在机床铸造中,重型车床、鲍床、磨床、立式车床等床身道轨,常利用冷铁来铸造以获得致密的珠光体组织。这些机床道轨的断面比床身壁部粗大,为了避免薄壁部分产生白口和引起过大的铸造应力,铸铁成份应介乎一级与二级之间(注),但此种铸铁在自然冷却条件下,道轨部分将产生不利于耐磨的疏松组织,析出大块石墨,因此要 Casting machine tools, heavy lathes, abalone, grinding machines, vertical lathes and other bed rails, often using cold-iron to cast to obtain dense pearlite tissue. The cross section of these machine tool rails should be thicker than the bed wall, and in order to avoid white spalling and excessive casting stress in the thin wall parts, the cast iron composition should be between the first and second class (Note) Under the condition of natural cooling, the track part will produce loose tissue that is not good for wearability and large bulk graphite will be precipitated