Deformation mechanism and control strategy of die cover in forging process

In response to the defects such as folding and thinning caused by uncontrollable deformation of the die cover in the forging process, the deformation mechanism of the die cover in the forging process was revealed through a combination of numerical simulation and experimental verification in this study, and a precise control strategy was proposed. It was found that the adhesive flow behavior between the die cover and the billet at the contact interface was the key mechanism that led to the accumulation of redundant materials at the bottom of the forging die, resulting in folding defects and continuous stretching and thinning of the outer wall fillet area. Based on the constructed multi-directional force behavior theory model, a collaborative control mechanism between the friction characteristics of the billet-die cover-forging die interface and the geometric dimensions of the billet was proposed. When the friction coefficient between the billet and the die cover μ bc significantly decreased while the friction coefficient between the die cover and the forging die μ cd moderately increased, and the initial billet outer end was not in contact with the die cover, the deformation of the die cover could be effectively suppressed. The forging experiment verified that the deformation behavior of the die cover could be accurately controlled by adjusting the geometric dimensions of the billet and the interface friction conditions, providing a theoretical basis and practical guidance for extending the service life of the forging die.