CN114309450A - Composite raw sand for metal casting - Google Patents

Abstract

The invention relates to a composite raw sand for metal casting. The components in percentage by weight include: 60-99.6% of quartz sand, 0.2-19% of limestone sand, and 0.2-40% of feldspar sand. The compositions of the present invention can eliminate casting penetration and sintering defects, swelling-type defects, and the like. b. Wide range of resource sources and low cost.

Description

A kind of composite raw sand for metal casting

technical field

The invention belongs to the field of foundry sand, in particular to a composite raw sand for metal casting.

Background technique

The method of pouring liquid metal into the mold cavity and waiting for the liquid metal to cool and solidify to obtain a casting blank is called casting. The casting system generally consists of a casting and a mold, and the mold is an essential part to give the casting shape.

Sand casting dominates foundry production. Sand molds are obtained by molding (core) sand produced by molding cores. Forming (core) sand is usually prepared from raw sand, binder, auxiliary materials (with/or without), and water (with/or without). Among them, raw sand is the most basic raw material for modeling and plays an important role in foundry production.

Quartz sand is the most commonly used and the largest amount of raw sand in sand casting production. However, the molding sand prepared with pure quartz sand is used for foundry production, and the disadvantage is that it is easy to cause infiltration and sintering defects of castings, and swelling defects.

SUMMARY OF THE INVENTION

Based on the defects of the prior art, the technical problem to be solved by the present invention is to provide a composite raw sand for metal casting.

The composite raw sand of the invention comprises the following components by weight percentage: 60-99.8% of quartz sand, 0.2-19% of limestone sand, and 0.2-40% of feldspar sand.

The limestone sand includes fine particles made by crushing and screening various ore rocks with limestone as the main component.

The feldspar sand includes fine particles made by crushing and screening various feldspar minerals.

The particle size of the quartz sand is 40-270 mesh.

The particle size of the limestone sand is 40-270 mesh.

The particle size of the feldspar sand is 40-270 mesh.

The components also include binders, auxiliary materials, and water.

The present invention relates to molding sand for metal foundry, wherein the molding sand contains the composite raw sand.

The components also include binders, auxiliary materials, and water.

The binder includes, but is not limited to, one or more of bentonite, ordinary clay, resin, water glass, and the like.

The auxiliary materials include but are not limited to one or more of carbonaceous materials and organic materials such as coal powder, graphite powder, asphalt, resin, heavy oil, residual oil, starch, rice flour, sawdust, straw powder, straw ash and the like.

Further, the composite raw sand can be directly added when preparing clay type (core) sand, water glass type (core) sand and resin type (core) sand for casting.

Or various raw material components of the composite raw sand can be added according to the proportions when preparing clay type (core) sand, water glass type (core) sand and resin type (core) sand for casting.

Or when the composite raw sand is used to prepare foundry clay type (core) sand, water glass type (core) sand and resin type (core) sand, it is usually composed of composite raw sand, binder, auxiliary materials (add/or without addition), water (with/or without addition).

beneficial effect

The composite raw sand of the present invention is used for the casting production of clay type (core) sand, water glass type (core) sand and resin type (core) sand, and the following beneficial effects can be obtained: defects, etc. b. Wide range of resource sources and low cost.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Intumescent defects are judged by visual inspection.

Example 1

Take 5000Kg of quartz sand, 40Kg of limestone sand and 200Kg of feldspar sand, and mix them in a sand mixer to produce sand evenly to obtain composite raw sand. When the test temperature of the composite raw sand is 1000℃, the gas production is 7.5ml/g, which is higher than that of pure quartz sand and feldspar sand, but far lower than that of pure limestone sand.

Take 1000Kg of composite raw sand and put it into a sand mixer, add 8% of bentonite and 4.2% of water (both the content of bentonite and water are relative to the total amount of composite raw sand), and after mixing, produce sand for use. Use the mixed wet sand to form the mold, and pour the ductile iron after the mold is closed. The surface of the casting is easy to clear sand, and the casting has no expansion defects.

Example 2

Take 5000Kg of quartz sand, 100Kg of limestone sand, and 500Kg of feldspar sand, respectively, add them to the sand mixer and mix them evenly, and then add 7% of water glass (the mass percentage of water glass relative to the total amount of composite original sand), and sand out after mixing. spare. When the test temperature is 1000℃, the gas generation of the mixed molding sand is 9.2ml/g, which is higher than that of pure quartz sand, but far lower than that of pure limestone sand.

Use the mixed water glass sand to shape, and pour the cast steel after the shape is combined. The surface of the casting is easy to clear sand, and the casting has no defects.

Example 3

Take 5000Kg of quartz sand, 30Kg of limestone sand, and 200Kg of feldspar sand, and mix them in a sand mixer to produce sand to obtain composite raw sand. When the test temperature of the composite raw sand is 1000℃, the gas generation is 6.5ml/g, which is higher than that of pure quartz sand and feldspar sand, but far lower than that of pure limestone sand.

Take 1000Kg of composite raw sand and mix it into a cold core box resin sand, use the mixed resin composite sand to make a core, and pour the alloy cast iron after the core is formed. Castings have no expansion defects.

Claims (7)

1. A composite raw sand, characterized in that, by weight percentage, the components comprise: 60-99.6% of quartz sand, 0.2-19% of limestone sand, and 0.2-40% of feldspar sand. 2 . The composite raw sand according to claim 1 , wherein the particle size of the quartz sand is 40-270 meshes. 3 . 3. The composite raw sand according to claim 1 is characterized in that, the particle size of the limestone sand is 40-270 mesh. 4. The composite raw sand according to claim 1, wherein the particle size of the feldspar sand is 40-270 mesh. 5 . A molding sand for metal foundry, characterized in that the molding sand contains the composite raw sand according to claim 1 . 6 . The molding sand according to claim 5 , wherein the components further comprise a binder, an auxiliary material, and water. 7 . 7. The application of the composite raw sand of claim 1 in the preparation of foundry clay molding sand, water glass molding sand or resin molding sand.