ES2772729T3 - High strength corrosion resistant aluminum alloys for use as fin raw material and manufacturing methods thereof - Google Patents

Abstract

Aluminum alloy comprising 0.7 - 3.0% by weight of Zn, 0.15 - 0.35% by weight of Si, 0.25 - 0.65% by weight of Fe, 0.05 - 0, 20% by weight of Cu, 0.75 - 1.50% by weight of Mn, 0.50 - 1.50% by weight of Mg, up to 0.10% by weight of Cr, up to 0.10% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder as Al.

Description

DESCRIPTION

High strength corrosion resistant aluminum alloys for use as fin raw material and fabrication methods thereof.

Countryside

This disclosure concerns the fields of materials science, materials chemistry, metallurgy, aluminum alloys, aluminum fabrication, and other related fields. More specifically, the disclosure provides novel aluminum alloys that can be used in a variety of applications, including, for example, as a fin stock for a heat exchanger.

Background

Heat exchangers are widely used in various applications, including, but not limited to, heating and cooling systems in various industrial and chemical processes. Many of these configurations use fins in thermally conductive contact with the exterior of tubes to provide greater surface area through which heat can be transferred between fluids. In addition, fins are used to regulate the flow of fluids through the heat exchanger. However, aluminum alloy heat exchangers have a relatively high susceptibility to corrosion. Corrosion ultimately leads to loss of coolant from the tubes and failure of the heating or cooling system. High strength corrosion resistant alloys are desirable for improved product performance. However, identifying alloy compositions and processing conditions that will provide such an alloy that addresses these failures has proven challenging.

The heat exchanger tubes can be made of copper or an aluminum alloy and the heat exchanger fins can be made of a different aluminum alloy (eg AA1100 or AA7072). The fins can be fitted over copper or aluminum tubes and mechanically assembled. Larger heating, ventilation, air conditioning and refrigeration (HVAC & R) units may require longer fins and it is important that they have sufficient strength for further processing (e.g., handling and / or shaping to coil). One method of maintaining fin strength is to provide thicker gauge fins; however, this can increase the cost and add weight.

WO 2015/173984 A1 describes an aluminum alloy fin material for heat exchanger containing, in mass%, Si: 0.6-1.6%, Fe: 0.5-1.2%, Mn: 1.2 - 2.6%, Zn: 0.4 - 3.0% and Cu: less than 0.2%, the remainder being Al and unavoidable impurities.

Summary

Embodiments encompassed by the invention are defined by the claims, not by this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the detailed description section below.

New aluminum alloys showing high strength and corrosion resistance are provided herein. The aluminum alloys described herein comprise 0.7 - 3.0% by weight of Zn, 0.15 - 0.35% by weight of Si, 0.25 - 0.65% by weight of Fe, 0 .05 - 0.20% by weight of Cu, 0.75 - 1.50% by weight of Mn, 0.50 - 1.50% by weight of Mg, up to 0.05% by weight of Cr, up to 0 .05 wt% Ti, and up to 0.15 wt% impurities, with the balance as Al. In one embodiment, the aluminum alloy comprises 1.0-2.5 wt% Zn, 0.2 - 0.35% by weight of Si, 0.35 - 0.60% by weight of Fe, 0.10 - 0.20% by weight of Cu, 0.75 - 1.25% by weight of Mn, 0 , 90-1.30% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder being Al. In another embodiment, the aluminum alloy comprises 1.5-2.5% by weight Zn, 0.17-0.33% by weight Si, 0.30-0.55% by weight Fe, 0.15 - 0.20% by weight of Cu, 0.80 - 1.00% by weight of Mn, 1.00 - 1.25% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05 % by weight of Ti, and up to 0.15% in weight of impurities, with the remainder as Al. Optionally, the aluminum alloy comprises 0.9 - 2.6% by weight of Zn, 0.2-0.33% by weight of Si, 0.49 - 0.6 % by weight of Fe, 0.15 - 0.19% by weight of Cu, 0.79 - 0.94% by weight of Mn, 1.13 - 1.27% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the balance as Al. Optionally, the aluminum alloy comprises 1.4-1.6% by weight of Zn, 0.2 - 0.33% by weight of Si, 0.49 - 0.6% by weight of Fe, 0.15 - 0.19% by weight of Cu, 0.79 - 0.94% by weight of Mn, 1.13-1.27% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder as Al. The alloy can be produced by casting (eg direct cold casting or continuous casting), homogenization, hot rolling, cold rolling and / or annealing. The alloy can be in an H or O temper.

The elastic limit of the alloy is at least 70 MPa. The tensile breaking strength of the alloy can be at least 170 MPa. Aluminum alloy can comprise electrical conductivity above 37% based on the International Annealed Copper Standard (IACS). Optionally, the aluminum alloy comprises a corrosion potential of 740 mV to -850 mV.

Also provided herein are products comprising the aluminum alloy as described herein. Products may include a fin raw material. Optionally, the gauge of the fin stock is 1.0mm or less (eg 0.15mm or less). Further provided herein are articles comprising a tube and a fin, wherein the fin comprises the fin stock material described herein.

Furthermore, methods for producing a metallic product are provided herein. The methods include the steps of casting an aluminum alloy as described herein to form a cast aluminum alloy, homogenizing the cast aluminum alloy, hot rolling the cast aluminum alloy to produce a rolled product, and rolling in cold rolled product to give final gauge product. Optionally, the methods further include a step of annealing the final gauge product. Products (eg, heat exchanger fins) obtained according to the methods are also provided herein.

