一、大断(丆口)球铁件的显微组织通常薄壁铸件中球状石墨形成很好,石墨分布于珠光体,铁素体或者混合体(珠光体+铁素体)基体中。增加铸件壁厚,不仅在凝固期间,而且在γ—α转变期间都会降低冷却速度。这样便导致石墨形状与尺寸的变化,同时也必然影响金属基体和机械性能的变化。 First, a large broken (mouth) Ductile Iron Microstructure Usually thin-walled castings in the formation of spherical graphite, graphite distributed in the pearlite, ferrite or mixture (pearlite + ferrite) matrix. Increasing the wall thickness of the casting reduces the cooling rate not only during solidification, but also during the γ-α transformation. This will lead to graphite shape and size changes, but also inevitably affect the metal matrix and mechanical properties change.