What are the characteristics of low pressure casting
Release time:
2020-11-13
Low pressure casting means that the mold is generally placed above a sealed crucible, and compressed air is introduced into the crucible to cause a low pressure (0.06～0.15MPa) on the surface of the molten metal
Low pressure casting means that the mold is generally placed above a sealed crucible, and compressed air is introduced into the crucible to cause a low pressure (0.06～0.15MPa) on the surface of the molten metal, so that the molten metal rises from the riser pipe to fill the mold and control Solidified casting method. This casting method has good feeding and dense structure, easy to cast large thin-walled complex castings, no risers, and a metal recovery rate of 95%. No pollution, easy to realize automation. However, the equipment cost is high and the production efficiency is low. Generally used for casting non-ferrous alloys.
Low pressure casting can use sand, metal, graphite, etc. The filling process is different from gravity casting such as metal casting and sand casting, and it is also different from pressure casting with high pressure and high speed filling. It has the following advantages:
1) Filling with pure liquid metal improves the purity of castings. Since the molten slag generally floats on the surface of the molten metal, the low-pressure casting is filled with the molten metal in the lower part of the crucible through the riser pipe, which completely avoids the possibility of the molten slag entering the mold cavity.
2) The liquid metal filling is stable, reducing or avoiding the tumbling, impact, and splashing of the liquid metal during filling, thereby reducing the formation of oxide slag.
3) The casting has good moldability. The molten metal is filled under pressure, which can improve the fluidity of the molten metal, which is beneficial to the formation of castings with clear contours and smooth surface, and is more beneficial for the molding of large thin-walled castings.
4) The casting crystallizes and solidifies under pressure, which can be fully fed and the casting structure is dense.
5) Improve the yield of molten metal. Under normal circumstances, there is no need for a riser, and the uncondensed metal in the riser pipe can be refluxed to the crucible for repeated use, which greatly improves the yield of molten metal. Generally up to 90%.
6) Convenient production and operation, good working conditions, high production efficiency, easy realization of mechanization and automation, low-pressure casting also has some shortcomings, equipment and mold investment is relatively large; in the production of aluminum alloy castings, the crucible and riser pipe are in long-term contact with molten metal , Easy to be corroded and scrapped, will also make the molten metal increase iron and deteriorate the performance.
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Copyright: Jinan Laizhi CNC Equipment Co., Ltd.
