JP2023061968A - Aluminum alloy for heat exchanger fins - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy for heat exchanger fins which reduces the thickness of a fin material and allows the fin to have high conductivity and excellent corrosion performance.

SOLUTION: An aluminum alloy fin stock material comprises about 0.9-1.4 wt.% of Si, 0.3-0.6 wt.% of Fe, 0.20-0.60 wt.% of Cu, 1.0-1.7 wt.% of Mn, 0.01-0.25 wt.% of Mg, 0.01-3.0 wt.% of Zn, and up to 0.10 wt.% of Ti, with the remainder being 0.15 wt.% or less of Al and impurities. The aluminum alloy fin stock material is produced by a process including the steps of: direct-chill-casting an ingot; hot-rolling the ingot after the casting; cold-rolling the aluminum alloy to an intermediate thickness; inter-annealing the cold-rolled aluminum alloy at a temperature of 200-400°C, and cold-rolling the material after the inter-annealing to achieve the % cold work (% CW) of 20-40%.

SELECTED DRAWING: Figure 1A

COPYRIGHT: (C)2023,JPO&INPIT

Description

PRIORITY CLAIM This application claims priority to US Provisional Application No. 62/727,806, filed September 6, 2018, the entirety of which is incorporated herein by reference.

The present invention relates to the fields of materials science, materials chemistry, metallurgy, aluminum alloys, aluminum fabrication, and related fields. The present invention provides novel aluminum alloys for use in the production of heat exchanger fins, which are useful in various heat exchanger devices such as automotive radiators, condensers, evaporators and related applications. used by the device.

The automotive heat exchanger industry places several demands on the aluminum material used in the production of heat exchanger fins (“fin stock”). Balancing these demands can be difficult. There is a need for an aluminum alloy fin stock that has high strength in both pre-braze and post-braze conditions, improved sag resistance implying good behavior during braze, and reduced fin erosion. . In order to reduce the weight of automobiles, it is desirable to reduce the size and weight of automobile heat exchangers to save resources and energy. Various methods have been investigated to achieve this goal, and one of the desirable solutions is to reduce the thickness of the aluminum fin stock. In order to reduce the thickness of the fin material, it is important to increase the strength after brazing and ensure sufficient brazeability. At the same time, heat exchanger fins must have high electrical conductivity and excellent corrosion performance compared to other heat exchanger components. For example, the heat exchanger fins may be more anodic than the heat exchanger tube stock, so that the fins act sacrificially. A desirable aluminum fin material would possess properties and parameters that balance the above requirements.

Embodiments of the inventive subject matter are defined by the claims, rather than by this summary. This summary is a high-level overview of various aspects of the invention and introduces some concepts that are further described in the Detailed Description section below. This summary is not intended to identify key features or critical features of the claimed subject matter, nor is it intended to be used in isolation in determining the scope of the claimed subject matter. do not have. The subject matter should be understood by reference to the entire specification, any or all drawings, and appropriate portions of each claim.

It has the required thickness (gauge) combination, can withstand brazing, has suitable mechanical properties before, during and after brazing, strength and strength suitable for high performance heat exchanger applications. It would be desirable to produce an aluminum fin stock that would exhibit conductive properties and a suitable corrosion potential. Further, it is desirable to produce aluminum fin stock from input metals that incorporate scrap aluminum in order to produce fin stock in an environmentally friendly and cost effective manner. Disclosed is an improved aluminum alloy fin stock possessing a combination of features and properties that make it suitable for the production of heat exchanger fins used, for example, in heat exchangers such as those used in the automotive industry. It is In one example, the improved aluminum alloy fin stock can be produced in sheet form at a desired thickness (gauge) suitable for the production of lightweight heat exchanger units. Aluminum alloy fin stocks are brazeable and exhibit strength characteristics before, during, and after brazing that make them attractive for automotive heat exchanger applications. More specifically, the disclosed improved aluminum alloy fin stock possesses pre-braze strength characteristics that reduce fin crushing problems during brazing. The disclosed aluminum alloy fin stock also possesses a sufficiently high thermal conductivity to be suitable for heat exchanger applications and is negative enough for the fins to act sacrificially during heat exchanger corrosion. It has a corrosion potential. In summary, the improved aluminum alloy fin stock has one or more of the following properties: high strength, desirable post-braze mechanical properties, desirable sag resistance, desirable corrosion resistance, and desirable electrical conductivity. At the same time, the aluminum alloy fin stock can be produced at least partially from input aluminum suitable for recycling. More specifically, the improved aluminum alloy fin stock contains a level of non-aluminum constituents, such as Cu, Fe, Mn, and Zn, which is within certain scrap aluminum as input metals. compatible with the levels of these elements found.

The disclosed aluminum alloy fin stock is produced in sheet form, plate form, or sheet form. A process for producing an improved aluminum alloy fin stock that incorporates one or more of casting, rolling, or annealing steps is also disclosed. In some cases, the process steps employed during the production of the improved aluminum alloy fin stock impart beneficial properties and characteristics to the material. In one exemplary process, improved aluminum alloy fin stock is produced by using one or more cold rolling steps. Each of the cold rolling steps may involve multiple cold rolling passes. A cold rolling step may be characterized by an achieved "cold work %" or "CW %". In order to achieve the required strength range of the aluminum alloy fin stock, it may be desirable to achieve a specified range or value of percent CW. In one example, an aluminum alloy fin stock may be produced by a process involving direct chill casting and cold working (cold rolling) to produce the desired pre-braze temper, such as the H14 temper. In other examples, the improved fin aluminum alloy material can be produced in various other strain hardened pre-braze tempers, such as H16, H18, or other H1X tempers. The process for producing aluminum alloy fin stock also includes hot rolling after direct chill casting, and intermediate annealing before the final cold rolling step (e.g., between the intermediate cold rolling step and the final cold rolling step). ). The term "intermediate annealing (IA)" refers to a heat treatment applied between cold rolling steps. The IA temperature can affect the properties of the aluminum fin material. For example, by lowering the IA temperature from 400° C. to 350° C., the grain size after brazing becomes coarser. The combination of percent CW and IA temperature used in this production, along with other factors such as the composition of the aluminum alloy, provide the desired properties.

The disclosed aluminum alloy fin stock can be used in a variety of applications, such as making fins for heat exchangers. In some cases, improved aluminum alloy fin stocks are useful for high performance, lightweight automotive heat exchangers. As some non-limiting examples, the aluminum alloy fin stock may be used in automotive heat exchangers such as radiators, condensers, and evaporators. However, the use and applications of the improved aluminum alloy fin stock are not limited to automotive heat exchangers, and the features and properties of the aluminum alloy fin stock are useful for uses other than the production of automotive heat exchanger fins. and other applications are envisioned. For example, improved aluminum alloy fin stock is used in heat exchangers and manufactured by brazing devices such as those used in heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems. can be used for