Additional aspects, objects and advantages will become apparent upon consideration of the detailed description of non-limiting examples that follow.

Brief description of the figures

Figure 1 contains digital images of exemplary alloys described herein along with a comparative alloy disclosed herein and tested for corrosion over various periods of time.

Figure 2 contains digital images of exemplary alloys described herein along with a comparative alloy described herein and tested for corrosion over various periods of time.

Detailed description

High strength, corrosion resistant aluminum alloys and methods of manufacturing and processing thereof are described herein. The aluminum alloys described herein show improved mechanical strength, corrosion resistance, and / or formability. The alloys provided herein include a constituent of zinc and can be especially useful as a sacrificial alloy (eg, as a fin stock material for use in combination with copper or aluminum alloy tubes in heat exchangers) . The disclosed alloy composition provides a material that has mechanical strength as well as sacrificial alloy characteristics. The alloy material can be formed into fin stock and mechanically attached to copper or aluminum alloy tubes. Fin stock can corrode as a sacrifice, thus protecting copper or aluminum alloy tubes from corrosion. Additionally, the aluminum alloy fin stock described herein has excellent mechanical strength that provides a thinner gauge aluminum alloy fin stock. The alloys can be used as fin feedstock in industrial applications, including heat exchangers, or in other applications. In a heat exchanger, the alloys serve as a sacrificial component, ensuring protection of other components of the heat exchanger (for example, a tube to which the alloy is attached).

Definitions and descriptions:

The terms "invention", "the invention", "this invention" and "the present invention" used herein are intended to refer broadly to all subject matter of this patent application and the claims that follow. It is to be understood that the statements containing these terms do not limit the subject matter described herein or do not limit the meaning or scope of the patent claims below.

In this description, reference is made to alloys identified by aluminum industry designations, such as "series" or "1xxx". For an understanding of the number designation system most commonly used to name and identify aluminum and its alloys, see “International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” or “Registration Record of Aluminum Association Alloy Designations and Chemicals. Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot ”, both published by The Aluminum Association.

As used herein, the meaning of "a", "an" or "the" includes references to singular and plural unless the context clearly indicates otherwise.

As used herein, a plate generally has a thickness greater than 15mm. For example, A plate may refer to an aluminum product that has a thickness greater than 15mm, greater than 20mm, greater than 25mm, greater than 30mm, greater than 35mm, greater than 40mm, greater than 45mm, greater than 50mm, or greater than 100mm.

As used herein, a shate (also known as a sheet plate) is generally 4mm to 15mm thick. For example, a shate can be 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15mm.

As used herein, a sheet generally refers to an aluminum product that is less than 4mm thick. For example, a sheet may have a thickness less than 4mm, less than 3mm, less than 2mm, less than 1mm, less than 0.5mm, less than 0.3mm, or less than 0.1mm.

In this application reference is made to the temper or alloy condition. For an understanding of the most commonly used alloy temper descriptions, see "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems." A temper or condition F refers to an aluminum alloy as it is manufactured. A temper or condition O refers to an aluminum alloy after annealing. An Hxx temper or condition, also referred to herein as H temper, refers to an aluminum alloy after cold rolling with or without heat treatment (eg, annealing). Suitable H tempers include HX1, HX2, HX3, HX4, HX5, HX6, HX7, HX8, or Hx 9 temperings. For example, aluminum alloy can be cold rolled only to result in a possible H19 temper. In a further example, the aluminum alloy can be cold rolled and annealed to result in a possible H23 temper.

The following aluminum alloys are described in terms of their elemental composition in percent by weight (% by weight) based on the total weight of the alloy. For each alloy, the remainder is aluminum, with a maximum weight% of 0.15% by the sum of the impurities.

As used herein, "electrochemical potential" refers to the susceptibility of a material to a redox reaction. The electrochemical potential can be used to evaluate the corrosion resistance of aluminum alloys described herein. A negative value can describe a material that is easier to oxidize (for example, losing electrons or increasing oxidation state) compared to a material with a positive electrochemical potential. A positive value can describe a material that is easier to reduce (eg, gain electrons or lower oxidation state) compared to a material with a negative electrochemical potential. Electrochemical potential, as used herein, is a vector quantity that expresses magnitude and direction.

As used herein, the meaning of "room temperature" can include a temperature of 15 ° C to 30 ° C, for example 15 ° C, 16 ° C, 17 ° C, 18 ° C, 19 ° C, 20 ° C, 21 ° C, 22 ° C, 23 ° C, 24 ° C, 25 ° C, 26 ° C, 27 ° C, 28 ° C, 29 ° C or 30 ° C. All ranges disclosed herein are to be understood to encompass each and every sub-range comprised therein. For example, a set range of "1 to 10" should be considered to include each and every subinterval between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subintervals that start with a minimum value of 1 or more, for example, from 1 to 6.1, and that end with a maximum value of 10 or less, for example, from 5.5 to 10,

Alloy compositions

Novel aluminum alloys are described below. In certain aspects, the alloys show high strength, resistance to corrosion and / or high formability. The properties of the alloys are achieved due to the elemental compositions of the alloys, as well as the methods of processing the alloys to produce the described sheets, plates and shates . Specifically, increased zinc (Zn) content provides alloys that preferentially corrode when bonded to copper or other aluminum alloy tubes, thus providing cathodic protection to the tubes. Surprisingly, the addition of Zn has shown an additional strengthening of solutes, in addition to the reinforcing effect of the increased magnesium (Mg) content. Additionally, an optimal Zn content has been observed. In some examples, Zn additions greater than 2.0% by weight are undesirable, as such amounts can have a detrimental effect on conductivity and self-corrosion rates. However, in some examples, it may be desirable to sacrifice those conductivity and corrosive properties to allow sufficient cathodic protection of the tube. To this end, a maximum Zn content of up to 3.0% by weight can be used to provide the desired strength, conductivity and corrosion properties.

