What is the ratio of pulverized coal bentonite and old sand in the clay sand production line

Molding sand type Ratio (mass ratio).

Old sand, new sand (and collapsed core sand), bentonite.

Premium) pulverized coal (premium).

Machine styling 90--95 5--10

Hand styling 90--95 5--10

Old sand New sand (and collapsed core sand) Bentonite (high quality) Pulverized coal (high quality.

Machine styling 90--95 5--10

High pressure molding 90--95 5--10

Hand styling 90--95 5--15

The specific yield of the collapse of the coated sand sand core should be determined according to the actual situation of the dust removal equipment, the batch production of different products, according to the amount of core, the actual amount of effective clay coal powder, the differential addition of auxiliary materials, generally speaking, how much to add is a bit too arbitrary, according to the product structure and so on, the same production line, differential addition of auxiliary materials, so as to effectively control the quality of the sand. If necessary, you can communicate, Zhu Ming 630369015 15851010199 Jiangsu Zhongzhu Machinery Technology Co., Ltd., providing a full set of services and facilities.

I understand that the traditional turning sand casting should be green sand casting, which is clay sand.

The general DAO is as follows:

Old sand: 95%.

New sand: 1-5% (mixed sand.

Add the amount of answer when returning).

Bentonite (clay): the amount added when mixing sand).

Pulverized coal (FS powder): the amount added when mixing sand).

A number of water, subject to the adjustment of the compaction rate to meet the requirements.

The content of each component of the old sand mentioned above is as follows: bentonite 7-9%, calcination reduction 3-6%, water content 1-2% or more.

The mud content of molding sand is recommended to be between, preferably between 10-11%.

This is conducive to controlling the moisture of the molding sand.

However, if you are producing a product that requires a high compaction rate, please increase the compaction rate appropriately.

A material used for modeling in sand casting. Molding sand is generally mixed by casting sand, molding sand binders and auxiliary additives and other modeling materials in a certain proportion, and silica sand containing natural clay can also be used. The role of molding sand in casting production is extremely important, and the casting waste caused by the poor quality of molding sand accounts for about 30 50 of the total casting waste.

The usual requirements for molding sand are: It has high strength and thermal stability to withstand various external forces and high temperatures. Good fluidity, that is, the ability of molding sand to move between sand particles under the action of external force or its own gravity.

A certain plasticity, that is, the ability of the molding sand to be deformed under the action of external force, and when the external force is removed, it can maintain the shape given. Good air permeability, that is, the ability of molding sand pores to permeate gas. High dispersibility, also known as sand extraction, is the performance of whether the molding sand is easy to destroy after the casting is solidified, and whether it is easy to remove from the casting.

Molding sand can be divided into clay sand, sodium silicate sand, cement sand, resin sand, etc. according to the different binders used. Clay sand, sodium silicate sand and resin sand are the most used.

Clay sand is made from a mixture of natural silica sand, clay, adjuvants and water. The clay used in the manufacture of green sand is bentonite, and the wet compressive strength is generally megapascals. With a water content and a permeability of more than 80, it is often used for machine modeling, but it can also be used for manual molding.

The sand mold made can be directly poured with molten metal without drying, which has the advantages of low production cost and short production cycle. Clay sand for wet molding accounts for about 60% of the molding sand used in foundry production. Due to the high moisture in the green sand, low strength and air permeability, the casting is prone to defects such as porosity, sand inclusion, sticky sand, and sand expansion, and the dimensional accuracy is also low, and it is generally only used for the production of small and medium-sized iron castings and casting non-ferrous alloy castings.

The clay used to make dry sand is ordinary clay with high moisture in the wet state. The sand mold made should be dried at a temperature of about 250 400 and then poured after closing, which is generally used for steel castings. Dry sand mold has been gradually eliminated due to high energy consumption, long production cycle and poor dimensional accuracy.

Sodium silicate sand is formulated by a mixture of silica sand, sodium silicate and adjuvants. The sand mold can be chemically hardened by blowing CO2, or it can be hardened by heat or by self-hardening under the action of hardener. This molding sand can be used to make sand molds for steel and iron castings.

