How to choose suitable sand for aluminum alloy casting ?
Release time：2019-10-28 16:49
In the process of aluminum alloy casting, the selection of sand is very important. The following is a brief introduction of Guorui technology to explain the importance of sand in the process of aluminum alloy casting.
Coated sand. Molding sand or core sand whose surface is covered with a layer of solid resin film before molding. There are two kinds of laminating processes: the cold process dissolves the resin with ethanol, and in the process of sand mixing, urotropine is added to make them cover the surface of the sand, ethanol volatilizes to obtain the coated sand; the hot process preheats the sand to a certain temperature, adds resin to make it melt, stirs to make the resin cover the surface of the sand, adds Urotropine aqueous solution and lubricant, cools, breaks and sieves to obtain the coated sand Sand.
The hot box coated sand process is to inject the sand mixed with casting sand, thermosetting resin and catalyst into the core box with a heating device, and heat it to 180-250 ℃, so that the sand near the surface of the core box is heated. Under the effect of temperature, the binder can polycondensate and harden in a short time, forming the core, without entering the drying point of the oven.
In the process of aluminum alloy casting, the hot box core shooter with coated sand is used. The dimensional accuracy of coated sand casting is ct7-ct8, and the surface roughness Ra is 6.3-12.5m. The forming quality of coated sand can reach the level of water glass investment casting technology, which is an ideal technology.
Damp sand is also called green sand. In the production of aluminum alloy casting, the sand mixture is mixed with bentonite as binder, water and other additives, which can be used for molding and core making. The sand mold (core) does not need to be dried and can be poured directly. This kind of sand is called damp mold sand in the casting field. At present, the tide mold sand is one of the most important casting processes.