As noted above, compositions and processes for producing improved aluminum alloy fin stocks result in materials that possess a combination of beneficial characteristics and properties that make them suitable for the manufacture of heat exchanger fins. . For example, an aluminum alloy fin material may have one or more of the following characteristics: pre-braze and post-braze mechanical properties such as tensile strength, post-braze sag resistance, thermal conductivity, and corrosion potential. shows a beneficial combination of An example is about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt%. weight percent Mn, about 0.01-0.25 weight percent Mg, about 0.1-3.0 weight percent Zn, and up to about 0.10 weight percent Ti, with the remaining Al and impurities being It is an aluminum alloy with a content of 0.15% by weight or less. Another example is about 0.9-1.35 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1 .7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn, and up to about 0.10 wt% Ti, with the balance being Al and Impurities are aluminum alloys with less than 0.15% by weight. Another example is about 0.9-1.4 wt% Si, about 0.35-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1 wt% .7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn, and up to about 0.10 wt% Ti, with the balance being Al and Impurities are aluminum alloys with less than 0.15% by weight. Some other examples are: about 0.9-1.2 wt% Si, 0.3-0.6 wt% Fe, 0.40-0.55 wt% Cu, 1.0-1.7 wt.% Mn, 0.01-0.1 wt.% Mg, and 0.1-3.0 wt.% Zn, with the balance of Al and impurities being 0.15 wt.% Aluminum alloys that are: about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.1- 1.60 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn, and up to 0.10 wt% Ti, with the balance Al and An aluminum alloy with no more than 0.15 wt.% impurities; about 0.9-1.4 wt.% Si, about 0.3-0.6 wt.% Fe, about 0.20-0.60 wt.% Cu, about 1.0-1.7 wt% Mn, about 0.05-0.2 wt% Mg, about 0.1-3.0 wt% Zn, and up to about 0.10 wt% An aluminum alloy containing Ti with the balance of Al and impurities not more than 0.15 wt.%; 20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt% Mg, about 1-3.0 wt% Zn, and up to about Aluminum alloy containing 0.10 wt.% Ti, with the remaining Al and impurities not exceeding 0.15 wt.%; about 0.9-1.4 wt.% Si, about 0.3-0.6 wt.% of Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt% Mg, about 1.5-2.75 wt% An aluminum alloy containing wt.% Zn and up to about 0.10 wt.% Ti, with the balance of Al and impurities not more than 0.15 wt.%. In the disclosed aluminum alloys, one or more of Zr, V, Cr or Ni is less than 0.05 wt%, less than 0.04 wt%, less than 0.03 wt%, less than 0.02 wt%, or may be present at less than 0.01% by weight. In some cases, one or more of Zr, V, Cr, or Ni is absent (ie, 0 wt%).

In some examples, the disclosed aluminum alloys have an ultimate tensile strength of at least 200 MPa when measured in a pre-braze state and/or at least 150 MPa when measured after braze. can have strength. In one example, the ultimate tensile strength of the aluminum alloy is 200-230 MPa when measured in the pre-braze state and/or greater than 170 MPa when measured after brazing. can have Aluminum alloys can have a corrosion potential of -760 mV or less when measured after brazing. Aluminum alloys can have a thermal conductivity greater than 40% (International Annealed Copper Standard, assuming 100% pure copper conductivity) when measured after brazing.

The disclosed aluminum alloys can be produced by processes including: Directly chill casting the aluminum alloy into an ingot; hot rolling the ingot after direct chill casting; after hot rolling, cold rolling the aluminum alloy to intermediate thickness; after cold rolling, 200°C and 400°C Intermediate annealing the aluminum alloy rolled to intermediate thickness at a temperature between (200-400° C.); ), resulting in a sheet having a thickness of 45-100 μm, 45-90 μm, 47-85 μm, or 50-83 μm. A further process can use continuous casting. The CW% achieved with the above process can be 30-40%. Intermediate annealing is between 320°C and 370°C (320-370°C), between 290°C and 360°C (290-360°C), or between 340°C and 360°C (340-360°C). temperature. Intermediate annealing times can be from 30 minutes to 60 minutes. A heat exchanger containing the improved aluminum alloy is also disclosed. The heat exchanger may be an automotive heat exchanger. A heat exchanger can be a radiator, condenser, or evaporator. Also disclosed are processes for making objects and devices comprising the improved alloys. One example of such a process is the process of making a heat exchanger, which comprises brazing at least one first aluminum alloy form made from the improved aluminum alloy with a second aluminum alloy form. assembling and securing the two or more aluminum forms together and joining the two or more aluminum forms until a joint is formed between the two or more aluminum forms by capillary action. to brazing temperature. It is also within the scope of this description to use the improved aluminum alloys to fabricate heat exchanger fins and other objects and devices. Other objects, features, and advantages of the present invention will become apparent from the detailed description below.

1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain size of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure prior to brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after standard brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 1 is a photograph showing the grain structure of an aluminum alloy sample prepared according to the present disclosure after high speed brazing; 4A-D show the effect of % cold working and intermediate annealing on different properties of aluminum alloy samples prepared according to the present disclosure. AD are photographs showing the grain structure of aluminum alloy samples prepared according to the present disclosure and subjected to standard brazing. AD are photographs showing the grain structure of aluminum alloy samples prepared according to the present disclosure and subjected to standard brazing. AD are photographs showing the grain structure of aluminum alloy samples prepared according to the present disclosure and subjected to high speed brazing. AD are photographs showing the grain structure of aluminum alloy samples prepared according to the present disclosure and subjected to high speed brazing. 1 is a photograph showing corrosion test results of coupons containing aluminum alloy samples prepared according to the present disclosure; 1 is a photograph showing corrosion test results of coupons containing aluminum alloy samples prepared according to the present disclosure; 1 is a photograph showing corrosion test results of coupons containing aluminum alloy samples prepared according to the present disclosure; 1 is a photograph showing corrosion test results of coupons containing aluminum alloy samples prepared according to the present disclosure; 1 is a photograph showing corrosion test results of coupons containing aluminum alloy samples prepared according to the present disclosure;

Described herein are high strength, corrosion resistant aluminum alloys and methods of making and processing them. The aluminum alloys described herein exhibit improved mechanical strength, corrosion resistance, and/or formability. The alloys provided herein contain increased silicon (Si), copper (Cu), manganese (Mn), and magnesium (Mg) compared to existing alloys. The alloys provided herein can have improved strength after brazing compared to existing alloys. The alloy material can be formed as fin stock and used in automotive heat exchangers such as radiators, condensers and evaporators. Aluminum fin stock may be used in other brazing applications, including but not limited to HVAC&R applications. Further, aluminum alloy fin stocks are useful for high performance and lightweight automotive heat exchangers. The fin material is designed to be less stable than the tube, so it corrodes faster than the tube. Heat exchangers are designed based on this sacrificial corrosion protection due to the fin material on the tubes. Thus, the fin stocks described herein provide this sacrificial protection to the tube.

DEFINITIONS AND DESCRIPTION As used herein, the terms "invention,""theinvention,""thisinvention," and "the present invention" It is intended to refer broadly to all of the subject matter of the application and to the claims that follow. Any specification containing these terms should not be understood to limit the subject matter described herein nor limit the meaning or scope of the following claims.

In this description, reference is made to alloys identified by aluminum industry designations such as "series" or "1xxx". For an understanding of the numbering systems 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 Re cord of Aluminum Association Alloy Designations and Chemical Compositions See 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 singular and plural references unless the context clearly dictates otherwise.

As used herein, plates generally have a thickness greater than about 15 mm. For example, the plate may be greater than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater than about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than about 45 mm, greater than about 50 mm, or greater than about 100 mm. It can refer to an aluminum product with thickness.

As used herein, a sheet (also referred to as a sheet plate) generally has a thickness of about 4mm to about 15mm. For example, the sheet can have a thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.

As used herein, sheet generally refers to aluminum products having a thickness of less than about 4 mm. For example, the sheet has a thickness of less than about 4 mm, less than about 3 mm, less than about 2 mm, less than about 1 mm, less than about 0.5 mm, less than about 0.3 mm, or less than about 0.1 mm, less than about 0.05 mm. can.

In this application, reference is made to alloy tempering or tempering. To understand the descriptions of the most commonly used alloy grades, refer to "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems". The F temper or temper refers to the aluminum alloys produced. O temper or temper refers to the aluminum alloy after annealing. The Hxx temper or temper, also referred to herein as the H temper, refers to aluminum alloys after cold rolling, with or without heat treatment (eg, annealing). Suitable H tempers include HX1, HX2, HX3, HX4, HX5, HX6, HX7, HX8, or HX9 tempers. For example, aluminum alloys can only be in the H19 temper when cold rolled. In a further example, an aluminum alloy can be cold rolled and annealed into a possible H23 temper.

The following aluminum alloys are described in terms of elemental composition in weight percent (wt%) based on the total weight of the alloy. In the particular example of each alloy, the balance being aluminum, the total maximum weight of impurities is 0.15 wt%.

