Authors: Yasuyuki Yokota Hiroyuki Shimizu Shigeo Nagaoka Kazuhiko Ito Hiroshi Arita
Publish Date: 2013/03/22
Volume: 56, Issue: 1-2, Pages: 43-47
Abstract
In the shipbuilding industry welding efficiency without deteriorating weld quality has been desired to as a consequence of the recent increase in the amount of shipbuilding and the size of ship hulls Especially an innovation in the welding efficiency and weld quality in horizontal fillet welding is a more important issue because the amount of horizontal fillet welding work generally accounts for 70 percent or higher of the total welding work for ship hulls One of highspeed horizontal fillet welding processes known as “Twin Tandem One Pool process” has been used in actual fabrication However the maximum welding speed of the twin tandem one pool process is approximately 15 m/min In order to increase welding speed and welding quality of the twin tandem one pool process the authors have employed an additional filler wire positioned between the two wires of the twin tandem one pool process The additional wire carries DCEN currents opposite to DCEP currents for the main welding wires thereby reducing arc interference and arc blow at high currents With this new technique the authors have improved the stability of the weld pool formation at high currents Consequently horizontal fillet welding at a speed of 20 m/min on primercoated steel plates has been achieved with excellent bead appearance shape and porosity resistance Recently this new process has just been installed in actual shipbuilding and it is confirmed that it truly contributes to improve welding efficiency and minimize repair time
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