Thick-walled large-diameter welded pipe

Welding Method

Weld thick-walled steel pipes first by cleaning the weld joint of oil, paint, water, rust, etc. Then, open the bevel according to the wall thickness; for thicker pipes, open a larger bevel, and for thinner pipes, a smaller one (using an angle grinder). Next, align the gaps, usually 1-1.5 times the diameter of the welding rod or wire. If the bevel is accidentally opened too large, leave it slightly smaller. At least three spot welds are needed, but four points are preferable for easier work. Weld in half-sections, starting from the point. Extend about one centimeter beyond the bottom point for better alignment from the opposite side. If the pipe has a thick wall, it should be welded in layers, at least two layers. One full-circle weld is required before welding the second layer.

Process Flow

Round billet → Heating → Piercing → Three-roller slitting, continuous rolling, or extrusion → Tube removal → sizing (or reduction) → Cooling → Straightening → Hydrostatic test (or flaw detection) → Marking