液面加压控制系统的快速性对铸件品质的影响

Effects of Speed Ability of Liquid Surface Pressure System on Low Pressure Castings Quality

根据流体力学原理,揭示出液面加压控制系统快速性越好,在填充水平面时,其速度高于液面上升的垂直速度的倍数就越大(可达100倍),因而在该处产生液、气两相流并向垂直部分推进,造成最后填充部位出现铸造缺陷,故快速性差的比例调节器比快速性好的组合阀更适用于作低压铸造的液面加压控制系统。

Based on the fluid mechanics principle,it is shown that if the speed ability of liquid surface pressure system is the better,the horizontal velocity will be higher（it can be up to hundreds times.）than the vertical velocity,when the molten metal fills the horizontal plane.So liquid-gas two-phase flow will appear in the horizontal plane,and it will move towards the vertical area,leading to the generation of cast defects at those areas finally filled.Therefore,the proportional controller with a slower speed ability than the combinational valves is more suitable for the low pressure die casting of liquid surface pressure system.