Medium-strength 7xxx series recycled aluminum alloy parts with high recycled material ratio and their preparation method

Abstract

This invention provides a medium-strength 7xxx series recycled aluminum alloy part with a high proportion of recycled material, comprising at least 75 wt% recycled aluminum material, which includes at least two different recycled aluminum materials derived from at least one of the 5xxx and 6xxx series aluminum alloys. Under T6 heat treatment, the medium-strength 7xxx series recycled aluminum alloy part with a high proportion of recycled material exhibits a tensile strength between 350-550 MPa, a yield strength between 300-500 MPa, and an elongation greater than 10%. Furthermore, this invention also provides a method for preparing the medium-strength 7xxx series recycled aluminum alloy part with a high proportion of recycled material.

Claims

1. A method for preparing a medium-strength 7xxx series recycled aluminum alloy with a high proportion of recycled materials, comprising: A raw material selection and composition design step, providing at least two recycled aluminum materials, wherein the recycled aluminum materials are derived from at least one of the 5xxx series and 6xxx series aluminum alloys; Based on the target alloy element content specifications of the desired medium-strength 7xxx series recycled aluminum alloy, the addition ratio of the recycled aluminum material and the virgin pure aluminum ingot is determined to obtain an initial mixture; a purification and refining step is performed, based on the target alloy element content specifications of the desired medium-strength 7xxx series recycled aluminum alloy, to purify and refine at least one of the recycled aluminum materials in the initial mixture, removing a portion of the content of at least one alloy element in the at least one recycled aluminum material, to obtain an intermediate product; A melting step, wherein different series of recycled aluminum materials, primary pure aluminum ingots, and intermediates obtained after the purification and refining step of the initial mixture are melted into an aluminum alloy molten soup, wherein the weight percentage of each alloying element in the aluminum alloy molten soup is not greater than the weight percentage of the corresponding alloying element of the target alloying element; and an alloy composition tempering step, wherein the weight percentage (wt%) of each alloying element in the aluminum alloy molten soup is adjusted to the content specification range of each alloying element corresponding to the target aluminum alloy, thereby obtaining a tempered aluminum alloy molten soup, wherein the content of the recycled aluminum alloy is at least 75 wt% based on the weight of the tempered aluminum alloy molten soup being 100 wt%.

2. The preparation method as described in claim 1, wherein, The sources of the at least two recycled aluminum materials may also be from at least one of the 1xxx series and 7xxx series aluminum alloys, wherein the 1xxx series aluminum alloy is selected from at least one of 1050, 1070 and 1100, and the 7xxx series aluminum alloy is selected from at least one of 7050 and 7150.

3. The preparation method as described in claim 1, wherein, The 5xxx series aluminum alloys of these recycled aluminum materials are selected from at least one of 5050, 5051 and 5056, and the 6xxx series aluminum alloys are selected from at least one of 6060, 6061 and 6063.

4. The preparation method as described in claim 1 further includes a casting step, wherein the quenched and tempered aluminum alloy molten metal is cast and subsequently extruded.

5. The preparation method as described in claim 1, wherein, The purification and refining step involves at least one of boron treatment and segregation purification treatment to remove at least a portion of the corresponding alloying elements.

6. The preparation method as described in claim 1, wherein, The composition of the quenched and tempered aluminum alloy molten metal includes: no more than 0.15 wt% silicon, no more than 0.2 wt% iron, no more than 0.4 wt% copper, no more than 0.30 wt% manganese, 0.5-2.0 wt% magnesium, 4.0-8.0 wt% zinc, no more than 0.2 wt% chromium, no more than 0.06 wt% titanium, no more than 0.25 wt% zirconium, and an equal amount of aluminum.

7. A medium-strength 7xxx series recycled aluminum alloy part with a high proportion of recycled material, prepared by the method of claim 1, wherein the medium-strength 7xxx series recycled aluminum alloy part with a high proportion of recycled material contains at least 75 wt% recycled aluminum material, and wherein the medium-strength 7xxx series recycled aluminum alloy part with a high proportion of recycled material has a tensile strength between 350-550 MPa, a yield strength between 300-500 MPa, and an elongation greater than 10% under T6 heat treatment.

8. Medium-strength 7xxx series recycled aluminum alloy parts with a high proportion of recycled materials as described in claim 7, wherein, The composition of this high-recycled-material-ratio medium-strength 7xxx series recycled aluminum alloy parts includes: no more than 0.15 wt% silicon, no more than 0.2 wt% iron, no more than 0.4 wt% copper, no more than 0.30 wt% manganese, 0.5-2.0 wt% magnesium, 4.0-8.0 wt% zinc, no more than 0.2 wt% chromium, no more than 0.06 wt% titanium, no more than 0.25 wt% zirconium, and a balanced amount of aluminum.

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