Manufacturing method for X120 steel-level spiral seam hidden arc welding tube

The invention discloses a manufacturing method for an X120 steel-level spiral seam hidden arc welding tube. The contents of various chemical components of the spiral seam hidden arc welding tube are optimally designed and a trace B element is added. The manufacturing method comprises the following steps: uncoiling; flattening; milling edges; pre-bending; molding; internally welding and externallywelding, or pre-finishing welding; layering a mother plate; performing ultrasonic flaw detection on a welding joint and X-ray flaw detection on the welding joint; expanding a tube end; testing a water pressure; performing ultrasonic flaw detection on the welding joint; performing X-ray flaw detection on the tube end; chamfering the tube end; and checking an end-product. The strength of the high-intensity spiral seam hidden arc welding tube manufactured by using the method is greatly increased, the molding stability in manufacturing process is greatly increased and the production cost is efficiently lowered.