25 Cr 鋳鉄の鋳放し組織および衝撃摩耗特性の制御

抄録

  High chromium white cast irons are now being produced in large tonnages for the crushing, grinding and mineral handling industries because of their excellent resistance to abrasion. This alloy have been used more widely in the austenite destabilization and air hardening conditions when a predominantly martensitic matrix structure is obtained. However, this alloy can be used in the as cast condition, when the matrix contains large amounts of austenite, which is obtained by rapid cooling of casting after solidification. The effect of holding time in the sand mold from pouring to shakeout is discussed in relation to microstructure, hardness, mechanical properties and abrasive wear resistance on as cast and air hardened 3 mass % C-25 mass % Cr white cast irons. Castings shaked out up to 1 hour after solidification result in the predominantly austenitic structure without any transformation to pearlite or bainite, consequently have high hardness, excellent resistance to abrasion and good hardenability.