The alloys and methods described herein can be used in industrial applications including sacrificial parts, heat dissipation, packaging, and materials of construction. The alloys described herein can be used as industrial fin raw material for heat exchangers. Industrial fin stock can be provided in a way that is more resistant to corrosion than industrial fin stock alloys (e.g. AA7072 and AA1100) and will still preferentially corrode, protecting other metal parts incorporated in a heat exchanger .

The alloys have the following elemental composition as provided in Table 1.

Table 1

In one embodiment, the alloys have the following elemental composition as provided in Table 2.

Table 2

In another embodiment, the alloys have the following elemental composition as provided in Table 3.

Table 3

In yet a further embodiment, the alloys have the following elemental composition as provided in Table 4.

Table 4

The alloy includes zinc (Zn) in an amount of 0.7% to 3.0% (for example, 1.0% to 2.5%, 1.5% to 3.0%, 0.9 % to 2.6%, or 1.4% to 1.6%) based on the total weight of the alloy. For example, the alloy may include, 84%, 1.13%,

%, %,, 72

%,

Zn. All percentages are expressed in% by weight. The zinc content can improve the corrosion resistance of the aluminum alloys described herein. Specifically, when zinc is incorporated at a level as described herein, such as 1.0% to 2.6%, the alloys exhibit greater corrosion resistance compared to the commonly used fin stock. in industrial processes (for example, 1xxx series and 7xxx series alloys). In some examples further, Zn may decrease corrosion resistance when incorporated at weight percentages exceeding those described herein. In still further examples, Zn can be incorporated into an aluminum alloy in an optimal amount, as described herein, to provide a suitable alloy for use as an industrial fin. For example, at Zn levels higher than those described herein, alloys for use as fins can corrode more rapidly than fins containing the described amount of Zn, resulting in perforations in the fin. As a result, the mechanical integrity and thermal performance of the heat exchanger can be compromised, thus affecting the life of the heat exchanger.

The disclosed alloy includes silicon (Si) in an amount of 0.15% to 0.35% (e.g., 0.20% to 0.35%, 0.17% to 0.33%, or 0.20% to 0.33%) based on the total weight of the alloy. For example, the alloy may include 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23 %, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33 %, 0.34% or 0.35% Si. All percentages are expressed in% by weight.

The alloy also includes iron (Fe) in an amount of 0.25% to 0.65% (e.g. 0.35% to 0.60%, 0.30 % to 0.55%, or 0.49 % to 0.6%) based on the total weight of the alloy. For example, the alloy may include 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33 %, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, 0.41%, 0.42%, 0.43 %, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.5%, 0.51%, 0.52%, 0.53 %, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63 %, 0.64%, or 0.65% Fe. All percentages are expressed in% by weight,

The disclosed alloy includes copper (Cu) in an amount of 0.05% to 0.20% (for example, 0.10% to 0.20%, 0.15% to 0.20%, or 0.15% to 0.19%) based on the total weight of the alloy. For example, the alloy may include 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13 %, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, or 0.2% Cu. All percentages are expressed in% by weight.

The alloy includes manganese (Mn) in an amount of 0.75% to 1.5% (for example, 0.75% to 1.25%, 0.80% to 1.00%, or 0, 79% to 0.94%) based on the total weight of the alloy. For example, the alloy may include 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, 0.81%, 0.82%, 0.83 %, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.9%, 0.91%, 0.92%, 0.93 %, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.0%, 1.01%, 1.02%, 1.03 %, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.1%, 1.11%, 1.12%, 1.13 %, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.2%, 1.21%, 1.22%, 1.23 %, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, 1.3%, 1.31%, 1.32%, 1.33 %, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39%, 1.4%, 1.41%, 1.42%, 1.43 %, 1.44%, 1.45%, 1.46%, 1.47%, 1.48%, 1.49%, or 1.5% of Mn. All percentages are expressed in% by weight.

The alloy includes magnesium (Mg) in an amount of 0.50% to 1.50% (for example, 0.90% to 1.30%, 1.00% to 1.25%, or 1, 13% to 1.27%) based on the total weight of the alloy. For example, the alloy may include 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58 %, 0.59%, 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68 %, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78 %, 0.79%, 0.8%, 0.81%, 0.82%, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88 %, 0.89%, 0.9%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98 %, 0.99%, 1.0%, 1.01%, 1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08 %, 1.09%, 1.1%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18 %, 1.19%, 1.2%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28 %, 1.29%, 1.3%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38 %, 1.39%, 1.4%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%, 1.46%, 1.47%, 1.48 %, 1.49%, or 1.5 Mg. All percentages are expressed in% by weight,

The alloy includes chromium (Cr) in an amount of up to 0.10% (for example, 0% to 0.05%, 0.001% to 0.04%, or 0.01% to 0.03%) based on the total weight of the alloy. For example, the alloy can include 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0 , 04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1% of Cr, In some cases, Cr is not present in the alloy (it is say, 0%). All percentages are expressed in% by weight.

The alloy includes titanium (Ti) in an amount up to 0.10% (for example, 0% to 0.05%, 0.001% to 0.04%, or 0.01% to 0.03%) based on the total weight of the alloy. For example, the alloy can include 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0 , 04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1% of Ti. In some cases, Ti is not present in the alloy (ie 0%). All percentages are expressed in% by weight.

