Stainless Steel 304 Flanges

Stainless Steel 304 Flanges are pipe connection components made of high-quality ASTM A182 F304 austenitic stainless steel through integral die forging and precision CNC machining. They are designed to provide high-pressure, zero-leakage sealing connections for pipelines, valves, and fluid equipment in industries such as oil and gas, fine chemicals, water treatment, food and beverage, pharmaceuticals, and marine engineering worldwide. 

Globally Recognized Certifications
Our factory is ISO 9001:2015 Quality Management System Certification, EU PED 2014/68/EU (Pressure Equipment Directive, essential for entering the European market), and CRN (Canadian Registration Number). All products come with 100% EN 10204 3.1 Material Certificates (MTC) to ensure successful project acceptance.

100% Die Forging Process
We refuse to use cut rings from medium-thick plates or castings. Our 304 flanges are all integrally forged from stainless steel round bars. The streamlined metal fiber structure is denser, eliminating internal porosity, air bubbles, and inclusions. The sealing surface roughness is strictly controlled within 125-250 AARH (Stock Finish) or customer-specified requirements, ensuring zero leakage under long-term high-pressure conditions.

Ready Stock and Flexible Delivery Time

Common specifications in stock: Slip-on, Weld Neck, and Blind flanges (sizes 1/2" - 12", pressure class 150/300) according to ASME B16.5 standards, with a readily available inventory of tens of thousands of tons, ready for packing and shipment within 48 hours.

Customized bulk orders: Delivery time is typically 15-30 days.

Minimum Order Quantity (MOQ): Sample orders are supported; tiered wholesale pricing is available for bulk purchases.

Compatible with stringent international standards
Specifications fully cover DN15 - DN5000 (or 1/2" to 200"). We can seamlessly match the standard systems of different countries and regions:

American Standards: ASME/ANSI B16.5, B16.47 Series A & B

European/German Standards: EN 1092-1 Type 01/11/05/12, corresponding DIN standards

Japanese/Other Standards: JIS B2220, BS 4504, GOST 12820/12821

Surface Hygiene Treatment Customized for Food/Pharmaceutical Industries
For high-cleanliness industries, we support fully automated pickling and passivation, shot blasting, and high-precision mirror polishing to thoroughly remove free iron contamination, improve intergranular corrosion resistance, and meet FDA and sanitary piping system standards.

Raw Material Spectroscopic Verification (PMI Input Inspection): All incoming stainless steel round bars must be traceable using a "Heat Number" system and 100% tested using a portable spectrometer (PMI) to ensure chemical composition meets standards.

Precision Forging: Strict control of initial and final forging temperatures is implemented. Forging compression of metal grains eliminates internal stress and optimizes mechanical properties.

CNC High-Precision Machining: High-precision CNC lathes and vertical lathes are used to machine water lines, bolt holes, and beveling, with tolerances strictly limited to within half of the standard allowable range.

Chemical Passivation and Surface Treatment: Trace amounts of iron ions are removed from machined surfaces using standard pickling and passivation solutions, forming a dense, chromium-rich protective film with excellent salt spray resistance.

Final Quality Gate (FQG): The QC team performs caliper measurements on bolt hole center distance, sealing surface roughness, and flange thickness. They can also cooperate with third-party organizations such as SGS, TÜV, and BV for on-site supervision and random inspections.

Non-standard Drawing Processing: Supports customizing non-standard flanges with special thicknesses, large diameters, or special hole spacings based on DWG/PDF drawings.

Customized Sealing Surface Roughness: Customizable with 125 AARH, 250 AARH, or smoother mirror finishes to suit specific gasket sealing requirements.

Customized Project Marking: Supports marking customer logos, project-specific contract numbers, and designated markings.

Packaging and Shipping Marks: Provides neutral packaging or customized shipping marks for distributors, facilitating direct customs clearance and distribution for wholesalers.