I. Product Function
1. Special pipe fittings for turning and branching of lined / overlay-welded composite steel pipes. The outer carbon steel base bears structural pressure, while the inner corrosion-resistant alloy layer isolates corrosive media, achieving integrated anti-corrosion support for the entire pipeline system;
2. Turning and branch node fittings for seawater desalination, power plant desulfurization and denitrification, and chemical acid-alkali highly corrosive medium conveying networks;
3. Transfer components for coastal high-salt sewage, drinking water transportation, and high-temperature oil and gas extraction and gathering composite pipelines;
4. Branching, direction-changing, and sealing connection pipe fittings for the inlet and outlet of large storage tanks and pressure vessels.
II. Specification and Material Parameter Table
Parameter Item | Production Range / Optional Type |
Nominal Diameter | DN50–DN3000; non-standard diameters can be customized |
Pipe Fitting Type | 90° / 45° elbows, equal tees / reducing tees |
Forming Process | 1. Mechanical lining and rolling composite process; 2. Fully automatic inner-wall overlay welding metallurgical composite process |
Carbon Steel Base Wall Thickness | 6mm–35mm |
Corrosion-Resistant Lining / Overlay Layer | 304, 316L, 2205 duplex stainless steel, Hastelloy |
Base Material | Q235, 20#, 16Mn, Q355B forged / stamped carbon steel |
External Wall Anti-Corrosion Process | 3PE coating, epoxy coal tar coating, high-temperature-resistant anti-rust coating |
Applicable Pressure Rating | PN10–PN63 |
III. Material Combination Application Scenarios
1. Carbon steel base + 304 lining: suitable for municipal tap water, agricultural irrigation, and non-corrosive normal-temperature low-pressure pipelines;
2. Carbon steel base + 316L lining / overlay welding: suitable for coastal saline sewage, seawater transportation, and mildly corrosive chemical working conditions;
3. Carbon steel base + 2205 duplex stainless steel overlay welding: suitable for power plant desulfurization and medium acid-alkali corrosion pipelines with high chloride ion content;
4. 20# carbon steel + Hastelloy overlay welding: suitable for high-temperature strong acid and highly corrosive chemical high-pressure process pipelines.
IV. Product Advantages
1. Two composite processes are available: the mechanical lining type offers high cost performance, while the overlay-welded type achieves metallurgical fusion with no risk of delamination or peeling, making it suitable for harsh high-temperature and high-pressure working conditions;
2. The inner walls of elbow curves and tee branching areas feature smooth transitions, resulting in low medium flow resistance, reduced scaling, and low erosion loss;
3. The outer carbon steel layer ensures overall rigidity and pressure-bearing strength, while the inner alloy layer resists corrosion and rust, combining structural strength with corrosion resistance;
4. Can be matched with composite straight pipes and composite flanges as a complete set, ensuring consistent anti-corrosion materials throughout the pipeline and eliminating weak corrosion points at joints;
5. Both ends are provided with unified standard welding bevels for convenient on-site welding installation, and the multi-layer external anti-corrosion coating extends service life in buried applications.