Optionally, the alloy compositions may further include other minor elements, sometimes referred to as impurities, in amounts of 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less of each. These impurities can include, but are not limited to, Ga, V, Ni, Sc, Ag, B, Bi, Zr, Li, Pb, Sn, Ca, Hf, Sr, or combinations thereof. Consequently, Ga, V, Ni, Sc, Ag, B, Bi, Zr, Li, Pb, Sn, Ca, Hf or Sr can be present in an alloy in amounts of 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less. The sum of all impurities does not exceed 0.15% (eg 0.1%). All percentages are expressed in% by weight. The remaining percentage of the alloy is aluminum.

In one embodiment, the aluminum alloys described herein include 0.9-2.6% Zn (eg 1.4-1.6% Zn), 0.2-0.33% Si 0.49 - 0.6% Fe, 0.15 - 0.19% Cu, 0.79 - 0.94% Mn, 1.13 - 1.27% Mg, up to 0.05% Cr, up to 0.05% Ti, and up to 0.15% impurities, with the balance being Al. For example, an exemplary alloy includes 1.53% Zn, 0.3% Si, 0.51% Fe, 0.17% Cu, 0.87% Mn, 1.21% Mg, 0.001% Cr, 0.016% Ti, and up to 0.15% total impurities, with the remainder as Al. In some examples, an exemplary alloy includes 1.00% Zn, 0.29% Si, 0.51% Fe, 0.16% Cu, 0.86% Mn , 1.2% Mg, 0.001% Cr, 0.011% Ti, and up to 0.15% total impurities, with the remainder being Al. In some examples, an exemplary alloy includes 2.04% Zn, 0.29% Si, 0.51% Fe, 0.17% Cu, 0.87% Mn, 1.21% Mg, 0.001% Cr, 0.015% Ti, and up to 0.15% impurity total s, with the remainder as Al. In some examples, an exemplary alloy includes 2.54% Zn, 0.29% Si, 0.51% Fe, 0.17% Cu, 0, 88% Mn, 1.23% Mg, 0.001% Cr, 0.012% Ti, and up to 0.15% total impurities, with the remainder being Al.

Alloy properties

The mechanical properties of the aluminum alloy can be controlled by various processing conditions depending on the intended use. The alloy may be produced (or provided) in an H temper (eg, HX1, HX2, HX3, HX4, HX5, HX6, Hx 7, hX8, or HX9 tempers). As an example, the alloy can be produced (or provided) in the H19 temper. H19 temper refers to products that are cold rolled. As another example, the alloy can be produced (or provided) in the H23 temper. H23 tempering refers to products that are cold rolled and partially annealed. As a further example, the alloy may be produced (or provided) in the O-temper. O-temper refers to products that are cold rolled and fully annealed.

In some non-limiting examples, the disclosed alloys have high strength in H temperings (eg, H19 temper and H23 temper) and high formability (that is, flexibility) in O temper. In some non-limiting examples, the alloys disclosed have good corrosion resistance in H tempering (eg H19 tempering and H23 tempering), and O tempering compared to conventional 7xxx and 1xxx series aluminum alloys employed as industrial fin raw material.

In certain aspects, aluminum alloys can have a yield strength (YS) of at least 70 MPa. In non-limiting examples, the elastic limit is at least 70 MPa, at least 80 MPa, at least 90 MPa, at least 100

MPa, at least 110 MPa, at least 120 MPa, at least 130 MPa, at least 140 MPa, at least 150 MPa, at least

160 MPa, at least 170 MPa, at least 180 MPa, at least 190 MPa, at least 200 MPa, at least 210 MPa, at least 220 MPa, at least 230 MPa, at least 240 MPa, at least 250 MPa, at least 260 MPa, at least 270 MPa, at least 280 MPa, at least 290 MPa, at least 300 MPa, at least 310 MPa, at least 320 MPa, at least 330 MPa, at least 340 MPa, at least 350 MPa or any between the same. In some cases, the elastic limit is 70 MPa to 350 MPa. For example, the yield strength can be 80 MPa to 340 MPa, 90 MPa to 320 MPa, 100 MPa to 300 MPa, 180 MPa to 300 MPa, or 200 MPa to 300 MPa.

The yield strength will vary based on the temper of the alloys. In some examples, the alloys described herein provided in an O temper may have a yield strength of at least 70 MPa to 200 MPa.

In non-limiting examples, the elastic limit of O-temper alloys is at least 70 MPa, at least 80 MPa, at least 90 MPa, at least 100 MPa, at least 110 MPa, at least 120 MPa, at least 130 MPa, at least 140 MPa, at least 150 MPa, at least 160 MPa, at least 170 MPa, at least 180 MPa, at least 190 MPa, at least 200 MPa or any one of the same.

In some additional examples, the alloys described herein in an H temper may have a yield strength of at least 200 MPa, at least 210 MPa, at least 220 MPa, at least 230 MPa, at least 240

MPa, at least 250 MPa, at least 260 MPa, at least 270 MPa, at least 280 MPa, at least 290 MPa, at least

300 MPa, at least 310 MPa, at least 320 MPa, at least 330 MPa, at least 340 MPa, at least 350 MPa or any of the same.

In certain aspects, aluminum alloys can have a tensile breaking strength (UTS) of at least 170 MPa. In non-limiting examples, the UTS is at least 170 MPa, at least 180 MPa, at least 190 MPa, at least 200 MPa, at least 210 MPa, at least 220 MPa, at least 230 MPa, at least 240 MPa, at least 250 MPa, at least 260 MPa, at least 270 MPa, at least 280 MPa, at least 290 MPa, at least 300 MPa, at least 310

MPa, at least 320 MPa, at least 330 MPa, at least 340 MPa, at least 350 MPa or any of the same.

