阅读说明：本技术 耐腐蚀铝合金型材及其制备方法 (Corrosion-resistant aluminum alloy section and preparation method thereof ) 是由 张骋 于 2019-11-29 设计创作，主要内容包括：本发明提供一种耐腐蚀铝合金型材的制备方法,通过对铝合金中的Mn、Fe、Si、Cu、Zn、Bi、Ni、Al的比例进行了优选调整,使铝合金型材具有了更高的强度与可挤压性能的均衡。采用浸镀锌处理和化学镀镍处理得到具有双层镀层的铝合金型材；其中外层为Ni镀层；内层为Al-Zn合金镀层。内层的Al-Zn合金镀层利用原电池原理,通过牺牲其中的化学性质活泼的Zn以保护包裹于其内部的铝合金型材不受腐蚀；外层的Ni镀层,利用Ni元素的抗腐蚀性质保护铝合金型材。双层镀层减少了Ni的使用量,并且提高了铝合金型材的耐腐蚀性能。本发明的耐腐蚀铝合金型材,抗拉强度为310～360MPa；伸长率为23～28；相对公知的5083铝合金型材,室温下的年腐蚀速率减小了17％～38％；300℃下的年腐蚀速率减小了23％～41％。(The invention provides a preparation method of a corrosion-resistant aluminum alloy section, which is characterized in that the aluminum alloy section has higher balance of strength and extrudability by optimally adjusting the proportion of Mn, Fe, Si, Cu, Zn, Bi, Ni and Al in the aluminum alloy. Obtaining an aluminum alloy section with a double-layer coating by adopting dip galvanizing treatment and chemical nickel plating treatment; wherein the outer layer is a Ni plating layer; the inner layer is an Al-Zn alloy coating. The Al-Zn alloy coating of the inner layer protects the aluminum alloy section wrapped in the inner layer from being corroded by sacrificing active Zn in chemical property by utilizing the principle of a galvanic cell; the outer Ni plating layer protects the aluminum alloy section by utilizing the corrosion resistance of Ni element. The double-layer plating layer reduces the usage amount of Ni and improves the corrosion resistance of the aluminum alloy section. The corrosion-resistant aluminum alloy section has the tensile strength of 310-360 MPa; the elongation is 23-28; compared with the known 5083 aluminum alloy section, the annual corrosion rate at room temperature is reduced by 17-38%; the annual corrosion rate at 300 ℃ is reduced by 23-41%.)

1. The preparation method of the corrosion-resistant aluminum alloy profile is characterized in that the corrosion-resistant aluminum alloy profile is composed of the following elements in percentage by weight: 1.2 to 1.35 wt% of Mn, 0.35 to 0.50 wt% of Fe, 0.40 wt% of Si, 0.08 to 0.18 wt% of Cu, and 0.08 wt% of Zn; 0.02 wt% of Bi; 0.03 to 0.05 wt% of Ni; the balance of Al and inevitable impurities; the content of each impurity element is less than or equal to 0.02 wt%, and the total content of the impurity elements is less than or equal to 0.10 wt%;

the preparation method of the corrosion-resistant aluminum alloy profile comprises the following steps:

step S1: adding Al-Mn intermediate alloy, Al-Fe intermediate alloy, Al-Si intermediate alloy, Al-Cu intermediate alloy and Al-Bi intermediate alloy into molten aluminum according to the proportion, mixing and smelting, and preparing aluminum alloy molten liquid after the added alloy solid is completely melted;

step S2: adding a refining agent into the molten aluminum alloy liquid, introducing inert gas, and refining the molten aluminum alloy liquid for 20-40 min;

step S3: injecting the refined aluminum alloy molten liquid into a mold, standing, cooling and homogenizing to prepare an aluminum alloy ingot;

step S4: extruding and molding an aluminum alloy ingot at the temperature of 500 ℃, then carrying out solution treatment at the temperature of 200-210 ℃ for 5 hours, and naturally cooling to room temperature to obtain an aluminum alloy section with the required shape and size;

step S5: carrying out dip galvanizing treatment on the aluminum alloy section to obtain the aluminum alloy section with an Al-Zn alloy coating;

step S6: and carrying out chemical nickel plating on the aluminum alloy section with the Al-Zn alloy coating to obtain the corrosion-resistant aluminum alloy section.

