A Processing Approach Incorporating Copper Backing-Wheel Device in Submerged Arc Welding for Manufacturing Cryogenic Storage Tanks

Abstract

A processing approach using a copper backing-wheel device was developed to aid the fabrication process of industrial cryogenic storage tanks manufactured under the ASME Section VIII Division 1. This research focused on the welding processes related to the cylindrical-body assembly. Two processing steps involving the root-run formation and the replacement with a sound outer-circumference joint were studied. Initially, tank fabrication is achieved through the application of both flux-cored arc welding and submerged arc welding. A new processing approach was proposed with the modified method in cross-section preparation, and a low-cost reusable copper backing-wheel device was developed to facilitate the root-run formation using only submerged arc welding. Temperature gradient through the device components along the heat-conduction path was monitored to assure the conductivity of the backing device. The results suggest that the proposed approach reduced manufacturing time by removing the initial flux-cored arc welding process used in the conventional welding method. As an effect, the new approach show promise reduces the overall manufacturing cost of tank fabrication. Based on radiographic testing of tanks fabricated using the new approach found that circumference joints required little or no welding repair suggesting higher joint quality.

Development of Grounding Device to Reduce Current Variation in Submerged Arc Welding Process for Pressure Vessel Fabrication

“…Overall, the low cost grounding device appeared to increase the soundness of the circumference welding joints suggesting its utility for any welding processes of a cylindrical tank using similar techniques. It also has a capability to incorporate with other assisting device [9].…”