In some cases, the UTS is 200 MPa to 320 MPa. For example, the UTS can be 200 MPa to 320 MPa, 190

MPa to 290 MPa, 300 MPa to 350 MPa, 180 MPa to 340 MPa, or 175 MPa to 325 MPa.

In some examples, the alloys described herein provided in an OR temper may have a UTS of at least 170 MPa to 250 MPa. In non-limiting examples, the UTS of the alloys in temper O is at least 170 MPa, at least 180 MPa, at least 190 MPa, at least 200 MPa, at least 210 MPa, at least 220 MPa, at least 230 MPa, at least minus 240 MPa, at least 250 MPa or whichever between them.

In some further examples, the alloys described herein in an H temper may have a UTS of at least 200 MPa, at least 210 MPa, at least 220 MPa, at least 230 MPa, at least 240 MPa, at least 250 MPa. , at least 260 MPa, at least 270 MPa, at least 280 MPa, at least 290 MPa, at least 300 MPa, at least 310 MPa, at least 320 MPa, at least 330 MPa, at least 340 MPa, at least 350 MPa or anyone among them.

In certain aspects, the alloy encompasses any yield strength that has sufficient formability to achieve an elongation of 9.75% or greater at O temper (eg, 10.0% or greater). In some examples, the elongation may be 9.75% or greater, 10.0% or greater, 10.25% or greater, 10.5% or greater, 10.75% or greater, 11.0%

or greater, 11.25% or greater, 11.5% or greater, 11.75% or greater, 12.0% or greater, 12.25% or greater, 12.5% or greater,

12.75% or greater, 13.0% or greater, 13.25% or greater, 13.5% or greater, 13.75% or greater, 14.0% or greater, 14.25% or greater, 14 , 5% or greater, 14.75% or greater, 15.0% or greater, 15.25% or greater, 15.5% or greater, 15.75% or greater, 16.0

% or greater, 16.25% or greater, 16.5% or greater, or any of the same.

In certain aspects, the alloy may have a corrosion resistance that provides a negative corrosion potential or electrochemical potential (Ecorr) of approximately -700 mV or less when subjected to

tested according to ASTM G69. In certain cases, a standard calomel electrode (SCE) open corrosion potential value can be -700 mV or less, -710 mV or less, -720 mV or less, -730 mV or less, -740 mV or less, -750 mV or less, -760 mV or less, -770 mV or less, -780 mV or less, -790 mV or less, -800 mV or less, -810 mV or less, -820 mV or less or less, -830 mV or less, -840 mV or less, -850 mV or less, or any between them. For example, aluminum alloy may have an open corrosion potential of -740 mV to -850 mV (eg, -750 mV to -840 mV or -770 mV to -830 mV).

In some examples, the alloy may have an average conductivity value above 36% based on the International Annealed Copper Standard (IACS) (for example, 37% IACS to 44% IACS). For example, the alloy may have an average conductivity value of 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, or anything in between. All values in% IACS.

Preparation and processing methods

In certain aspects, the disclosed alloy composition is a product of a disclosed method. Without intending to limit the disclosure, aluminum alloy properties are partially determined by the formation of microstructures during alloy preparation. In certain aspects, the method of preparation for an alloy composition can influence or even determine whether the alloy will have suitable properties for a desired application.

Wash

The alloy described herein can be cast using a casting method known to those of skill in the art. For example, the casting process may include a direct cooling (DC) casting process. The Dc casting process is performed according to standards commonly used in the aluminum industry as is known to one of ordinary skill in the art. The DC process can provide an ingot. Optionally, the ingot can be flaked prior to subsequent processing. Optionally, the casting process can include a continuous casting (CC) process.

The cast aluminum alloy can then undergo additional processing steps. For example, processing methods as described herein may include the steps of homogenization, hot rolling, cold rolling, and / or annealing.

Homogenization

The homogenization step may include heating a cast aluminum alloy as described herein to achieve a homogenization temperature of or at least 570 ° C (e.g., at least 570 ° C, at least 580 ° C, at least 590 ° C, at least 600 ° C, at least 610 ° C, or whatever between them). For example, cast aluminum alloy can be heated to a temperature of 570 ° C to 620 ° C, 575 ° C to 615 ° C, 585 ° C to 610 ° C, or 590 ° C to 605 ° C. In some cases, the heating rate at homogenization temperature can be 100 ° C / hour or less, 75 ° C / hour or less, 50 ° C / hour or less, 40 ° C / hour or less, 30 ° C / hour or less, 25 ° C / hour or less, 20 ° C / hour or less, 15 ° C / hour or less, or 10 ° C / hour or less. In other cases, the rate of heating to homogenization temperature can be 10 ° C / min to 100 ° C / min (for example, 10 ° C / min to 90 ° C / min, 10 ° C / min at 70 ° C / min, from 10 ° C / min to 60 ° C / min, from 20 ° C / min to 90 ° C / min, from 30 ° C / min to 80 ° C / min, from 40 ° C / min at 70 ° C / min, or from 50 ° C / min to 60 ° C / min).

The cast aluminum alloy is then allowed to be held at a specified temperature (ie, held at the stated temperature) for a period of time. According to a non-limiting example, the cast aluminum alloy is then allowed to hold at a specified temperature for up to 5 hours (eg, 10 minutes to 5 hours, inclusive). For example, the cast aluminum alloy can be kept at a temperature of at least 570 ° C for 10 minutes, 20 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or whatever in between.