2. The method of producing a corrosion-resistant aluminum alloy profile according to claim 1, wherein after step S4 and before step S5, the aluminum alloy profile is subjected to a reverse quenching treatment and then an aging treatment;

wherein, the temperature control of the reverse quenching treatment is divided into a low-temperature heat preservation stage, a rapid heating stage and a high-temperature heat preservation stage; controlling the temperature at-100 ℃ in the low-temperature heat preservation stage, and preserving the heat for 180 min; the temperature in the rapid heating stage is increased from-100 ℃ to 150 ℃, and the average heating rate is 20 ℃/min; controlling the temperature at 150 ℃ in the high-temperature heat preservation stage, and preserving the heat for 180 min;

the temperature of the aging treatment is controlled to be 190-210 ℃, and the duration time is 6-8 h.

3. The method for preparing the corrosion-resistant aluminum alloy profile according to claim 1, wherein the zinc immersion plating treatment of the step S5 sequentially comprises four stages of pickling, first zinc immersion, zinc immersion removing and second zinc immersion:

wherein the temperature of the first zinc dipping stage and the second zinc dipping stage is 25 ℃, and the zinc dipping solution is strong alkaline solution of sodium zincate; the soaking time of the aluminum alloy section in the zinc soaking solution in the first zinc soaking stage is 30-50 s; in the second zinc dipping stage, the aluminum alloy section is dipped in the zinc dipping solution for 15-20 s; the thickness of the finally formed Al-Zn alloy coating is 5-8 mu m;

the zinc immersion removing adopts nitric acid water solution with the volume ratio of 1:1 as zinc immersion removing agent.

4. The method for preparing the corrosion-resistant aluminum alloy profile according to claim 1, wherein the nickel plating solution for the electroless nickel plating treatment of step S6 comprises: 30g/L of nickel sulfate and 30g/L, pH of sodium hypophosphite of 10, the temperature of the nickel plating solution is 80 ℃, and the nickel plating time is 30-60 s; the thickness of the nickel coating of the obtained corrosion-resistant aluminum alloy section is 0.8-2 mu m.

5. The method for preparing the corrosion-resistant aluminum alloy section according to claim 1, wherein the temperature of the mixed melting in the step S1 is 750-780 ℃.

6. A corrosion-resistant aluminum alloy profile, which is prepared by the method of any one of claims 1 to 5.

Technical Field

The invention relates to the field of aluminum alloy production, in particular to a corrosion-resistant aluminum alloy section and a preparation method thereof.

Background

Aluminum alloy profiles are the most widely used non-ferrous metals in industrial applications. Because the aluminum alloy section has the characteristics of low density, high strength ratio, easy processing and forming, good welding performance and the like, the aluminum alloy section accounts for the proportion in the use of lightweight designs of automobile machinery, aerospace and the like. However, the strength and corrosion resistance of the existing aluminum alloy section still need to be further improved so as to meet the requirements of production and life on the aluminum alloy section.

Disclosure of Invention

In order to provide an aluminum alloy section with higher strength and better corrosion resistance, the invention provides the following technical scheme:

the invention provides a preparation method of a corrosion-resistant aluminum alloy profile, which comprises the following elements in percentage by weight: 1.2 to 1.35 wt% of Mn, 0.35 to 0.50 wt% of Fe, 0.40 wt% of Si, 0.08 to 0.18 wt% of Cu, and 0.08 wt% of Zn; 0.02 wt% of Bi; 0.03 to 0.05 wt% of Ni; the balance of Al and inevitable impurities; the content of each impurity element is less than or equal to 0.02 wt%, and the total content of the impurity elements is less than or equal to 0.10 wt%;

the preparation method of the corrosion-resistant aluminum alloy profile comprises the following steps:

step S1: adding Al-Mn intermediate alloy, Al-Fe intermediate alloy, Al-Si intermediate alloy, Al-Cu intermediate alloy and Al-Bi intermediate alloy into molten aluminum according to the proportion, mixing and smelting, and preparing aluminum alloy molten liquid after the added alloy solid is completely melted;

step S2: adding a refining agent into the molten aluminum alloy liquid, introducing inert gas, and refining the molten aluminum alloy liquid for 20-40 min;

step S3: injecting the refined aluminum alloy molten liquid into a mold, standing, cooling and homogenizing to prepare an aluminum alloy ingot;

step S4: extruding and molding an aluminum alloy ingot at the temperature of 500 ℃, then carrying out solution treatment at the temperature of 200-210 ℃ for 5 hours, and naturally cooling to room temperature to obtain an aluminum alloy section with the required shape and size;

step S5: carrying out dip galvanizing treatment on the aluminum alloy section to obtain the aluminum alloy section with an Al-Zn alloy coating;

step S6: and carrying out chemical nickel plating on the aluminum alloy section with the Al-Zn alloy coating to obtain the corrosion-resistant aluminum alloy section.

