Stainless Steel 904L Flanges

SS 904L flanges are your solution for service conditions that stress conventional stainless grades. The alloy is stable in sulphuric and phosphoric acid environments and reliable in chloride bearing systems such as seawater. It is also more resistant to pitting and crevice corrosion than conventional types, which has a direct impact on service life and maintenance intervals in critical piping assemblies.

Types of SS 904L Flanges

The product portfolio covers all common connection geometries of industrial piping systems.

Weld Neck Flanges (WNRF): For high-pressure and -temperature service. Tapered hub to minimize stress concentration at the joint.

Slip-On Flanges: Easier to line up and weld. Used for medium-pressure applications where speed of installation is important.

Blind Flanges (BLRF): Used for the termination of a piping system or vessel nozzle.

Threaded Flanges: Great for applications where welding is not an option due to material or job site conditions.

Socket Weld Flanges: Widely used for high-pressure piping of small diameter. Pipe is inserted into a socket and welded.

Lap Joint Flanges: Used with stub ends, which provide free rotation to align bolt holes during assembly.

Spectacle blind flanges: Two plates used to isolate or connect a section of pipeline by rotation.

Orifice Flanges: Flanges having tapped holes for the installation of orifice plates for flow measurement.

Features & Benefits

SS 904L Flanges provide a combination of corrosion resistance, mechanical strength and process compatibility which normal austenitic grades can not reliably provide.

• ● High molybdenum content between 4.00% and 5.00% provides superior resistance to pitting and crevice corrosion in chloride-rich environments.
• ● Nickel contents of 23 to 28% help resist stress corrosion cracking in aggressive media under tensile load.
• ● Ultra-low carbon specification (maximum 0.020%) prevents carbide precipitation in the heat-affected zone during welding.
• ● Copper in the alloy chemistry improves resistance to reducing acids, especially sulphuric and phosphoric acids, in a wide range of concentrations.
• ● The minimum tensile strength of SS 904L Flanges is 490 MPa, which provides structural integrity in high-pressure piping applications.
• ● The alloy also retains its corrosion resistance in seawater and marine environments where regular grades like 316L would normally fail.
• ● As indicated by the minimum elongation of 35%, the material has good ductility and is able to absorb stress without brittle fracture under load.

Technical Specifications

SS 904L Flanges conform to internationally recognised standards across dimensions, pressure ratings, and face configurations.

Chemical Properties

Grade 904L stainless steel carries a tightly controlled chemical composition that directly drives its corrosion performance in service.

Mechanical Properties

The mechanical profile of SS 904L Flanges confirms suitability for demanding structural and pressure-bearing service conditions.

Equivalent Grades

SS 904L is recognised under multiple international standards. The table below covers the most commonly referenced designations.

Applications / Industries

SS 904L Flanges are the material of choice wherever process fluids, operating temperatures, or environmental exposure exceed what standard stainless steel grades can reliably handle.

Quality Testing & Inspection

Quality assurance at Eckhardt Steel begins well before a flange reaches the dispatch stage. Each batch of SS 904L Flanges is subject to Positive Material Identification (PMI), which cross-references the alloy's elemental chemistry against the certified mill test report to confirm grade authenticity. Hardness testing per ASTM E18 is performed to verify that the heat treatment of the material has yielded the mechanical properties required by the governing specification.

Hydrostatic testing per ASME is performed to verify the pressure integrity of the piping system and to verify that there are no leakage paths under rated service conditions. Dimensional inspection includes bore diameter, outside diameter, bolt circle, flange thickness and face finish, all inspected to ANSI B16.5 or project specific dimensional standard. Each flange is visually and surface inspected for seams, laps or finish irregularities that could impact field performance before packing.

All shipments are fully documented. Mill test reports, heat and lot certificates and compliance declarations to purchase order standard are provided. Third-party inspection by independent accredited agencies can be arranged on request, and witness inspection is accommodated for critical supply contracts.

SUPPLIERS AND EXPORTER OF STAINLESS STEEL 904L FLANGES IN GUJARAT

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SUPPLIERS AND EXPORTER OF STAINLESS STEEL 904L FLANGES IN ODISHA