Stainless Steel 316 Flanges

316/316L stainless steel flanges are pipe fittings forged from high-quality ASTM A182 F316/F316L stainless steel, designed to achieve a secure seal between pipes, valves, pumps, and high-pressure equipment. Due to the introduction of molybdenum (Mo) into the material, this series of flanges exhibits excellent resistance to chloride pitting corrosion, crevice corrosion, and superior high-temperature creep strength. 

Quality Management System: Certified by ISO 9001:2015 international quality system.

Pressure Equipment Directive: Strictly compliant with EU PED 2014/68/EU and German AD 2000-W0 pressure equipment standards.

Special Operating Conditions: Flange products meeting NACE MR0175 / ISO 15156 requirements for resistance to hydrogen sulfide (H2S) stress corrosion cracking can be provided according to the needs of oil and gas projects.

Corrosion Resistance:

Containing 2%-3% molybdenum (Mo), the flange exhibits significantly superior resistance to pitting and crevice corrosion compared to 304 stainless steel in chloride-containing environments (such as seawater and salt spray) and reducing acid media like acetic acid and phosphoric acid.

Precision CNC Machining:

Advanced multi-axis CNC machining centers are used for precision machining of the sealing surfaces, bevels, and bolt holes. Strict control over the surface roughness of the raised face (RF) and waterline (Serrated Finish) ensures it fully complies with the ASME B16.5 standard's Ra range of 3.2μm - 6.3μm, guaranteeing a perfect fit between the flange and gasket and eliminating potential system leaks.

Stable High and Low Temperature Mechanical Properties:

After standard solution treatment, the flange has a uniform microstructure. Even under extreme conditions such as high-temperature, high-pressure steam or cryogenic ultra-low temperatures, it maintains excellent tensile strength, yield strength, and impact toughness, meeting the stringent requirements of petrochemical and pressure vessel applications.

Full Coverage of Mainstream International Standards
Fully supports all pressure ratings from Class 150 to Class 2500, and PN6 to PN400. Dimensions, tolerances, and mating conform to international standards, ensuring inventory interchangeability for overseas wholesale customers and reducing compatibility risks during on-site installation.

100% Raw Material Verification:

All incoming forgings and bars are sourced from large, reputable steel mills. Not only are the original material certificates (MTCs) checked batch by batch, but 100% chemical composition is also re-verified via Positive Material Identification (PMI) using handheld XRF spectrometers to ensure that the proportions of key elements such as chromium, nickel, and molybdenum fully meet standards.

Full-Process Production Monitoring:

Strict process flow management is implemented, with digital monitoring of forging start temperature, final forging temperature, solution heat treatment temperature rise curve, and holding time to eliminate internal residual stress and optimize the metal grain flow structure.

Comprehensive Non-Destructive Testing (NDT) Capabilities
In addition to routine dimensional, tolerance, and surface roughness inspections, we can provide a full range of NDT services and issue professional reports according to the technical specifications of overseas engineering projects:

Ultrasonic Testing (UT) – Detects internal defects in forgings

Penetrating Testing (PT) – Inspects for micro-cracks on the surface

Hardness Testing (HB/HV) – Ensures mechanical properties meet standards

100% Raw Material Traceability
Each flange surface is permanently stamped or laser-marked, clearly indicating: Heat No., Lot No., material grade, dimensions, pressure rating, and applicable standards. Based on the heat number, it is possible to directly trace back to the initial steelmaking heat's chemical composition and mechanical property report.

Third-Party Inspection and Material Certificate Support

By default, we provide: Material Test Certificate conforming to EN 10204 3.1.

Third-party collaboration: We fully support and cooperate with international third-party inspection agencies such as SGS, Lloyd's Register, BV, and TÜV for factory audits, on-site witnessed sampling, and finished product acceptance.

High-Quality Raw Material Procurement: High-quality stainless steel raw materials conforming to ASTM A182 specifications are selected, accompanied by original material certificates.

Heavy Forging: Large-scale hydraulic free forging or precision die forging is used according to specifications to ensure the density of the forgings and eliminate casting defects.

Solution Annealing: Heating to 1040℃-1150℃ followed by rapid water cooling eliminates processing stress and restores optimal corrosion resistance.

CNC Precision Machining: CNC lathes are used to machine internal holes, external diameters, flange faces, and water lines; CNC multi-hole drilling machines ensure precise bolt hole spacing.

Surface Treatment and Passivation: Pickling, passivation, sandblasting, or electropolishing are performed to form a dense, chromium-rich protective film, improving appearance and rust resistance.

Final Inspection and Compliant Packaging: Finished products undergo comprehensive quality inspection and are properly packaged for shipment.