The application of aluminum alloy is becoming more and more widespread with the development of the industry. Many factors are promoting the application of aluminum alloys, such as environmental protection, reduction of greenhouse gas emissions, development of light weight, etc. When we need to deal with aluminum alloy, it is necessary to know and understand aluminum alloy in first choice.


  1. What is aluminum alloy?

Aluminum alloy is the most abundant metal material in the earth’s crust. It is composed of elemental aluminum added with various alloying elements, the main elements are copper, silicon and magnesium. Aluminum alloy has low density, but relatively high strength, close to or more than high-quality steel, good plasticity, can be processed into a variety of profiles, has excellent electrical conductivity, thermal conductivity and corrosion resistance, widely used in industry, the use of the second only to steel.


  1. Classification of aluminum alloy

According to the type of production process, aluminum alloy can be divided into forged aluminum alloy and cast aluminum alloy.

Forged aluminum alloy, which is produced in the form of ingots or billets and subsequently produced by various processes, such as rolling, extrusion, deformation, drawing, etc., can be processed into parts by end users. It is the deformation of metal material in solid state at high temperature to achieve the shape you want.

Cast aluminum alloy is an ingot alloy made by casting method. It needs to be preferred to melt the metal and then pour it into the model.


  1. The difference between forged aluminum alloy and cast aluminum alloy.

In a ship, forged aluminum alloy has no more than 4% of alloying elements, good ductility, high strength, excellent thermoplasticity, better forging performance, good mechanical properties for later processing.

In contrast, the alloying elements of cast aluminum alloys are generally more than 10%, with many internal and external defects, lower ductility and strength, and unfavorable to post-processing, but very suitable for casting. 4.


  1. What are heat treatable and non-heat-treatable aluminum alloys?

Forged and cast aluminum alloys include heat treatable and non-heat-treatable aluminum alloys respectively.

Non-heat treatable aluminum alloys cannot provide significant solution and precipitation hardening effect during solution heat treatment and aging process, so they can only improve their strength through strain hardening, such as cold rolling or wire drawing and other cold processing methods.


Heat treatable aluminum alloys are alloys whose major alloying elements (and some minor alloying elements) can provide significant solution and precipitation hardening during solution heat treatment and aging, and thus can improve their strength and hardness.


  1. Aluminum alloy series

Just like everyone has a name, the name or grade of a forged aluminum alloy is made up of 4 digits. They represent different meanings, where the first number is used to distinguish the series to which the aluminum alloy belongs and its main alloy composition.


alloy series


Alloy elements

1XXXAl: >=99%

Not heat treatable. Extremely ductile and has excellent corrosion resistance. 1100 is the softest aluminum alloy among 1XXX series

2XXXcopper / CuHeat treatable. High strength, commonly used in aerospace and aircraft
3XXXManganese / MnNot heat treatable. Moderate strength and good corrosion resistance. Can be used for making cookware, aluminum beverage cans, etc.
4XXXSilicon / SiBoth non-heat-treatable and heat-treatable alloys. Mostly used for manufacturing welding wire.
5XXX magnesium / MgNon-heat treatable. High strength, good weldability and resistance to marine corrosion. Mostly used for making pressure vessels, tanks, marine applications, etc.
6XXXSilicon and magnesium /

Si / Mg

Heat treatable. Medium strength. Has good corrosion resistance. 6061 is a very common aluminum alloy in this series.
7XXXZinc / ZnHeat treatable. Very strong and can be used in the manufacture of aircraft.
8XXXother elements.


  1. Casting Aluminum alloy names – The main difference between the casting alloy name system and the wrought aluminum alloy name system is that the latter has a decimal point in the designation. For example, in alloy A360.0, A means it is a modification of the original alloy 360, 3 means its main alloying element is silicon copper/magnesium silicon, 60 is the serial number of the alloy, and the 0 after the decimal point means it is a final moulding casting.


Wrought aluminum alloy Numbering system

AlloyPrincipal Alloying elements
1xx.x> 99.000%
3xx.xSi Cu / Mg


With the development of society, the use of aluminum is becoming more and more widespread, therefore, it is helpful to know some basic knowledge of aluminum for our work and life.