Relationship between casting quality and porosity
Characteristics of stomata: most of them are near the surface, with
large size, and the inner surface of oval or pear shaped pores is
Pore formation process:
Pouring - water vapor (one part is discharged from the parting surface
and the vent hole, the other part is gathered on the surface as a
high-pressure center point) - the air pressure rises and dissolves into
the metal - one part escapes from the molten metal - gate, the rest is
in the casting, forming the air hole.
Prevent the occurrence of porosity: reduce the amount of molding sand (core sand) and increase the ability of mold exhaust.
析出气孔: 溶于金属液中的气体在冷凝过程中，因气体溶解度下降而析出，使铸件形成气孔，原因: 金属熔化和浇注中与气体接触(H2 O2 NO CO等) 特征: 分布广，气孔尺寸甚小，影响气密性。
Precipitated porosity: during the condensation process of gas dissolved
in liquid metal, the gas will be precipitated due to the decrease of gas
solubility, which will cause the formation of porosity in the casting.
The reason: metal melting and gas contact during pouring (H 2O 2No Co,
etc.) feature: wide distribution, very small pore size, affecting air
反应气孔: 金属液与铸型材料，型芯撑，冷铁或溶渣之间，因化学反应生成的气体而形成的气孔。如: 冷铁有锈 Fe3O4 + C –Fe + CO 冷铁附近生成气框格护坡模具 箱体护坡模具 华尔街铜牛 电阻柜 接地电阻柜 电缆保护接地箱 隔离墩模具 化粪池模具
Reaction pore: the pore formed by gas generated by chemical reaction
between molten metal and casting material, core support, cold iron or
slag. For example: there is rust in cold iron, and pores are formed near
Fe3O4 + C – Fe + CO cold iron to prevent: the surface of cold iron core
support shall be free of rust, oil stain and dry.