What is Ni-hard and Ni-resist cast iron?
Ni-hard – Typical microstructure of white cast iron consists of iron carbide in pearlite matrix. Its hardness is 300-500BHN. Increasing the brittle iron carbide increases the hardness and wear-resistance of cast iron but impairs impact resistance. Addition of Nickel (3.5-6.5%) and chromium (1.5-9.0%) to cast iron gives a very good wear-resistant material whose microstructure consists of massive carbides in austenite-martensite matrix. Ni strengthens the matrix and adding chromium, which is a carbide stabilizer, counteracts the graphitizing effect of Ni. This wear-resistant material is Ni-hard cast iron. Ni-resist – These are austenitic cast irons in which Ni content lies between 13.5 and 36%.