According to the preparation method of the corrosion-resistant aluminum alloy profile, provided by the invention, preferably, after the step S4 and before the step S5, the aluminum alloy profile is subjected to reverse quenching treatment and then aging treatment;

wherein, the temperature control of the reverse quenching treatment is divided into a low-temperature heat preservation stage, a rapid heating stage and a high-temperature heat preservation stage; controlling the temperature at-100 ℃ in the low-temperature heat preservation stage, and preserving the heat for 180 min; the temperature in the rapid heating stage is increased from-100 ℃ to 150 ℃, and the average heating rate is 20 ℃/min; controlling the temperature at 150 ℃ in the high-temperature heat preservation stage, and preserving the heat for 180 min;

the temperature of the aging treatment is controlled to be 190-210 ℃, and the duration time is 6-8 h.

According to the preparation method of the corrosion-resistant aluminum alloy section, the temperature of the mixed smelting in the step S1 is preferably 750-780 ℃.

According to the preparation method of the corrosion-resistant aluminum alloy profile, the immersion galvanizing treatment in the step S5 preferably sequentially comprises four stages of pickling, first immersion galvanizing, and second immersion galvanizing for zinc immersion removal:

wherein the temperature of the first zinc dipping stage and the second zinc dipping stage is 25 ℃, and the zinc dipping solution is strong alkaline solution of sodium zincate; the soaking time of the aluminum alloy section in the zinc soaking solution in the first zinc soaking stage is 30-50 s; in the second zinc dipping stage, the aluminum alloy section is dipped in the zinc dipping solution for 15-20 s; the thickness of the finally formed Al-Zn alloy coating is 5-8 mu m;

the zinc immersion removing adopts nitric acid water solution with the volume ratio of 1:1 as zinc immersion removing agent.

In the preparation method of the corrosion-resistant aluminum alloy profile provided by the invention, the nickel plating solution of the electroless nickel plating treatment in the step S6 preferably comprises: 30g/L of nickel sulfate and 30g/L, pH of sodium hypophosphite of 10, the temperature of the nickel plating solution is 80 ℃, and the nickel plating time is 30-60 s; the thickness of the nickel coating of the obtained corrosion-resistant aluminum alloy section is 0.8-2 mu m.

The invention also provides a corrosion-resistant aluminum alloy section prepared by the method.

The invention has the advantages or beneficial effects that:

according to the preparation method of the corrosion-resistant aluminum alloy section, the proportion of Mn, Fe, Si, Cu, Zn, Bi, Ni and Al in the aluminum alloy is preferably adjusted, so that the aluminum alloy section provided by the invention has higher balance of strength and extrudability. Performing immersion galvanizing treatment and chemical nickel plating treatment on the aluminum alloy section with the optimized composition to obtain an aluminum alloy section with a double-layer coating on the surface; wherein the plating layer of the outer layer is a Ni plating layer; the coating of the inner layer is an Al-Zn alloy coating. The Al-Zn alloy coating of the inner layer protects the aluminum alloy section bar wrapped in the Al-Zn alloy coating from corrosion by sacrificing active Zn in chemical property by utilizing the principle of a primary battery; the outer Ni plating layer protects the aluminum alloy section by utilizing the self corrosion resistance of Ni element. The double-layer coating design reduces the usage amount of expensive metal materials, namely Ni, and improves the corrosion resistance of the aluminum alloy section.

The corrosion-resistant aluminum alloy section prepared by the method has the tensile strength sigma_b310-360 MPa; elongation delta₁₀23 to 28; compared with the known 5083 aluminum alloy section, the annual corrosion rate at room temperature is reduced by 17-38%; compared with the known 5083 aluminum alloy section, the annual corrosion rate at 300 ℃ is reduced by 23-41%.

Detailed Description

In view of the deficiencies in the prior art, the inventors have conducted extensive research and extensive practice to provide a technical solution of the present invention, and further explain the technical solution, its implementation process, principles, and the like.

