Recent Developments in Hard and Soft Vacuum Electron-Beam Welding

Abstract

Electron-beam welding at hard vacuum (10−6–10−3 Torr) has been a valued and increasingly widely used method of metal joining ever since its origination in the middle 1950's by Dr. J. A. Stohr. Extensive application of the process has been made by the aircraft and aerospace industry, in particular, for primary structural members. Means have been developed to permit the welding of such parts along straight or irregular paths over lengths of more than thirty feet. The increasing interest to apply electron-beam welding to an even broader range of industrial welding situations has led to development of high production, short pumpdown time machines that weld in the soft vacuum range of 0.001–1.0 Torr at rates of more than 1000 parts/h. Some of the recently developed means to accomplish this in a particular case are described in detail. This paper also discusses the new developments which greatly simplify initial alignment of the electron beam and the workpiece, and make possible the guidance of the beam along the straight or irregular welding path. Some discussion of the special equipment facilities required for production of these weldments is included.