As used herein, "electrochemical potential" refers to the susceptibility of a material to redox reactions. Electrochemical potential can be used to assess the corrosion resistance of the aluminum alloys described herein. Negative values can describe materials that readily oxidize (eg, lose electrons or increase oxidation state) when compared to materials with positive electrochemical potentials. A positive value can describe a material that is easily reduced (eg gains electrons or loses oxidation state) when compared to a material with a negative electrochemical potential. Electrochemical potential, as used herein, is a vector quantity that describes magnitude and direction.

As used herein, the term “room temperature” means a temperature of about 15° C. to about 30° C., such as about 15° C., about 16° C., about 17° C., about 18° C., about 19° C., about 20° C. °C, about 21 °C, about 22 °C, about 23 °C, about 24 °C, about 25 °C, about 26 °C, about 27 °C, about 28 °C, about 29 °C, or about 30 °C.

All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, the stated range "1 to 10" should be considered to include any and all subranges between (and including) the minimum value 1 and the maximum value 10, i.e., all subranges Starting with a minimum value of 1 or more, eg 1-6.1, and ending with a maximum value of 10 or less, eg 5.5-10.

Alloy Composition A novel aluminum alloy is described below. The properties of the aluminum alloy fin material differ depending on its composition. The aluminum alloy fin stock disclosed herein possesses several advantageous properties. The aluminum alloy fin stock can be produced in sheet, sheet, or plate form and possesses desirable strength before, during, and after brazing, even at gauges of 200 μm or less than 100 μm, It is suitable for manufacturing fins for heat exchanger applications. Aluminum alloy materials also possess thermal conductivity and corrosion potential that are suitable for the production of fin stocks.

The aluminum alloy fin stocks disclosed herein can include higher contents of one or more of Cu, Si and Mg compared to known fin stock alloys. The composition of the aluminum alloy fin material and/or its production process reduces fin shattering during brazing, increases post-braze strength, improves thermal conductivity, improves sag resistance, and increases anodic corrosion potential, etc. , resulting in improved material properties. Aluminum alloy fin stocks possess one or more of improved strength, thermal conductivity, and corrosion potential compared to known alloys used to produce fin stocks. The relatively high level of non-aluminum content within the aluminum alloy fin stock allows for a variety of metal inputs by allowing production from input metals that incorporate easily recyclable aluminum.

In some examples, the aluminum alloy fin stock is produced by a process that includes a heat treatment (intermediate annealing) step prior to the final cold rolling step. The intermediate annealing is performed at a temperature of 200° C. to 400° C. for about 30 minutes to 2 hours (eg, about 1 hour to 2 hours). Intermediate annealing is followed by a cold rolling step resulting in a specified reduction in thickness ("cold work %", defined later in this specification). In some instances, a combination of the above process steps (intermediate annealing followed by cold rolling) increases pre-braze strength and improves post-braze coarse grain structure, thereby improving The improved sag resistance of the aluminum fin material and its impact on thermal conductivity and corrosion potential result in a material with a favorable combination of characteristics and properties.

In some examples, the alloy can have the following elemental composition provided in Table 1.
Table 1

In some examples, the alloy can have the following elemental composition provided in Table 2.
Table 2

In some examples, the alloy can have the following elemental composition as provided in Table 3.
Table 3

In some examples, the alloy may have the following elemental composition as provided in Table 4.
Table 4

In some examples, the alloy can have the following elemental composition as provided in Table 5.
Table 5

In some examples, the alloy may have the following elemental composition as provided in Table 6.
Table 6

In some examples, the alloy may have the following elemental composition as provided in Table 7.
Table 7

In some examples, the alloy can have the following elemental composition as provided in Table 8.
Table 8

In some examples, the alloy can have the following elemental composition as provided in Table 9.
Table 9

In some examples, the alloy may have the following elemental composition as provided in Table 10.
Table 10

In some examples, the alloy contains about 0.9 wt% to about 1.4 wt% (eg, about 0.95 wt% to about 0.35 wt%, about 1.0 wt%, based on the total weight of the alloy). 0 wt% to about 1.30 wt%, about 1.10 wt% to 1.2 wt%, 0.8 wt% to 1.30 wt%) of silicon (Si). For example, the alloy may contain about 0.90 wt%, about 0.91 wt%, about 0.92 wt%, about 0.93 wt%, about 0.94 wt%, about 0.95 wt%, about 0.95 wt%. 96 wt%, about 0.97 wt%, about 0.98 wt%, about 0.99 wt%, about 1.00 wt%, about 1.01 wt%, about 1.02 wt%, about 1.03 wt% % by weight, about 1.04% by weight, about 1.05% by weight, about 1.06% by weight, about 1.07% by weight, about 1.08% by weight, about 1.09% by weight, about 1.10% by weight %, about 1.11 wt%, about 1.12 wt%, about 1.13 wt%, about 1.14 wt%, about 1.15 wt%, about 1.16 wt%, about 1.17 wt% , about 1.18 wt%, about 1.19 wt%, about 1.20 wt%, about 1.21 wt%, about 1.22 wt%, about 1.23 wt%, about 1.24 wt%, about 1.25 wt%, about 1.26 wt%, about 1.27 wt%, about 1.28 wt%, about 1.29 wt%, about 1.30 wt%, about 1.31 wt%, about 1.32 wt%, about 1.33 wt%, about 1.34 wt%, about 1.35 wt%, about 1.36 wt%, about 1.37 wt%, about 1.38 wt%, about 1 .39 wt %, or about 1.40 wt % Si. All percentages are expressed in weight percent. Among other things, the Si content affects the melting temperature of aluminum alloys. An increase in the Si content lowers the melting point of the aluminum alloy. Therefore, in order for an aluminum alloy fin stock to be brazeable, the Si content of the alloy should be low enough so that the alloy does not melt during the brazing cycle. On the other hand, a relatively high Si content in the alloy leads to the formation of AlMnSi dispersoids, resulting in beneficial dispersoid strengthening of the matrix and improved strength properties of the alloy. The Si content used in the disclosed fin stock alloys balances the above factors.

In some examples, the alloy also contains about 0.30 wt% to about 0.60 wt% (eg, about 0.35 wt% to about 0.60 wt%, about 0 wt%, based on the total weight of the alloy). Iron (Fe) in an amount of .40 wt% to about 0.60 wt%, or from about 0.41 wt% to about 0.47 wt%, for example, the alloy contains about 0.30 wt%, about 0 .31 wt%, about 0.32 wt%, about 0.33 wt%, about 0.34 wt%, about 0.35 wt%, about 0.36 wt%, about 0.37 wt%, about 0. 38 wt%, about 0.39 wt%, about 0.40 wt%, about 0.41 wt%, about 0.42 wt%, about 0.43 wt%, about 0.44 wt%, about 0.45 wt% % by weight, about 0.46% by weight, about 0.47% by weight, about 0.48% by weight, about 0.49% by weight, about 0.50% by weight, about 0.51% by weight, about 0.52% by weight %, about 0.53 wt%, about 0.54 wt%, about 0.55 wt%, about 0.56 wt%, about 0.57 wt%, about 0.58 wt%, about 0.59 wt% or about 0.60 wt.% Fe, all percentages expressed in wt. It is often beneficial to control the Fe content of aluminum alloys in order to influence the content of coarse intermetallics.

In some examples, the disclosed alloys contain about 0.2 wt% to about 0.60 wt% (e.g., about 0.20 wt% to about 0.40 wt% or about 0.40% to about 0.55% by weight) of copper (Cu). For example, the alloy may contain about 0.20 wt%, about 0.21 wt%, about 0.22 wt%, about 0.23 wt%, about 0.24 wt%, about 0.25 wt%, about 0.25 wt%. 26 wt%, about 0.27 wt%, about 0.28 wt%, about 0.29 wt%, about 0.30 wt%, about 0.31 wt%, about 0.32 wt%, about 0.33 wt% % by weight, about 0.34% by weight, about 0.35% by weight, about 0.36% by weight, about 0.37% by weight, about 0.38% by weight, about 0.39% by weight, about 0.40% by weight %, about 0.41 wt%, about 0.42 wt%, about 0.43 wt%, about 0.44 wt%, about 0.45 wt%, about 0.46 wt%, about 0.47 wt% , about 0.48 wt%, about 0.49 wt%, about 0.50 wt%, about 0.51 wt%, about 0.52 wt%, about 0.53 wt%, about 0.54 wt%, It may contain about 0.55 wt%, about 0.56 wt%, about 0.57 wt%, about 0.58 wt%, about 0.59 wt%, or about 0.60 wt% Cu. All percentages are expressed in weight percent. Cu in solid solution increases the strength of aluminum alloys. An increase in Cu content can also lead to the formation of Cu-containing AlMnCu dispersoids, which store Mn and dissolve during brazing, resulting in release of Mn into solid solution. This process improves strength after brazing. The relatively high Cu content of the fin stock alloy allows for reduced cost and increased recyclability.

