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Sand Casting - Excellence and Versatility by Donghua

Donghua (DH) specializes in sand casting, a metal-forming process that involves the creation of a mold from a 3D sand pattern, which is subsequently filled with molten metal to produce the casting.


Our expertise extends to both automatic and manual molding operations for green and resin sand casting. Leveraging state-of-the-art equipment and extensive experience, we produce a vast array of sand castings with weights ranging from 1kg to 0.5 tons. We accommodate various material specifications to produce sand castings using a diverse range of materials, including carbon steel, steel alloy, stainless steel, cast iron, brass, and aluminum.


To ensure the highest quality products, we conduct comprehensive on-site testing with premium inspection equipment:

  • Spectrographic and manual quantitative analysis

  • Carbon sulfur analysis

  • Coordinate Measuring Machine (CMM)

  • Metallographic analysis

  • Hardness testing

  • Mechanical property analysis

  • Hydraulic testing

  • Leak detection

  • Impact testing

  • Salt spray testing

  • Paint thickness testing

  • Non-Destructive Testing (NDT) including X-ray, Magnetic Particle Testing (MT), and Ultrasonic Testing (UT)


1. Mold making

A pattern is placed in a sandbox, and resin is mixed using resin sand processing machines. The mixture is then injected into the sandbox containing the pattern and gating features. The mold is heated to a high temperature, allowing the sand to harden. The pattern and gating features are then removed.

Resin Sand Casting- Sand Shells 1.jpg
Resin Sand Casting machine 2.jpg
Resin Sand Casting machine 1.jpg

2. Pouring

Molten metal is poured into the gating system, filling the mold. Once cooled and solidified, castings along with gates, runners, and risers are produced.

3. Divesting

The resin sand mold is broken down to remove the castings, and the gating system is cut off using sawing machines. The resin is recycled and reused.


4. Finishing

The casting is ground and shot-blasted to achieve a smooth surface. Hand tooling and welding are employed to address impurities and defects. For certain parts, a hydraulic straightening machine may also be utilized.

welding robot-2.jpg

5. Heat Treatment

Heat treatment enhances the casting's strength, hardness, toughness, ductility, and corrosion resistance, ensuring superior product quality.

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