Cast Aluminum/Aluminium Alloys Summary

This is a break down of most of the cast aluminium alloys available, however, there are some of these that we do not cast. For a break down on all the cast aluminium alloys we manufacture, please go to either Our Most Popular Alloys or Cast Aluminium Alloy we Produce

Introduction

Aluminum is a metal that can be combined with specific amounts of other elements including copper, magnesium, silicon, zinc, and manganese, to alter its mechanical and physical qualities, making it suitable for different applications. If you mix aluminum with magnesium, you’ll get a strong and lightweight alloy that’s great for use in aerospace and automotive. It has low density, is corrosion resistant, and has good thermal conductivity. Their low weight makes them ideal for use in areas where reduced weight is important. A natural oxide layer forms on the aluminum alloy’s surface, making it corrosion resistant and keeping it protected in all different environments. In spite of their low density, they are strong and durable, factors that make them useful in projects where strength and weight have to be carefully balanced. Aluminium alloys are characterisd by being:

• Relatively Lightweight.
• Resistance to Corosion.
• Have a high strength to weight ratio.
• Formable and malleable.

Aluminum alloys do have some limitations. For one, they have a lower melting point than most other structural metals, which means they won’t be the best fit for high-temperature tasks. They’re not as hard as other metals, so won’t likely survive as much wear and tear. Certain alloys can also be quite expensive, so they might not be as cost-effective as other materials in certain situations.

Helpful Equivalance Links

If you are more familiar with:

• the EN-1982: 2008 or 2017 and need to find equivalents.
• the old BS 1490 designations and need to find equivalents.
• if you want the complete UNS listing and wish to find equivalents or near equivalent.

The Aluminium Designations

As with the Copper alloys, there are a number of designation systems with which we are familiar, as we must deal with customers from all corners of the earth . They are:

• ANSI/AA (The Aluminum Association) - There is a different designation system for Cast vs Wrought alloys. Wrought Aluminium has 4 digits wih no decimal, Cast Alloys have 3 before the decimal point and one after (###.#), the first digit informs you of the aluminum's main alloying element. In all other groups of aluminum alloys (2xx.x through 9xx.x) the second two digits signify different alloys in the group. The last digit indicates the product form: casting (designated by 0) or ingot (designated by 1 or 2 depending on chemical composition limits.)
• UNS (Unified Numbering System) - This format begins with one letter A, followed by five numbers: A #####. The numbers are very often similar to the pre-existing designations from AA.
• EN (European Norm) - This format starts with EN, followed by AC (cast alloys) or AW (wrought alloys) and a four-digit code, very similar to the ones from the AA system: EN AC/AW ####
• ISO (International Organization for Standardization) - Gets composed of the prefix AL, followed by the main alloying element percentages. With this naming system, you can easily identify the key metals that are mixed in the specific aluminum alloy."
• BS1490 (British Standard) - (LM0 to LM31) Discontinued but persists as a legacy from Colonial days and Anglophone countries.

We use the ANSI/AA designaion system as it is the most complete and most widely used of thee designation systems.

Wrought Aluminium Alloys

As mentioned the ANSI/AA provides a different designation system for Cast vs Wrought alloys. We break these down into those that are Heat Treatable and those hat are not (ie. they can only be Strain Hardended)

Strain Hardening

• 1xxx Series - Al- Pure aluminum. Aluminum of 99.00% or higher purity has many applications, especially in the electrical and chemical fields. These grades of aluminum are characterized by excellent corrosion resistance, high thermal and electrical conductivities, low mechanical properties, and excellent workability. Moderate increases in strength may be obtained by strain hardening. Iron and silicon are the major impurities.
• 3xxx Series - Al-Mn / Al-Mn-Cu Aluminum-manganese alloys. Manganese is the major alloying element of 3xxx series alloys. These alloys generally are non-heat-treatable but have about 20% more strength than 1xxx series alloys. Because only a limited percentage of manganese (up to about 1.5%) can be effectively added to aluminum, manganese is used as a major element in only a few alloys. However, one of these, the popular 3003 alloy, is widely used as a general-purpose alloy for moderate-strength applications requiring good workability.
• 5xxx Series - Al-Mg / Al-Mg-Mn Aluminum-magnesium alloys. The major alloying element in 5xxx series alloys is magnesium. When it is used as a major alloying element or with manganese, the result is a moderate-to-high-strength workhardenable alloy. Alloys in this series possess good welding characteristics and good resistance to corrosion in marine atmospheres.

