Development of automated welding processes for field fabrication of thick-walled pressure vessels: electron beam method. Second quarterly report, 1 January--31 March 1978

A project to develop and demonstrate an electron beam welding procedure for welding 8'' thick SA387 Grade 22 Class 2 (2/sup 1///sub 4/ Cr--1 Mo) steel is reported. The progress made during the period January-March 1978 is summarized. The steel ordered for use in the project has not yet been received, which has resulted in a delay of the scheduled work. A procedure for eliminating unwanted displacements of the electron beam and the electron beam weld arising from magnetic fields was developed. A magnetic shield was designed, fabricated, and shown to be effective at protecting the electron beam from magnetic fields between the steel plate and the electron gun. Magnetic fields existing within the steel plate were shown to be of no concern.