ISO 9001:2015 & PED 2014/68/EU Approved Forged Flange Works Class 150 To Class 2500, ½″ To 60″, RF / FF / RTJ Facings Manufacturer Of Stainless Steel 904L Flanges Since 2012, 19+ Export Markets

Stainless Steel 904L Flanges

Stainless Steel 904L Flanges Quick Reference

Manufacturing ProcessOpen-Die Forging, Ring Rolling, CNC Machining
Grade / UNSUNS N08904 / WNR 1.4539
FormsWeld Neck, Slip On, Blind, Socket Weld, Lap Joint, Threaded
Delivery TimeEx-Stock: 2–4 Days • Forged-To-Order: 4–6 Wks
Sizes In Stock½″–24″ (B16.5), 26″–60″ (B16.47)
Pressure Class150, 300, 400, 600, 900, 1500, 2500 LBS
Facing MachinedRF, FF, RTJ, Tongue & Groove, Male & Female
Governing Flange StandardASME B16.5, B16.47, B16.36, EN 1092-1
Delivery ConditionSolution Annealed & Water Quenched
MTC CertificateEN 10204 3.1 and 3.2
Raw Material StandardASTM A182 F904L Forgings
OriginIn-House Forged In India
25Ni • 20Cr • 4.5Mo
Super Austenitic Chemistry
Nickel and molybdenum levels far above 316L for aggressive acid duty
1.0–2.0% Cu
Deliberate Copper Addition
The alloying move that targets dilute sulphuric and phosphoric acid attack
C 0.020% Max
Low-Carbon Weldable Grade
Carbide precipitation held back so weld zones resist intergranular attack
Non-Magnetic
Fully Austenitic Structure
No ferrite phase, so no magnetic response and no ferrite-check dispute
7.95 g/cm³
Density (UNS N08904)
19–23% Cr with 23–28% Ni per ASTM A182 F904L chemistry
B16.5 / B16.47 / 1092-1
Dimensionally Compliant
Bolt circle, facing and hub gauged against the code on every ring
stainless steel 904l flanges
0 · at glance

Mortec At A Glance

Established

Since 2012 • 15+ yrs experience

Manufacturing Units

2 in-house units • Taloja & Mazgaon

Stockyard Area

8,850+ sq.ft • Ready-stock inventory

Certifications

ISO 9001:2015, PED • GST, IEC & MSME

Clientele

100+ clients • India & export markets

Export Reach

19+ countries • GCC, Africa & Americas

Testing Offered

Mechanical, chemical & NDT • MTC EN 10204 3.1 & 3.2

Shipment Documents

Invoice, Packing List • COO, COI, MTC, BL & Lab Report

High-Quality ASTM A182 F904L Blind Flange Manufacturer in India at Factory Prices

Acid lines and seawater headers punish ordinary austenitic flanges fast. Stainless Steel 904L survives where 316L rings fail. It offers 25% nickel and 4.5% molybdenum, copper-bearing strength. We forge and machine these flanges factory-direct in Mumbai.

Buyers across Jebel Ali, Durban, Nairobi and Edmonton trust us. Our paperwork clears customs without any argument or delay. We provide EN 10204 3.1 and 3.2 certificates always. ASTM A262 Practice E reports come standard too. Third-party witness and NACE MR0175 qualification are available. Send your flange schedule for a live Mumbai rate.

01 · Specification

Stainless Steel 904L Flanges Specification

Straight from the forge shop, no trader margin, full traceability. Trusted Stainless Steel 904L flanges exporter, shipping to 19+ countries.

stainless steel 904l flanges specification

SS F904L RTJ Flange Approvals & Compliance

  • PED 2014/68/EU certified forge shop
  • NACE MR0175 / ISO 15156 on request

Stainless Steel 904L Ring Type Joint Flange Testing

  • IGC test to ASTM A262 Practice E
  • PMI, hardness, ultrasonic & DP checks

ASME SA182 Grade F904L Plate Flange Bore & Finish

  • Bored to SCH 5S through SCH 160
  • Pickled & passivated, 125–250 µin AARH face

ASTM A182 F904L Slip On Flange Export Packing & Shipping Marks

  • Fumigated plywood cases, face protectors
  • Heat number hard-stamped on every rim

904L SS Weld Neck Flange Documentation For EU, GCC & African Buyers

  • CE / PED file for European consignees
  • COO, COI & TPI reports for GCC tenders

WNR 1.4539 Flange Non-Standard & Drawing-Based Machining

  • Off-code drilling & special bolt circles
  • Reducing, expander & long-hub variants

Leak-Proof UNS N08904 Socket Weld and Lap Joint Flange as per ANSI B16.5 for Extreme Environments

02 · Range

904L SS Weld Neck Flange Size, Class & Facing Range

What we hold, what we forge to order, and the facings our CNC line cuts – confirm the exact callout on your RFQ.