Heat Treatable

• 2xxx Series - Al-Cu-Mg / Al-Cu-Si-Mg Aluminum-copper alloys - Copper is the principal alloying element in 2xxx series alloys, often with magnesium as a secondary addition. These alloys require solution heat treatment to obtain optimum properties; in the solution heat-treated condition, mechanical properties are similar to, and sometimes exceed, those of low-carbon steel. In some instances, precipitation heat treatment (aging) is employed to further increase mechanical properties. This treatment increases yield strength, with attendant loss in elongation; its effect on tensile strength is not as great. Alloys in the 2xxx series are particularly well suited for parts and structures requiring high strength-to-weight ratios and are commonly used to make truck and aircraft wheels, truck suspension parts, aircraft fuselage and wing skins, structural parts, and those parts requiring good strength at temperatures up to 150 °C (300 °F).
• 6xxx Series - Al-Mg-Si-Mn Heat-treatable aluminum-silicon-magnesium alloys. Alloys in the 6xxx series contain silicon and magnesium approximately in the proportions required for formation of magnesium silicide (Mg2Si), thus making them heat treatable. Although not as strong as most 2xxx and 7xxx alloys, 6xxx series alloys have good formability, weldability, machinability, and corrosion resistance, with medium strength.
• 7xxx Series - Al-Zn-Mg / Al-Zn-Mg-Cu Heat-treatable aluminum-zinc alloys. Zinc, in amounts of 1 to 8%, is the major alloying element in 7xxx series alloys, and when coupled with a smaller percentage of magnesium results in heat-treatable alloys of moderate to very high strength. Usually other elements, such as copper and chromium, are added in small quantities. Dilute additions of scandium also improve properties. 7xxx series alloys are used in airframe structures, mobile equipment, and other highly stressed parts.

Either
• 4xxx Series - Aluminium Silicon Alloys. The major alloying element in 4xxx series alloys is silicon, which can be added in sufficient quantities (up to 12%) to cause substantial lowering of the melting range without producing brittleness. Most alloys in this series are non-heat treatable. The alloys containing appreciable amounts of silicon become dark gray to charcoal when anodic oxide finishes are applied and hence are in demand for architectural applications. Alloy 4032 has a low coefficient of thermal expansion and high wear resistance; thus it is well suited to production of forged engine pistons.
• 8xxx Series - Other. These alloys constitute a wide range of chemical compositions.

Cast Aluminium Alloys

Aluminum casting alloys are based on the same alloy systems as those of wrought aluminum alloys, are strengthened by the same mechanisms (with the general exception of strain hardening), and are similarly classified into non-heat-treatable and heat treatable types.

Cast Aluminum alloys come in seven different categories, according to their chemical makeup, primary alloying elements, and physical characteristics. These are:

• 1xx.x Series - No alloy - pure Aluminium.
• 2xx.x series - Aluminum-copper cast alloys. The 2xx.x aluminum-copper group includes compositions capable of developing the highest strengths among all casting alloys, and these alloys are used where this is a predominant requirement. The 2xx.x alloys also have the highest strengths and hardnesses of all casting alloys at elevated temperatures (to 300 °C, or 600 °F), and this factor accounts for their use in some applications. Heat treatment is required with the 2xx.x alloys for development of highest strength and ductility and must be properly applied to ensure high resistance to stress-corrosion cracking. General corrosion resistance of these alloys is lower than those of other types of casting alloys, and protection by surface coatings is required in critical applications.
• 3xx.x series - Aluminum-silicon-copper/magnesium cast alloys. The highest-volume-usage alloys are those in the 3xx.x group, which, in addition to silicon, contain magnesium, copper, or both, and in specific cases, supplementary additions of nickel or beryllium. In general, they fall into one of three types: Al-Si-Mg, Al-Si-Cu, or Al-Si-Cu-Mg. The subset of alloys containing both copper and magnesium have higher strengths at elevated temperatures.
• 4xx.x series - Aluminum-silicon cast alloys. Alloys of the 4xx.x group, based on the binary aluminumsilicon system and containing from 5 to 12% Si, find many applications where combinations of moderate strength and high ductility and impact resistance are required. Bridge railing support castings are a representative example.
• 5xx.x series - Aluminum- magnesium cast alloys. The primary advantage of castings made of Al-Mg alloys is high corrosion resistance, especially to seawater and marine atmospheres. These alloys are suitable for welded assemblies and are often used in architectural and other decorative or building needs. Aluminum-magnesium alloys also have good machinability and an attractive appearance when anodized.
• There is no 6xx.x series.
• 7xx.x Series - The 7xx.x aluminum-zinc-magnesium alloys are notable for their combinations of good finishing characteristics, good general corrosion resistance, and the capability of developing high strength through natural aging without heat treatment.
• 8xx.x Series - These Alloys contain ~6% Sn and small amounts of copper and nickel for strengthening. These alloys were developed for bearing applications (tin imparts lubricity), for example, connecting rods and crankcase bearings for diesel engines.