What materials are used in gravity die casting?

Gravity die casting (GDC) uses two key types of materials: mold materials and casting materials, both optimized for the process’s low-pressure, gravity-driven filling method.
Mold Materials: The reusable permanent mold (die) is typically made of cast iron or steel (e.g., H13 tool steel), which can withstand high temperatures (670–710°C for aluminum casting) and repeated use. Cast iron molds offer good heat retention and cost-effectiveness, while steel molds have higher durability (mold life 50,000–200,000 shots for aluminum alloys).
Casting Materials: Aluminum alloys are the most common (80% of GDC applications), including A356, A380, ADC12, AlSi9Cu3 — these have high fluidity and low shrinkage. Other materials include copper alloys (brass, bronze) and magnesium alloys, but aluminum is preferred for its lightweight, cost-efficiency, and mechanical properties. For high-strength parts, A356 T6 is the top choice for GDC, with tensile strength up to 320 MPa.