1、低压铸造和重力铸造Lowpressurecastingandhighpressurecasting 低压铸造是液体金属在压力作用下充填型腔，以形成铸件的一种方法。由于所用的压力较低，所以叫做低压铸造。其工艺过程是：在密封的坩埚（或密封罐）中，通入干燥的压缩空气，金属液在气体压力的作用下，沿升液管上升，通过浇口平稳地进入型腔，并保持坩埚内液面上的气体压力，一直到铸件完全凝固为止。然后解除液面上的气体压力，使开液管中未凝固的金属液流坩埚，再由气缸开型并推出铸件。Low pressure casting is a
2、method of molten metal fills the cavity under the pressure and then forms the casting .due to the pressure is not high ,so it is called low pressure casting .The technical process is : in the hermetic crucible (or sealed pot ) injecting the dry compressed a
3、ir ,molten metal under the effect of gas pressure goes up along the pipe then through the gate placidly run into the cavity ,then keep the gas pressure upper the liquid in the crucible until the casting solidification totally .then remove the gas pressure t
4、o make the unfreezing metal in the pipe for opening run back into the crucible and at the same time use the cylinder open cavity to detrusion the casting . 低压铸造独特的优点表现在以下几个方面： The unique characteristics of low pressure casting performed as below : 1．液体金属
5、充型比较平稳； Molten metal full the cavity smoothly. 2．铸件成形性好，有利于形成轮廓清晰、表面光洁的铸件，对于大型薄壁铸件的成形更为有利； The forming property is good and in favor of forming the edge shapeness and surface bright and clean .It is favorable for the large casting parts with thin section
6、casting 3．铸件组织致密，机械性能高； The tissue of casting is densification ,and mechanical behavior is high . 4．提高了金属液的工艺收得率，一般情况下不需要冒口，使金属液的收得率大大提高，收得率一般可达90％。 低压铸造独特的优点表现在以下几个方面： The unique characteristics of low pressure casting performed as below : 1．液体金属充型比较平稳
7、； Molten metal full the cavity smoothly. 2．铸件成形性好，有利于形成轮廓清晰、表面光洁的铸件，对于大型薄壁铸件的成形更为有利； The forming property is good and in favor of forming the edge shapeness and surface bright and clean .It is favorable for the large casting parts with thin section castin
8、g 3．铸件组织致密，机械性能高； The tissue of casting is densification ,and mechanical behavior is high . 4．提高了金属液的工艺收得率，一般情况下不需要冒口，使金属液的收得率大大提高，收得率一般可达90％。 低压铸造独特的优点表现在以下几个方面： The unique characteristics of low
