Lift tube in low pressure casting

Abstract

The invention discloses a lift tube in low pressure casting. The lift tube in the low pressure casting comprises an outer tube and an inner tube, wherein the outer tube and the inner tube are concentrically arranged, a silicon carbide thin film is arranged on the inner wall of the inner tube, a damper which is fixedly connected with the lift tube is arranged at the inlet position of the lift tube, and a plurality of small holes are evenly formed in the side face of the damper. According to the lift tube in the low pressure casting, metal splashing in pouring and impact agitation of remained metal at the bottom of a crucible are reduced, inclusion defects are gradually overcome, casting quality is obviously improved, meanwhile the lift tube has expected intensity, good bearing ability and abrasion resistance due to the fact that structure of concentrically arrangement of a metal tube and a non-metal tube is adopted, and moreover unexpected chemical reaction between the metal tube and molten metal is effectively prevented from happening due to the fact that the silicon carbide thin film and a fire-resistant cement tube can well prevent the molten metal from being immersed into the metal tube.

Description

technical field [0001] The invention relates to the field of die-casting machines, in particular to a low-pressure casting liquid riser. Background technique [0002] Low-pressure casting is a method of filling the cavity with liquid metal under lower pressure to form a casting. The process is to pass dry compressed air into a sealed container. Under the action of gas pressure, the liquid metal Rising along the riser pipe, it enters the mold cavity smoothly through the gate, and maintains the gas pressure on the liquid surface in the crucible; after the casting is completely solidified, the gas pressure on the liquid surface is released, so that the unsolidified liquid metal in the riser pipe Reflux the crucible and remove the casting. [0003] Due to the relatively stable liquid metal filling in low-pressure casting, good casting formability, clear outline, smooth surface, compact structure, high mechanical properties, high process yield, good working conditions, and easy ...

AI Technical Summary

Problems solved by technology

[0004] 1. When pouring, when the liquid metal enters the cavity through the riser, metal splashes are likely to occur, causing secondary oxidation inclusions, cold beans and other casting defects;

[0005] 2. When the liquid metal flows back, the liquid metal flow directly impacts the bottom of the crucible, which will form an impact and agitation on the metal at the bottom of the crucible, resuspending the inclusions at the bottom of the sedimented crucible, and these inclusions will enter with the liquid metal flow in the next pouring Castings, causing inclusion defects in castings;

[0006] 3. For the metal liquid riser, since the temperature of the molten metal in the crucible or melting furnace is often as high as 800 to 1000°C, if the metal liquid riser (for example, iron pipe) is soaked in high temperature metal liquid (for example, aluminum water), it will cause the metal components of the riser to enter the high-temperature molten metal. If the two metals are not the same, it will seriously affect the quality of the product, and the riser itself will also be greatly damaged. In addition, due to Metal expands when heated, which also affects the metal riser

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