Shell Mold Sand Casting Sand

Since the 1990s, different properties of coated sand which is used in the Shell Mold Casting have been developed in China, which can be divided into dry and wet types according to its performance characteristics.The dry state includes: general class, high temperature resistant class, high strength and low gas generation class, easy to break up class, centrifugal casting class and so on.Wet coated sand includes mechanical sand and manual sand.The main components, characteristics and application range of all kinds of coated sand are as follows:

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1. Common coated sand for shell mold casting

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Its composition usually consists of quartz sand thermoplastic phenolic resin, ullotropine and calcium stearate, without any additives.Usually for the amount of the resin under the request of a certain intensity is relatively high, does not have high temperature resistant, low inflation and low gas features, applicable to some requirements is not high, the structure is relatively simple iron castings production.

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2. High strength and low hair gas coated sand for shell mold casting?

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Is on the basis of ordinary coated sand, by joining the feature of "additives" and adopt the new preparation process, make the resin have fallen sharply, the gas evolution significantly reduced, and can delay the gas velocity.The coated sand has the characteristics of high strength, low expansion, low gas emission, slow gas emission, etc., especially suitable for the sand core with low air emission in cast iron parts, small and medium cast steel parts, such as the sand core of valve body.

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3. High temperature resistant film coated sand for shell mold casting

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The sand generally refers to the high thermal strength of coated sand, long heat resistance time, small deformation at high temperature, and not high fire resistance.It is through the special craft formulation technology (typically in the silica sand coated with a certain amount of inert material such as sand milling, high chrome ore, containing carbon or other inert materials, etc.), to produce excellent high temperature performance and comprehensive new coated sand casting performance.It has the characteristics of high temperature resistance, high strength, low expansion, low gas emission and slow gas emission.Especially suitable for the complex thin-walled precision castings, such as automobile engine cylinder block, cylinder head, etc.) and the high demand of steel, such as container Angle and the train brake buffer shell etc.) production, which can effectively eliminate the adhering sand, casting defects such as deformation, cracking and porosity.

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4. Easy to ulcerate coated sand for shell mold casting

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It is a kind of film - coated sand for non - ferrous metal (especially aluminum alloy) casting.The sand has good strength and excellent low temperature dispersion.It is used to produce non-ferrous metal (aluminum alloy, copper alloy, etc.) castings. It does not need to be reheated to remove sand.

5. Centrifugal casting coated sand shell mold casting

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The coated sand is suitable for centrifugal casting process and can be used as an alternative for coating production.According to the casting pipe material, diameter and technical requirements different, can be processed into different properties of centrifugal casting coated sand.Different from other kinds of film - coated sand, the density of the film - coated sand is higher, the gas volume is lower and the gas speed is slow.

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6. Wet mechanical coated sand shell mold casting

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It is a film - coated sand that is wet at room temperature.Long stored at room temperature not natural curing (can be stored more than 1 year), according to the requirements of the different casting technology can be used wet high strength and low gas and so on various properties of coated sand, which can completely replace the hot core box of precoated sand sand (shoot shoot core machine head need not adapted to the production of various materials and various types of castings).

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7. Wet hand coated sand for shell mold casting

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The wet - pressure strength of the coated sand can be arbitrarily adjusted within 0.1-0.3MPa.Storage period more than 3 months, suitable for manual or core (similar to the tung oil sand and resin sand), at room temperature after demoulding, type (core) put into oven or oven heating, the heating temperature of 250 ~ 350 ??, the heating time 3 ~ 10 min, cured type (core) has high strength, low gas evolution, creep deformation is small, no moisture absorption, etc.The coated sand is suitable for the production of single piece, small batch and high precision castings, especially for township enterprises.It is worth noting that when the mold (core) is heated and solidified, it must wait until the furnace temperature reaches the required temperature before putting it into the heating.