CN114309450A

CN114309450A - Composite raw sand for metal casting

Info

Publication number: CN114309450A
Application number: CN202111510266.7A
Authority: CN
Inventors: 朱世根; 胡菊芳; 朱巧莲
Original assignee: Yiwu Yunxi New Material Technology Co ltd; Donghua University
Current assignee: Yiwu Yunxi New Material Technology Co ltd; Donghua University
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2022-04-12

Abstract

The invention relates to composite raw sand for metal casting, which comprises the following components in percentage by weight: 60-99.6% of quartz sand, 0.2-19% of limestone sand and 0.2-40% of feldspar sand. The composition can eliminate the defects of casting penetration and sintering, expansion and the like. b. Wide resource source and low cost.

Description

Composite raw sand for metal casting

Technical Field

The invention belongs to the field of casting molding sand, and particularly relates to composite raw sand for metal casting.

Background

The method of pouring liquid metal into a cavity of a mold and obtaining a cast blank after the liquid metal is cooled and solidified is called casting. A casting system generally consists of a casting and a mold, which is an essential part for imparting a shape to the casting.

Sand casting dominates the foundry practice. The sand mold is obtained by molding and core-making from molding (core) sand. The molding (core) sand is generally prepared from raw sand, a binder, auxiliary materials (with or without addition), and water (with or without addition). Among them, raw sand is the most basic molding material and plays an important role in casting production.

The quartz sand is the most common raw sand with the largest consumption in sand casting production, has wide sources and lower price, and can meet the general requirements of various metal casting production. However, the molding sand prepared from the pure quartz sand is used for casting production, and has the defects of easy casting infiltration and sintering defects, expansion defects and the like.

Disclosure of Invention

Based on the defects of the prior art, the invention aims to provide the composite raw sand for metal casting.

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

The limestone sand comprises various ore rocks which take limestone as a main component and are crushed and sieved to prepare fine particles.

The feldspar sand comprises fine particles prepared by crushing and screening various feldspar minerals.

The granularity of the quartz sand is 40-270 meshes.

The granularity of the limestone sand is 40-270 meshes.

The granularity of the feldspar sand is 40-270 meshes.

The components also comprise a binder, an auxiliary material and water.

The molding sand for metal casting contains the composite raw sand.

The components also comprise a binder, an auxiliary material and water.

The binder includes but is not limited to one or more of bentonite, common 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, rice straw ash and the like.

Further, the composite raw sand may be directly added in the preparation of clay type (core) sand, water glass type (core) sand and resin type (core) sand for casting.

Or the raw material components of the composite raw sand can be respectively added according to the proportion when clay type (core) sand, sodium silicate type (core) sand and resin type (core) sand for casting are prepared.

Or when the composite raw sand is used for preparing clay type (core) sand, water glass type (core) sand and resin type (core) sand for casting, the composite raw sand is generally prepared from the composite raw sand, a binder, auxiliary materials (with or without addition), and water (with or without addition).

Advantageous effects

The composite raw sand is used for casting production of clay type (core) sand, sodium silicate type (core) sand and resin type (core) sand, and can obtain the following beneficial effects: a. can eliminate the defects of casting infiltration and sintering, expansion and the like. b. Wide resource source and low cost.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

The swelling defects were judged by visual inspection.

Example 1

Taking 5000Kg of quartz sand, 40Kg of limestone sand and 200Kg of feldspar sand, and uniformly mixing in a sand mixer to produce sand, thus obtaining the composite raw sand. The gas evolution of the composite raw sand at the test temperature of 1000 ℃ 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.

Putting 1000Kg of composite raw sand into a sand mixer, adding 8% of bentonite and 4.2% of water (the bentonite and the water are both in mass percentage relative to the total amount of the composite raw sand), and discharging sand for later use after mixing. And molding and stripping the mixed green sand, and pouring the ductile iron piece after mold assembly. The surface of the casting is easy to remove sand, and the casting has no expansion defects.

Example 2

Respectively adding 5000Kg of quartz sand, 100Kg of limestone sand and 500Kg of feldspar sand into a sand mixer for uniform mixing, adding 7% of water glass (mass percentage of the water glass relative to the total amount of the composite raw sand), and discharging sand for later use after mixing. The gas evolution of the mixed molding sand at the test temperature of 1000 ℃ is 9.2ml/g, which is higher than that of pure quartz sand but far lower than that of pure limestone sand.

Molding by using mixed sodium silicate sand, and casting a steel casting after mold assembling. The surface of the casting is easy to remove sand, and the casting is free of defects.

Example 3

Taking 5000Kg of quartz sand, 30Kg of limestone sand and 200Kg of feldspar sand, and uniformly mixing in a sand mixer to produce sand, thus obtaining the composite raw sand. The gas evolution of the composite raw sand at the test temperature of 1000 ℃ is 6.5ml/g, which is higher than that of pure quartz sand and feldspar sand but far lower than that of the pure limestone sand.

1000Kg of composite raw sand is mixed to prepare resin sand for a cold box, the mixed resin composite sand is used for preparing a core, and an alloy iron casting is cast after the core is placed and closed. The casting has no expansion defects.

Claims

1. The composite raw sand is characterized by comprising the following components in percentage by weight: 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 granularity of the quartz sand is 40-270 meshes.

3. The composite raw sand according to claim 1, wherein the limestone sand has a particle size of 40 to 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 casting, characterized in that it contains the composite raw sand according to claim 1.

6. The molding sand of claim 5, wherein said components further comprise a binder, an auxiliary material, and water.

7. Use of the composite raw sand of claim 1 for preparing clay molding sand, water glass molding sand or resin molding sand for foundry.