The cast aluminum alloy can be cooled from the first temperature to a second temperature that is lower than the first temperature. In some examples, the second temperature is greater than 555 ° C (for example, greater than 560 ° C, greater than 565 ° C, greater than 570 ° C, or greater than 575 ° C). For example, cast aluminum alloy can be cooled to a second temperature of 555 ° C to about 590 ° C, 560 ° C to 575 ° C, 565 ° C to 580 ° C, 570 ° C to 585 ° C. , from 565 ° C to 570 ° C, from 570 ° C to 590 ° C, or from 575 ° C to 585 ° C. The cooling rate at the second temperature can be 10 ° C / min to 100 ° C / min (for example, 20 ° C / min to 90 ° C / min, 30 ° C / min to 80 ° C / min, 10 ° C / min to 90 ° C / min, 10 ° C / min to 70 ° C / min, 10 ° C / min to 60 ° C / min, 40 ° C / min to 70 ° C / min or from 50 ° C / min to 60 ° C / min).

The cast aluminum alloy can then be allowed to hold at the second temperature for a period of time. In some cases, the ingot is allowed to hold at a specified temperature for up to 5 hours (eg, 10 minutes to 5 hours, inclusive). For example, the ingot can be kept at a temperature of 560 ° C to 590 ° C for 10 minutes, 20 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours or any in between.

Hot rolling

After the homogenization step, a hot rolling step can be performed. In certain cases, cast aluminum alloys are hot rolled with a hot rolling mill inlet temperature range of 560 ° C to 600 ° C. For example, the inlet temperature can be 560 ° C, 565 ° C, 570 ° C, 575 ° C, 580 ° C, 585 ° C, 590 ° C, 595 ° C, or 600 ° C. In certain cases, the hot rolling outlet temperature can range from 290 ° C to 350 ° C (eg 310 ° C to 340 ° C). For example, the hot rolling outlet temperature can be 290 ° C, 295 ° C, 300 ° C, 305 ° C, 310 ° C, 315 ° C, 320 ° C, 325 ° C, 330 ° C, 335 ° C, 340 ° C, 345 ° C, 350 ° C or any of the same.

In certain cases, the cast aluminum alloy may be hot rolled to a thickness gauge of 2mm to 15mm (eg 2.5mm to 12mm gauge). For example, cast aluminum alloy can be hot rolled to 2mm thickness gauge, 2.5mm thickness gauge, 3mm thickness gauge, 3.5mm thickness gauge, 3.5mm thickness gauge, 4mm, 5mm thickness gauge, 6mm thickness gauge, 7mm thickness gauge, 8mm thickness gauge, 9mm thickness gauge, approximately 10mm thickness gauge, approximately gauge 11mm thick, about 12mm thickness gauge, 13mm thickness gauge, 14mm thickness gauge or 15mm thickness gauge. In certain cases, the cast aluminum alloy can be hot rolled to a gauge greater than 15mm (ie a plate). In other cases, the cast aluminum alloy may be hot rolled to a gauge of less than 4mm (ie one sheet).

Cold rolling

A cold rolling step can be carried out after the hot rolling step. In certain aspects, the rolled product from the hot rolling step can be cold rolled to a sheet (eg, below 4.0mm). In certain aspects, the rolled product is cold rolled to a thickness of 0.4mm to 1.0mm, 1.0mm to 3.0mm, or 3.0mm to less than 4.0mm. In certain aspects, the alloy is cold rolled to 3.5mm or less, 3mm or less, 2.5mm or less, 2mm or less, 1.5mm or less, 1mm or less, 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less. For example, the rolled product can be cold rolled to 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm , 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm , 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm , 2.9mm, 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm , 3.9mm, 4.0mm, or any of these.

In one case, the aluminum alloy processing method described herein may include the following steps. A homogenization step can be performed by heating a cast aluminum alloy as described herein to achieve a homogenization temperature of 590 ° C for a period of time of approximately 12 hours, in which cast aluminum alloys are allowed. which are kept at a temperature of 590 ° C for approximately 2 hours. The cast aluminum alloys can then be cooled to 580 ° C and allowed to stand for 2 hours at 580 ° C. The cast aluminum alloys can then be hot rolled to a gauge of 2.5mm thick. Cast aluminum alloys can be cold rolled to a gauge of less than 1.0 mm thick (eg, 1.0 mm or less or 0.15 mm or less), providing an aluminum alloy sheet.

Annealing

Optionally, the aluminum alloy sheet can be annealed by heating the sheet from room temperature to an annealing temperature of 200 ° C to 400 ° C (e.g. 210 ° C to 375 ° C, 220 ° C to 350 ° C , 225 ° C to 345 ° C, or 250 ° C to 320 ° C). In some cases, the heating rate at the annealing temperature can be 100 ° C / hour or less, 75 ° C / hour or less, 50 ° C / hour or less, 40 ° C / hour or less, 30 ° C / hour or less, 25 ° C / hour or less, 20 ° C / hour or less, 15 ° C / hour or less, or 10 ° C / hour or less. The sheet can be kept at temperature for a period of time. In certain aspects, the sheet is allowed to hold at a certain temperature for up to about 6 hours (eg, 10 seconds to 6 hours, inclusive). For example, the sheet can be kept at a temperature of 230 ° C to 370 ° C for 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, 85 seconds, 90 seconds, 95 seconds, 100 seconds, 105 seconds, 110 seconds, 115 seconds, 120 seconds, 125 seconds, 130 seconds, 135 seconds, 140 seconds, 145 seconds, 150 seconds, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes , 90 minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, 120 minutes, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours , 6 hours or any between them. In some examples, the sheet is not annealed.

