alloy and greatly reduces the processability. Cu is added to some alloys to increase strength, but reduces the corrosion resistance of the material. At present, relevant research mainly focuses on adjusting the alloy composition of materials and improving the deformation heat treatment process, but the corrosion resistance of Al-Mg-Si aluminum alloys needs to be further improved. Based on the principle of multi-element microalloying, the invention designs a novel Al-Mg-Si alloy and a preparation method to improve the strength and corrosion resistance of the alloy.

Contents of the invention

The invention provides a micro-alloyed medium-strong corrosion-resistant aluminum alloy and a preparation method thereof. The aluminum alloy has high corrosion resistance and good mechanical properties, and the preparation method is simple and easy, and the cost is low.

In order to solve the above problems, the present invention adopts the following technical solutions.

A medium-strong corrosion-resistant micro-alloy aluminum alloy, the components and their weight percentages are as follows: the content of Mg element is 0.4-0.8%, the content of Si element is 0.5-1.0%, the content of Cu element is 0.3-0.6%, and the content of Mn element 0.2-0.4%, the content of Er element is 0.15-0.35%, the content of Zr element is 0.10-0.25%, the content of B element is 0.01-0.06%, the content of Fe element is ≤0.15%, and the total content of other impurity elements is ≤0.15%. Al is a balancing element.

A method for preparing a micro-alloy medium-strong corrosion-resistant aluminum alloy comprises the following steps:

(1) Proportioning raw materials: according to the components and weight percentages proportioning raw materials described in claim 1;

(2) Raw material smelting: under the temperature condition of 755～785℃, firstly melt the high-purity aluminum ingot, then add Al-Er10, Al-Zr5, Al-Mn10, Al-B3, Al-Cu50, Al-Si15 master alloy , add 99.99% magnesium and covering agent after the master alloy is melted;

(3) Refining: add hexachloroethane to the completely melted molten metal for degassing treatment, and fully stir. During refining, the metal temperature is maintained within the range of 730°C to 750°C. After refining, it should be fully allowed to stand. The standing time is not less than 30 minutes;

(4) Casting: when the temperature of the molten metal drops to 700°C to 720°C, after it has been allowed to stand sufficiently, the molten metal is poured into a metal mold with a temperature of 400°C to 440°C to obtain an alloy ingot;

(5) Three-level homogenization treatment: the alloy ingot obtained in step (4) is subjected to three-level homogenization treatment, the first stage is kept at 320-380°C for 6-20h, and the second stage is kept at 420-450°C 10~25h, the third stage is at 480~530℃ for 15~20h;

(6) Extrusion deformation treatment: the alloy ingot obtained in step (5) is subjected to extrusion deformation treatment, the extrusion temperature is 485° C. to 520° C., the deformation coefficient is 10 to 20, and forced air cooling is adopted;

(7) Pre-stretch deformation treatment: the alloy obtained in step (6) is subjected to pre-stretch deformation treatment, and the tensile deformation is 15% to 45%;

(8) Aging treatment: performing aging treatment on the alloy obtained in step (7), the aging temperature is 160-190° C., and the aging time is 10-30 h, and finally the aluminum alloy is obtained.

The beneficial effects of the present invention are as follows: ① The content and ratio of Mg, Si and Cu elements in the aluminum alloy are rationally optimized to obtain higher strength with lower alloy content. ② Add trace amounts of B elements and Er elements to purify the grain boundaries and improve the corrosion resistance of the aluminum alloy; ③ Add Zr, Er, and Mn elements to the aluminum alloy to form primary Al ₃ (Er, Zr) and Al ₆ ( Fe, Mn) phase, inhibit high-temperature extrusion recrystallization, achieve the purpose of refining the grain and improving the corrosion resistance of the alloy; ④Use a three-stage homogenization heat treatment process to make the secondary Al ₃ (Er, Zr) phase in the structure Uniformly dispersed and precipitated to further improve the strength and fracture toughness of the aluminum alloy; ⑤Using the deformation aging process to make the Mg ₂ Si phase uniformly dispersed and precipitated in the grain boundary to further improve the strength and corrosion resistance of the aluminum alloy; ⑥Using Er replaces the Sc element, so that the aluminum alloy obtains comprehensive properties such as high strength and corrosion resistance, and at the same time reduces the production cost of the aluminum alloy. The implementation of the above alloy composition design and preparation process ensures that the alloy has excellent mechanical properties.

