Simulation and experiment for crack arrest in remanufacturing

摘要

Remanufacturing is the only way for sustainable development of mechanical equipment manufacturing. For remanufacturing blanks containing cracks, the primary task is the prevention of crack propagation to ensure effectiveness of the manufacturing processes to follow. When pulsed current passes through a specimen, due to the existence of crack, the temperature around the crack tips rises sharply and may even climb above the fusion point of the material, which causes the crack tip to become blunt. In this work, with compressor rotor blade material FV520B as a specimen, the distributions of current density, temperature field, and stress field are calculated at the instant of discharge based on the thermo-electro-structure coupled theory. The crack arrest experiment is performed on high pulsed current discharge device of type HCPD-I. By making comparisons of morphology, microstructure, and size of fusion zone and heat-affected zone (HAZ) around the crack tip before and after energizing, the relationships between the sizes of fusion zone and the HAZ and the discharge energy and the current path are derived. The obvious partition and refined grains around the crack tip are prominent because of violent temperature change. The experimental and simulation results are found in fine agreement. The high current pulsed discharge can be used effectively to prevent a crack to further expand and show substantial potentials for application in remanufacturing domain.