Improve pouring liquid metal mold in pressure but also by the electromagnetic force to the liquid metal to achieve, this approach is the magnetic casting. Its basic principle isto cast off the magnetic pump is installed in the liquid metal to pass, in order to establish the magnetic field; at the same time, DC are also introduced into this segment has established the field of liquid metal flow, in alternating magnetic and electric fields, the formation of the electromagnetic force direction and the liquid metal flow the same, in order to improve the liquid metal mold filling pressure. This method can be used to make the metal in the mould cavity flow than static casting by direct velocity metal indenters the runner to increase 2~2.5 times. In the use of such casting method has several points should be paid attention to:
1 liquid metal is poured into the runner must maintain the continuity of liquid metal flow, intermediate cannot appear to flow. So we must pay great attention to the spruesize design and electromagnetic pump and current value choice.
The 2 magnetic pump should be placed in the water outside the level, thereby reducing the consumption of metal casting system.
3 liquid metal mold filling should be carried out in magnetic pump pressure 0.01~0.05MPa, so as to ensure the liquid metal to flow speed requirements in the cavity, avoiding intermediate drying. In the mold is filled, we should raise the magnetic pump pressure to 0.12~0.3MPa, to improve the feeding ability of castings, castings appear to prevent hole.
4 in the design of gating system should make in this part of the runner of magnetic pump within the liquid metal in the last solidification, which must establish the following:casting solidification sequence -- other gating system -- magnetic pump ingate,because before the pressure can only be built magnetic pump and liquid metal in themold to maintain the liquid metal magnetic the pump runner in the no solidification.Cast researchers to adopt this method in investment casting ceramic shell casting thealloy compressor blade body length up to 260mm. When pouring the liquid metal fillingthe cavity of the blades is carried out in the electromagnetic pump pressure 0.035~0.04MPa condition. This ensures that the liquid metal to 1.4~1.7m/s in the cavity flow rate, thus ensuring the blade surface of cast no cold shut flow mark,forming good. The centrifugal casting this blade is the blade body twist, the presence of cold insulation and loose leaf surface of casting, qualified rate and low metalutilization coefficient.
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