阅读说明：本技术 一种用于汽车外饰的铝合金及其制备方法 (Aluminum alloy for automobile exterior trim and preparation method thereof ) 是由 罗红来 丁强东 郑达 于 2020-12-31 设计创作，主要内容包括：本发明属于铝合金加工技术领域,涉及一种用于汽车外饰的铝合金及其制备方法。本发明通过对铝合金成分的优化,完善铝棒制备工艺,通过制备方法的改进和工艺参数的合理选择,最大程度降低杂质含量,在提高铝合金表面处理后的氧化良率和挤压铝合金的机械性能的同时,使其具有更好的表面质量,大大提高了铝合金铸棒的综合性能。(The invention belongs to the technical field of aluminum alloy processing, and relates to an aluminum alloy for automobile exterior trim and a preparation method thereof. The invention improves the preparation process of the aluminum bar by optimizing the components of the aluminum alloy, reduces the impurity content to the maximum extent by improving the preparation method and reasonably selecting the process parameters, improves the oxidation yield of the aluminum alloy after surface treatment and the mechanical property of the extruded aluminum alloy, simultaneously has better surface quality, and greatly improves the comprehensive performance of the aluminum alloy cast bar.)

1. The aluminum alloy for the automobile exterior trim is characterized by comprising the following chemical components in percentage by mass: 0.4-0.5% of Si, 0.015-0.025% of Fe, 0.05-0.08% of Cu, 0-0.01% of Mn, 0.51-0.56% of Mg, 0-0.005% of Cr, 0-0.005% of Ni, 0-0.01% of Zn, 0.005-0.014% of Ti, and the balance of Al and inevitable impurities.

2. The aluminum alloy for automobile exterior trimming according to claim 1, wherein the aluminum alloy comprises the following chemical components in percentage by mass: 0.4-0.45% of Si, 0.015-0.02% of Fe, 0.05-0.06% of Cu, 0-0.01% of Mn, 0.52-0.55% of Mg, 0-0.005% of Cr, 0-0.005% of Ni, 0-0.01% of Zn, 0.005-0.01% of Ti, and the balance of Al and inevitable impurities.

3. The aluminum alloy for automobile exterior trimming according to claim 1, wherein the aluminum alloy comprises the following chemical components in percentage by mass: 0.42% of Si, 0.018% of Fe, 0.055% of Cu, 0.008% of Mn, 0.53% of Mg, 0.001% of Cr, 0.003% of Ni, 0.006% of Zn, 0.006% of Ti, and the balance of Al and inevitable impurities.

4. The aluminum alloy for automotive exterior, as recited in claims 1 to 3, wherein the aluminum alloy has a chemical composition in which Mg and Si are present in a mass ratio of 1.2 to 1.5.

5. A method for producing an aluminum alloy for automobile exterior according to claim 1, comprising:

s1: preparing raw materials according to the chemical composition of the aluminum alloy in the claim 1;

s2: firstly, placing the refined aluminum ingot in a smelting furnace, heating to 740 and 750 ℃ to melt the refined aluminum ingot into aluminum liquid, and adding the rest metal raw material;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: adding a refining agent into the alloy liquid of the smelting furnace again and introducing argon for refining;

s5: filtering the aluminum liquid by a plate filter of 40-60 meshes and then filtering by a pipe filter;

s6: and introducing the molten aluminum into a crystallizer for casting to obtain the aluminum alloy cast rod.

6. The method for preparing aluminum alloy for automobile exterior trim according to claim 4, wherein the refining agent is MgCl₂And KCl.

7. The method for preparing aluminum alloy for automobile exterior trim according to claim 4, wherein the MgCl is adopted₂And KCl in a mass ratio of 1: (1-2).

8. The method as claimed in claim 4, wherein the aluminum alloy cast rod obtained by casting is further cooled by air cooling at a cooling rate of 350-.

Technical Field

The invention belongs to the technical field of aluminum alloy processing, and relates to an aluminum alloy for automobile exterior trim and a preparation method thereof.