Detailed ways

The idea, specific structure and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to The protection scope of the present invention. The various technical features in the invention can be combined interactively on the premise of not conflicting with each other.

Example 1

Table 1-1 shows the composition and weight percentage of the aluminum alloy.

Aluminum alloy components and weight percentages described in Table 1-1

Ingot No. Mg Si Cu Er Zr B mn Fe al 1# 0.60 0.84 0.50 0.25 0.15 0.04 0.30 <0.15 margin 2# 0.45 0.93 0.45 0.16 0.20 0.06 0.25 <0.15 margin 3# 0.75 0.65 0.60 0.32 0.10 0.05 0.35 <0.15 margin

The preparation method of aluminum alloy described in the present invention is:

(1) Proportioning raw materials: Proportioning raw materials according to the components and weight percentages shown in Table 1-1;

(2) Raw material smelting: under the temperature condition of 775 ℃, first melt the high-purity aluminum ingot, and then add Al-Er10, Al-Zr5, Al-Mn10, Al-B3, Al-Cu50, Al-Si15 in the middle Alloy, add 99.99% magnesium and covering agent after the master alloy is melted;

(3) Refining: add hexachloroethane to the completely melted molten metal for degassing treatment, and fully stir. During refining, the metal temperature should be maintained within the range of 740°C. Not less than 30 minutes;

(4) Casting: When the temperature of the molten metal drops to 700°C, after it has been allowed to stand sufficiently, the molten metal is poured into a metal mold with a temperature of 430°C to obtain an alloy ingot;

(5) Three-stage homogenization treatment: the alloy ingot obtained in step (4) is subjected to three-stage homogenization treatment, the first stage is kept at 360°C for 9h, the second stage is held at 440°C for 24h, and the third stage is held at 440°C for 24h. Insulate at 520°C for 24 hours;

(6) Extrusion deformation treatment: the alloy ingot obtained in step (5) is subjected to extrusion deformation treatment, the extrusion temperature is 520 ° C, the deformation coefficient is 18, and forced air cooling is adopted;

(7) tensile deformation treatment: the alloy obtained in step (6) is subjected to tensile deformation treatment, and the tensile deformation amount is 30%;

(8) Aging treatment: performing aging treatment on the alloy obtained in step (7), the aging temperature is 175°C, and the aging time is 12h, and finally the aluminum alloy is obtained.

Table 1-2 is a list of properties of alloys prepared by the above steps.

Table 1-2 List of properties of alloys prepared by the above steps

Ingot No. Tensile strength/MPa Yield strength/MPa Elongation/% Salt spray corrosion rate g/(m ² ·d) 1# 328 306 twenty two 0.014 2# 345 318 17.3 0.016 3# 337 309 19.2 0.013

It can be seen from Table 1-2 that: the high thermal conductivity aluminum alloy described in the present invention can be stably produced under the preparation process described above. g/(m ² ·d), the mechanical properties are much higher than the traditional 6063 aluminum alloy level, but the corrosion resistance is higher than that of 6063 aluminum alloy. Therefore, there is great application potential in the fields of automobiles, high-speed rail, ships, and marine engineering.

Example 2

Table 2-1 shows the composition and weight percentage of the aluminum alloy.

Aluminum alloy components and weight percentages described in Table 2-1

Ingot No. Mg Si Cu Er Zr B mn Fe al 4# 0.50 0.90 0.35 0.20 0.13 0.02 0.30 <0.15 margin 5# 0.65 0.83 0.45 0.24 0.18 0.04 0.35 <0.15 margin 6# 0.75 0.75 0.60 0.32 0.10 0.05 0.35 <0.15 margin

The preparation method of aluminum alloy described in the present invention is:

(1) proportioning raw materials: according to the composition and weight percentage proportioning raw materials shown in table 3;

(2) Raw material smelting: under the temperature condition of 765 ℃, first melt the high-purity aluminum ingot, and then add Al-Er10, Al-Zr5, Al-Mn10, Al-B3, Al-Cu50, Al-Si15 in the middle Alloy, add 99.99% magnesium and covering agent after the master alloy is melted;

(3) Refining: add hexachloroethane to the completely melted molten metal for degassing treatment, and fully stir. During refining, the metal temperature is maintained within the range of 735°C. After refining, it should be fully allowed to stand. Not less than 30 minutes;

