Development of Automated Welding Processes for Field Fabrication of Thick-Walled Pressure Vessels: Electron Beam Method. Seventh Quarterly Report, April 1-June 30, 1979

摘要

A total of 449 experimental welds have been made to date. Partial penetration welding procedures capable of producing defect-free, 4-inch deep welds have been developed in the horizontal position. The travel speed that can be acceptably used for partial penetration welding of 2 1/4 Cr-1 Mo is larger for 6-inch thick plate than for 8-inch thick plate. Although defect-free welds can be made with soft vacuum conditions, hard vacuum conditions produce the most reliable performance. A procedure for welding an 8-inch thick joint has been developed. A small test plate was welded, radiographed, and cross sectioned and found to be acceptable. A large 8-inch thick test plate was welded and found to contain porosity. Difficulties in uniformly moving this large plate appear to be responsible for the porosity encountered. A mechanical modification to the welding equipment is being made and the large plate will be welded again. 3 figures. (ERA citation 05:011068)