Ductile iron castings have been used in almost all major industrial sectors, requiring high strength, plasticity, toughness, wear resistance, resistance to severe thermal and mechanical shocks, high or low temperatures, corrosion resistance and dimensional stability. In order to meet these variations in the conditions of use, ductile iron has many grades that provide a wide range of mechanical and physical properties.
Most ductile iron castings, as specified by ISO 1083, are mainly produced in non-alloyed state. Obviously, this range includes high strength grades with a tensile strength greater than 800 Newtons per square millimeter and an elongation of 2%. The other extreme is a highly plastic grade with an elongation of more than 17% and a correspondingly low intensity (minimum of 370 Newtons per square millimeter). Strength and elongation are not the basis for the designer's choice of materials, while other decisive important properties include yield strength, modulus of elasticity, wear and fatigue strength, hardness and impact properties. In addition, corrosion resistance and oxidation resistance as well as electromagnetic properties may be critical to the designer. In order to meet these special uses, a set of austenitic ductile irons, usually called Ni-Resis ductile iron, was developed. These austenitic ductile irons are mainly alloyed with nickel, chromium and manganese and are listed as international standards.
It is a pearlitic spheroidal graphite cast iron with medium and high strength, medium toughness and plasticity, high comprehensive performance, good wear resistance and vibration damping, and good casting process performance. It can be changed by various heat treatments. Mainly used in various power machinery crankshafts, camshafts, connecting shafts, connecting rods, gears, clutch plates, hydraulic cylinders and other components.