Definition and core functions of spiral steel pipes for marine engineering pipelines

Spiral steel pipes for marine engineering pipelines are spiral welded steel pipes designed specifically for marine environments. They are manufactured using strip steel coils through spiral forming and double-sided submerged arc welding processes, and have high strength, corrosion resistance, compression resistance, and impact resistance. They are suitable for deep-sea oil and gas transportation, submarine cable protection, cross sea bridge pile foundations, and other scenarios, meeting the strict requirements of marine engineering for pipeline salt spray resistance, high pressure resistance, and long-term durability. Its core function is to ensure the stability and safety of marine engineering facilities through structural optimization and anti-corrosion technology.

Technical characteristics and manufacturing processes

1. Material and structural design

Raw materials: X70/X80 high-grade steel or Q345B low-alloy steel is used, and the strip steel is pre treated with leveling and edge cutting to ensure mechanical properties and processing accuracy.

Ultra thick wall design: such as a spiral steel pipe with a diameter of 1500 × 32mm (wall thickness of 32mm), which can withstand the impact of deep-sea high pressure and geological disasters, with a single weight of 56 tons

2. Anti corrosion and compressive performance

Multi layer anti-corrosion technology: For seawater corrosion, 3PE anti-corrosion (epoxy powder+adhesive+polyethylene) or hot-dip galvanizing process is used, with a salt spray corrosion resistance time of more than 30 years.

High pressure bearing capacity: The wall thickness range is 8-32mm, with a maximum pressure bearing capacity of 2.5MPa (such as DN1200 with a wall thickness of 12mm). Spiral welds disperse stress, and the impact resistance is 30% higher than that of straight seam pipes.

3. Manufacturing process

Double sided submerged arc welding: using automatic double wire welding technology, the weld seam gap is controlled within 1-3mm, the inner and outer welds are 100% ultrasonic inspected, and defects are automatically reported and repaired.

Intelligent detection: The entire production process passes the water pressure test (1.5 times the working pressure) and X-ray re examination, with a pass rate of ≥ 99.5%.

Application scenarios and typical cases

Deep sea oil and gas transportation

Used for mainline transportation from subsea oil and gas fields to onshore pipelines, such as 426 × 8mm spiral steel pipes (DN400) that can withstand high pressure and seawater corrosion, ensuring stable transportation of oil and gas resources.

Cross sea bridge beam pile foundation

Large diameter spiral steel pipes (such as DN1500) are used for bridge support structures to resist seawater erosion and geological settlement.

Offshore wind power engineering

Thick walled spiral steel pipes (wall thickness ≥ 20mm) are used as foundation piles for wind turbine towers, suitable for complex marine environments and high load conditions.

Production standards

The material complies with GB/T 9711 (Petroleum and Natural Gas Steel Pipe Standard) and classification society (such as CCS, DNV) specifications.

Implement SY/T 0413 (3PE anti-corrosion) or ISO 12944 (ship coating standard) for anti-corrosion.

Ultra thick wall and high-strength materials: Promote X80/X100 steel grade steel pipes, such as 32mm ultra thick wall design, to enhance the compressive strength of deep-sea engineering.