1.Required strength Consider what type of strength characteristics are needed for the part, such as tensile strength, compression strength, or yield strength. The material choice will depend on the intended application and the load that the part will be subjected to.   2.Wear resistance Consider whether the part will be subjected to abrasion or friction and choose a material that can withstand those conditions for the required duration of use.   3.Corrosion resistance Consider whether the part will be exposed to harsh environments that could cause corrosion or rust over time, and choose a material that can resist or minimize these effects.   4.Machinability Consider whether the material will be easy to machine and produce good surface finishes without excessive tool wear or breakage.   5.Cost Consider the cost of the material, taking into account how it will affect the overall cost of the part, including machining costs, finishing costs, and any subsequent assembly requirements it may have.