【摘要】 通过解剖铸件、金相分析、化学成分分析与定向凝固的方ＰＪ，研究了ＺＨＡ１６７－５－２－２．Ｌｉｍａ和Ｓｔｏｎｅ Ｂｒｏｎｚｅ三个牌号黄铜大型螺旋桨内铁的偏析及对晶 粒尺寸的影响，发现铁在后凝区富集，使后凝区晶粒比初凝区细。通过研究提 出：（ｌ）铝、锰黄铜大型铸件内铁的偏析难以避免；因而，（２）用于生产大型铸 件的黄铜含铁量不宜超过１％，以减少铁偏析的影响；（３）为了保证大型螺旋桨 压力面晶粒细密．应当采取控制凝固方向的措施。更多还原

【Abstract】 The macrosegregation of iron and its effect on grain size in large propeller castings made from alloys ZHA1 67-5-2-2, Lima and Stone Bronze are investi- gated with metallographical and chemical analysis along the blade section. The build-up of iron is taken place in the zone of last solidification, and finer grain size in that zone is found. The following conclusions can be reached from this investigation: 1) It is difficult that the macrosegregation of iron in large propeller castings made from high-strength brasses can be avoided. 2) It is expected that large castings made from high-strength brasses, the Fe content is limited to 1 % or so. 3) Solidification control must be carried out for latge casting in order that a fine grain size can be obtained on the press- ure surface of the propeller blade.更多还原