Repair of EDM induced surface cracks by pulsed electron beam irradiation

This study investigates the use of the large-area electron beam irradiation technique to improve the properties of the EDM’d surface of AISI 310 stainless steel so that a tolerable, or even desirable recast layer may be produced. The short cycle-time of the irradiation process combined with the large incident area of 60 mm diameter makes it an attractive surface modification technique for metal moulds and engineering components. This study showed that by varying acceleration voltages and the number of irradiation cycles (shots), that as well as an improvement of surface finish, repair of cracks induced by the EDM process is possible. The mechanism of this repair is also investigated. XRD analysis also shows that crystalline texture can be introduced by the irradiation process with the (1 1 1) planes of the austenite phase orienting parallel to the surface. This has potential advantages for introducing anisotropic layers for enhanced corrosion resistance.