Which is better, forging or casting a crankshaft?

There are two main manufacturing processes for crankshafts: forging and casting. Each has its own advantages and disadvantages, and is suitable for different engine requirements.

Advantages of forged crankshafts:
1. High strength and fatigue resistance, suitable for high-speed, high-power engines (such as performance cars and racing cars).
2. Continuous internal metal fibers provide better impact resistance and longer life.

Disadvantages of forged crankshafts:
1. High production cost, complex processing, and high price.
2. Relatively heavy, making it difficult to achieve lightweight design.

Advantages of cast crankshafts:
1. Low manufacturing cost, suitable for mass production (such as family cars).
2. More complex structures (such as hollow crankshafts) can be designed, achieving lightweight design.

Disadvantages of cast crankshafts:
1. Lower strength, potentially causing cracks or deformation due to long-term high-load operation.
2. Poor fatigue resistance, unsuitable for extreme operating conditions.

How to choose between forging and casting?
1. Forged crankshafts are preferred for high-performance engines (such as turbocharged engines and racing cars) to ensure reliability and durability. 2. Ordinary family cars typically use cast crankshafts, balancing economy and practicality.

In summary: There's no absolute superiority or inferiority; the key depends on the engine's purpose and requirements. Forging is suitable for extreme performance, while casting is more economical and practical.