Austenitic alloy cast iron with high wear resistance - contains nickel, chromium, copper and manganese and has narrow hardness range after annealing

摘要

Austenitic cast iron, for mfg. castings exposed to frictional wear, esp. thin-walled castings with high hardness. The alloy has compsn. 2.5-3.5% C, 1-2.5% Si, 0.2-8.0% Mn, 1-5% Cr, 2-5.5% Cu, 10-20% Ni, 0.5% P, 0.1% S, remainder iron plus is not >2% impurities. The castings have an initial Brinell hardness (BHN) >300 kp/cm2; and are then soft-annealed at 550-850 degrees C for 0.25-2.0 hrs. to obtain a desired BHN >250 kp/cm2. The initial BHN is pref. 365-420, the castings then being annealed over 1 hr. at 800-820 degrees C to obtain BHN 290-350 kp/cm2. The castings are pref. used for rings and gliding sealing rings (in pumps) or for seals, valve seat rings, or bushes in IC engines etc.