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SS 904L Washers Manufacturer & Exporter in India

Explore SS 904L Washers Manufacturer & Exporter in India manufactured for demanding industrial applications with reliable strength, corrosion resistance and compliance with international standards.
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-196

Min Temp

870

Max Temp

🌡

870

Suitable for continuous service up to approximately 870°C under typical operating conditions.

⚡

620

Typical tensile strength around 620 MPa depending on product form and heat treatment.

🛡

Very Good

Very Good corrosion resistance in a wide range of industrial environments.

⚖

8

Typical density is approximately 8.0 g/cm³.

Product Overview

What are SS 904L Washers?

SS 904L washers are high-alloy austenitic stainless steel flat, spring, and locking washers manufactured from UNS N08904 material conforming to ASTM A240 and ASTM B625. Designed for exceptional resistance to strong reducing acids, chloride-induced pitting, and crevice corrosion, SS 904L washers are widely specified in aggressive chemical, marine, and pharmaceutical environments where standard 304/316 washers fail.

The high nickel (24-26%) and molybdenum (4-5%) content, combined with copper addition, provides superior corrosion resistance in sulfuric acid, phosphoric acid, and seawater. SS 904L washers are non-magnetic, maintain excellent ductility, and are suitable for use in both cryogenic and elevated temperature applications up to 400°C.

Quick Specifications

MaterialStainless Steel 904L
UNS NumberN08904
DIN Number1.4539
Material StandardASTM A240 / ASTM B625
Washer Standard (Metric)DIN 125 / DIN 127 / DIN 9021
Washer Standard (Inch)ASME B18.22.1
TypeFlat, Spring, Lock, Tab, Serrated
Diameter RangeM3-M100 / 1/8"-4"
Tensile Strength490 MPa (71 ksi) min
Yield Strength220 MPa (32 ksi) min
HardnessMax 90 HRB
? All washers supplied with full traceability and NABL-accredited lab certification. PMI and IGC test available on request.

Complete the Fastener Set

Other SS 904L Fastener Products Available from RealBolt

RealBolt also manufactures the complete SS 904L fastener range from certified stainless steel bar stock, including SS 904L Bolts, SS 904L Nuts, SS 904L Screws, SS 904L Studs, and SS 904L Threaded Rods. All SS 904L fastener types are produced to ASTM with full EN 10204 MTC 3.1/3.2 documentation.
SS 904L Bolts
SS 904L Nuts
SS 904L Screws
SS 904L Studs
SS 904L Threaded Rods

Technical Data

SS 904L Washers Dimensions, Sizes & Thread Standards

SS 904L Washers are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 125 (flat), DIN 127 (spring), DIN 9021 (large OD), and ASME B18.22.1. Custom OD/ID and thickness available. Metric and inch sizes supplied as per project requirements. All SS 904L washers dimensions conform to applicable DIN, ISO, and ASME B18 standards.

Flat Washer Dimensions - Metric (DIN 125A)

Size (M)Inner Dia (mm)Outer Dia (mm)Thickness (mm)
M33.270.5
M66.4121.6
M88.4161.6
M1010.5202.0
M1213.0242.5
M1617.0303.0
M2021.0373.0
M2425.0444.0
M3031.0564.0
M3637.0665.0
M4243.0786.0
M4849.0926.0
M5657.01058.0
M6465.01158.0
M7273.013010.0
M8081.014010.0
M100101.018012.0

Dimensional & Material Standards

StandardCoversType
DIN 125Flat washersMetric
DIN 127Spring lock washersMetric
DIN 9021Large OD washersMetric
ASME B18.22.1Plain & lock washersInch
ISO 7089Flat washersMetric
ISO 7090Chamfered washersMetric
Material StandardRequirement
ASTM A240Plate/strip - UNS N08904
ASTM B625Sheet/plate - UNS N08904
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

SS 904L Chemical Composition

SS 904L Washers are manufactured from an iron-chromium-nickel alloy with chromium (16–26%), nickel (8–28%), and grade-specific molybdenum additions per ASTM and ASTM A193/A194. Chromium content governs the self-healing passive oxide film; molybdenum (2–6%) enhances chloride pitting resistance; and carbon content determines sensitization risk in welded assemblies.

Chemical Composition per ASTM A240 / B625

ElementComposition (%)
Chromium (Cr)19.0-23.0
Nickel (Ni)23.0-28.0
Molybdenum (Mo)4.0-5.0
Copper (Cu)1.0-2.0
Carbon (C)0.02 max
Manganese (Mn)2.0 max
Silicon (Si)1.0 max
Phosphorus (P)0.045 max
Sulphur (S)0.035 max
Iron (Fe)Balance
? All heats verified by spectrometry. IGC and PMI test reports available on request.

Why SS 904L Alloy Composition Matters for Washers

High Nickel & Molybdenum — Acid & Chloride Resistance
The elevated nickel (23–28%) and molybdenum (4–5%) content in SS 904L provides outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-rich and acidic environments, making these washers ideal for chemical and marine applications.
Copper Addition — Sulphuric Acid Performance
Copper (1–2%) enhances resistance to sulphuric and phosphoric acids, allowing SS 904L washers to outperform standard stainless steels in fertilizer, pulp & paper, and acid processing plants.
Low Carbon — No Sensitization
With a maximum carbon content of 0.02%, SS 904L washers are immune to intergranular corrosion after welding or high-temperature exposure, ensuring long-term reliability in critical bolted joints.

