Analysis of Core Forging Processes: Differences and Application Scenarios of Hot Forging, Cold Forging and Warm Forging

Analysis of Core Forging Processes: Differences and Application Scenarios of Hot Forging, Cold Forging and Warm Forging

Forging is a key process that uses external force to induce plastic deformation of metal blanks to obtain parts with desired shape, size and performance. As the three core forging processes, hot forging, cold forging and warm forging have significant differences in process characteristics, applicable materials and application scenarios due to different processing temperatures. Reasonable selection of process type is crucial for improving part quality and reducing production costs. The following analyzes the differences and suitable scenarios of the three from core dimensions.

Hot forging is a forging process carried out above the recrystallization temperature of metals (usually above 800℃ for steel). At high temperatures, metals have good plasticity and low deformation resistance, enabling one-time forming of parts with complex shapes. It is suitable for processing large, thick-walled or complex-shaped blanks, such as automotive crankshafts, connecting rods, and construction machinery gears. Its advantages include low forming difficulty, high production efficiency, ability to improve the internal structure of metals and enhance the mechanical properties of parts. The disadvantages are that oxide scale will be generated during the heating process, resulting in low part precision, requiring additional machining afterwards, and high energy consumption.

Cold forging is a forging process carried out at room temperature without heating the blank. This process can maximize the retention of the original metal structure, resulting in parts with high dimensional accuracy and low surface roughness. It can realize little or no cutting processing, significantly reducing material waste and subsequent processing costs. Cold forging is suitable for metal materials with good plasticity, such as aluminum, copper and low-carbon steel, and common products include small precision components such as bolts, nuts and watch parts. However, cold forging has high deformation resistance, requiring high equipment tonnage, and cannot process large or high-hardness parts. In addition, the blank needs pre-treatment such as annealing in advance to improve plasticity.

Warm forging is a forging process carried out between room temperature and recrystallization temperature (usually 200-800℃ for steel), combining the advantages of both hot forging and cold forging. Compared with hot forging, warm forging generates less oxide scale and achieves higher part precision; compared with cold forging, it has lower deformation resistance, lower equipment load, and can process parts with higher complexity. Warm forging is suitable for medium and large parts requiring both precision and mechanical properties, such as automotive half shafts, gearbox gears and bearing rings. However, warm forging has strict requirements on temperature control accuracy, requiring precise heating equipment, and the process control difficulty is slightly higher than that of hot forging and cold forging.

Summary of Process Selection: Hot forging is preferred for large and complex parts and scenarios with low precision requirements; cold forging can be selected for small precision parts and mass production pursuing high cost performance; warm forging is the optimal choice for medium and large high-precision parts and when balancing performance and cost needs. Only by combining part size, precision requirements, material characteristics and production costs can the precise adaptation of forging processes be achieved.