Background

In the field of automobile exterior trimming parts, 6401 aluminum alloy is widely applied at present, and mainly comprises magnesium and silicon and Mg₂Si is a main strengthening phase, has the characteristics of medium strength, good corrosion resistance, good welding performance, easy extrusion forming, good oxidation coloring performance and the like, and is suitable for automobile luggage racks, doors, windows, automobile bodies, radiating fins, various decorative strips and decorationsParts and other automobile exterior parts.

The selection of the aluminum alloy raw material components has important influence on the subsequent bending shape stability, the appearance surface quality after surface treatment, the corrosion resistance, the wear resistance and the mechanical property, but the defect rate of the conventional 6401 aluminum alloy material after surface treatment caused by the raw material components is about 2 percent. Still have the cost high, oxidation qualification rate is low, seriously influences the delivery progress of product and the economic benefits of enterprise.

Therefore, in order to reduce the working difficulty and the cost for the subsequent process, the aluminum alloy profile which improves the oxidation yield of the aluminum alloy after surface treatment, improves the mechanical property of the extruded aluminum alloy profile and better meets the surface treatment requirement has important significance.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides an aluminum alloy for automobile exterior trim and a preparation method thereof, which improve the oxidation yield of the aluminum alloy after surface treatment and the mechanical property of an extruded aluminum alloy and have better surface quality.

The purpose of the invention can be realized by the following technical scheme: the aluminum alloy for the automobile exterior trim comprises the following chemical components in percentage by mass: 0.4-0.5% of Si, 0.015-0.025% of Fe, 0.05-0.08% of Cu, 0-0.01% of Mn, 0.51-0.56% of Mg, 0-0.005% of Cr, 0-0.005% of Ni, 0-0.01% of Zn, 0.005-0.014% of Ti, and the balance of Al and inevitable impurities.

Preferably, the aluminum alloy comprises the following chemical components in percentage by mass: 0.4-0.45% of Si, 0.015-0.020% of Fe, 0.05-0.06% of Cu, 0-0.01% of Mn, 0.52-0.55% of Mg, 0-0.005% of Cr, 0-0.005% of Ni, 0-0.01% of Zn, 0.005-0.01% of Ti, and the balance of Al and inevitable impurities.

Preferably, the aluminum alloy comprises the following chemical components in percentage by mass: 0.42% of Si, 0.018% of Fe, 0.055% of Cu, 0.008% of Mn, 0.53% of Mg, 0.001% of Cr, 0.003% of Ni, 0.006% of Zn, 0.006% of Ti, and the balance of Al and inevitable impurities.

The gloss of the material can be influenced by overhigh Mg and Si content in the aluminum alloy, so that the subsequent processing is influenced by overhigh strength of the aluminum alloy; if the contents of Mg and Si are too low, the strength of the aluminum alloy is insufficient.

The Fe content is controlled because the low luster of the aluminum alloy after the anodic oxidation treatment and the reduced mechanical property are caused by the over-high Fe content; if the Fe content is too low, the aluminum alloy after anodic oxidation treatment has high gloss and the cost is high.

In the invention, the Zn content is not required to be too high, and the excessive Zn content can cause bright spots on the surface of the oxidized aluminum alloy. Wherein, the addition of a small amount of Mn, Cr, Ni and other components can eliminate the adverse effect of Fe element, and the addition of excessive amount can cause abnormal luster after the anodic oxidation treatment of the aluminum alloy. The Cu element is dissolved in the Al matrix in a solid way, so that the strength of the aluminum alloy is improved, and the color of the aluminum alloy after anodic oxidation treatment is changed. Ti plays a role in refining grains, but excessive Ti can cause abnormal luster and color of the material after anodic oxidation treatment, and the cost is high.

In the above aluminum alloy for automotive exterior, the aluminum alloy has a chemical composition in which the mass ratio of Mg to Si is 1.2 to 1.5. The reason why the mass ratio of Mg to Si is controlled in the present invention is that when the Mg/Si ratio is controlled to be 1.2 to 1.5, excess Si exists, and the existence of excess Si leads to good workability of the entire aluminum alloy.