Fastest Moving 2″ 150# 3″ 300# 4″ 150# 6″ 300# 8″ 150#

Size & Standard Coverage

ASME B16.5½″ to 24″
ASME B16.47 Series A26″ to 60″
ASME B16.47 Series B26″ to 60″
ASME B16.36 Orifice1″ to 24″
EN 1092-1DN 15 to DN 600
JIS B22205K, 10K, 16K, 20K

Facings We Machine

Raised Face (RF)Most ordered, 1.6 mm or 6.4 mm
Flat Face (FF)For cast or lined mating parts
Ring Type Joint (RTJ)R, RX & BX groove profiles
Tongue & GrooveLarge and small type
Male & FemaleLarge and small type
Face Finish125–250 µin AARH serrated

Pressure Classes Forged

Class 150PN 20 Class 300PN 50 Class 400PN 68 Class 600PN 100 Class 900PN 150 Class 1500PN 250 Class 2500PN 420
03 · Codes We Follow

ASME SA182 Grade F904L Forged Flange Standards

Bolt circle, hub profile and facing on every ring are gauged against these codes before it leaves inspection.

ASTM A182 F904L
ASME SA182
ASME B16.5
ASME B16.47
ASME B16.36
ASME B16.48
EN 1092-1
Client-Specific
04 · Product Range

904L Stainless Steel Flange Types

A leading 904L Stainless Steel Flange supplier in India, carrying every common pattern in ready stock. Our Stainless Steel 904L Flanges Manufacturer In Mumbai stocks Class 150 to 2500 flanges

904L SS Weld Neck Flange

904L SS Weld Neck Flange

ASME B16.5 • Butt Weld Hub
  • Tapered hub carries pipe-wall stress
  • First choice for cyclic & high-pressure lines
ASTM A182 F904L Slip On Flange

ASTM A182 F904L Slip On Flange

Class 150–600 • Twin Fillet Weld
  • Slides over pipe, easier site alignment
  • Lower cost route for low-pressure duty
Stainless Steel 904L Blind Flange

Stainless Steel 904L Blind Flange

Solid Disc • No Bore
  • Seals vessel nozzles & line terminations
  • Drilled for future tie-ins on request
UNS N08904 Socket Weld Flange

UNS N08904 Socket Weld Flange

Small Bore • Counterbored
  • Pipe seats in a machined socket
  • Common on ½″–2″ instrument tie-ins
Stainless Steel 904L Lap Joint Flange

Stainless Steel 904L Lap Joint Flange

With Stub End • Free To Rotate
  • Swivels for quick bolt-hole alignment
  • Only the stub end contacts the media
SS 904L Threaded Flange

SS 904L Threaded Flange

NPT / BSP • No Welding
  • Screwed bore for no-hot-work areas
  • Used on utility & low-pressure headers
904L SS Tongue and Groove Flange

904L SS Tongue and Groove Flange

Matched Pair • Large / Small Type
  • Mating rings trap the gasket fully
  • Stops gasket blow-out on acid duty
ASTM A182 F904L Spectacle Flange

ASTM A182 F904L Spectacle Flange

ASME B16.48 • Figure-8
  • Flip to isolate or open the line
  • Position visible from ground level
Werkstoff No 1.4539 Orifice Flange

Werkstoff No 1.4539 Orifice Flange

ASME B16.36 • With Jack Screws
  • Radial tappings for flow measurement
  • Supplied as a set with plates & bolting
SS F904L Long Weld Neck Flange

SS F904L Long Weld Neck Flange

Extended Hub • Vessel Nozzle
  • Hub doubles as a short nozzle barrel
  • Bored to pipe ID or left standard bore
05 · Dimension Chart

ASTM A182 F904L Slip On Flange Dimension Chart

Reference figures only – check the governing edition of ASME B16.5 or your isometric before you release the order.