(4) Casting: When the temperature of the molten metal drops to 710°C, after it has been allowed to stand sufficiently, the molten metal is poured into a metal mold with a temperature of 440°C to obtain an alloy ingot;

(5) Three-stage homogenization treatment: the alloy ingot obtained in step (4) is subjected to three-stage homogenization treatment, the first stage is kept at 350°C for 10h, the second stage is held at 430°C for 24h, and the third stage is held at 430°C for 24h. Insulate at 510°C for 24 hours;

(6) extrusion deformation treatment: the alloy ingot obtained in step (5) is subjected to extrusion deformation treatment, the extrusion temperature is 510 ° C, the deformation coefficient is 15, and the forced air cooling method is adopted;

(7) tensile deformation treatment: the alloy obtained in step (6) is subjected to tensile deformation treatment, and the tensile deformation amount is 35%;

(8) Aging treatment: performing aging treatment on the alloy obtained in step (7), the aging temperature is 165° C., and the aging time is 18 hours, and finally the aluminum alloy is obtained.

Table 2-2 is a list of properties of alloys prepared through the above steps.

Table 2-2 List of properties of alloys prepared by the above steps

Ingot No. Tensile strength/MPa Yield strength/MPa Elongation/% Salt spray corrosion rate g/(m ² ·d) 4# 332 304 18.9 0.015 5# 326 310 20.4 0.010 6# 347 329 18.2 0.016

It can be seen from Table 2-2 that: the high thermal conductivity aluminum alloy described in the present invention can be stably produced under the preparation process described above. g/(m ² ·d), the mechanical properties are much higher than the traditional 6063 aluminum alloy level, but the corrosion resistance is higher than that of 6063 aluminum alloy. Therefore, there is great application potential in the fields of automobiles, high-speed rail, ships, and marine engineering.

The preferred embodiments of the present invention have been described in detail above, but the invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent modifications or replacements without violating the spirit of the present invention. These equivalent modifications or replacements are all within the scope defined by the claims of the present application.

Claims (2)

1. strong Alcoa in a kind of microalloy, which is characterized in that each component and its weight percent are：Mg constituent contents are 0.4~0.8%, Si constituent content be 0.5~1.0%, Cu constituent contents be 0.3~0.6%, Mn constituent contents be 0.2~ 0.4%, Er constituent content are that 0.15~0.35%, Zr constituent contents are 0.10~0.25%, B element content be 0.01~ 0.06%, Fe constituent content≤0.15%, the total content≤0.15%, Al of other impurity elements is balance-element.

2. the preparation method of strong Alcoa in a kind of microalloy, which is characterized in that the preparation method comprises the following steps：

(1) raw material is matched：Component described in accordance with the claim 1 and its weight percent match raw material；

(2) raw material melting：Under 755~785 DEG C of temperature conditions, first high-purity aluminium ingot is melted, Al-Er10, Al- is then added Zr5, Al-Mn10, Al-B3, Al-Cu50, Al-Si15 intermediate alloy are added 99.99% magnesium after intermediate alloy fusing and cover Lid agent；

(3) it refines：Carbon trichloride is added in the molten metal being completely melt and carries out degassing processing, and is sufficiently stirred, when refining In the range of metal temperature maintains 730 DEG C~750 DEG C, sufficient standing should be carried out after refining, time of repose is not less than 30 minutes；

(4) it pours into a mould：When molten metal temperature is down to 700 DEG C~720 DEG C, it is 400 that molten metal, which is poured into temperature, after sufficient standing DEG C~440 DEG C of metal dies in, you can obtain alloy cast ingot；

(5) three-level Homogenization Treatments：The alloy cast ingot that step (4) is obtained carries out three-level Homogenization Treatments, and the first stage is 320 6~20h is kept the temperature at~380 DEG C, second stage keeps the temperature 10~25h at 420~450 DEG C, and the phase III is at 480~530 DEG C Keep the temperature 15~20h；

(6) crimp is handled：To step (5) obtain alloy cast ingot carry out crimp processing, squeeze temperature be 485 DEG C~ 520 DEG C, deformation coefficient is 10~20, is cooled down using forced air-cooling；

(7) pre-tension deformation is handled：Pre-tension deformation processing is carried out to the alloy that step (6) obtains, stretcher strain amount is 15% ~45%；

(8) ageing treatment：Ageing treatment, 160~190 DEG C of aging temp are carried out to the alloy that step (7) obtains, aging time is 10~30h finally obtains the aluminium alloy.