In some examples, the sheet is heated to an annealing temperature of 200 ° C to 400 ° C at a constant rate of 40 ° C / hour to 50 ° C / hour. In some respects, the sheet is allowed to hold at annealing temperature for 3 hours to 5 hours (for example, for 4 hours). In some cases, the sheet is cooled from the annealing temperature at a constant rate of 40 ° C / hour to 50 ° C / hour. In some examples, the sheet is not annealed.

Methods of use

The alloys and methods described herein can be used in industrial applications including sacrificial parts, heat dissipation, packaging, and materials of construction. The alloys described herein can be used as industrial fin raw material for heat exchangers. The industrial fin stock can be provided in a manner that is more resistant to corrosion than currently employed industrial fin stock alloys (e.g. AA7072 and AA1100) and will still preferentially corrode while protecting other metal parts incorporated in a heat exchanger. hot. The aluminum alloys disclosed herein are suitable substitutes for metals conventionally used in indoor and outdoor HVAC units. As used herein, the meaning of "indoor" refers to a placement contained within any human-produced structure with controlled environmental conditions. As used herein, the meaning of "outdoor" refers to a placement not fully contained in any human-made structure and exposed to geological and meteorological environmental conditions including air, solar radiation, wind, rain, sleet. , snow, freezing rain, ice, hail, dust storms, humidity, aridity, smoke (for example, tobacco smoke, smoke from household fires, smoke from industrial incinerators and smoke from wild fires), pollution, combustible exhaust substances fossils, biofuel exhaust substances, salts (for example, air with high salt content in regions close to a salt water body), radioactivity, electromagnetic waves, corrosive gases, corrosive liquids, galvanic metals, galvanic alloys, corrosive solids, plasma, fire, electrostatic discharge (for example, lightning), biological materials (for example, animal waste, saliva, excreted oils , vegetation), particles blown by the wind, change in barometric pressure and change in daytime temperature. The aluminum alloys described herein provide improved corrosion performance and strength compared to currently used alloys.

The following examples will serve to further illustrate the present invention without, however, constituting any limitation thereof. During the studies described in the following examples, standard procedures were followed, unless otherwise indicated. Some of the procedures are described below for illustrative purposes.

Examples

Example 1: Mechanical properties

Exemplary and comparative alloys were prepared, as shown in Table 5, according to the methods described herein. Alloys 1, 2, 3 and 4 are exemplary alloys created according to methods described herein. Alloy 5 is a comparative alloy prepared according to methods described herein. Alloy A is type AA7072, which is currently used as an industrial fin raw material in commercial applications. Alloy B is type AA1100, which is currently used as an industrial fin raw material in commercial applications.

Table 5

All expressed as% by weight

The mechanical properties of exemplary alloys and comparative alloys were determined according to ASTM B557. Specifically, the alloys were subjected to tensile, elongation, and conductivity tests. Yield strength (YS), tensile breaking strength (UTS), percentage elongation (IE) and percentage of international annealed copper standard (% IACS) were determined. The results of the tests are summarized in Table 6.

Table 6

Alloy Gauge YS UTS EI% IACS YS UTS IE% IACS YS UTS EI% IACS

* Comp. B tempered was in H22 temper during testing.

The excellent strength of the exemplary alloys compared to alloys currently used as industrial fin raw material is evident from the tensile test results. The exemplary alloys had an average conductivity of approximately 37-44% IACS. As shown above in Table 6, the exemplary alloys described herein exhibit exceptional mechanical properties compared to comparative alloys and can be excellent commercial alloys used in industrial fin feedstock applications.

Example 2: Corrosion properties

The corrosion properties of the exemplary alloys described herein and the comparative alloys described herein, elemental compositions of which are provided in Table 5 were determined. In addition, the corrosion properties of two additional comparative tube alloys. Comparative Alloy C is an aluminum tube alloy containing 0.15% by weight of Zn and Comparative Alloy D is a type AA1235 aluminum alloy commonly used in heat exchangers. Open circuit corrosion potential values were measured according to ASTM G69. Corrosion test results are summarized in Table 7. Comparative Alloy C and Comparative Alloy D aluminum tube alloys had an average open corrosion potential value versus SCE of -741mV.

Table 7

* AA1100 alloy tempered was in H22 temper during testing.

The differences in corrosion resistance values between Alloys 1-5 and Comparative Alloy C are shown below in Table 8.

Table 8

The differences in corrosion resistance values between Alloys 1-5 and Comparative Alloy D are shown below in Table 9.

Table 9

The exemplary alloys in all temperings (eg, H19, H23, and O) exhibited comparable electrochemical potential values to comparative alloys. The differences between alloys 1-5 and comparative alloy C and between alloys 1-5 and comparative alloy D ranged from 15-80 mV. The data show that alloys 2, 3, 4 and 5 are acceptable for preparing fins that act as sacrificial anodes.

Exemplary alloys with variable Zn subjected to electrochemical corrosion tests also showed a near linear correlation between Zn content and electrochemical potential. On average, a 0.1 wt% increase in Zn provided an approximately 9 mV increase in electrochemical potential. Exemplary alloys with a Zn content of about 2.5% by weight or greater exhibited a more negative corrosion potential, indicating that incorporation of Zn greater than about 2.5% by weight may not be desirable to achieve certain properties. Zn can be optimally added to be corrosion resistant enough to serve as a sacrificial alloy in a heat exchanger but still preferably corrode earlier than any primary functional metal part of a heat exchanger, further suggesting that alloys as Examples described herein are excellent replacements for alloys currently used in industrial fin stock.