Class 150 Flange Outside Diameter, Thickness & Drilling (inches) as per ASME B16.5
NPSFlange O.D.Min. ThicknessBolt CircleNo. of BoltsBolt Hole Dia.
½″3.500.442.3840.62
¾″3.880.502.7540.62
1″4.250.563.1240.62
1½″5.000.693.8840.62
2″6.000.754.7540.75
3″7.500.946.0040.75
4″9.000.947.5080.75
6″11.001.009.5080.88
8″13.501.1211.7580.88
10″16.001.1914.25121.00
12″19.001.2517.00121.00
16″23.501.4421.25161.12
20″27.501.6925.00201.25
24″32.001.8829.50201.38

Send your enquiry today to our Stainless Steel 904L Flanges Manufacturer In India for fast quotes

Rings forged, bored and faced under one roof, so your delivery date does not depend on anyone else.

Request Quote Now
06 · Composition

WNR 1.4539 Flange Chemical Composition

High nickel, molybdenum and copper balance per ASTM A182 F904L. This mix carries 904L through reducing acid service safely. ASTM A182 F904L Blind Flange resists sulphuric and phosphoric acid corrosion

Chemical Composition – UNS N08904 (% by weight)
Ni23.0–28.0Nickel
Cr19.0–23.0Chromium
Mo4.00–5.00Molybdenum
Cu1.00–2.00Copper
Mn2.00 maxManganese
Si1.00 maxSilicon
C0.020 maxCarbon
FeBalanceIron
07 · Strength Data

UNS N08904 Socket Weld Flange Mechanical Properties

Minimum room-temperature values for solution-annealed F904L forgings. Each figure is confirmed on the mill certificate

Tensile Strength490 MPa / 71 ksi min
Yield Strength (0.2%)220 MPa / 32 ksi min
Elongation35% min
Reduction Of Area40% min
08 · Sealing

SS F904L RTJ Flange Facing Types & Gasket Seating

Pick the facing that suits your gasket and class. Most flange leaks are won or lost here.

Raised Face (RF)1.6 mm on Class 150 & 300, 6.4 mm above. Pairs with spiral wound gaskets.
Flat Face (FF)Full-face seat for cast, GRP or rubber-lined mating parts.
Ring Type Joint (RTJ)R, RX or BX groove for metal ring gaskets. Standard choice from Class 600 up.
Tongue & Groove / Male & FemaleInterlocking pair confines the gasket on acid and slurry duty.

Standard serrated finish is 125–250 µin AARH. Smooth or stock finishes cut to your gasket maker’s advice.

09 · Cross-Reference

Stainless Steel 904L Lap Joint Flange Equivalent Grades

Cross-check 904L against the designation your home standard or inspector works to.

USAASTM / UNS (USA)

  • UNS N08904
  • ASTM A182 F904L / ASME SA182

GermanyDIN / WNr (Germany)

  • WNr 1.4539
  • X1NiCrMoCu25-20-5

European UnionEN (Europe)

  • EN 1.4539
  • EN 1092-1 flange dimensions

UKBS (United Kingdom)

  • 904S13
  • Now superseded by EN 1.4539

JapanJIS (Japan)

  • SUS 890L
  • JIS B2220 flange patterns

SwedenSS (Sweden)

  • SS 2562
  • Confirm exact match with your inspector
Global Reach

Your 904L Flange Partner Across The Middle East & GCC

Gulf desalination and fertiliser contractors use our ready stock. We are an established SS 904L flange exporter. GCC consignments clear within days of confirmation.

Middle East & GCC
UAEJebel Ali, UAE
UAESharjah, UAE
Saudi ArabiaDammam, KSA
TurkeyIzmir, Turkey
QatarDoha, Qatar
10 · RFQ Checklist

SS 904L Threaded Flange Ordering Checklist

Send these eight lines and we skip the back-and-forth. A firm price lands the same working day.

Nominal size and quantity per size
Flange type – weld neck, slip on, blind, socket weld
Pressure class or PN rating
Facing and required face finish
Bore schedule for weld neck rings
Dimensional standard – ASME, EN or JIS
Certificate type and any third-party witness
Discharge port or delivery PIN code
11 · Comparison

Stainless Steel 904L Flanges vs SS 316L Flanges

Every procurement desk asks this before approving the price gap. Here is the honest side-by-side.

