SURFACE TENSION TRANSFER (STT)

STT® Open Root – The semi-automatic open root welding procedure

 

1. Start arc on sidewall, not in gap. 2. After puddle is established, maintain the arc on the forward portion of the puddle. 3. Move across the gap. 4. Move slightly up the sidewall. 5. Stay in the puddle and move the electrode back across the gap. Move the electrode down the joint in a half-moon motion. 6. Continue moving back and forth (weaving) across the gap until reaching the 1 o’clock position. 7. At 1 o’clock, stop weaving. Concentrate the arc on forward weld puddle and move down the pipe joint until you reach the 5 o’clock position. 8. At 5 o’clock, reposition the torch angle to be perpendicular to the pipe. 9. End the weld at 6 o’clock by moving the arc onto the sidewall. 10. DO NOT stop welding while in the root. This may cause pin holes.