Melting Process and Spiking Phenomenon in Electron Beam Welding

A Study on Electron Beam Welding Phenomena (Report 3)

Abstract

Melting process and spiking phenomenon have been investigated in electron beam welding. X-rays generated as a consequence of beam-metal interaction were measured at some specific sites of 3 mm in length along penetration using Xe-proportional counter simultaneously with taking highspeed photography of the molten metal flow to clarify a melting process.
The results obtained were as follows.
(1) Spiking phenomenon was most likely to occur when the electron beam .was focussed on the root portion of penetration.
(2) Melting process and spiking phenomenon were dominated by the periodical flow of the molten metal.
(3) Soon after the periodical ejection of the molten metal, the beam cavity was clear of the molten metal and the electron beam was free to drill the bottom causing the spike.
(4) it is effective in monitoring spiking phenomenon to detect electrons emitted from interacting point using a probe biased 6V with respect to the specimen.