| High-frequency welded pipe | Cold-forming of steel strip followed by high-frequency electric-resistance welding | Approximately 21.3–610 mm | Approximately 1.5–20 mm | GB/T 3091, ASTM A53, ASTM A500, API 5L | Water transmission, structural work, building columns, mechanical components, and low-to-medium-pressure service | High-volume standardized production with strong emphasis on dimensional consistency and delivery speed |
| Longitudinal submerged-arc welded pipe | Steel plate formed into a cylinder and welded along the longitudinal seam using submerged-arc welding | Approximately 406–1,422 mm | Approximately 6–40 mm | API 5L, GB/T 9711, ASTM A252, ASTM A671 | Long-distance oil and gas pipelines, large water projects, piling, and heavy structural engineering | Project-based production for large-diameter and higher-wall-thickness requirements |
| Spiral submerged-arc welded pipe | Helical forming of steel strip with continuous submerged-arc welding on the spiral seam | Approximately 219–3,620 mm | Approximately 6–25 mm | API 5L, GB/T 9711, ASTM A252 | Municipal water pipelines, drainage, irrigation, piling, and large-diameter transmission lines | Cost-efficient large-diameter production with flexible use of available steel coil |
| Structural welded pipe | ERW, HFW, or submerged-arc welding, depending on diameter and structural load requirements | Commonly 21.3–1,422 mm | Commonly 2–40 mm | GB/T 6725, GB/T 3094, ASTM A500 | Steel buildings, bridges, towers, machinery frames, and architectural structures | Specification-driven supply based on yield strength, geometry, tolerances, and fabrication needs |
| Line pipe for energy and utilities | ERW, HFW, longitudinal SAW, or spiral SAW, selected according to diameter, pressure, and service conditions | Approximately 60–1,422 mm | Approximately 3–40 mm | API 5L and GB/T 9711 | Crude oil, natural gas, refined products, industrial water, and utility networks | Qualification-focused supply involving chemical composition, toughness, weld inspection, and hydrostatic testing |
| Boiler, heat-exchanger, and pressure-service pipe | Precision welded forming with controlled heat treatment, nondestructive testing, and dimensional inspection | Commonly 10–610 mm | Commonly 1.5–30 mm | ASTM A178, ASTM A249, ASTM A269, and applicable GB standards | Boilers, heat exchangers, condensers, process equipment, and industrial heating systems | Higher-value technical production requiring tighter surface, weld, and pressure-performance controls |
| Coated and finished welded pipe | Base pipe production followed by galvanizing, three-layer polyethylene, fusion-bonded epoxy, painting, or lining | Depends on the underlying ERW or SAW pipe | Depends on the underlying pipe specification | ISO 21809, AWWA C213, ASTM A53, API 5L, and project-specific specifications | Buried pipelines, marine works, water treatment, fire protection, and corrosive environments | Value-added supply combining pipe manufacturing, surface protection, testing, and export packing |