Stainless Steel 2205 Duplex Stainless Steel Din6923 Hex Flange Nut Lock Nut

This product is a 2205 duplex stainless steel flanged hexagonal nut (also known as 2205 with backing nut, flange anti-loosening nut), which is a high-end industrial fastener specially designed for extreme working conditions such as high corrosion, high load, and high vibration. The product uses 2205 duplex stainless steel (national standard grade 022Cr23Ni5Mo3N, ASTM A182 F51) as the core base material. It is manufactured through multiple processes such as precision cold heading, tapping, solution heat treatment, and passivation, featuring the ultimate corrosion resistance of austenitic stainless steel and the extremely high strength of ferritic stainless steel. Its resistance to pitting and crevice corrosion is more than twice that of 316 stainless steel. With an integrated flanged surface structure, it provides stable, long-lasting, and safe connection and fastening solutions for high-end fields such as marine engineering, chemical industry, seawater desalination, and papermaking.

2205 dual-phase stainless steel exclusive material, super corrosion resistance + high strength dual advantages

2205 dual-phase stainless steel has an austenite + ferrite dual-phase structure, with PREN (corrosion resistance equivalent) ≥ 35. Its resistance to chloride ions, pitting corrosion, and stress corrosion far exceeds that of 304/316 stainless steel. It can work stably in extreme corrosive environments such as high salt spray, strong acid and alkali, and seawater; at the same time, its tensile strength ≥ 655 MPa, yield strength ≥ 450 MPa, which is twice that of ordinary 304/316 stainless steel, can withstand extremely high loads, perfectly solving the problems of corrosion and deformation of ordinary stainless steel in high-corrosion and heavy-load scenarios, and is non-magnetic, meeting the standards for high-end industrial use.

Integrated flange face hexagonal structure, anti-loosening and anti-slip + double advantages without gaskets

Strictly following the international standard GB/T 6177.1 (ISO 4161, DIN 6923), the integrated flange face + hexagonal head structure. The flange face has the function of increasing the contact area, which can disperse the compressive force and avoid damaging the surface of the workpiece. At the same time, no additional flat washers are required, simplifying the installation process; the anti-slip teeth pattern on the flange face (for some specifications) can enhance friction, improve anti-loosening and anti-vibration performance, and perfectly adapt to high-vibration and high-load scenarios.

High-precision tapping process, tight engagement and uniform force

Using a fully automatic precision tapping process, the thread accuracy reaches 6H grade, with full tooth shape, no burrs, no slippage, and is tightly meshed with the same specification bolts, with uniform force, excellent anti-loosening and anti-vibration performance, capable of withstanding long-term vibration and impact loads, avoiding the risk of loosening and detachment, and ensuring the long-term stability of the connection.

Solution for solid solution acid washing and passivation, dual improvement of performance and lifespan

The product undergoes 1050-1100℃ solid solution heat treatment + acid washing and passivation treatment, eliminating internal stress, optimizing the proportion of dual-phase structure, and maximizing the anti-corrosion performance and mechanical properties; the surface has high smoothness, no oxide scale, no scratches, a shiny appearance, and enhances corrosion resistance, reduces stress concentration, and extends the product lifespan.

Full specification coverage, customized service

Covering all series of screw thread specifications from M3 to M24, and supporting non-standard customization. Customized special screws, special flange dimensions of flange nuts can be provided according to customer requirements, meeting the personalized fastening needs of high-end equipment and special working conditions.

Evaluation of procurement for marine engineering enterprises: "This 2205 duplex stainless steel flange nut for marine platforms has outstanding resistance to salt fog corrosion. It has been used in a seaside high-salt fog environment for 5 years without rusting or loosening. The one-piece flange eliminates the need for gaskets, ensuring high installation efficiency. Installation with standard torque results in stable connections, fully meeting the strict requirements of marine engineering."

Evaluation by a chemical plant equipment engineer: "All the high-corrosion fastenings for chemical reactors and desulfurization equipment use this nut. The 2205 duplex stainless steel is resistant to strong acids and strong alkalis, and can resist stress corrosion. It has not failed after three years of use. The flange surface distributes pressure, protecting the workpiece. The thread precision is high. We have repurchased it many times."

Evaluation by a shipbuilding enterprise for procurement: "All the fastenings for ship equipment and seawater desalination devices use this nut. It is resistant to seawater corrosion, has high strength, and is suitable for high-vibration and high-salt fog conditions of ships. Installation is convenient, significantly reducing maintenance costs in the future. The quality is extremely reliable."

Evaluation by the procurement department of an environmental protection equipment factory: "All the fastenings for sewage treatment and desulfurization and denitrification equipment use this nut. It is resistant to chloride ion corrosion, has high strength, perfectly adapting to the high-corrosion conditions of environmental protection equipment. Installation with standard torque results in stable connections. Customer feedback is very good. It has become our standard accessory."

Petrochemical industry

Equipment such as oil refining units, chemical reactors, transportation pipelines, and heat exchangers are securely connected. 2205 and 2507 duplex steel perform exceptionally well in media containing hydrogen sulfide and chloride ions; 904L is suitable for non-oxidizing acid environments such as sulfuric acid and phosphoric acid.

Marine engineering

Offshore oil platforms, seawater desalination devices, and ship equipment. 2507 super duplex steel has excellent resistance to pitting and crevice corrosion in seawater environments and is the preferred material for marine engineering fasteners.

Nuclear energy

Nuclear island equipment, conventional island equipment, and flue gas desulfurization devices. 660 precipitation hardening steel is used for high-temperature and high-pressure components; 321 stainless steel is used for pipeline systems. rail traffic

High-speed rail, subway vehicle and track infrastructure construction. The products possess high strength, fatigue resistance, vibration resistance and other characteristics, ensuring operational safety.

Environmental protection equipment

Equipment for desulfurization and denitrification of flue gas, sewage treatment, and waste incineration. 317L and 904L have excellent corrosion resistance in environments containing chlorine-containing waste gas and acidic wastewater.