Ni-Resist Cast iron Specificcation
Addition of sufficient amount of nickel to cast iron produced an austenitic structure which has unique and superior properties. Ni-resist cast iron is devided in two groups.These are flake and ductile spheroidal iron.Properties and specification of these irons have mentioned in some standards as DIN 1694, ASTM A436 and A439. Fllowing table shows equivalent grades in different standards.
Pattern making allowance ( shrinkage allowance) of ni resist cast irons depends on nickel content. up to 25% nickel, foundryman should consider 2% shirinkage. For more than 25 to 32% nickel content 1.5% shirinkage allowance should be considered.
As time passes, ductile grades , because of higher strength,ductility and elevated temprature properties, are becoming more prominent. However gray alloys with lower cost, fewer foundry problems and better machinability are still in many foundries.In general the properties of these alloys are as following :
Corrosion Resistance -
Wear resistance -
Toughness and low temperatore properties-
Heat Resistance -
ASTM A436 Gray Ni-Resist Iron
ASTM A439 Ductile Ni-Resist Iron