The higher carbon content (2.7%~4.0%) inand the carbon existed mainly in the form of flake graphite ,the fracture is grizzly , so ,this kind of iron casting is called grey iron .
Grey iron casting process has characteristic of low melting (1145~1250℃), small shrinkage during the solidification process , compressive strength and hardness approaching carbon steel ,batter cushioning ability . In addition , it has good abrasion resistance due to the existence of flake graphite .It has batter castability and cutting process , too.
Grey iron casting process generally also includes nodular cast iron , mottled cast iron , inoculated cast iron , rare earth grey cast iron and so on.
Grey iron casting process is low cost and cheap , also widely applied , this kind of iron casting output more than 80 percent of the total output.
This kind of iron casting mainly apply to produce some parts that low load , abrasion resistant and shock absorber ,like machine tool bed , gear case , belt sheave , pedestal , cylinder body of automobile , cylinder heat , hand wheel and so on.
Its brand is letter “HT”+ digit (minimum tensile strength).