In some examples, the alloy contains about 1.0 wt% to about 1.7 wt% (eg, about 1.10 wt% to about 1.65 wt%, about 1.0 wt% to about 1.65 wt%, based on the total weight of the alloy). 15 wt% to about 1.35 wt%, or about 1.2 wt% to about 1.35 wt%) of manganese (Mg). For example, the alloy may contain about 1.0 wt%, about 1.01 wt%, about 1.02 wt%, about 1.03 wt%, about 1.04 wt%, about 1.05 wt%, about 1.0 wt%. 06 wt%, about 1.07 wt%, about 1.08 wt%, about 1.09 wt%, about 1.1 wt%, about 1.11 wt%, about 1.12 wt%, about 1.13 wt% % by weight, about 1.14% by weight, about 1.15% by weight, about 1.16% by weight, about 1.17% by weight, about 1.18% by weight, about 1.19% by weight, about 1.2% by weight %, about 1.21 wt%, about 1.22 wt%, about 1.23 wt%, about 1.24 wt%, about 1.25 wt%, about 1.26 wt%, about 1.27 wt% , about 1.28 wt%, about 1.29 wt%, about 1.3 wt%, about 1.31 wt%, about 1.32 wt%, about 1.33 wt%, about 1.34 wt%, about 1.35 wt%, about 1.36 wt%, about 1.37 wt%, about 1.38 wt%, about 1.39 wt%, about 1.4 wt%, about 1.41 wt%, about 1.42 wt%, about 1.43 wt%, about 1.44 wt%, about 1.45 wt%, about 1.46 wt%, about 1.47 wt%, about 1.48 wt%, about 1 .49 wt.%, about 1.50 wt.%, about 1.51 wt.%, about 1.52 wt.%, about 1.53 wt.%, about 1.54 wt.%, about 1.55 wt.%, about 1.5 wt. 56 wt%, about 1.57 wt%, about 1.58 wt%, about 1.59 wt%, about 1.60 wt%, about 1.61 wt%, about 1.62 wt%, about 1.63 wt% % by weight, about 1.64% by weight, about 1.65% by weight, about 1.66% by weight, about 1.67% by weight, about 1.68% by weight, about 1.69% by weight, or about 1.7% by weight It may contain weight percent Mn. All percentages are expressed in weight percent. Mn in solid solution increases the strength of aluminum alloys and shifts the corrosion potential to a more cathodic state. When present, dispersoids of (FeMn)-Al ₆ or Al ₁₅ Mn ₃ Si ₂ in fine and dense dispersions enhance the strength of aluminum alloys through particle strengthening. _Depending on composition and solidification rate, Fe, Mn, Al, and Si may have _{microstructures such as Al15(FeMn)3Si2, Al5FeSi, or Al8FeMg3Si6 , to name a few} . During solidification, the various intermetallic components, or particles, within the metal combine to form. Higher Mn contents, especially in combination with higher Fe contents, can lead to the formation of coarse Mn—Fe intermetallics.

In some examples, the alloy contains about 0.1 wt% to about 3.0 wt% (eg, about 0.5 wt% to about 2.8 wt%, about 1.0 wt%, based on the total weight of the alloy). 0 wt% to about 2.5 wt%, about 1.5 wt% to about 3.0 wt%, about 1.5 wt% to about 2.75 wt%, or about 1.9 wt% to about 2.5 wt%. 6% by weight) of zinc (Zn). For example, the alloy may contain about 0.1 wt%, about 0.11 wt%, about 0.12 wt%, about 0.13 wt%, about 0.14 wt%, about 0.15 wt%, about 0.1 wt%. 16 wt%, about 0.17 wt%, about 0.18 wt%, about 0.19 wt%, about 0.2 wt%, about 0.21 wt%, about 0.22 wt%, about 0.23 wt% % by weight, about 0.24% by weight, about 0.25% by weight, about 0.26% by weight, about 0.27% by weight, about 0.28% by weight, about 0.29% by weight, about 0.3% by weight %, about 0.31 wt%, about 0.32 wt%, about 0.33 wt%, about 0.34 wt%, about 0.35 wt%, about 0.36 wt%, about 0.37 wt% , about 0.38 wt%, about 0.39 wt%, about 0.4 wt%, about 0.41 wt%, about 0.42 wt%, about 0.43 wt%, about 0.44 wt%, about 0.45 wt%, about 0.46 wt%, about 0.47 wt%, about 0.48 wt%, about 0.49 wt%, about 0.5 wt%, about 0.51 wt%, about 0.52 wt%, about 0.53 wt%, about 0.54 wt%, about 0.55 wt%, about 0.56 wt%, about 0.57 wt%, about 0.58 wt%, about 0 .59 wt.%, about 0.6 wt.%, about 0.61 wt.%, about 0.62 wt.%, about 0.63 wt.%, about 0.64 wt.%, about 0.65 wt.%, about 0.6 wt.%, about 0.64 wt.%, about 0.65 wt.%. 66 wt%, about 0.67 wt%, about 0.68 wt%, about 0.69 wt%, about 0.7 wt%, about 0.71 wt%, about 0.72 wt%, about 0.73 wt% % by weight, about 0.74% by weight, about 0.75% by weight, about 0.76% by weight, about 0.77% by weight, about 0.78% by weight, about 0.79% by weight, about 0.8% by weight %, about 0.81 wt%, about 0.82 wt%, about 0.83 wt%, about 0.84 wt%, about 0.85 wt%, about 0.86 wt%, about 0.87 wt% , about 0.88 wt%, about 0.89 wt%, about 0.9 wt%, about 0.91 wt%, about 0.92 wt%, about 0.93 wt%, about 0.94 wt%, about 0.95 wt%, about 0.96 wt%, about 0.97 wt%, about 0.98 wt%, about 0.99 wt%, about 1.0 wt%, about 1.01 wt%, about 1.02 wt%, about 1.03 wt%, about 1.04 wt%, about 1.05 wt%, about 1.06 wt%, about 1.07 wt%, about 1.08 wt%, about 1 .09 wt.%, about 1.1 wt.%, about 1.11 wt.%, about 1.12 wt.%, about 1.13 wt.%, about 1.14 wt.%, about 1.15 wt.%, about 1.0 wt. 16 wt%, about 1.17 wt%, about 1.18 wt%, about 1.19 wt%, about 1.2 wt%, about 1.21 wt%, about 1.22 wt%, about 1.23 wt% % by weight, about 1.24% by weight, about 1.25% by weight, about 1.26% by weight, about 1.27% by weight, about 1.28% by weight, about 1.29% by weight, about 1.3% by weight %, about 1.31 wt%, about 1.32 wt%, about 1.33 wt%, about 1.34 wt%, about 1.35 wt%, about 1.36 wt%, about 1.37 wt% , about 1.38 wt%, about 1.39 wt%, about 1.4 wt%, about 1.41 wt%, about 1.42 wt%, about 1.43 wt%, about 1.44 wt%, about 1.45 wt%, about 1.46 wt%, about 1.47 wt%, about 1.48 wt%, about 1.49 wt%, about 1.5 wt%, about 1.51 wt%, about 1.52 wt%, about 1.53 wt%, about 1.54 wt%, about 1.55 wt%, about 1.56 wt%, about 1.57 wt%, about 1.58 wt%, about 1 .59 wt.%, about 1.6 wt.%, about 1.61 wt.%, about 1.62 wt.%, about 1.63 wt.%, about 1.64 wt.%, about 1.65 wt.%, about 1.6 wt. 66 wt%, about 1.67 wt%, about 1.68 wt%, about 1.69 wt%, about 1.7 wt%, about 1.71 wt%, about 1.72 wt%, about 1.73 wt% % by weight, about 1.74% by weight, about 1.75% by weight, about 1.76% by weight, about 1.77% by weight, about 1.78% by weight, about 1.79% by weight, about 1.8% by weight %, about 1.81 wt%, about 1.82 wt%, about 1.83 wt%, about 1.84 wt%, about 1.85 wt%, about 1.86 wt%, about 1.87 wt% , about 1.88 wt%, about 1.89 wt%, about 1.9 wt%, about 1.91 wt%, about 1.92 wt%, about 1.93 wt%, about 1.94 wt%, about 1.95 wt%, about 1.96 wt%, about 1.97 wt%, about 1.98 wt%, about 1.99 wt%, about 2.0 wt%, about 2.01 wt%, about 2.02 wt%, about 2.03 wt%, about 2.04 wt%, about 2.05 wt%, about 2.06 wt%, about 2.07 wt%, about 2.08 wt%, about 2 .09 wt%, about 2.1 wt%, about 2.11 wt%, about 2.12 wt%, about 2.13 wt%, about 2.14 wt%, about 2.15 wt%, about 2. 16 wt%, about 2.17 wt%, about 2.18 wt%, about 2.19 wt%, about 2.2 wt%, about 2.21 wt%, about 2.22 wt%, about 2.23 wt% % by weight, about 2.24% by weight, about 2.25% by weight, about 2.26% by weight, about 2.27% by weight, about 2.28% by weight, about 2.29% by weight, about 2.3% by weight %, about 2.31 wt%, about 2.32 wt%, about 2.33 wt%, about 2.34 wt%, about 2.35 wt%, about 2.36 wt%, about 2.37 wt% , about 2.38 wt%, about 2.39 wt%, about 2.4 wt%, about 2.41 wt%, about 2.42 wt%, about 2.43 wt%, about 2.44 wt%, about 2.45 wt%, about 2.46 wt%, about 2.47 wt%, about 2.48 wt%, about 2.49 wt%, about 2.5 wt%, about 2.51 wt%, about 2.52 wt%, about 2.53 wt%, about 2.54 wt%, about 2.55 wt%, about 2.56 wt%, about 2.57 wt%, about 2.58 wt%, about 2 .59 wt%, about 2.6 wt%, about 2.61 wt%, about 2.62 wt%, about 2.63 wt%, about 2.64 wt%, about 2.65 wt%, about 2. 66 wt%, about 2.67 wt%, about 2.68 wt%, about 2.69 wt%, about 2.7 wt%, about 2.71 wt%, about 2.72 wt%, about 2.73 wt% % by weight, about 2.74% by weight, about 2.75% by weight, about 2.76% by weight, about 2.77% by weight, about 2.78% by weight, about 2.79% by weight, about 2.8% by weight %, about 2.81 wt%, about 2.82 wt%, about 2.83 wt%, about 2.84 wt%, about 2.85 wt%, about 2.86 wt%, about 2.87 wt% , about 2.88 wt%, about 2.89 wt%, about 2.9 wt%, about 2.91 wt%, about 2.92 wt%, about 2.93 wt%, about 2.94 wt%, It may contain about 2.95 wt%, about 2.96 wt%, about 2.97 wt%, about 2.98 wt%, about 2.99 wt%, or about 3.0 wt% Zn. All percentages are expressed in weight percent. Zn is typically added to aluminum alloys to shift the corrosion potential towards the anodic end of the scale. In the disclosed finstock aluminum alloys, the relatively high Zn content of up to 3 wt. A higher anodic corrosion potential allows the fins made from the alloy to act sacrificially to protect the heat exchanger tubes, thus improving the overall corrosion resistance of the heat exchanger.

