By Tricia Lobo
Updated Mar 24, 2022
Shielded metal arc welding (SMMAW) is the industry‑standard method for joining natural gas pipelines. The process begins with a series of tack welds to secure the pipes in place, followed by a continuous butt weld that forms the permanent joint. If you’re new to pipe welding, we recommend hiring a certified pipe welder who has mastered the nuances of working with pressurized gas lines.
Remove all slag, rust, oil, and debris from the weld surfaces. The cleaner and smoother the joint, the stronger the final weld.
Position the two pipe sections so that their mating faces are flush. Use a clamp to hold the alignment firmly before welding.
Apply evenly spaced, uniform tack welds around the circumference of the joint. These small welds lock the pipes together and keep the joint stable during the main weld.
Complete a continuous weld around the entire joint. For pipe diameters under 2 mm, use a curved, zig‑zag motion; for thicker pipes, a straight bead is preferred.
Never weld a live natural gas pipe unless you have proven experience and the right equipment. Proper welding parameters—adequate heat input, correct wire feed, and appropriate joint design—are essential to prevent pipe burnout or brittle welds. In many cases, specialized software is required to calculate the optimal settings for each pipe size and material.
