低压铸造和重力铸造

力和低pressure casting and high pressure castinLo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 method of molten metal fills the cavity under the pre ssure and then forms the casting .due to the pressure is not high ,so it is cal led low pressure casting .The technical process is : in the hermetic crucible ( or sealed pot ) injecting the dry compressed air ,molten metal under the effectof 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 untilthe casting solidification totally .then remove the gas pressure to make the un freezing 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 sur face bright and clean .It is favorable for the large casting parts with thin se ction casting3．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； 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 se ction casting3．铸件组织致密，机械性能高；.high is mechanical behavior,anddensification iscasting of The tissue4．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； 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 sur face bright and clean .It is favorable for the large casting parts with thin se ction casting3．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％。

Improve the yield rate of the molten metal,normally don't need the deadhead,and make the yield rate a high improvement,usually can achieve 90%.此外，劳动条件好；设备简单，易实现机械化和自动化，也是低压铸造的突出优点。

in addition ,working condition is good ,equipments is not complicated and easyto realise mechanization and automation are also the highlight advantage .重力铸造是指金属液在地球重力作用下注入铸型的工艺，也称浇铸。

广义的重力铸造包括砂型浇铸、金属型浇铸、熔模铸造、消失模铸造，泥模铸造等；窄义的重力铸造专指金属型浇铸。

Gravity casting is that molten metal run in to the mould with the pressure of e arth gravity ,it is also named pouring casting, generalized pouring casting inc l. Sand casting ,metal mould casting ,investment casting ,evanescent mold casti ng and mud die casting ,ect. Narrowly pouring casting is the metal mould castin g .把金属材料做成所需制品的工艺方法很多，如铸造、锻造、挤压、轧制、拉延、冲压、切削、粉末冶金等等。

其中，铸造是最基本、最常用的工艺。

There are many ways to make the metal materials into the requested goods ,such as ,casting ,forging ,extrsion ,rolling ,madrelling ,punching ,cutting , powder metallurgy ,ect. Among them ,casting is the most basic and common technology熔化的金属液注入用耐高温材料制作的中空铸型内，冷凝后得到预期形状的制品，这就是铸造。

所得到的制品就是铸件made by heat-mouldaltitude medium injected into thebeing metal The molten resisting material ,then freezing to the shape as anticipated ,that is the pr ocess of the casting . and the freezing pasts is the casting.铸造可按铸件的材料分为黑色金属铸造（包括铸铁、铸钢）和有色金属铸造（包括铝合金、铜合金、锌合金、镁合金等）。

精密铸件厂专业从事有色金属铸造，重点是铝合金和锌合金铸造。

Casting can divide to black metal casting (incl. Cast iron, cast steel ) and no nferrous metals (incl. Aluminium alloy , copper alloy , zinc alloy , magnesium alloy ,ect.) .Precision casting factory are specially engaged in nonferrous metal casting ,and aluminium alloy and zinc alloy are the emphasises .按铸型的材料分为砂型铸造和金属型铸造。

精密铸件厂对这两种铸造工艺都得心应手，并自行设计、制造这两类铸造模具。

According to the material ,casting can devide to sand mould casting and metal m ould casting . Precision casting is facility with the two types of castings and design by themselves and produce the two typses moulds .压力铸造是指金属液在其他外力（不含重力）作用下注入铸型的工艺。