Grain Refinement & Solidification Control for Cast Copper Alloys
铸铜合金的晶粒细化与凝固控制
标签：晶粒细化, 变质处理, 冷铁, 凝固控制
细晶提升砂型铜铸件的强度与气密性：铝青铜靠 3–4% 铁（C95400 常规做法）或加 0.05–0.1% 钛细化柱状晶；黄铜可加 0.02–0.05% 锆；锡磷青铜加微量混合稀土（铈镧 0.02–0.05%）减少粗大枝晶。工艺配合：薄壁热节处放乙炔焰熏黑的冷铁提高局部形核率，浇温每降 10–20℃ 晶粒明显变细，但须防浇不足。晶粒度按 ASTM E112 评级，细化后铝青铜抗拉强度可提高 10–15%，气密试验合格率同步改善。
Fine grains raise strength and pressure-tightness in sand-cast copper alloys: aluminium bronze refines columnar grains with 3–4% Fe (standard in C95400) or 0.05–0.1% Ti; brass takes 0.02–0.05% Zr; phosphor tin bronze uses trace Ce-La mischmetal (0.02–0.05%) against coarse dendrites. Process support: soot-blackened chills at thin hot spots boost local nucleation, and dropping pour temperature 10–20°C visibly refines grain — watch for misruns. Grade grain size to ASTM E112; refined aluminium bronze gains 10–15% tensile strength with better leak-test pass rates.