The corrosion-resistant aluminum alloy section provided by the invention has higher balance of strength and extrudability by optimally adjusting the proportion of Mn, Fe, Si, Cu, Zn, Bi, Ni and Al in the aluminum alloy.

As one aspect of the technical scheme of the invention, the invention relates to a preparation method of a corrosion-resistant aluminum alloy profile, which comprises the following elements in percentage by weight: 1.2 to 1.35 wt% of Mn, 0.35 to 0.50 wt% of Fe, 0.40 wt% of Si, 0.08 to 0.18 wt% of Cu, and 0.08 wt% of Zn; 0.02 wt% of Bi; 0.03 to 0.05 wt% of Ni; the balance of Al and inevitable impurities; the content of each impurity element is less than or equal to 0.02 wt%, and the total content of the impurity elements is less than or equal to 0.10 wt%;

the preparation method of the corrosion-resistant aluminum alloy profile comprises the following steps:

step S1: adding Al-Mn intermediate alloy, Al-Fe intermediate alloy, Al-Si intermediate alloy, Al-Cu intermediate alloy and Al-Bi intermediate alloy into molten aluminum according to the proportion, mixing and smelting, and preparing aluminum alloy molten liquid after the added alloy solid is completely melted;

step S2: adding a refining agent into the molten aluminum alloy liquid, introducing inert gas, and refining the molten aluminum alloy liquid for 20-40 min;

step S3: injecting the refined aluminum alloy molten liquid into a mold, standing, cooling and homogenizing to prepare an aluminum alloy ingot;

step S4: extruding and molding an aluminum alloy ingot at the temperature of 500 ℃, then carrying out solution treatment at the temperature of 200-210 ℃ for 5 hours, and naturally cooling to room temperature to obtain an aluminum alloy section with the required shape and size;

step S5: carrying out dip galvanizing treatment on the aluminum alloy section to obtain the aluminum alloy section with an Al-Zn alloy coating;

step S6: and carrying out chemical nickel plating on the aluminum alloy section with the Al-Zn alloy coating to obtain the corrosion-resistant aluminum alloy section.

In some embodiments, the molten aluminum in step S1 is melted from a pure aluminum source at a temperature above the melting point of aluminum.

In some embodiments, after step S4 and before step S5, the aluminum alloy profile is counter quenched and then aged;

wherein, the temperature control of the reverse quenching treatment is divided into a low-temperature heat preservation stage, a rapid heating stage and a high-temperature heat preservation stage; controlling the temperature at-100 ℃ in the low-temperature heat preservation stage, and preserving the heat for 180 min; the temperature in the rapid heating stage is increased from-100 ℃ to 150 ℃, and the average heating rate is 20 ℃/min; controlling the temperature at 150 ℃ in the high-temperature heat preservation stage, and preserving the heat for 180 min;

the temperature of the aging treatment is controlled to be 190-210 ℃, and the duration time is 6-8 h.

In some embodiments, the temperature of the mixed smelting of step S1 is 750 to 780 ℃.

In some embodiments, the zinc immersion plating process of step S5 includes four stages of acid cleaning, first zinc immersion, and second zinc immersion for zinc immersion removal in sequence:

wherein the temperature of the first zinc dipping stage and the second zinc dipping stage is 25 ℃, and the zinc dipping solution is strong alkaline solution of sodium zincate; the soaking time of the aluminum alloy section in the zinc soaking solution in the first zinc soaking stage is 30-50 s; in the second zinc dipping stage, the aluminum alloy section is dipped in the zinc dipping solution for 15-20 s; the thickness of the finally formed Al-Zn alloy coating is 5-8 mu m;

the zinc immersion removing adopts nitric acid water solution with the volume ratio of 1:1 as zinc immersion removing agent.

In some embodiments, the electroless nickel plating solution of step S6 consists of: 30g/L of nickel sulfate and 30g/L, pH of sodium hypophosphite of 10, the temperature of the nickel plating solution is 80 ℃, and the nickel plating time is 30-60 s; the thickness of the nickel coating of the obtained corrosion-resistant aluminum alloy section is 0.8-2 mu m.

As another aspect of the technical scheme of the invention, the invention relates to a corrosion-resistant aluminum alloy section prepared by the method.

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. Therefore, the detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention without making creative efforts, belong to the protection scope of the invention.