Spiral steel pipes are made by bending strip steel in a spiral direction using a coiling machine, followed by capacitive double-sided submerged arc welding. During the production of spiral steel pipes, issues such as incomplete welds and misaligned edges are common. However, the most difficult issue to control is the formation of pinholes at the butt weld seam of the spiral steel pipe.
Spiral submerged arc welded steel pipe manufacturers analyze the causes of pinholes as follows:
1. Insufficient current supplied to the welding torch and insufficient capacitance time during welding. The weld surface hardens before the capacitance is fully penetrated, resulting in unpenetrated sand particles or air bubbles inside.
2. Improper alignment when the strip steel enters the bending section, resulting in an excessively large gap between the strip steel sections.
3. Failure to promptly clean rust or oxide scale from both sides of the strip steel during butt welding.
4. Production equipment was not maintained or tidied promptly. Dust or dirt on the workbench may accidentally fall into the welding seam of the steel strips.
5. The temperature or humidity in the work area is too low or too high, which affects the temperature and dryness of the welding point.
Post time: Apr-03-2026