I. Product Function
1. Special sealing connector for overlay-welded composite steel pipes. The carbon steel base bears structural pressure, while the inner-wall overlay-welded corrosion-resistant alloy layer directly contacts corrosive media;
2. Connection accessory for highly corrosive composite pipeline networks used in chemical desulfurization, seawater desalination, and high-salinity sewage systems;
3. Sealing flange for the inlet and outlet of high-temperature oil and gas systems, pressure vessels containing acid and alkali media, and large storage tanks;
4. Supporting flange for complete anti-corrosion pipeline systems, including overlay-welded composite elbows, tees, and lined overlay-welded pipelines.
II. Specification and Material Parameter Table
Parameter Item | Production Range / Optional Type |
Nominal Diameter | DN50–DN2000; non-standard sizes can be customized |
Pressure Rating | PN10, PN16, PN25, PN40, PN63 high-pressure ratings |
Forming Process | Carbon steel forged base + inner-wall fully automatic submerged arc / plasma overlay welding metallurgical composite process |
Base Material | Q235, 20#, 16Mn, Q355B carbon forged steel |
Overlay-Welded Corrosion-Resistant Surface Layer | 304, 316L, 2205 duplex stainless steel, Hastelloy, Monel alloy |
Sealing Face Type | RF raised face, MFM male and female face, RJ ring joint face for high-pressure applications |
Applicable Standard | HG/T20592, GB/T9113, ASTM A182 |
III. Material Combination Application Scenarios
1. Carbon steel base + 316L overlay-welded layer: suitable for seawater, saline sewage, and mildly corrosive chemical pipelines under normal-temperature conditions;
2. Carbon steel base + 2205 duplex stainless steel overlay-welded layer: suitable for power plant desulfurization and medium acid-alkali working conditions with high chloride ion content;
3. Carbon steel base + Hastelloy overlay-welded layer: suitable for strong acid and highly corrosive chemical high-temperature process pipelines;
4. 20# carbon steel base + corrosion-resistant alloy overlay-welded layer: suitable for high-temperature steam and high-temperature oil and gas conveying systems.
IV. Product Advantages
1. The overlay-welded layer forms metallurgical fusion with the flange base, eliminating the risk of delamination or peeling, with bonding strength far higher than lined composite flanges;
2. The outer forged carbon steel base provides strong rigidity and excellent pressure-bearing performance, while the inner alloy layer resists corrosion and medium erosion;
3. It can be perfectly matched with overlay-welded composite steel pipes and composite pipe fittings, ensuring unified anti-corrosion materials throughout the pipeline and eliminating local corrosion weak points;
4. The sealing face is precision-machined and provides reliable sealing when matched with corresponding gaskets, making it suitable for harsh working conditions involving high temperature, high pressure, and strong corrosion;
5. The overlay welding thickness can be adjusted as required, allowing customized corrosion-resistant layers for different corrosive environments and significantly extending equipment service life.