SS 304 / 304L / 304H Washers Manufacturer & Exporter in India

Explore SS 304 / 304L / 304H Washers Manufacturer & Exporter in India manufactured for demanding industrial applications with reliable strength, corrosion resistance and compliance with international standards.

-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 304 / 304L / 304H Washers?

SS 304 / 304L / 304H washers are austenitic stainless steel fastener components manufactured from UNS S30400, S30403, and S30409 bar or sheet stock conforming to ASTM A193, ASTM F436, and ASTM A240. The 18% chromium and 8% nickel composition delivers a passive oxide layer that resists oxidation, mild acids, and atmospheric corrosion across a broad temperature range.

The three sub-grades serve distinct engineering requirements: 304 is the general-purpose standard, 304L limits carbon to 0.03% max to prevent sensitisation in welded assemblies, and 304H raises carbon to 0.04-0.10% to sustain creep strength above 425°C. All three grades are widely specified under ASME B18.22.1, DIN 125, and ISO 7089 for flanged joints, structural connections, and pressure vessel assemblies worldwide.

Quick Specifications

Material	SS 304 / 304L / 304H
UNS Number	S30400 / S30403 / S30409
DIN Number	1.4301 / 1.4307 / 1.4948
Material Standard	ASTM A240 / ASTM A276
Washer Standard (Metric)	DIN 125 / DIN 9021 / ISO 7089 / ISO 7093
Washer Standard (Inch)	ASME B18.22.1 / ASTM F436
Type Range	Flat, Spring, Lock, Fender, Ogee, Dock
Diameter Range	M3-M100 / #4-4"
Tensile Strength	515 MPa (75 ksi) min
Yield Strength	205 MPa (30 ksi) min
Hardness	Max 92 HRB / 201 HB

? All material certified by NABL-accredited laboratory. PMI available on request.

Complete the Fastener Set

Other SS 304 / 304L / 304H Fastener Products Available from RealBolt

RealBolt also manufactures the complete SS 304 / 304L / 304H fastener range from certified bar stock per ASTM, including Bolts, Nuts, Screws, Studs, and Threaded Rods in all standard configurations. All SS 304 / 304L / 304H fastener types ship with EN 10204 MTC 3.1/3.2 documentation and are available in standard sizes and custom-machined specials.

SS 304 / 304L / 304H Bolts

SS 304 / 304L / 304H Nuts

SS 304 / 304L / 304H Screws

SS 304 / 304L / 304H Studs

SS 304 / 304L / 304H Threaded Rods

Technical Data

SS 304 / 304L / 304H Washers Dimensions, Sizes & Thread Standards

SS 304 / 304L / 304H Washers are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 125 (flat washers, normal series) / DIN 9021 (flat washers, large series) / ISO 7089 / ISO 7093. Custom OD and thickness available. Inch dimensions per ASME B18.22.1 and ASTM F436.

Flat Washer Dimensions - Metric (DIN 125 / ISO 7089)

Bolt Size (M)	ID (mm)	OD (mm)	Thickness (mm)	Large Series OD (mm)	Large Series Thk (mm)
M3	3.2	7	0.5	9	0.8
M4	4.3	9	0.8	12	1.0
M5	5.3	10	1.0	15	1.2
M6	6.4	12	1.6	18	1.6
M8	8.4	16	1.6	24	2.0
M10	10.5	20	2.0	30	2.5
M12	13.0	24	2.5	37	3.0
M16	17.0	30	3.0	50	3.0
M20	21.0	37	3.0	60	4.0
M24	25.0	44	4.0	72	5.0
M30	31.0	56	4.0	92	6.0
M36	37.0	66	5.0	110	8.0
M42	43.0	78	7.0	125	8.0
M48	50.0	92	8.0	145	10.0
M56	58.0	105	9.0	165	10.0
M64	66.0	115	9.0	185	12.0

Dimensional & Material Standards

Standard	Covers	Series
DIN 125	Flat washers, normal series	Metric
DIN 9021	Flat washers, large series	Metric
ISO 7089	Plain washers, normal series, 200 HV	Metric
ISO 7093	Plain washers, large series	Metric
ASME B18.22.1	Plain washers, type A & B	Inch
ASTM F436	Hardened washers for structural use	Inch
DIN 127	Spring lock washers	Metric

Material Standard	Requirement
ASTM A240	Sheet/plate - UNS S30400/S30403/S30409
ASTM A276	Bar/rod - UNS S30400/S30403/S30409
ASTM F738M	Fastener mechanical properties, metric
EN 10204 3.1	Mill test certificate
EN 10204 3.2	TPI-witnessed MTC

Material Chemistry

SS 304 / 304L / 304H Chemical Composition

SS 304 / 304L / 304H 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

Element	SS 304 (%)	SS 304L (%)	SS 304H (%)
Chromium (Cr)	18.0-20.0	18.0-20.0	18.0-20.0
Nickel (Ni)	8.0-10.5	8.0-12.0	8.0-10.5
Carbon (C)	0.08% max	0.03% max	0.04-0.10%
Manganese (Mn)	2.0% max	2.0% max	2.0% max
Silicon (Si)	0.75% max	0.75% max	0.75% max
Phosphorus (P)	0.045% max	0.045% max	0.045% max
Sulphur (S)	0.030% max	0.030% max	0.030% max
Nitrogen (N)	0.10% max	0.10% max	0.10% max
Iron (Fe)	Balance	Balance	Balance

? All heats verified by NABL-accredited spectrometry. PMI available on request.