Corrosion properties of the exemplary alloys described herein and the comparative alloys described herein were also determined according to ASTM G71. Specifically, the corrosion properties were measured using zero resistance amperometry (ZRA). The galvanic compatibility of ZRA was measured where the exemplary alloys were used as the fin stock and Comparative Alloy C and Comparative Alloy D was used as the tube stock. The results shown in Tables 10 and 11 represent the average current for the last four hours of the cycle as performed according to the test method. Table 10 shows the ZRA results for alloys 1-5 galvanically coupled to comparative alloy C.

Table 10

As shown in Table 10, alloys 1, 2, 3, and 4, containing 1 to 2.5% by weight of Zn, exhibited a positive corrosion current indicating that exemplary fin alloys provided sacrificial protection to tube alloys.

Table 11 shows the ZRA results for alloys 1-5 galvanically coupled to comparative alloy D.

Table 11

As shown in Table 11, alloys 1, 2, 3 and 4, containing 1 to 2.5 % by weight of Zn, exhibited lower corrosion currents than exemplary alloys coupled with the comparative alloy. C, but still provided sacrificial protection to the tube alloy. All exemplary fin alloys showed that a shield current was being provided to the comparative alloy C and comparative alloy D tubes throughout the test period.

The compatibilities of exemplary fin alloys bonded to Comparative Alloy C and Comparative Alloy D tube alloys were also evaluated according to ASTM G85 Annex 3. Synthetic seawater, acidified to 2.8 - 3.0, was used pH. The exemplary fin samples were mechanically assembled to the tube alloys and corroded over a 4 week exposure. As shown in Figures 1 and 2, the samples showed progressively more corrosion on the exemplary alloys, as the zinc content increased from 2% to 2 5%. This is particularly true for the exemplary alloys coupled to comparative alloy D. Based on these data, Zn levels less than 2% by weight are preferred in some cases, but can be optimized depending on the tube composition.

The aluminum alloys described herein provide sacrificial corrosion characteristics and mechanical characteristics that allow the fabrication of reduced metal thickness aluminum alloy fin stock. The reduced metal fin stock thickness maintains sacrificial protection for copper or aluminum alloy tubes in contact with the fins. The aluminum alloys described herein can also be used in other situations where mechanical strength is desired in combination with sacrificial characteristics.

Claims (13)

i. Aluminum alloy comprising 0.7 - 3.0% by weight of Zn, 0.15 - 0.35% by weight of Si, 0.25 - 0.65% by weight of Fe, 0.05 - 0, 20% by weight of Cu, 0.75 - 1.50% by weight of Mn, 0.50 - 1.50% by weight of Mg, up to 0.10% by weight of Cr, up to 0.10% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder as Al. 2. Aluminum alloy according to claim 1, comprising 1.0-2.5% by weight of Zn, 0.2-0.35% by weight of Si, 0.35-0.60% by weight of Fe 0.10-0.20% by weight of Cu, 0.75-1.25% by weight of Mn, 0.90-1.30% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder being Al. Aluminum alloy according to claim 1, comprising 1.5-2.5% by weight of Zn, 0.17-0.33% by weight of Si, 0.30-0.55% by weight of Fe , 0.15-0.20% by weight of Cu, 0.80-1.00% by weight of Mn, 1.00-1.25% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder being Al. Aluminum alloy according to claim 1, comprising 0.9-2.6% by weight of Zn, 0.2-0.33% by weight of Si, 0.49-0.6% by weight of Fe 0.15 - 0.19% by weight of Cu, 0.79 - 0.94% by weight of Mn, 1.13-1.27% by weight of Mg, up to 0.05% by weight of Cr, up to 0 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder as Al. 5. Aluminum alloy according to claim 1, comprising 1.4-1.6% by weight of Zn, 0.2-0.33% by weight of Si, 0.49-0.6% by weight of Fe 0.15 - 0.19% by weight of Cu, 0.79 - 0.94% by weight of Mn, 1.13-1.27% by weight of Mg, up to 0.05% by weight of Cr, up to 0 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the remainder as Al. Fin raw material comprising the aluminum alloy of any of claims 1-5. Fin raw material according to claim 6, wherein a gauge of the fin raw material is 1.0 mm or less. Fin stock according to claim 6, wherein a gauge of the fin stock is 0.15mm or less. 9. An article comprising a tube and a fin, wherein the fin comprises the fin raw material according to any of claims 6-8. 10. Method of production of a metallic product, comprising: casting an aluminum alloy to form a cast aluminum alloy, wherein the aluminum alloy comprises 0.7 - 3.0% by weight of Zn, 0.15 - 0.35% by weight of Si, 0.25 - 0.65% by weight of Fe, 0.05 - 0.20% by weight of Cu, 0.75 - 1.50% by weight of Mn, 0.50 - 1.50% by weight of Mg, up to 0.05% by weight of Cr, up to 0.05% by weight of Ti, and up to 0.15% by weight of impurities, with the balance being Al; homogenize the cast aluminum alloy; hot rolling the cast aluminum alloy to produce a rolled product; and Cold roll the rolled product to a final gauge product. The method of claim 10, further comprising annealing the final gauge product. 12. Aluminum alloy product, wherein the aluminum alloy product is prepared by the method according to claim 10 or 11. An aluminum alloy product according to claim 12, wherein the aluminum alloy product comprises a heat exchanger fin.