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。Lowpressurecastingisamethodofmoltenmetalfillsthecavityunderthepressureandthenformsthecasting。duetothepressureisnothigh，soitiscalledlowpressurecasting。Thetechnicalprocessis:inthehermeticcrucible(orsealedpot)injectingthedrycompressedair,moltenmetalundertheeffectofgaspressuregoesupalongthepipethenthroughthegateplacidlyrunintothecavity,thenkeepthegaspressureuppertheliquidinthecrucibleuntilthecastingsolidificationtotally.thenremovethegaspressuretomaketheunfreezingmetalinthepipeforopeningrunbackintothecrucibleandatthesametimeusethecylinderopencavitytodetrusionthecasting。低压铸造独特的优点表现在以下几个方面：Theuniquecharacteristicsoflowpressurecastingperformedasbelow1.液体金属充型比较平稳；Moltenmetalfullthecavitysmoothly。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；Theformingpropertyisgoodandinfavorofformingtheedgeshapenessandsurfacebrightandclean。Itisfavorableforthelargecastingpartswiththinsectioncasting3•铸件组织致密,机械性能高；Thetissueofcastingisdensification,andmechanicalbehaviorishigh。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：Theuniquecharacteristicsoflowpressurecastingperformedasbelow1.液体金属充型比较平稳；Moltenmetalfullthecavitysmoothly。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；Theformingpropertyisgoodandinfavorofformingtheedgeshapenessandsurfacebrightandclean.Itisfavorableforthelargecastingpartswiththinsectioncasting3•铸件组织致密，机械性能高；Thetissueofcastingisde...
