Classification of Forging Processes

Forging processes are primarily classified based on the forming method, equipment capabilities, and the structural characteristics of the parts. Common processes include open-die forging, closed-die forging, and smith forging (using auxiliary dies). Open-die forging relies on hammers or presses to progressively deform the metal billet; it is suitable for producing single units, small batches, and large-scale forgings. Closed-die forging involves shaping the billet within a specialized die cavity, offering high dimensional accuracy and production efficiency, making it ideal for mass production. Smith forging falls between open-die and closed-die forging; it offers good process flexibility and is widely used for small-to-medium batch production.

Forging processes can also be categorized by temperature: hot forging, warm forging, and cold forging. Hot forging is performed after heating the metal to a high temperature; the material exhibits high plasticity and low resistance to deformation, allowing for the production of parts with complex shapes and large dimensions. Warm forging operates at lower temperatures than hot forging, balancing sufficient plasticity with improved dimensional accuracy and surface quality. Cold forging is typically performed at room temperature, yielding parts with high dimensional precision and superior surface quality, though it places greater demands on equipment capabilities and material plasticity.

Forging operations can also be classified by the specific forming steps involved, such as upsetting, drawing out, punching, bending, and cutting. These operations are usually combined strategically based on the forging's structure, material properties, and technical specifications, rather than being used in isolation. Parts with simple structures may require fewer steps, whereas complex shapes with strict dimensional requirements necessitate a multi-step, progressive forming process. A well-chosen combination of processes and sequences minimizes material waste and boosts production efficiency while ensuring the forging's dimensional accuracy and internal quality.