In certain examples, the alloy contains about 0.01 wt% to about 0.25 wt% (eg, about 0.05 wt% to about 0.20 wt% or about 0.10 wt%), based on the total weight of the alloy. % to about 0.20% by weight). For example, the alloy may contain about 0.01 wt%, about 0.02 wt%, about 0.03 wt%, about 0.04 wt%, about 0.05 wt%, about 0.06 wt%, about 0.04 wt% 07 wt%, about 0.08 wt%, about 0.09 wt%, about 0.1 wt%, about 0.11 wt%, about 0.12 wt%, about 0.13 wt%, about 0.14 wt% % by weight, about 0.15% by weight, about 0.16% by weight, about 0.17% by weight, about 0.18% by weight, about 0.19% by weight, about 0.2% by weight, about 0.21% by weight %, about 0.22 wt%, about 0.23 wt%, about 0.24 wt%, or about 0.25 wt% Mg. All percentages are expressed in weight percent. Mg contributes to the strength of the aluminum alloys described herein through solid solution strengthening.

In some examples, the ratio of Cu to Zn is 2:1 to 1:15, such as 1:1 to 1:10, or 1:5 to 1:10. The ratio of Cu to Zn is 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 , 1:11, 1:12, 1:13, 1:14, or 1:15.

The aluminum alloys described herein may contain up to about 0.10 weight percent (eg, 0 to about 0.05 weight percent, about 0.001 weight percent to about 0.04 weight percent), based on the total weight of the alloy. , or about 0.01% to about 0.03% by weight) of titanium (Ti). For example, the alloy may contain about 0.001 weight percent, about 0.002 weight percent, about 0.003 weight percent, about 0.004 weight percent, about 0.005 weight percent, about 0.006 weight percent, about 0.006 weight percent, 007 wt%, about 0.008 wt%, about 0.009 wt%, about 0.01 wt%, about 0.02 wt%, about 0.03 wt%, about 0.04 wt%, about 0.05 wt% wt%, about 0.06 wt%, about 0.07 wt%, about 0.08 wt%, about 0.09 wt%, or about 0.1 wt% Ti. In some cases Ti is not present in the alloy (ie 0 wt%). All percentages are expressed in weight percent.

Optionally, the alloy composition contains an amount of Other trace elements, sometimes referred to as impurities, may also be included. These impurities may include, but are not limited to Ga, V, Ni, Sc, Ag, B, Bi, Zr, Li, Pb, Sn, Ca, Hf, Sr, or combinations thereof. Therefore, Ga, V, Ni, Sc, Ag, B, Bi, Zr, Li, Pb, Sn, Ca, Hf, or Sr is 0.05 wt% or less, 0.04 wt% or less, 0.03 wt% % or less, 0.02 wt.% or less, or 0.01 wt.% or less in the alloy. In certain aspects, the sum of all impurities does not exceed 0.15 wt% (eg, 0.1 wt%). All percentages are expressed in weight percent. In certain embodiments, the remaining percentage of the alloy is aluminum.

Processes for Making Aluminum Alloy Fin Stocks In certain aspects, the disclosed alloy compositions are the product of the disclosed methods. Without intending to limit the disclosure, the properties of aluminum alloys are determined in part by the formation of microstructures during alloy preparation. In certain embodiments, the method of preparation of the alloy composition can influence or even determine that the alloy has suitable properties for a desired application.

A process for producing aluminum alloy fin blanks can use direct chill (DC) casting of aluminum alloys into ingots. After DC casting, the process includes preheating the ingot for hot rolling. Preheat temperature and hot rolling time are finely controlled to low levels to retain large grain size and high strength after the finished fin blank is brazed. In some examples, prior to hot rolling, the ingot is preheated in a furnace at a suitable heating rate, e.g., 50°C/hr, for up to about 12 hours, up to about 500°C, e.g. , after which the temperature is maintained at about 450-500° C., eg, about 470-480° C., for 5-7 hours (“soaking” or “soaking”). After preheating and soaking, the ingot is hot rolled to 2-10 mm, such as 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. This may be referred to as the "exit gauge" after hot rolling.