Stainless Steel 904L Flanges

  • Nickel: 23.0–28.0%
  • Molybdenum: 4.0–5.0%
  • Copper: 1.0–2.0%, added on purpose
  • Best For: Sulphuric, phosphoric & chloride-rich media
  • Relative Cost: Higher, longer service life

Stainless Steel 316L Flanges

  • Nickel: 10.0–15.0%
  • Molybdenum: 2.0–3.0%
  • Copper: Not an alloying addition
  • Best For: General process, food & mild marine duty
  • Relative Cost: Lower, shorter life in acid
Global Reach

904L Flanges Crated & Container-Ready For African Projects

Mining, fertiliser and water treatment buyers across Southern, East and West Africa order in project lots.

Africa & South East Asia
South AfricaDurban, SA
South AfricaRichards Bay, SA
UgandaKampala, Uganda
IndonesiaSurabaya, Indonesia
VietnamHai Phong, Vietnam

As a trusted Stainless Steel 904L Flanges Exporter, we ship to 19+ countries reliably

Project lots are crated, marked and handed to your forwarder as one clean consignment.

Request Export Quote
12 · Performance

904L SS Tongue and Groove Flange Corrosion Performance In Acid Service

Plant engineers specify 904L for one clear reason. A standard austenitic ring is back on maintenance within a season.

Dilute Sulphuric Acid Resistance
Phosphoric Acid & Fertiliser Duty
High Resistance To Chloride Stress-Corrosion Cracking
Strong Pitting & Crevice Resistance From 4–5% Mo
Seawater & Brine Handling Service
Low Carbon Resists Weld-Zone Sensitisation
13 · Pricing

Stainless Steel 904L Ring Type Joint Flange Price Factors

Four variables set the per-kg rate. Send yours and the quote returns the same day. Factory-direct pricing, no trader markup.

Nickel & Moly Index904L carries twice the nickel of 316L, so LME moves hit harder.
Size & Pressure ClassA Class 900 ring takes far more forged metal than Class 150.
Facing & Machining TimeRTJ and tongue-and-groove take longer on the CNC than plain RF.
Inspection LevelIGC testing, TPI witness and NACE qualification add to landed cost.
Global Reach

Edmonton To Mexico City – 904L Flanges Shipped To Order

Oil sands, mining and process fabricators across North and Latin America work off our stock list.

Americas
CanadaEdmonton, Canada
CanadaMontreal, Canada
USAHouston, USA
MexicoMexico City, Mexico
VenezuelaMaracaibo, Venezuela

Stainless Steel 904L Flanges Supplier In India With IGC-Tested Heats

Each ring ships with its ASTM A262 Practice E report attached to the certificate file.

Get Supplier Quote
14 · How It’s Made

SS F904L Long Weld Neck Flange Manufacturing Process

Four stages take the billet from furnace to finished ring. ISO-certified works, quality without compromise.

1

Billet Cutting

F904L billet sawn to ring weight against the heat number.

2

Forging & Ring Rolling

Upset, punched and rolled for continuous grain flow.

3

Solution Annealing

Water quenched, then pickled and passivated to strip scale.

4

CNC & Inspection

Bore, facing and drilling machined, gauged and hard-stamped.

15 · Turnaround

904L Stainless Steel Flange Delivery Estimate

Payment confirmation starts the clock. Pick the freight mode that suits your site programme.

Ready-Stock Release

Common classes and facings leave Mumbai in 2–4 working days

Ocean Freight (FCL / LCL)

Budget route for project lots, roughly 18–35 days port to port

Air Cargo (Express)

Flown out in 3–7 days when a shutdown cannot wait

Port-Wise ETA

Send the discharge port or PIN code for a dated ETA

Ocean legs shift with vessel schedules and berth availability. The dated ETA locks once your booking is confirmed.

16 · Quality

Werkstoff No 1.4539 Orifice Flange Testing & Certification

Call for any of these at enquiry stage and the result is recorded against your heat number.

PMI Testing
IGC Test (A262 Practice E)
Hardness Test
Tensile Test
Dye Penetrant Test
Ultrasonic Test
Third-Party Inspection
Heat Number Traceability
17 · Industries

ASTM A182 F904L Spectacle Flange Applications

The sectors that keep 904L on their approved materials list. Buyers in India and export markets rely on quick dispatch.

Sulphuric Acid Plants
Fertiliser & Phosphate Processing
Seawater Desalination
Mining & Metal Refining
Pulp & Paper Bleaching
Flue Gas Desulphurisation
Oil & Gas Processing
Food & Pharmaceutical Plant
18 · Track Record

SS 904L Flange Supply References

A sample of recent flange dispatches across our GCC, Africa and Americas customer base.