Fastener Performance

SS 904L Washers Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for SS 904L Washers per ASTM. SS 904L washers achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Bolt SizeRecommended Washer OD (mm)Recommended Washer Thickness (mm)
M8161.6
M10202.0
M12242.5
M16303.0
M20373.0
M24444.0
M30564.0
M36665.0
?? Installation: Always use SS 904L washers with matching SS 904L bolts/nuts for optimal corrosion resistance. Avoid mixing with carbon steel hardware in chloride or acid service.

Industry Applications

SS 904L Washers Applications — Industries & End Uses

SS 904L Washers from RealBolt are specified across food and dairy, pharmaceutical, marine, chemical processing, and oil and gas where very good corrosion resistance and 620 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples.
SS 904L washers are the preferred choice for bolted joints in sulfuric acid, phosphoric acid, and acetic acid process equipment, including reactors, heat exchangers, and storage tanks. Their high resistance to reducing acids and chloride stress corrosion ensures long-term sealing integrity in aggressive chemical environments.
Flat and spring washers in SS 904L are used in seawater-cooled heat exchangers, desalination plants, and offshore platform assemblies. Their immunity to pitting and crevice corrosion in chloride-rich marine atmospheres makes them ideal for splash zone and submerged bolted connections.
SS 904L washers are specified for hygienic bolted joints in pharmaceutical reactors, food processing vessels, and clean-in-place (CIP) systems. Their non-magnetic, low-carbon composition prevents contamination and ensures compliance with stringent hygiene standards.
Washers for digesters, bleach towers, and chemical recovery systems where exposure to acidic liquors and chlorides is common. SS 904L provides superior service life compared to 316L in these demanding environments.

SS 904L Washers Standards & International Certifications

SS 904L Washers from RealBolt Engineering Industries are manufactured to internationally recognised fastener dimensional standards covering thread form, tolerances, strength grades, and quality requirements. Every batch ships with EN 10204 MTC 3.1/3.2, IS 12427 compliance, ISO 3506 material certification, NACE MR0175, and PMI (XRF) reports — available on request for all orders.
Standards
DIN 125A DIN 126 DIN 127 DIN 128 DIN 433 DIN 434 DIN 436 DIN 6796 DIN 6797 DIN 9021 ISO 7089 ISO 7090 ISO 7091 ISO 7092 ISO 7093 ISO 7094 ASME B18.21.1 EN ISO 7089 BS 4320 IS 5372 IS 1367 IS 12427
Certifications
ISO 9001:2015PED 2014/68/EUNABL LabEN 10204 3.1 / 3.2

Buy SS 904L Washers from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified SS 904L Washers — for competitive pricing, EN 10204 MTC 3.1/3.2 documentation, and fast Mumbai dispatch. Standard sizes are ex-stock; custom dimensions accepted with 2–3 week lead time. Request your quote today.
022-6743-7972
+91 90226 36025
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Answers for Buyers

SS 904L Washers — Frequently Asked Questions

Browse expert answers to common questions about SS 904L Washers from RealBolt — covering ASTM A193/A194 grades, chloride resistance, temperature limits, sensitization, sizes, and MTC documentation. Contact our technical team directly for project-specific guidance on SS 904L washers selection and pricing.
SS 904L washers are available to DIN 125 (flat), DIN 127 (spring), DIN 9021 (large OD), ISO 7089/7090, and ASME B18.22.1 (inch). Custom shapes such as tab, serrated, and conical washers can be manufactured to drawing or international standards. All washers are supplied with EN 10204 3.1 certification and full traceability.
It is not recommended to use SS 904L washers with carbon steel bolts in corrosive or chloride-rich environments, as galvanic corrosion may occur. For optimal corrosion resistance, always pair SS 904L washers with matching SS 904L or high-alloy stainless steel bolts and nuts.
Yes – SS 904L washers offer excellent resistance to pitting, crevice corrosion, and stress corrosion cracking in seawater and marine atmospheres. They are widely used in desalination, offshore, and shipbuilding applications where standard stainless steels fail.
No formal MOQ for standard sizes (M6-M36) held in stock – we supply from single pieces for urgent maintenance. Custom OD/ID or thickness washers have a minimum order of 10 kg. Quantity price breaks are available at 50 pcs, 200 pcs, and 500 pcs.

Industrial Cities We Serve:

  • Ahmedabad
  • Aurangabad
  • Bengaluru
  • Chennai
  • Coimbatore
  • Faridabad
  • Gandhidham
  • Greater Noida
  • Gurugram
  • Hazira
  • Hosur
  • Hyderabad
  • Jamnagar
  • Jamshedpur
  • Ludhiana
  • Mumbai
  • Mundra
  • Mysuru
  • Nagpur
  • Nashik
  • Navi Mumbai
  • Noida
  • Pune
  • Rajkot
  • Sanand
  • Surat
  • Thane
  • Tiruppur
  • Vadodara
  • Visakhapatnam

Countries We Export To:

  • US
  • Canada
  • Mexico
  • Germany
  • UK
  • France
  • Italy
  • Spain
  • Netherlands
  • Belgium
  • Poland
  • Sweden
  • Norway
  • Denmark
  • Turkey
  • UAE
  • Saudi Arabia
  • Qatar
  • Oman
  • Kuwait
  • Bahrain
  • South Africa
  • Egypt
  • Nigeria
  • Australia
  • New Zealand
  • Singapore
  • Malaysia
  • Indonesia
  • Thailand
  • Vietnam
  • South Korea
  • Japan
  • Brazil