4. Implementation of the main processes

4.1 Comparison of hot and cold forming

The forming temperatureT is a fundamental parameter, as it determines the value of the plastic flow stress (figure 18 ) and the ductility of the metal. A distinction is made between cold forming and hot forming. It should be noted that these terms have two meanings which may not coincide. In forming shops, cold forming means shaping a metal initially at 20°C; hot forming means preheating the metal before shaping to the highest possible temperature, i.e. to obtain a product with acceptable properties.