Pre-welding quality includes joint quality and weld quality.
(1) Forming seam no wrong edge or wrong edge less than the specified value, the general provisions of the wrong edge ≤ 8% of the thickness, the maximum does not exceed 1.5mm.
(2) To ensure that the weld penetration and the appropriate amount of melting, it is necessary to ensure that welding does not crack, does not burn through the phenomenon, but also to control the weld height, welding seam remaining height does not affect.
(3) Continuous bead, forming a good, in order to facilitate the guarantee of the quality of the final welding.
(4) The weld does not exist welding deviation, porosity, cracks, slag, burn through and the back of the weld and other defects, the weld center deviation ≤ 1 mm.
(5) No electric arc burns, splashing small, does not affect the pipe bevel and surface quality.
(6) Weld and base metal match, weld metal physical and chemical properties to meet quality requirements.
