Precoated Sand Casting – Shell Molding Process by Leesh

Precoated Sand Casting: Excellence in Shell Molding

Precoated sand casting is a standout process in metal forming, and at Leesh, we master it through advanced shell molding (shell mold process). This technique, paired with our expertise, delivers high-quality castings for global clients.

What is Precoated Sand Casting?

Precoated sand casting uses sand grains pre-coated with a resin binder. When heated, the resin cures, forming strong, precise molds. This differs from traditional sand casting, as the precoated layer ensures uniform bonding—key to consistent part quality.

Shell Molding (Shell Mold Process)

The shell mold process is central to our precoated sand casting. Here’s how it works:

1. A heated metal pattern (typically 200–300°C) is covered with precoated sand.
2. The resin melts, adhering the sand to the pattern, forming a thin, hard “shell.”
3. The shell is removed, assembled, and used to cast molten metal.

This process yields molds with sharp details and smooth surfaces, ideal for complex parts.

Advantages of Precoated Sand Casting

• High Precision: Tight dimensional tolerances and fine surface finishes reduce post-processing needs.
• Complex Shapes: Easily handles intricate designs, from thin walls to detailed features.
• Consistency: Precoated sand ensures uniform mold quality, minimizing defects like porosity.
• Efficiency: Shell molds are lightweight and fast to produce, speeding up production cycles.

Leesh: Your Global Partner

Leesh stands out with:

• Expert Team: Experienced engineers oversee every step, from mold design to casting, ensuring optimal results.
• Top Facilities: Well-maintained equipment guarantees stable production and consistent quality.
• Global Reach: We supply precoated sand castings worldwide, adapting to diverse industry needs (automotive, machinery, etc.).

Choose Leesh for precoated sand casting via shell molding—where precision, reliability, and global service meet.

FAQ: Common Questions About Our Wear-Resistant Bushings

Q1: How does Cr2021 High-Chromium Iron compare to standard Manganese Steel for bushings? While Manganese steel relies on work-hardening (impact) to become hard, our Cr2021 High-Chromium cast iron possesses intrinsic hardness right out of the box. With a hardness greater than 58 HRC, our wear-resistant bushing offers superior performance in low-impact, high-abrasion environments where standard manganese steel would wear out too quickly.

Q2: What is the expected service life of these sand-cast bushings? Service life depends on the specific operating conditions, but generally, high-chrome alloy bushings can outlast standard carbon steel or low-alloy alternatives by 2 to 3 times. The specialized heat treatment process ensures the carbide structure resists sliding abrasion, significantly reducing maintenance frequency and equipment downtime.

Q3: Can the material hardness be customized beyond 58 HRC? Yes. We understand that extreme applications require extreme solutions. While our standard specification is >58 HRC, we can adjust the chemical composition and heat treatment cycles to enhance the hardness or modify the toughness according to your specific user needs. Please contact our engineering team with your technical drawings.

Q4: Is the sand casting method reliable for high-precision applications? Absolutely. We utilize advanced sand casting techniques combined with rigorous post-casting machining. This allows us to produce wear-resistant bushings with complex shapes and excellent internal structural integrity, free from significant porosity. All parts undergo dimensional inspection to ensure they fit your machinery perfectly.