大型薄壁铝合金铸件树脂砂型低压铸造设备的研究

Low-pressure Casting Equipment and Technologies for Thin-wall Al-Alloy Parts in Resin Sand Molds

介绍了一种树脂砂型专用的低压铸造设备,适用于优质大型薄壁铝合金铸件的生产。设备工作时,熔体在压缩空气的作用下按设定工艺自下而上充型,并在压力下凝固成形。该设备使用了自行研制的组合阀,具有良好的压力跟踪性能。充型速率、加压顺序和加压时间等工艺参数均由自行研制的控制软件精确控制。利用该设备,铸件单件浇注重量1.8 t。与传统的重力铸造相比,低压铸造生产的铸件易获得良好的冶金质量,组织致密,抗拉强度和延伸率高。用该设备生产的A357铸件,其本体切取试样σb>320 MPa,δ>5%,针孔度级别低。目前国内已有几家单位采用这种设备和工艺,生产出了优质大型薄壁铝合金铸件。

A low pressure casting equipment has been developed, which is specially designed for the production of large-size thin-walled high-quality aluminum alloy parts with resin sand molds. In this equipment, molten metal will be pushed upward into the mold at predetermined rate by compressed air, and solidified at an increased pressure. The equipment uses assembled valve system developed ourselves, and has sensitive pressure-adjusting property. All of the casting parameters, including filling rate, pressure-exerting sequence, pressure hold time etc. , can be closely controlled by a self-designed computer program. Up to 2 tons casting can be produced with the equipment. Compared to the castings produced under conventional gravity conditions, the castings under counter-gravity condition have generally high soundness, higher tensile strengths and ductility. For castings of A357 alloy, δb is greater than 320 MPa, and 8 is greater than 5%. The pinhole defects are also degraded obviously. The equipment and the technology have been widely adopted by several users in China for the production of large-size thin-walled aluminum alloy castings with high property requirements.