This means that this extrusion is a 4000 series aluminium alloy that has 4.0% of the magnesium content. 4000 series aluminium alloys are non-heat treatable and contain at least 4.0% magnesium with a maximum of 1.0% copper. 4041 is a non-heat treatable alloy, and is often used in general purpose applications. The mechanical properties of this material are not as good as those of 4043, but it does have better formability and weldability, and it is less likely to suffer from stress corrosion. 4043 is a non-heat treatable alloy that is used for many general purpose applications. The mechanical properties of this material are better than those of 4041, but it is less likely to suffer from stress corrosion. 4047 is a non-heat treatable alloy with high magnesium content. It is used for many general purpose applications. The mechanical properties of this material are better than those of 4043, but it is less likely to suffer from stress corrosion. What does 4040 mean for aluminum extrusion? This means that this extrusion is a 4000 series aluminium alloy that has 4.0% of the magnesium content. 4000 series aluminium alloys are non-heat treatable and contain at least 4.0% magnesium with a maximum of 1.0% copper. The mechanical properties of this material are not as good as those of 4043, but it does have better formability and weldability, and it is less likely to suffer from stress corrosion. Are 4040 aluminum extrusion good? They are a great option for those who need a strong and durable material that is also lightweight. 4040 aluminum extrusions are great for a variety of applications including construction, manufacturing, and automotive applications. Is 4040 aluminum extrusion strong? It's strength is due to the fact that the alloy contains a high percentage of magnesium which imparts the material with great strength, hardness and wear resistance. Is 4040 aluminum extrusion heat treatable? No, 4040 is not a heat treatable alloy. Heat treating is a process that can be used to improve the mechanical properties of certain metals. However, it is not a viable option for aluminum alloys as the properties of aluminum cannot be significantly improved by heat treating. This means that 4040 aluminum extrusions cannot be strengthened by heat treating, but they can still be used in applications where high strength is needed. See more details about 4040 aluminum extrusion in AliExpress Video Page.