The core of routine maintenance for longitudinally welded steel pipes lies in monitoring the integrity of the longitudinal weld, the condition of the anti-corrosion coating, and operational parameters. Regular inspections, cleaning, protective measures, and defect repairs are essential to prevent crack propagation or leakage caused by stress concentration.
Specialized Weld Inspection: Conduct quarterly (or monthly in harsh environments) visual inspections of longitudinal welds to check for cracks, undercut, or corrosion. For pressurized or critical piping, perform annual inspections-incorporating ultrasonic or magnetic particle testing-to detect internal lack of fusion or fatigue cracks, with a specific focus on the weld heat-affected zone.
Anti-corrosion Coating Maintenance: Inspect external anti-corrosion coatings (e.g., 3PE, galvanizing) for peeling or scratches. If damage is detected, clean, grind, and recoat the area with compatible material within 48 hours; ensure that bare metal is strictly prevented from coming into contact with corrosive media.
Surface Cleaning and Protection: Regularly remove oil, welding spatter, and accumulated dust. Use specialized cleaning agents for stainless steel to prevent chloride ion corrosion; keep carbon steel dry and well-ventilated to avoid moisture accumulation that accelerates electrochemical corrosion.
Operational Monitoring: Monitor internal pressure fluctuations, abnormal vibrations, and medium compatibility. Prevent overpressure, water hammer, or corrosive media from accelerating fatigue failure in longitudinal welds; inspect supports and hangers to ensure they are not loose, which could subject welds to additional stress.
Storage and Environmental Management: Store idle steel pipes indoors; outdoor stacking is strictly prohibited. For long-term inactivity, apply nitrogen blanketing or anti-rust oil to prevent oxidation of the inner walls.
