This research investigated the microstructure and properties of brake shoes produced from high phosphorus grey cast iron with varied proportions of alloy elements. The contents of three main alloy elements in three brake shoes were 3.37C–1.64Si–2.21P, 3.17C–1.82Si–2.00P and 2.96C–2.03Si–1.79P. The graphite–austenite eutectic temperatures varied with chemical composition choice, while phosphide eutectic temperature started at 936 °C for all three compositions. The microstructures show that differences in carbon, silicon and phosphorus in the high phosphorus grey cast iron brake shoes affected number, density and length of graphite flakes. Increasing the phosphorus (from 2.00–2.21%wt) and carbon (from 3.17–3.37%wt) increased the porosity and decreased the steadite formation leading to the lowest hardness and wear resistance. The highest area fraction of steadite phase (37%) and the lowest porosity were the brake shoes with 1.79wt% phosphorus, which obtained the highest hardness of 283 HB and the highest wear resistance, superior to the brake shoes with 2.00wt% or 2.21wt% phosphorus. The highest 2.21 wt% phosphorus in brake shoe gave the highest area fraction of ferrite soft phase and the lowest area fraction of steadite hard phase, with overall the lowest hardness of 223 HB.

本研究调查了由不同比例合金元素的高磷灰铸铁制成的制动蹄的微观结构和性能。三种制动蹄中三种主要合金元素的含量分别为3.37C-1.64Si-2.21P、3.17C-1.82Si-2.00P和2.96C-2.03Si-1.79P。石墨-奥氏体共晶温度随化学成分的选择而变化，而所有三种成分的磷化物共晶温度均从 936 °C 开始。微观结构表明，高磷灰铸铁闸瓦中碳、硅和磷的差异影响石墨片的数量、密度和长度。增加磷（从 2.00-2.21%wt）和碳（从 3.17-3.37%wt）会增加孔隙率并减少斯氏体的形成，导致硬度和耐磨性最低。斯氏体相面积分数最高（37%），孔隙率最低的是磷含量为1.79wt%的制动蹄，其硬度最高为283HB，耐磨性最高，优于磷含量为2.00wt%或2.21的制动蹄wt% 磷。闸瓦中磷含量最高的 2.21 wt% 铁素体软相的面积分数最高，而斯氏体硬相的面积分数最低，整体硬度最低，为 223 HB。