The pre-weld quality of straight seam steel pipe includes weld quality and weld quality.
(1) Joints (i.e. formed joints) have no wrong edges or the wrong edges are less than the prescribed value. Generally, the prescribed error amount is less than 8% thickness and the maximum is not more than 1.5mm.
(2) In order to ensure proper penetration depth and welding quantity, it is necessary to ensure that the weld does not crack after welding, does not produce combustion phenomenon, and also controls the height of the weld. The height of the weld does not have an effect.
(3) The welds are continuous and well-shaped to help ensure the final external welding quality.
(4) There are no welding deviation, pore, crack, slag, combustion and back welding defects in the weld, which requires the center deviation of the weld to be less than 1 mm.
(5) No arc burns, small spatter, no impact on the end groove and surface quality.
(6) The physical and chemical properties of the weld metal meet the quality requirements when the weld seam matches the base metal.