Small common sense of coated sand-LIANXIN SAND GROUP

Small common sense of coated sand

Release time:

2021-05-14

Coated sand is mainly selected high-quality natural quartz sand as raw sand, thermoplastic phenolic resin, urotropine and reinforcing agent as raw materials. According to the different skills of the user needs, in the curing speed, film removal, fluidity, collapsibility, casting appearance finish, storage and other aspects of the appropriate adjustment ratio. It is one of the best modeling materials for cars, tractors, hydraulic parts, etc. Lianxin silica sand is a film manufacturer.

　　Main features

1. Vibration sand cleaning, high strength, low gas, low expansion;

2, the shell can not afford to layer, good thermal stability, good thermal conductivity, good fluidity, the appearance of the casting is smooth;

3. The shell layer is uniform and does not shelled, and the curing speed is fast;

Curing agent, lubricant, additive

Coated sand curing agent practice is urotropine, the amount of resin is 5%-20%. In order to meet some special requirements (such as anti-shelling, fast polymerization, etc.), some companies have developed special curing agents.

The main role of the additive is to improve the function of the coated sand. The widely used additives mainly include high temperature resistant additives, easily collapsing additives, strengthening and toughening additives, anti-sticking sand additives and wet additives. Many coated sand plants have unique additive formulations, and the function of additives plays an important role in the production of special coated sand, which is one of the core competitiveness of the coated sand market.

　　Production process

Through the dry mixing method, cold film method, warm film method, hot film method four stages, the production of coated sand is almost always selected hot film method.

There are many kinds of coated sand production lines in China. There are about 2000~2300 semi-automatic production lines for craft feeding, and nearly 50 full-automatic production lines controlled by computer, effectively improving the output and product stability.

　　Main Products

The main types of commercial coated sand in China are as follows:

It is composed of quartz sand, thermoplastic phenolic resin, urotropine and calcium stearate, without relevant additives. Applicable to the production of general iron castings.

It is a replacement product of general coated sand, which is prepared by relevant additives and selection of new technology. Its strength is more than 30% higher than that of general coated sand, and its gas emission is also significantly reduced. It is suitable for producing messy fine iron castings.

It has the characteristics of high strength and long heat resistance at high temperature, and is suitable for the production of car engine block, cylinder head, container corner and other messy thin-walled cast iron parts.

It has good strength and excellent low-temperature collapse function, and is suitable for the production of non-ferrous metal castings.

In order to get used to the needs of different products, a series of special coated sand have been developed, such as: coated sand for centrifugal casting, chilled coated sand, wet coated sand, anti-sticking sand, anti-veining, anti-orange peel coated sand, etc.

In the past 10 years, the function of coated sand has been greatly improved, and some new detection targets have been added accordingly:

Heat resistant moment-test coated sand core at high temperature (700-1500 DEG C) adhere to the strength, no deformation, no collapse time.

The main problems in the detection of coated sand in China are

(1) The testing methods of most enterprises are not perfect. Basically stay in the initial stage of testing room temperature strength, melting point, particle size and gas output;

(2) The accuracy and stability of domestic coated sand testing equipment are not high. Under the field conditions of different manufacturers, the functional objectives of coated sand detected by the same equipment are sometimes quite different, for example, the tensile strength at room temperature can differ by more than 10kg, and the gas emission can differ by more than 5 ml.