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近年来,对铸件质量的要求明显地提高,特别是致密度、强度和机械加工性能。为了满足这些要求使用低含磷量的原料。对需要高致密度去耐液压和气压的铸件,如阀类铸件,为获得最大致密度而保持低含磷量是重要的。但是低含磷量对铸铁的致密度有着影响的同时,会出现金属粘砂和结疤缺陷。磷在铸铁凝固时,偏析在晶界和热节上,在950℃凝固成一种复杂的,低熔点的共晶。这种磷共晶在个别区域
In recent years, the requirements for the quality of castings have been significantly improved, particularly in terms of density, strength and machinability. In order to meet these requirements, the use of low phosphorus content of raw materials. For castings that require high densification to withstand hydraulic and pneumatic pressures, such as valve castings, it is important to maintain a low phosphorus content for maximum density. However, the low phosphorus content has an impact on the density of cast iron at the same time, there will be metal sticky sand and scarring defects. Phosphorus in the cast iron solidification, segregation in the grain boundary and hot section, solidified at 950 ℃ into a complex, low melting point eutectic. This phosphorus eutectic in individual areas