The process for producing aluminum alloy fin stock then includes a cold rolling step to create the desired thickness (gauge) and other properties of the material. For example, after the hot rolling step, the hot rolled aluminum alloy is cold rolled to reduce the thickness of the material during the first cold rolling step to 1-2 mm, for example a thickness or gauge of 1 mm (initial cold rolling step). rolling gauge). This can include multiple cold rolling passes. It is then further cold rolled during an intermediate cold rolling step to a thickness or gauge of 100-200 μm (intermediate cold rolling gauge). This may also involve multiple passes. Depending on the hot rolling gauge, desired final thickness, and other properties discussed below, an aluminum alloy may require more or fewer cold rolling passes to achieve the desired gauge. The number of cold rolling passes is not limited and can be suitably adjusted depending, for example, on the desired thickness of the final sheet and other properties of the material.

After intermediate cold rolling, the process for producing the aluminum alloy fin stock may include intermediate annealing steps to produce desired properties of the aluminum alloy fin stock. The term "intermediate annealing" refers to heat treatments applied during the cold rolling step. As described herein, intermediate annealing is applied between the intermediate cold rolling step and the final cold rolling step. Intermediate annealing heats the aluminum alloy to about 200°C to about 400°C, such as about 225°C to about 400°C, about 225°C to about 375°C, about 225°C to about 350°C, about 225°C to about 325°C, about 300°C. C. to about 375.degree. C., about 325.degree. C. to about 350.degree. C., about 340.degree. C. to about 360.degree. Hold for 3-5 hours, for example about 4 hours, then cool. A period of temperature maintenance between about 200° C. and about 400° C. can be referred to as "soaking" or "soaking." A constant rate of 40° C./hour to 50° C./hour, for example 50° C./hour, can be applied to the heating and cooling of the material before and after immersion. Intermediate annealing conditions affect the structure and properties of aluminum alloy fin stocks in various ways. For example, higher intermediate annealing temperatures can reduce post-braze strength. Accordingly, intermediate annealing conditions are selected within the ranges specified herein to provide the desired properties of the aluminum alloy fin stock.

いくつかの実施形態では、ＣＷ％は３５％以下であるが、他のいくつかの実施形態では、ＣＷ％は、３５％より大きい。最終冷間圧延ステップ後、本発明のアルミニウム合金フィン素材は、約４５～１００μｍ、４５～９０μｍ、４７～８５μｍ、または５０～８３μｍの厚さ（ゲージ）を保有する。 After intermediate annealing, a final cold rolling is performed with a final cold rolling of 20% to 45%, 25% to 40%, 20% to 40%, 20% to 35%, 25% to 35%, or 5% to 45%. A cold work % (CW%) is achieved during the cold rolling step (which can include multiple cold rolling passes).

In some embodiments, CW% is 35% or less, while in some other embodiments, CW% is greater than 35%. After the final cold rolling step, the aluminum alloy fin stock of the present invention possesses a thickness (gauge) of about 45-100 μm, 45-90 μm, 47-85 μm, or 50-83 μm.

The final cold rolling step affects the structure and properties of the aluminum alloy fin stock. For example, increasing the CW% increases the pre-braze strength (ultimate tensile strength (UTS), yield strength (YS), or both measured in pre-braze conditions) of an aluminum material. Therefore, the CW% used is adjusted within the ranges specified herein to achieve the desired properties of the aluminum alloy fin stock.

The process of producing the aluminum alloy fin stock disclosed herein can be performed in a manner that results in an aluminum material having the desired temper. For example, aluminum that has been subjected to this process and can be described as having or being an "H1X" temper (e.g., an H14 temper) and/or a "strain hardening", "cold work", and/or "H1X" temper (e.g., H14 temper) materials can be provided. In some examples, the improved finstock aluminum alloy materials described herein may be produced in H14, H16 or H18 tempers. It should be understood that specific property ranges are associated with quality designations. It should also be understood that the temper designation refers to the pre-braze properties of the material.

Properties The aluminum alloy fin stock disclosed herein possesses several advantageous properties, features, or parameters. These properties, individually or in various combinations, allow the aluminum alloy materials described herein to be used in the production of fins for heat exchangers. However, it should be understood that the scope of the invention is not limited to any particular use or application, and that the properties of aluminum alloy fin stocks can be advantageous in a variety of other applications. Some of these properties are described below. Some other properties, which may not be specifically described, may result from the compositions and/or production processes used to fabricate the aluminum alloy fin stocks described herein.

Some embodiments of the aluminum alloy materials described herein are manufactured as sheets, eg, sheets less than 4 mm thick, eg, 45-100 μm thick. Aluminum alloy sheet can be produced in H1X tempers, such as H14 H16 or H18 tempers. The aluminum alloy materials described herein may possess one or more of the following properties in any combination: 210 MPa or greater (in other words, at least 210 MPa), measured in the pre-braze condition; or UTS of 210-230 MPa, measured after brazing, 150 MPa or more (i.e., at least 150 MPa) or UTS of 150-170 MPa, measured after brazing, sag resistance of 25-33 mm; , 40-48, 43-47, or 44-45 IACS; open circuit potential corrosion value (vs. standard calomel electrode (SCE), also called “corrosion potential”) of −740 mV or less (eg, −750 mV), and / or a coarse post-braze grain microstructure of 80-400 μm. Parameters measured "after brazing" or "post-brazing" (also referred to as "post-braze") measured the aluminum alloy samples between 595°C and 610°C. and then cooled to room temperature in about 20 minutes, measured after a simulated brazing cycle. Parameters measured before brazing (“pre-brazing” or “pre-brazed” conditions), also called “pre-brazing” parameters, are Measured before or without subjecting to a brazing cycle.

The disclosed aluminum alloy fin stock has improved strength and electrical conductivity and exhibits lower corrosion potential values. The disclosed aluminum alloy fin stock is also capable of withstanding copper accelerated salt spray (CASS) testing for at least 20 days according to ASTM B368 (2014) without separation from the brazed joint. CASS testing is generally performed by forming coupons of fins and tubes, brazing them to form a joint, and subjecting the brazed coupons to the test. Due to the properties and advantages described above, the aluminum alloy fin stock of the present invention can be advantageously used in a variety of uses and applications that are described in more detail below.

Uses and Applications The aluminum alloy fin stocks described herein can be used in a variety of applications including, but not limited to, heat exchangers. In one example, the aluminum alloy fin stock can be used in automotive heat exchangers such as, but not limited to, radiators, condensers, and evaporators. For example, improved aluminum alloy fin stocks are used in the manufacture of a variety of devices that use heat exchangers and are produced by brazing, such as devices used in heating, ventilation, air conditioning, and refrigeration (HVAC&R). be able to. Uses and applications of the aluminum alloy fin stocks described herein, as well as objects, forms, devices and the like made of or including the aluminum alloys described herein are within the scope of the present invention. contained within. Processes for making, producing, or manufacturing such objects, forms, devices, and the like are also included within the scope of this invention.

The aluminum alloys described herein are suitable for fabrication or manufacturing processes that require joining metal surfaces by brazing. Brazing is a metal joining process in which a filler material is heated above its melting point and distributed between two or more intimate parts by capillary action. The use of aluminum alloys in brazing and related processes, and the results, such as objects made according to manufacturing processes involving brazing, are commonly referred to as "brazing applications." The heat exchanger components described herein are joined by brazing during the manufacturing process. The filler metal melts during brazing and becomes available to flow to the contact points between the components being brazed by capillary action.

