Meeting Energy Demands with a New Welding Process

In particular, these materials often are subject to thermal expansion or contraction, frost and/or other environmental loadings that can easily damage steel and the welds. Special pipeline and joint designs, in conjunction with proper filler metal selection, are helping to protect against such issues.

To date, several classifications of self-shielded flux-cored wires have proven successful for welding high-strength pipelines worldwide. These wires have been specially formulated to generate low levels of spatter and create an easily removable slag, which helps speed inter-pass and post-weld clean up. They also require no shielding gas, making them ideal for welding outdoors and eliminating the time and need for setting up shielding tents to protect gas coverage.

In addition, these wires provide good vertical-down capabilities and offer higher deposition rates than stick electrodes to help improve productivity. Good self-shielded flux-cored options for welding high-strength pipelines include those with AWS classifications: E71T8-Ni1 J H8, E81T8-Ni2 J H8, E91T8-G H8 and E111T8-G H8.

New welding equipment designs, including self-shielded flux-cored guns and wire feeders, have also helped complement the efficiencies of these wires. For example, some wire feeders designed for self-shielded flux-cored wires include dual-schedule features that allow welding operators to change wire feed speeds and voltages easily when welding at the top of the pipe (12 o’clock to 4 o’clock positions) compared to when welding in the 4 o’clock to 6 o’clock positions. This provides greater puddle control as the welding position changes around the pipe.

Newer suitcase-style, voltage-sensing wire feeders also help. These wire feeders protect wires from external contaminants like mud or dust and adjust to changes in voltage to offer precise arc control. Some contractors have also found the addition of wireless remote controls adds to productivity when welding on high-strength pipe. This equipment allows welding operators to change parameters at the point of use (as opposed to at the power source location), and eliminates clutter of another cable surrounding the pipe.

It is likely that a shift to the self-shielded flux-cored process will continue as contractors seek to complete projects faster and for less cost. It is equally likely that filler metal and welding equipment manufacturers will be challenged to build on this technology and offer even more solutions for meeting the strict welding requirements of high-strength pipe. Doing so not only helps give contractors a competitive edge, but it also helps address the ongoing demand for more energy sources worldwide.