6″ Class 300 Weld Neck Flange Set – Acid Line Replacement

RF facing, bored to SCH 40S, IGC test report attached.

Fertiliser Plant Contractor, South Africa

RICHARDS BAY, SOUTH AFRICA

12″ Class 150 Blind Flange – Desalination Intake Header

Pickled and passivated, EN 10204 3.2 with TPI witness.

Water Treatment EPC, UAE

JEBEL ALI, UAE

4″ Class 600 RTJ Flange – Process Skid Fabrication

R-groove machined, NACE MR0175 qualified heat.

Skid Package Fabricator, Canada

EDMONTON, CANADA

3″ Class 150 Slip On Flange – Bleach Plant Piping

Flat face, full-face gasket seat, heat number stamped.

Pulp & Paper Mill, Kenya

MOMBASA, KENYA

Top Export Countries

Canada Canada UK United Kingdom Germany Germany Netherlands Netherlands Italy Italy UAE UAE Saudi Arabia Saudi Arabia South Africa South Africa Kenya Kenya Uganda Uganda Thailand Thailand Malaysia Malaysia Philippines Philippines Mexico Mexico Turkey Turkey
20 · More FAQs

Stainless Steel 904L Flange Types – Buyer FAQs

Spec-level answers on the exact flange type you are sourcing – confirm final dimensions against the governing code.

What size range does ASTM A182 F904L Slip On Flange cover?
  • ½″ to 24″ under ASME B16.5
  • 26″ to 60″ under ASME B16.47
  • Class 150 to Class 2500
  • RF, FF facing standard
When is a Stainless Steel 904L Blind Flange used?
  • Seals line ends, no bore
  • Class 150–2500, ½″–60″
  • Solid disc, drilled on request
  • RF, FF, RTJ facing available
What makes 904L SS Weld Neck Flange different from other types?
  • Tapered hub, full penetration weld
  • Best for cyclic, high-pressure lines
  • Bored SCH 5S to SCH 160
  • ASME B16.5 dimensional standard
Is WNR 1.4539 Flange the same as UNS N08904?
  • Yes, same chemistry, different naming system
  • WNR is the German Werkstoff number
  • Equivalent to ASTM A182 F904L
  • Confirm exact cross-reference with your inspector
What sizes are common in UNS N08904 Socket Weld Flange?
  • Mostly ½″ to 2″ sizes
  • Counterbored socket, no butt weld
  • Class 150 to 2500 available
  • Used on small-bore instrument lines
How does Stainless Steel 904L Lap Joint Flange work on site?
  • Free-rotating ring over stub end
  • Only stub end contacts media
  • Eases bolt-hole alignment on site
  • Common with lined pipe systems
What connection type does SS 904L Threaded Flange use?
  • NPT or BSP threaded bore
  • No welding, no hot work
  • Used on low-pressure utility lines
  • Class 150 and 300 typical
Where is 904L SS Tongue and Groove Flange specified?
  • Matched pair, large or small type
  • Confines gasket fully, no blow-out
  • Preferred for acid, slurry duty
  • Custom machined to mating pair
Stainless Steel 904L Flanges – Why Mortec Manufacturing Co?
Forged from solution-annealed 904L billet, sensitisation-free at weld zones
Ex-stock weld neck, slip on and blind rings, pickled and passivated
Every 904L flange heat IGC-tested per ASTM A262 Practice E
Odd bores and off-standard drilling machined to your flange drawing

Materials


Standard


Products

Certifications & Credentials
Certified to PED 2014/68/EU for the manufacture of forged steel products
Stock, distribute and trade Steel Flanges, Nuts and Bolts, and precision-machined parts in Nickel Alloys, High Temperature Alloys and Super Alloys
Since 2012, exporting Oil and Gas piping items built to NACE MR0175 / ISO 15156 across the Egypt, Tunisia, Netherlands, Azerbaijan, South Africa, Algeria, Saudi Arabia and Morocco
Hold the largest import and stock inventory of bolting accessories, in both ferrous and non-ferrous metals, in India

Authorized Supplier For The Following Companies - Material At Reseller Price For Traders

Associated Companies - ADNOC, SABIC, Saudi Aramco, GASCO, ORPIC, KNPC, QATARGAS

Get A Quick Quote