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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.

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Capabilities

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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:

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  • 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)

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Process

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1. Mold making

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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.

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2. Pouring

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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

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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.

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4. Finishing

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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.

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5. Heat Treatment

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

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