There are over 1000 registered aluminium alloy grade number in the world. Each grade has different status,namely obvious difference in strength,hardness,corrosion resistance, machinability,weldability and ornamental property. It is hard and unnecessary to satisfy all the afoesaid requirements when you select aluminium alloy. Set the order of priority according to requirements in term of products performance of product must be guaranteed.

  
Strength

   Strength is an important factor to be considerde in product design, especially when aluminium alloy conponent is used ad structural unit,proper alloy should be chosen according to pressure load. pure aluminium. has the lowest strength while 2*** series and 7***series aluminium alloy has the highest strenght. To some extent,strength and hardness have positive correlativity.

    
Hardness

   Many customers pay more attention to the hardness of aluminium material.Hardness is directly related with chemical composition of alloy.Different grades vary in hardness. The hardness declines gradually in the order from 7*** series,2*** series,4*** series,6*** series,5*** series,3*** series, and 1 grade series.

   
Corrosion Resistance

  Corrsion resistance includes resstance against chemical corrosion, electrochemical corrosion, strees corrosion,etc. Generally,pure aluminium-grade 1 has the highest corrosion  resistance. Grade 5 has good perfprance,which is followed by 3*** series and 6***series; 2*** series & 7*** series bad performance. In term of corrosion resistance, select aluminium material according to its working environment. If aluminium alloy weth igh strenty is used in corrosive environment,various anti-corrosion alclad matereals have to be employed.

   
Processability

  Processability includes shaping property and machinability. Shaping property is correlative with status,generally material with high strength is not casy to be shaped.If the grade number of aluminium alloy is determined,the strength at different status has to be considered.If aluminium material is to be bent,drawn or punched,complete annealing of aluminium alloy has the best performance in shaping while material under heat treatment has the worst performance. The machinability of aluminium alloy is highly correlative with composition of alloy. Generally the alloy with high strength has relatively high machinability while the alloy with low strength has lower machinability. If the alloy is used to producemould or machanical part,which requires machining, the machinability of alloy is an important factor to be considered.

   
Weldability

  It is not a problem to weld most of aluminium alloy some 5*** series aluminium alloy is specially designed for welding. It is relatively hard to weld some 2*** series and 7*** series aluminium alloys.

   
Ornamental property

   If aluminium material is applied to decoration or some special case. its surface must be anodized or finished to obtain corresponding color and surface texture. In this case,It's ornamental property is an important factor to be considered. Generally, material with high corrosion resistance has excellent performance in anodizing ,surface treatment and finishing.

   
Other Features

   Besides the aforesaid properties, you should take electrical conductivity,wearaility and heat resistance into consideration while selecting material.