One exemplary object that can be fabricated using the aluminum alloy fin stocks described herein is a heat exchanger. A heat exchanger is produced by an assembly of parts comprising tubes, plates, fins, headers and side supports, to name a few. For example, a heatsink is constructed with tubes, fins, headers, and side supports. With the exception of the fins, which are typically bare, meaning not covered with an Al—Si alloy, all other parts of the heat exchanger are typically brazed clad on one or both sides. covered. Once assembled, the heat exchanger units are secured by bands or such devices to hold the units together by fluxing and brazing. Brazing is usually done by passing the unit through a tunnel furnace. Brazing can also be done by immersion in molten salt or by a batch or semi-batch process. The unit is heated to a brazing temperature of 590° C.-610° C. and soaked at a suitable temperature until the joint is created by capillary action and then cooled below the solidus temperature of the filler metal. The heating rate depends on the type of furnace and the size of the heat exchanger produced. Some other examples of objects that can be made using the aluminum alloy fin stocks described herein are evaporators, radiators, heaters or condensers.

Embodiment 1 contains about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1 .7 wt.% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, balance Al and impurities is an aluminum alloy that is 0.15% by weight or less.

Embodiment 2 is the aluminum alloy of any preceding or subsequent embodiment, wherein the aluminum alloy comprises about 0.95-1.35 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn , containing up to about 0.10 wt. % Ti, with the remaining Al and impurities up to 0.15 wt.

Embodiment 3 is an aluminum alloy of any preceding or subsequent embodiment, wherein the aluminum alloy comprises about 0.9-1.4 wt% Si, about 0.35-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn , containing up to about 0.10 wt. % Ti, with the remaining Al and impurities up to 0.15 wt.

Embodiment 4 is an aluminum alloy of any preceding or subsequent embodiment, wherein the aluminum alloy comprises about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.40 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn , containing up to about 0.10 wt. % Ti, with the remaining Al and impurities up to 0.15 wt.

Embodiment 5 is an aluminum alloy of any preceding or subsequent embodiment, wherein the aluminum alloy comprises about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.40-0.55 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn , containing up to about 0.10 wt. % Ti, with the remaining Al and impurities up to 0.15 wt.

Embodiment 6 is the aluminum alloy of any preceding or subsequent embodiment, wherein the aluminum alloy comprises about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.1-1.65 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn , containing up to about 0.10 wt. % Ti, with the remaining Al and impurities up to 0.15 wt.

Embodiment 7 is the aluminum alloy of any preceding or subsequent embodiment, wherein the aluminum alloy comprises about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.05-0.2 wt% Mg, about 0.1-3.0 wt% Zn , containing up to about 0.10 wt. % Ti, with the remaining Al and impurities up to 0.15 wt.

Embodiment 8 contains about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1 .7 wt.% Mn, about 0.01-0.25 wt.% Mg, about 1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with 0 remaining Al and impurities. 0.15% by weight or less of the aluminum alloy.

Embodiment 9 contains about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1 .7 wt.% Mn, about 0.01-0.25 wt.% Mg, about 1.5-2.75 wt.% Zn, up to about 0.10 wt.% Ti, balance Al and impurities is an aluminum alloy that is 0.15% by weight or less.

Embodiment 10 contains about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1 .7 wt% Mn, about 0.01-0.25 wt% Mg, about 0.1-3.0 wt% Zn, up to about 0.05 wt% Ti, with the balance being Al and impurities is an aluminum alloy that is 0.15% by weight or less.

Embodiment 11 is an aluminum alloy according to any preceding or subsequent embodiment, the alloy produced by a process comprising: Directly chill casting the aluminum alloy into an ingot; hot rolling the ingot after direct chill casting; after hot rolling, cold rolling the aluminum alloy to intermediate thickness; after cold rolling, at 200-400°C Intermediate annealing of the aluminum alloy rolled to intermediate thickness; Sheets with a thickness of 90 μm, 47-85 μm, or 50-83 μm are obtained.

Embodiment 12 is the aluminum alloy of the preceding or following embodiments, with intermediate annealing at 250-360°C or 290-360°C.

Embodiment 13 is an aluminum alloy according to any preceding or subsequent embodiment, with an intermediate annealing time of 30-60 minutes.

Embodiment 14 is an aluminum alloy according to any preceding or subsequent embodiment with a CW% of 30-40%.

Embodiment 15 is an aluminum alloy according to any preceding or subsequent embodiment, wherein the aluminum alloy is at least 200 MPa when measured in a pre-braze condition or at least 150 MPa when measured after braze. one or both ultimate tensile strengths.

Embodiment 16 is an aluminum alloy according to any preceding or subsequent embodiment, wherein the aluminum alloy has a corrosion potential of -740 mV or less when measured after brazing.

Embodiment 17 is an aluminum alloy according to any preceding or subsequent embodiment, wherein the aluminum alloy has a thermal conductivity of greater than 40% IACS when measured after brazing.

Embodiment 18 is a heat exchanger comprising an aluminum alloy according to any preceding or subsequent embodiment.

Embodiment 19 is a heat exchanger comprising joining at least one first aluminum alloy form made from the aluminum alloy of any preceding or subsequent embodiment with a second aluminum alloy form by brazing The process involves assembling and securing two or more aluminum forms together and joining two or more aluminum forms until a joint is created between the two or more aluminum forms by capillary action. heating the aluminum form to a brazing temperature.

Embodiment 20 is the process of Embodiment 19, wherein the first aluminum alloy is capable of withstanding CASS testing according to ASTM B368 (2014) for at least 20 days without debonding.

Embodiment 21 is the use of aluminum alloys in the fabrication of any preceding or subsequent embodiment of the heat exchanger fins.

The following examples serve to further illustrate the invention, but at the same time do not constitute any limitation thereof. On the contrary, various embodiments, modifications and equivalents thereof may be used which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the invention. should be clearly understood.

Example 1
Nine aluminum alloy samples were prepared with the compositions shown in Table 11 below. Each sample contains up to 0.15 wt% impurities, the balance being Al. Each sample was prepared by direct chill casting an aluminum alloy into an ingot and then hot rolling. Ingots produced by DC casting were preheated for hot rolling. The ingot was then hot rolled to the exit gauge and then cold rolled to the initial cold roll gauge. The ingot was then further cold rolled to an intermediate cold rolled gauge. The ingot was then intermediate annealed. After an intermediate anneal, a final cold rolling was performed to achieve a CW% of 20-40%, resulting in each sample having a thickness of 45 μm to 100 μm.
Table 11

Each of the samples in Table 11 were then tested for mechanical properties, electrical conductivity, corrosion potential, and solidus temperature before brazing, after standard brazing, and after high speed brazing. During standard brazing, the samples were heated to a temperature of 605° C. and cooled to room temperature for approximately 45 minutes to simulate the temperature-time profile of a commercial brazing process. High speed brazing was performed at much faster heating and cooling rates compared to standard brazing cycles. The material was heated to a temperature of 600-605° C. and cooled to room temperature in about 20 minutes. Yield strength, ultimate tensile strength, and uniform elongation were measured for all samples. Testing was performed according to the ASTM B557 standard. Three samples of each alloy variant were tested and the average values reported for both pre-braze and post-braze conditions. Electrical conductivity was reported as IACS% (International Annealed Copper Standard, assuming 100% pure copper conductivity). Yield strength, ultimate tensile strength and elongation results are shown in Table 12 below. The solidus temperature is also reported in Table 12. The thermal conductivity and corrosion potential measured after brazing are reported in Table 13. The experimental alloy had a minimum brazing resistant yield strength of 55 Mpa and a higher ultimate tensile strength than the comparative example 1 alloy.

表１３

The open circuit potential corrosion value versus standard calomel electrode (SCE) of -764 mV for Comparative Example 1 compared to -735 mV for alloy H indicates that the difference in corrosion potential between the tube alloy and the fin alloy is about We have shown that fin deformation will act sacrificially for all tube alloys when maintained between 30 and 150 mV.
Table 12

Table 13

Each of Sample Comparative Examples 1 and AH was photographed using an optical microscope. Microstructural characterization was performed to investigate dispersoids, intermetallic size and distribution, and grain structure before and after brazing. The microstructure was investigated by etching the samples with 2.5% _HBF4 for 60 seconds after desmutting with _HNO3 . 1A-I show the microstructure before brazing, FIGS. 2A-I show the microstructure after standard brazing, and FIGS. 3A-I show the microstructure after fast cycle brazing. Barker's etching was used to reveal the grain structure. 4A-I show the top views of the grain structure after standard brazing, and FIGS. 5A-I show the top views of the grain structure after fast cycle brazing. Also, each of Sample Comparative Examples 1 and A-H shows cross-sectional crystals before brazing (FIGS. 6A-I), after standard brazing (FIGS. 7A-I), and after high-speed brazing (FIGS. 8A-I). Photographed to show the grain structure. For each set of micrographs, Panel A corresponds to Comparative Example 1, Panel B corresponds to Sample A, Panel C corresponds to Sample B, and so on.

