Forging Process Control by Additional Rocket Force

Technological processes such as forging, die forging, and pile driving are realized as a result of a collision between two bodies. After the impact the bodies' energy transforms to plastic or elastic deformations of the colliding bodies. This paper studies both theoretically and experimentally the influence of impact parameters such as forces, accelerations, velocities, time and energy on deformation and shape forming of parts achieved by forging with additional controlled force applied during the impact. Two experimental set-up (machines) for generating of additional force in forging with hammer have been developed and tested. The first one is a forging hummer with attached rocket engine (IRE). IRE was developed in Bulgaria and certified in Russia. Rocket engine is applicable for propelling hammering machines - a high-speed forging hammer and a diesel hammer for pile fixing. Possibilities for broadening the technological capabilities of these machines by the use of IRE are also shown. The second forging laboratory set-up uses compressed air to generate additional force as well as to control the impact. The introduction of additional force in forging leads to decreasing of the coefficient of restitution. In order to control the working conditions in forging the dynamics of the impact process is analysed. Many experiments on different parts and materials are done by different set of forging parameters using controlled impact. An increase of the specimen deformation was obtained compared to the common free-fall impact deformation as well as a decrease of the rebound to zero (we called that a sticking impact). Our theoretical results are confirmed by experiments. The obtained theoretical and experimental results show that controlled impact enhances forging process. Keywords—Forging, Control of Impact, Deformations, Experiments.