Pre-welding of straight seam steel pipes

Pre-welding of straight seam steel pipes: pre-welding includes seams and welds.

1. The joint (that is, the forming seam) has no misalignment or the misalignment is less than the specified value. Generally, the amount of misalignment is ≤ 8% of the plate thickness, and the maximum is not more than 1.5mm.

2. To ensure that the weld has a suitable penetration depth and deposition amount, it is necessary to ensure that there is no cracking after welding, no burn-through phenomenon, and the height of the weld must be controlled so that the reinforcement of the external weld will not be affected.

3. The weld bead is continuous and formed, to facilitate the external welding after the guarantee.

4. There are no defects such as welding deviation, air holes, cracks, slag inclusions, burn-through, and back welding bumps in the weld seam, and the center deviation of the weld seam is required to be ≤ 1mm.

5. There is no arc burn, or little splash, and does not affect the bevel and surface of the pipe end.

6. The weld seam matches the base metal, and the physical and chemical properties of the weld metal meet the requirements.