Microstructure and Mechanical Properties of 28 % High Chromium White Cast Iron

The chemical composition of the metal and carbide phase, hardness, and common mechanical properties of cast iron, ICH28H2 cast iron, a type of high-chromium white cast iron, and the dependence of hardening, annealing, and tempering process types were studied. Therefore, annealing and hardening heat treatments were employed, and the results were compared to measurements in the as-cast state. The metal matrix exhibited content within the range of 16.8% to 19.7% Cr and 71.9% to 76% Fe, while the carbide phase showed 63.4% to 64.7% Cr and 23% to 24.8% Fe. The Cr carbide in high Cr white iron primarily appeared as (Fe, Cr)7C3 type, leading to the calculated chemical formula of the eutectic carbide as (Fe2Cr5)C3. The as-cast white iron displayed a hardness of 53 HRC, which increased marginally to 56.2 HRC after hardening. This suggests that the 28% Cr white iron alloy does not exhibit a significant hardness enhancement compared to the cast state, attributed to its high Cr content. The hardness of the metal phase directly influences the overall hardness change of the alloy, while the carbide hardness is dependent on its Cr content. Abrasive wear studies revealed that 28% Cr white cast iron exhibited superior wear resistance in the as-cast state compared to the hardened state, aligning with research indicating that cast iron demonstrates optimal wear resistance in its cast state.