Method for Producing an Aluminum Alloy, and Component

Description

BACKGROUND AND SUMMARY

The present disclosure relates to a process for producing an aluminum alloy, and to a component made at least in part from the aluminum alloy.

For the manufacture of cast components by diecasting, aluminum-silicon alloys have been established for years, especially subeutectic alloys with silicon contents between 9% and 11.5% by weight. These alloys are standardized in EN AC 43500. They are manufactured predominantly from primary sources. The recycled fractions are comparatively low, and the CO₂ balance is correspondingly poor.

It is therefore an object of the present disclosure to specify a process for producing an aluminum alloy and a component, made at least in part from the aluminum alloy, that are more sustainable than the known approaches.

The present disclosure is directed to a process for producing an aluminum alloy having the following composition:

• • 8.0% to 11.5% by weight of silicon (Si),
  • max. 0.3% by weight of iron (Fe),
  • max. 0.1% by weight of copper (Cu),
  • 0.3% to 0.8% by weight of manganese (Mn),
  • 0.1% to 0.6% by weight of magnesium (Mg),
  • max. 0.25% by weight of titanium (Ti),
  • aluminum (Al) as the balance, and
  • impurities max. 0.1% by weight individually and 0.4% by weight in total,
  • wherein at least 50% by weight of recycled material is added to primary aluminum in order to form the above composition.

It has been found that, surprisingly, with the aforementioned alloy composition, in spite of the high recycled fraction of at least 50% by weight, preferably at least 60% by weight, 70% by weight, 80% by weight, or even 90% by weight, both static properties (Rp_0.2) and dynamic properties (plastic forming characteristics) in the F, T5, T64, T6 and T7 states give at least comparable results to the standard alloys. What is crucial here in the present context is the advantageous widening of the standard limits (standard: EN AC 43500) that enables the high recycled fractions. The Si content has accordingly been extended from 9% to 11.5% by weight to from 8% to 11.5% by weight, the Fe content from 0.25% to 0.3% by weight, the Cu content from 0.05% to 0.1% by weight, the Mn content from 0.4% to 0.8% by weight to from 0.3% to 0.8% by weight, and the Ti content from 0.15% to 0.25% by weight.

Primary aluminum is aluminum which is produced by fused salt electrolysis from aluminum oxide. Aluminum oxide is obtained from the aluminum ore bauxite. Primary aluminum is also called smelter aluminum.

Accompanying and trace elements (Cr, Ni, Zn, Sn, Pb, but also Mo, Zr, V) may account for a total of max. 0.4% by weight (0.15% by weight according to the standard), and individually max. 0.1% by weight (0.05% by weight according to the standard) (Cr—chromium, Ni—nickel, Sn—tin, Pb—lead, Mo—molybdenum, Zr—zirconium, V—vanadium).

Appropriately, the above composition is formed by adding individual alloy constituents and/or correspondingly selecting and sorting the recycled material.

In one embodiment, the alloy comprises at least 50% by weight, preferably at least 60% by weight, 70% by weight, 80% by weight, or 90% by weight, of recycled material.

In one embodiment, the alloy preferably comprises 50% to 90% by weight of recycled material, further preferably 60% to 90% by weight, 70% to 90% by weight, or 80% to 90% by weight. The higher the recycled fraction, the more sustainable the alloy.

In one embodiment, the alloy comprises the following composition:

• • 8.0% to 9.0% by weight of silicon,
  • 0.25% to 0.3% by weight of iron,
  • 0.05% to 0.1% by weight of copper,
  • 0.3% to 0.4% by weight of manganese,
  • 0.1% to 0.6% by weight of magnesium,
  • 0.15% to 0.25% by weight of titanium,
  • aluminum as the balance, and
  • impurities max. 0.1% by weight individually and 0.4% by weight in total.

The ranges stated above, in one embodiment, should be understood such that the limits are also included in the sense of “not more than” or “not less than”. Alternatively, the limits may also be excluded, at least in part.

Even though the values are largely outside the standard, comparable properties to those with the standard alloy can be achieved, although at the same time extremely high recycled fractions of preferably up to 90% by weight, or even more, are possible.

The aluminum alloy is especially an aluminum diecast alloy. By the process of the disclosure, it is possible to distinctly increase the recycled fractions in the production of aluminum alloys. The (diecast) alloy produced by the process especially has an excellent usability in motor vehicle and engine construction.

The disclosure is also directed to a component produced from an alloy of the present disclosure. The component is preferably a cast component, especially a diecast component.

Further advantages and features will be apparent from the description that follows of an embodiment of the method with reference to the appended FIGURE.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1: a schematic diagram for illustration of one embodiment of the process.

DETAILED DESCRIPTION OF THE DRAWING

FIG. 1 shows a schematic diagram for illustration of one embodiment of the process for producing an aluminum alloy 30 having the following composition:

• • 8.0% to 11.5% by weight of silicon,
  • max. 0.3% by weight of iron,
  • max. 0.1% by weight of copper,
  • 0.3% to 0.8% by weight of manganese,
  • 0.1% to 0.6% by weight of magnesium,
  • max. 0.25% by weight of titanium,
  • aluminum as the balance, and
  • impurities max. 0.1% by weight individually and 0.4% by weight in total,
  • wherein at least 50% by weight of recycled material 12 is added to primary aluminum 20 in order to form the above composition.

Appropriately, the alloy comprises at least 50% by weight, preferably at least 70% by weight, especially preferably 70% to 90% by weight, of recycled material 12.

Appropriately, the above composition is formed by adding individual alloy constituents 22 and/or selecting the recycled material 12 accordingly, for which purpose scrap 10 is sorted accordingly. Also included in the diagram here is the fact that, depending on the composition of the recycled material 12, it is possible to dispense with the addition of individual alloy constituents; cf. the “middle alloy constituent 22” in FIG. 1, from which no arrow is directed to the alloy 30. In particular, the proportions of the primary aluminum 20 and of the individual alloy constituents are dependent on the composition of the recycled material 12.

LIST OF REFERENCE NUMERALS

• • 10 scrap
  • 12 recycled material, selected scrap residues
  • 20 primary aluminum
  • 22 alloy constituent
  • 30 aluminum alloy