Ductile iron covers produced via resin sand casting (or furan resin) offer superior strength, high dimensional accuracy, and smooth surface finishes for heavy-duty municipal applications. This process is ideal for large, complex covers, providing better, more consistent quality than traditional green sand molding, especially for, but not limited to, weight ranges of 7kg–154kg. 

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For smaller, lighter, or less complex covers, other methods like green sand molding may be more cost-effective. 

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