Stainless Steel Flange Manufacturer for EPC Projects
Factory-direct stainless steel flanges up to DN4000 in SS304, 316L, duplex 2205 & 2507. Compliant with ASME, DIN, GOST, JIS & API standards. ISO 9001 & PED certified. Exported to 50+ countries.
⚠️ ONLY supply stainless steel products.
As a stainless steel flange manufacturer capable of flanges up to 4 meters in diameter.
QUOTE IN 24 HOURS
From drawing review to pricing — standard and custom orders accepted. MOQ from 1 piece.
100% IN-HOUSE
Forging, machining, and inspection under one roof at our Wenzhou factory. Full traceability from billet to shipment.
STAINLESS STEEL FLANGE
MOST POPULAR FLANGES
As a stainless steel flange manufacturer in Wenzhou, China, Longan produces standard and custom flanges in all major types — from DN15 slip-on flanges to DN4000 large-diameter custom flanges — to ASME, DIN, JIS, GOST, and GB/T standards.
We specialize in manufacturing industrial flanges up to 4 meters in diameter, meeting the demands of heavy-duty applications in oil & gas, petrochemical, power generation, and large infrastructure projects.
All flanges are forged, machined, and inspected in-house at our Wenzhou facility, ensuring dimensional precision, structural integrity, and full international standard compliance. We hold ISO 9001, ISO 14001, ISO 45001, CE, and PED certifications, with quality processes including NDT, hardness testing, and complete material traceability. MOQ starts from 1 piece, with quotes delivered within 24 hours.
In making stainless steel flanges, the raw materials are first tested with spectral detection. This process checks for impurities and ensures the materials are of good quality. It helps make sure the stainless steel flanges are strong and meet industry standards.
The process begins with precision cutting that raw materials are cut into appropriate sizes. Then, they undergo forging to achieve the desired shape and strength. Next, rolling refines the shape further. Finally, CNC machines finish the Stainless Steel flanges.
It involves using machining centers for shaping and high-speed drilling machines for creating holes. Machining centers handle cuts and shaping, while high-speed drilling machines ensure hole placement.
To insure the quality of Stainless Steel flanges, we begin with spectral detection to analyze the material composition. After that, we conduct thorough inspection tests to verify the accuracy and durability.
Once the Stainless Steel flanges are finished, they are stored in a warehouse. Then, they are packed for shipment. Logistics professionals handle their transportation, ensuring delivery to the intended use unit. Upon arrival, the Stainless Steel flanges are ready for installation and operation.
Longan supplies forged stainless steel flanges to ASME B16.5 Class 150–2500 for upstream, midstream, and downstream oil & gas pipelines. Weld neck and blind flanges are standard for high-pressure applications.
PIPELINE JUNCTION
For aggressive media and corrosive environments, Longan manufactures flanges in SS316L, duplex 2205, and super duplex 2507 — materials chosen for their resistance to chloride pitting and stress corrosion cracking.
VALVE & PUMP LINK
Large-diameter flanges up to DN4000 are commonly specified for power plant piping systems, desalination plants, and municipal water infrastructure. Longan's in-house forging capability covers these sizes without outsourcing.
DISASSEMBLY & CARE
Where hygiene, traceability, and easy disassembly matter, Longan produces slip-on, socket weld, and lap joint flanges in SS304/316L with smooth machined finishes and full MTC documentation.
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13,Jun 2026
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