Abstract
High chromium white cast irons (HCWCIs) are widely used in abrasive and corrosive environments. However, alloys compliant with industrial specifications often exhibit markedly different performance. This paper investigates the influence of the Cr/C ratio and carbide volume fraction (%CVF) on phase evolution, microstructure, and degradation behaviour in twelve HCWCI alloys with varied Cr and C contents. Thermodynamic predictions from Thermo-Calc simulations were complemented by real-time thermal analysis to account for non-equilibrium solidification. Phase constitution and transition behaviour were validated with optical and scanning electron microscopy, and X-ray diffraction. Mechanical properties, three-body abrasion wear resistance, and electrochemical corrosion behaviour in synthetic mine water(pH 3) were evaluated. Subtle compositional variations within ASTM A532 limits produce pronounced differences in carbide morphology, matrix stability, and degradation response. An optimal compositional window, defined by Cr/C of ~12 and %CVF of ~33, provides a favourable balance between hardness, fracture toughness, and abrasion resistance, whereas corrosion resistance is primarily controlled by retained Cr in the matrix. The findings establish a microstructure-based framework for the rational optimisation of HCWCIs for demanding wear-corrosion service conditions.