A preparation method of the aluminum alloy for the automobile exterior trim comprises the following steps:

s1: preparing raw materials according to the chemical components of the aluminum alloy;

s2: firstly, placing the refined aluminum ingot in a smelting furnace, heating to 740 and 750 ℃ to melt the refined aluminum ingot into aluminum liquid, and adding the rest metal raw material;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: adding a refining agent into the alloy liquid of the smelting furnace again and introducing argon for refining;

s5: filtering the aluminum liquid by a 40-60ppi plate filter, and then filtering by a tube filter;

s6: and introducing the molten aluminum into a crystallizer for casting to obtain the aluminum alloy cast rod.

The aluminum liquid is filtered by the plate filter and the tube filter, so that the content of the aluminum slag in the aluminum liquid is reduced to the maximum extent, and the influence of the aluminum slag on the final aluminum alloy finished product is reduced to the minimum.

In the above method for preparing an aluminum alloy for automobile exterior trim, the refining agent is MgCl₂And KCl.

In the above method for producing an aluminum alloy for exterior automotive trim, the MgCl₂And KCl in a mass ratio of 1: (1-2).

In the preparation method of the aluminum alloy for the automobile exterior trim, the finished aluminum alloy obtained by casting is also cooled by air cooling at the cooling speed of 350-plus-500 ℃/min.

Compared with the prior art, the invention has the following beneficial effects: the invention improves the preparation process of the aluminum bar by optimizing the components of the aluminum alloy, reduces the impurity content to the maximum extent by improving the preparation method and reasonably selecting the process parameters, improves the oxidation yield and the mechanical property of the aluminum alloy after surface treatment, simultaneously has better surface quality and greatly improves the comprehensive performance of the aluminum alloy cast bar.

Detailed Description

The following are specific examples of the present invention and further describe the technical solutions of the present invention, but the present invention is not limited to these examples.

Example 1:

s1: preparing raw materials: 0.42% of Si, 0.018% of Fe, 0.055% of Cu, 0.008% of Mn, 0.53% of Mg, 0.001% of Cr, 0.003% of Ni, 0.006% of Zn, 0.006% of Ti, and the balance of Al and inevitable impurities;

s2: firstly, placing a refined aluminum ingot in a smelting furnace, heating to 750 ℃ to melt the refined aluminum ingot into aluminum liquid, and adding the rest metal raw material;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: adding a refining agent into the alloy liquid of the smelting furnace again and introducing argon for refining; the refining agent is MgCl with the mass ratio of 1:1₂And a KCl mixture.

S5: filtering the aluminum liquid by a plate filter of 40 meshes, and then filtering by a pipe filter;

s6: introducing the aluminum liquid into a crystallizer for casting to obtain an aluminum alloy cast rod, and cooling the aluminum alloy cast rod by air cooling at the cooling speed of 400 ℃/min.

Example 2:

s1: preparing raw materials: 0.40% of Si, 0.015% of Fe, 0.05% of Cu, 0.52% of Mg, 0.005% of Ti, and the balance of Al and inevitable impurities;

s2: firstly, placing a refined aluminum ingot in a smelting furnace, heating to 750 ℃ to melt the refined aluminum ingot into aluminum liquid, and adding the rest metal raw material;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: adding a refining agent into the alloy liquid of the smelting furnace again and introducing argon for refining; the refining agent is MgCl with the mass ratio of 1:2₂And a KCl mixture.

S5: filtering the aluminum liquid by a 60-mesh plate filter and then filtering by a tube filter;

s6: introducing the aluminum liquid into a crystallizer for casting to obtain an aluminum alloy cast rod, and cooling the aluminum alloy cast rod by air cooling at the cooling speed of 350 ℃/min.

