Thick-walled large diameter welded pipe

Welding Method

First, clean the oil, paint, water, and rust from the welding joint thoroughly. Then, bevel the joint according to the wall thickness, making it larger for thicker walls and smaller for thinner ones (using an angle grinder). Next, ensure the gap between the bevels is generally 1 to 1.5 times the diameter of the welding rod or wire. If the bevel is accidentally too large, leave it slightly smaller. The spot weld should consist of at least three points, but four points are preferable for ease of work. Weld in half-and-half segments, starting from the beginning. The weld should extend about one centimeter beyond the bottom point for a good connection from the opposite side. If the steel pipe has a thick wall, it should be layered, at least in two layers. The entire circumference should be welded in one layer 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 testing (or flaw detection) → Marking