ductile iron means that it can get globular graphite through spheroidizing and inoculation，improve the mechanical properties of cast iron effectively, ductile Iron also especially improves the plasticity and toughness , it gets strength which is higher than the steel .
Ductile Iron is a kind of high strength casting iron material which develops from 1950s，ductile Iron’s comprehensive performance is close to steel，it is based on the excellent performance，ductile Iron has been successfully used in casting complex stress, strength, toughness, wear resistance requirements of the higher parts. Ductile iron has been the rapid development of casting iron material which application is very extensive. “replacing steel with iron”mainly refers to the ductile iron.
Ductile iron castings almost gets application in all major industrial sectors，these departments have requirments of high strength, plasticity, tenacity, thermostability or low temperature ,corrosion resistance and dimensional stability,etc.
In order to satisfy these changes which are in the conditions of using ，ductile iron has many numbers , it offers a wide range of mechanical and physical properties.
The passage above talks about the concept of ductile iron
ductile iron have almost been applied in many main industrial sectors, where high strength, good plasticity, excellent toughness and wear resistance, intense heat and mechanical shock resistances, high temperature or low temperature resistance, anti-corrosion and dimensional stability are requested. In order to meet these changes in use, ductile iron have multiple plate numbers at present, which provides a wide range of mechanical properties and chemical properties.
Most of ductile iron are produced in non-alloyed forms according to the provisions of ISO1083. Obviously, the range contains those plate numbers, which features tensile strength > 800n/mm2 and extensibility=2%. There’s those ones having features of high plasticity, which can reach >17% in extensibility but corresponding tensile strength is lower (the minimum=370n/mm2). The 2 properties mentioned above aren’t the only standards based on selecting materials. Other important performances are determined, including yield strength, elastic modulus, wearability, fatigue strength, stiffness and impact strength.
Pearlitic ductile iron have features of medium-high strength, medium toughness and plasticity, high comprehensive performance, excellent wearability and anti-vibration and good casting property. These properties can be changed by different heat treatments. They’re mainly used in crankshafts, crankshafts, connecting shafts, link rods, gears, clutch discs, hydraulic cylinders and other components in all kinds of power machines.