Casting
Molten metal is poured into a sand mold, allowed to cool and solidify, and then machined. Complex-geometry parts such as engine blocks and cylinder heads are typical automotive castings.
Advantages: low cost, great shape flexibility.
Drawbacks: lower mechanical properties; internal porosity or shrinkage can reduce strength and durability.
Typical pouring temperature: 1,350–1,650 °C.
Forging
A solid billet is plastically deformed under high pressure in forging equipment. The resulting grain flow is highly compact, giving the part superior load-bearing capacity. Critical, high-stress components—crankshafts, connecting rods, gears—are usually forged.
Advantages: higher density and strength, excellent mechanical performance (high fatigue resistance, good heat dissipation, greater safety, tight molecular structure, lighter weight, will not shatter on impact, long life).
Drawbacks: higher cost because of complex processing and premium raw material; machining can be more involved.
Typical forging temperature: 1,100–1,200 °C.
Therefore, process selection must be based on each part’s operating conditions, performance requirements and special specifications to guarantee product quality.
author: Wangbo