Example 2
Alloy samples C, E, G, and H were prepared as in Example 1, except that the CW% was varied during the intermediate annealing at 350°C (before brazing). The results are shown in Table 14 below and in Figure 9A. As shown below and in FIG. 9A, yield strength was improved when greater than 35% CW was performed compared to when less than 35% CW was performed. With the exception of sample E, the ultimate tensile strength also increased above 35% CW compared to when less than 35% CW was done. Except for sample H, the % elongation decreased when more than 35% CW was done compared to when less than 35% CW was done.
Table 14

Example 3
Alloy samples C, E, G, and H were prepared as in Example 1, except that the CW% was changed after an intermediate anneal at 350°C (post-braze). The results are shown in Table 15 below and in Figure 9B. As shown below and in FIG. 9B, except for sample G, the yield strength was improved when >35% CW was performed compared to when <35% CW was performed. Except for sample H, the ultimate tensile strength decreased when more than 35% CW was done compared to when less than 35% CW was done. In general, the % elongation remained about the same or decreased when >35% CW was performed compared to when <35% CW was performed.
Table 15

Example 4
Alloy samples C, E, G and H were prepared as in Example 1, except that the intermediate annealing temperature was varied with CW (before brazing) greater than 35%. The results are shown in Table 16 below and in Figure 9C. Yield strength, ultimate tensile strength, and percent elongation all decreased at higher intermediate annealing temperatures, as shown below and in FIG. 9C.
Table 16

Example 5
Alloy samples C, E, G and H were prepared as in Example 1, except that the effect of intermediate annealing temperature on CW >35% (after brazing) was varied. The results are shown in Table 17 below and in Figure 9D. At higher intermediate annealing temperatures, yield strength decreased, elongation increased, and ultimate tensile strength remained the same (Sample C) or decreased (Samples E, G, and H), as shown below and in FIG. 9D.
Table 17

Alloy samples C, E, G, and H were then subjected to either standard cycle or fast cycle brazing and photographed as described above. For samples that were intermediate annealed at 250° C. and subjected to a standard brazing cycle, the top view grain size after brazing is shown in FIGS. 10A-D, FIG. 10C corresponds to sample G and FIG. 10D corresponds to sample H. FIG. Similarly, for samples that were intermediate annealed at 350° C. and subjected to a standard brazing cycle, the top view grain size after brazing is shown in FIGS. 11A-D, FIG. 11B corresponds to sample E, FIG. 11C corresponds to sample G, and FIG.

For samples that were intermediate annealed at 250° C. and subjected to a high speed brazing cycle, the top view grain size after brazing is shown in FIGS. 12A-D, FIG. 12C corresponds to sample G and FIG. 12D corresponds to sample H. FIG. Similarly, for samples that were intermediate annealed at 350° C. and subjected to high speed brazing cycles, the top view grain size after brazing is shown in FIGS. 13A-D, FIG. 13B corresponds to sample E, FIG. 13C corresponds to sample G, and FIG. Based on the images of the grain structure, it is observed that increasing the CW% above 35% reduces the grain size after brazing due to the increased driving force for recrystallization, This effect is not believed to have an adverse effect on sag resistance. Similarly, decreasing the intermediate annealing temperature from 350° C. to 250° C. and decreasing the CW % results in a coarser grain size after brazing. Combinations of intermediate annealing temperatures and CW% were carefully selected based on the desired properties needed. For example, different combinations of IA and CW % may be required to obtain crush resistance and coarse grain size of the fin.

Example 6
Comparative samples and samples C, E, G and H were prepared as in Example 1 and subjected to brazing. Coupons of fins and tubes were bonded for each sample and each coupon was subjected to CASS testing according to ASTM B368 (2014). The CASS test was conducted for 40 days. Corrosion activity was characterized by examining the braze joints and the fins at 10, 20 and 40 days. At the end of 40 days, each fin acted sacrificially to protect the tube.

The results presented for Examples 2-5 confirm that some elements, such as Mg and Cu, play a role in contributing to the yield strength and ultimate tensile strength of the alloy. However, increased Mg and Cu are typically expected to also lead to increased corrosion when compared to samples with lower amounts of Mg and Cu. The images shown in Figures 14A-E are metallographic cross-sections taken at 100x magnification. Surprisingly and unexpectedly, as shown in FIGS. 14A-E, samples with increased amounts of Mg and Cu did not exhibit increased corrosion compared to samples with lower amounts of Mg and Cu. . Thus, each of Samples C, E, G and H performed similarly to the Comparative Sample with respect to corrosion, but possessed other superior properties.

All patents, patent specifications, publications, and abstracts cited above are hereby incorporated by reference in their entirety. Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the following claims.

Claims (20)

about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less aluminum alloy. about 0.95-1.35 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. about 0.9-1.4 wt% Si, about 0.35-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.40 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.40-0.55 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.1-1.65 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.05-0.2 wt% Mg, about 0.1-3.0 wt% Zn, up to about 0.10 wt% Ti, and 0.15 wt% remaining Al and impurities % or less. about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 1.5-2.75 wt.% Zn, up to about 0.10 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. about 0.9-1.4 wt% Si, about 0.3-0.6 wt% Fe, about 0.20-0.60 wt% Cu, about 1.0-1.7 wt% Mn, about 0.01-0.25 wt.% Mg, about 0.1-3.0 wt.% Zn, up to about 0.05 wt.% Ti, with the balance Al and impurities being 0.15 wt. % or less. The alloy is
directly chill casting the aluminum alloy into an ingot;
hot rolling the ingot after the direct chill casting;
cold rolling the aluminum alloy to an intermediate thickness after the hot rolling;
intermediate annealing of the aluminum alloy rolled to the intermediate thickness at 200 to 400° C. after the cold rolling;
after the intermediate annealing, cold rolling the aluminum alloy to achieve a cold work % (CW%) of 20-40%;
and wherein the sheet has a thickness of 45-100 μm, 45-90 μm, 47-85 μm, or 50-83 μm. The aluminum alloy of claim 10, wherein said intermediate annealing is at 250-360°C or 290-360°C. Aluminum alloy according to claim 10 or 11, wherein said intermediate annealing time is 30-60 minutes. The aluminum alloy according to any one of claims 10-12, wherein the CW% is 30-40%. wherein said aluminum alloy has an ultimate tensile strength of at least 200 MPa when measured in a pre-braze condition and/or of at least 150 MPa when measured after braze. 14. The aluminum alloy according to any one of Items 1 to 13. An aluminum alloy according to any preceding claim, wherein the aluminum alloy has a corrosion potential of -740 mV or less when measured after brazing. An aluminum alloy according to any one of the preceding claims, wherein the aluminum alloy has a thermal conductivity of greater than 40% IACS when measured after brazing. A heat exchanger comprising the aluminum alloy according to any one of claims 1-16. A process for making a heat exchanger comprising joining by brazing at least one first aluminum alloy form made from the aluminum alloy of any one of claims 1 to 17, the process comprising:
assembling and securing two or more of said aluminum forms together;
heating the two or more aluminum forms to a brazing temperature until a joint is formed between the two or more aluminum forms by capillary action;
The above process, including 19. The process of claim 18, wherein the first aluminum alloy is capable of withstanding at least 20 days of CASS testing according to ASTM B368 (2014) without removal from the joint. Use of the aluminum alloy according to any one of claims 1 to 16 for making heat exchanger fins.

Images