Example 3:

s1: preparing raw materials: 0.45% of Si, 0.02% of Fe, 0.06% of Cu, 0.01% of Mn, 0.55% of Mg, 0.005% of Cr, 0.005% of Ni, 0.01% of Zn, 0.01% of Ti, and the balance of Al and inevitable impurities;

s2: firstly, placing a refined aluminum ingot in a smelting furnace, heating to 750 ℃ to melt the refined aluminum ingot into aluminum liquid, and adding the rest metal raw material;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: refining again in the alloy liquid of the smelting furnaceIntroducing argon gas into the agent for refining; the refining agent is MgCl with the mass ratio of 1:1.5₂And a KCl mixture.

S5: filtering the aluminum liquid by a 50-mesh plate filter and then filtering by a tube filter;

s6: introducing the aluminum liquid into a crystallizer for casting to obtain an aluminum alloy cast rod, and cooling the aluminum alloy cast rod by air cooling at the cooling speed of 400 ℃/min.

Comparative example 1:

s1: preparing raw materials: 0.38% of Si, 0.01% of Fe, 0.02% of Cu, 0.42% of Mg, and the balance of Al and inevitable impurities;

s2: firstly, placing a refined aluminum ingot in a smelting furnace, heating to 740 ℃, melting into aluminum liquid, and adding the rest metal raw materials;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: adding a refining agent into the alloy liquid of the smelting furnace again and introducing argon for refining; the refining agent is MgCl with the mass ratio of 1:2₂And a KCl mixture.

S5: filtering the aluminum liquid by a plate filter of 40 meshes, and then filtering by a pipe filter;

s6: introducing the aluminum liquid into a crystallizer for casting to obtain an aluminum alloy cast rod, and cooling the aluminum alloy cast rod by air cooling at the cooling speed of 400 ℃/min.

Comparative example 2:

s1: preparing raw materials: 0.65% of Si, 0.038% of Fe, 0.12% of Cu, 0.08% of Mn, 0.80% of Mg, 0.012% of Cr, 0.06% of Ni, 0.013% of Zn, 0.08% of Ti, and the balance of Al and inevitable impurities;

s2: firstly, placing a refined aluminum ingot in a smelting furnace, heating to 740 ℃, melting into aluminum liquid, and adding the rest metal raw materials;

s3: adding a refining agent into the alloy liquid of the smelting furnace for refining, and carrying out slagging-off treatment;

s4: adding a refining agent into the alloy liquid of the smelting furnace again and introducing argon for refining; the refining agent is MgCl with the mass ratio of 1:1₂And a KCl mixture.

S5: filtering the aluminum liquid by a plate filter of 40 meshes, and then filtering by a pipe filter;

s6: introducing the aluminum liquid into a crystallizer for casting to obtain an aluminum alloy cast rod, and cooling the aluminum alloy cast rod by air cooling at the cooling speed of 500 ℃/min.

Table 1: comparison of Properties of aluminum alloys obtained in examples 1 to 3 and comparative examples 1 to 2

In conclusion, the invention optimizes the components of the aluminum alloy, reduces impurities, perfects the preparation process of the aluminum bar, improves the preparation method and reasonably selects process parameters, improves the oxidation yield of the aluminum alloy after surface treatment and the mechanical property of the extruded aluminum alloy, has better surface quality and greatly improves the comprehensive performance of the aluminum alloy cast bar.

The technical scope of the invention claimed by the embodiments of the present application is not exhaustive, and new technical solutions formed by equivalent replacement of single or multiple technical features in the technical solutions of the embodiments are also within the scope of the invention claimed by the present application; in all the embodiments of the present invention, which are listed or not listed, each parameter in the same embodiment only represents an example (i.e., a feasible embodiment) of the technical solution, and there is no strict matching and limiting relationship between the parameters, wherein the parameters may be replaced with each other without departing from the axiom and the requirements of the present invention, unless otherwise specified.

The technical means disclosed by the scheme of the invention are not limited to the technical means disclosed by the technical means, and the technical scheme also comprises the technical scheme formed by any combination of the technical characteristics. While the foregoing is directed to embodiments of the present invention, it will be appreciated by those skilled in the art that various changes may be made in the embodiments without departing from the principles of the invention, and that such changes and modifications are intended to be included within the scope of the invention.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.