Sodium silicate sand has shortcomings such as difficulty in sand removal and old sand is not easy to regenerate, and its application is limited to a certain extent. Since the 70s, some progress has been made in the research of old sand regeneration.

Resin self-hardening sand is formulated by a mixture of silica sand, resin, and hardener. Commonly used resins are furan resins, alpha phenolic resins, and urethane resins. The sand mold made of this molding sand has high strength, accurate size, good collapsing and low energy consumption, and can be used for the production of cast steel, cast iron and cast non-ferrous alloy castings, with high surface quality and dimensional accuracy of castings.

Resin self-hardening sand is a promising molding sand.

There are three kinds of clay sand, sodium silicate sand, and resin sand.

After the clay sand is poured, the surface is sintered, and the general proportion is 3%, and this part is to be removed; Then there is the production of fine powder in the molding process, which is extremely unfavorable for the ventilation of casting, and it must be removed! It is best to control the amount of new sand added at about 8%-10% each time, which is very good for the surface of the casting!

For general castings, if the old sand is enough after sifting, do not add new sand, only add a small amount of pulverized coal and bentonite, and if it is not enough, the new sand is proportionally configured and add enough amount.

You can add it by 10% of the weight, after the sieve is finished, or you can add it regularly, once a week or a month, but remember to add other accessories at the same time, such as bentonite, wood chips, etc.!

Core sand is generally composed of sand core body, core head, core bone, exhaust device and hoisting structure.

Molding sand is generally made of casting raw sand, molding sand binders and auxiliary additives and other modeling materials mixed in a certain proportion. Molding sand, which can be divided into surface sand, filling sand and single sand, etc. The surface sand is a layer of molding sand that adheres closely to the casting, and the quality requirements are high.

After the surface sand layer, the filled sand is not in contact with the molten metal, and the quality requirements are not strict.

Sand molds and cores are made from molding sand and core sand. Mould (core) sand is made by mixing raw sand, binder, water and additives in a certain proportion. Binders include clay, water glass, tung oil, grease, etc., and the most widely used is cheap and abundant clay.

Mould (core) sand that uses clay as a binder is called clay sand. The molding (core) sand with other binders is called sodium silicate sand, oil sand, and grease sand. Composition of molding (core) sand:

1.Sand - The main component of raw sand (i.e. new sand) is quartz (Si02). For foundry sand, the silica content in the raw sand is required to be 85%-97%.

It is better to have a round shape and uniform size of the sand particles. In order to reduce costs, the used sand can also be mixed with molding sand after proper treatment. For small foundry workshops that are generally produced by hand, only the old sand is often sieved to remove sand balls, iron blocks, iron nails, wood chips and other debris.

2.Binder - The substance that can make the sand particles bond to each other is called a binder, and the commonly used binder is clay. Clay is mainly divided into two categories: ordinary clay and bentonite.

Wet (sand mold is not dried after modeling) molding sand generally uses bentonite with good bonding performance, while dry (sand mold is dried after modeling) molding sand mostly uses ordinary clay.

3.Additives - substances added to improve the properties of molding (core) sand are called additives. Commonly used additives are pulverized coal, wood chips, etc. The addition of pulverized coal can prevent the casting from sticking to the sand, so that the surface of the casting is smooth, and the addition of wood chips can improve the air permeability of the mold and core.

4.Water - The clay and raw sand are mixed together by water, and have a certain strength and air permeability. Too much moisture makes the molding sand too humid, low strength, easy to stick to the mold during molding, and makes the molding operation difficult; If the moisture is too small, the molding sand will be dry and brittle, and it is difficult to shape and mold.

Therefore, the moisture should be appropriate, and the strength can reach the maximum value when the weight ratio of clay to moisture is 3:1. In addition, in order to prevent sand sticking on the surface of the casting and make the surface of the casting smooth, the surface of the casting cavity is often covered with a layer of refractory material, which is called puffing.

Usually on the wet surface of iron castings, sprinkle a layer of graphite powder or talcum powder, and on the wet surface of steel castings, sprinkle quartz powder. For the surface of dry type and core, a layer of paint can be brushed, while graphite powder and clay water agent can be used for iron castings, and quartz powder plus clay water agent is commonly used for steel castings.