Automatic Orbital Welding Head for Shipboard Use where Accessibility is Limited

摘要

This project used test welds to demonstrate the automatic welding or 'U' bends to a simulated bank of economizer tubes. This welding was accomplished using a prototype head designed to fit within the limited space available. A mock-up simulated a section of the economizer tube bank for the Frigate USS Downes (FF 1070). A remote control system was also developed for the prototype head. In this welding operation, the 'U' bend is first fitted up with Electric Boat (EB) consumable inserts and tack welded. The EB insert is then fused using the pulsed current Gas tungsten Arc Welding (GTAW) method with the prototype head. A two piece 'outsert' is then tack welded over the root pass. The joint is completed by making a pair of fusion passes over the 'outsert' with the head. Delivery of the prototype head was made to NAVSSES after the contractor completed an abbreviated series of qualifications tests including liquid penetrant, radiographic and metallurgical analyses. Plans to continue with a full series of qualification tests were postponded because Navy approved joint designs had not yet provided allowances for use of devices like the 'outserts'. A design of an alternate head for the 'U' bend application was developed with a partially open head to facilitate weld head installation and observation. An automatic cold wire feed system was added to eliminate the use of the outsert. This alternate head was not build or tested under the work covered by this interim report. Keywords: Automatic pipe welding.