Why SS 304 / 304L / 304H Alloy Composition Matters for Washers

304L (C = 0.03%) — Weld Sensitisation Prevention

Reducing carbon below 0.03% prevents chromium carbide precipitation at grain boundaries during welding. 304L washers used in welded assemblies retain full corrosion resistance in the heat-affected zone without post-weld annealing.

304H (C 0.04–0.10%) — Elevated Temperature Creep Strength

The higher carbon range in 304H stabilises the austenite matrix at temperatures above 425°C, resisting creep relaxation under sustained bolt load. This makes 304H washers the correct choice for high-temperature flange assemblies in boilers, heat exchangers, and steam piping.

18% Cr + 8% Ni — Passive Film Stability

The 18-8 composition forms a self-repairing chromium oxide passive film that resists oxidation, mild acids, and atmospheric corrosion. Under bolt heads and nut bearing faces, this passive layer prevents fretting corrosion and galvanic attack in most industrial environments.

Fastener Performance

SS 304 / 304L / 304H Washers Mechanical Properties & Torque & Proof Load Reference

The table below lists mechanical properties and proof load reference for SS 304 / 304L / 304H Washers per ASTM. SS 304 / 304L / 304H washers achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Washer Bearing Load Reference - Flat Washers (DIN 125 / ISO 7089)

Bolt Size	ID (mm)	OD (mm)	Thickness (mm)	Max Bearing Load (kN)
M8	8.4	16	1.6	12
M10	10.5	20	2.0	20
M12	13.0	24	2.5	30
M16	17.0	30	3.0	55
M20	21.0	37	3.0	85
M24	25.0	44	4.0	125
M30	31.0	56	4.0	200
M36	37.0	66	5.0	290

?? Note: Bearing load values are indicative for annealed 304/304L/304H at ambient temperature. For elevated temperature service above 425°C, specify 304H grade. Always verify against actual bolt preload and flange face material.

Industry Applications

SS 304 / 304L / 304H Washers Applications — Industries & End Uses

SS 304 / 304L / 304H 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.

Pressure Vessels & Flanged Piping

SS 304 flat washers and spring washers are standard components in ASME B16.5 and B16.47 flanged piping assemblies across chemical, petrochemical, and water treatment plants. 304L is specified where welded nozzle connections are involved to prevent sensitisation. 304H is selected for steam service above 425°C per ASME Section VIII requirements.

Food, Beverage & Pharmaceutical Processing

The 18-8 austenitic composition meets FDA and EU 10/2011 food contact material requirements. SS 304 washers are used in food processing equipment, dairy pipework, brewery vessels, and pharmaceutical clean-room structural connections where hygiene, cleanability, and mild acid resistance are essential.

Construction & Architectural Cladding

SS 304 fender washers and large-series flat washers are widely used in curtain wall cladding systems, roofing fixings, structural glazing, and facade panel connections. The passive chromium oxide layer resists urban atmospheric corrosion and acid rain without surface treatment or painting.

Water & Wastewater Treatment

Flat and spring washers in SS 304 are specified for pump flanges, filter housings, clarifier mechanisms, and pipe support brackets in potable water and wastewater treatment plants. The grade resists chlorinated water at ambient temperature and complies with WRAS and NSF/ANSI 61 requirements for water contact applications.

SS 304 / 304L / 304H Washers Standards & International Certifications

SS 304 / 304L / 304H 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 9001:2015NABL LabPED 2014/68/EUMTC 3.1 / 3.2FDA Compliant

Buy SS 304 / 304L / 304H Washers from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified SS 304 / 304L / 304H 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.

Answers for Buyers

SS 304 / 304L / 304H Washers — Frequently Asked Questions

Browse expert answers to common questions about SS 304 / 304L / 304H 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 304 / 304L / 304H washers selection and pricing.

What is the difference between SS 304, 304L, and 304H washers?

The three grades share the same 18% chromium and 8% nickel base but differ in carbon content and resulting performance. SS 304 (C = 0.08%) is the general-purpose grade for most ambient-temperature applications. SS 304L (C = 0.03%) is specified wherever washers are used in welded assemblies – the low carbon prevents sensitisation and intergranular corrosion in the heat-affected zone without post-weld annealing. SS 304H (C 0.04-0.10%) is required for sustained service above 425°C, where the higher carbon content maintains creep strength and resists stress relaxation under bolt load. When both weld compatibility and elevated temperature service are required simultaneously, 304L and 304H cannot be dual-certified – specify the grade that matches the dominant service condition.

Which washer standard should I specify - DIN 125, ISO 7089, or ASME B18.22.1?

The choice depends on the bolt standard and project specification. DIN 125 and ISO 7089 cover the same metric flat washer geometry and are interchangeable for most applications – ISO 7089 specifies a 200 HV hardness requirement that DIN 125 does not. ASME B18.22.1 covers inch-series plain washers in Type A (narrow) and Type B (wide) series and is required for ASME-coded pressure vessel and piping work in North America. For large-OD washers to distribute load on soft flanges or timber, specify DIN 9021 or ISO 7093 (large series). Always confirm the washer standard matches the bolt standard on the project data sheet.

Are SS 304 washers suitable for outdoor and marine environments?

SS 304 washers perform well in rural and urban atmospheric environments and resist mild industrial pollution. However, in coastal marine environments with direct seawater splash or immersion, 304 is susceptible to chloride-induced pitting and crevice corrosion – particularly under the washer bearing face where oxygen depletion creates crevice conditions. For marine splash zones, offshore structures, or any application involving chloride concentrations above 200 ppm, upgrade to SS 316 or 316L washers, which contain 2-3% molybdenum for significantly improved pitting resistance. SS 304 is acceptable for inland freshwater service and intermittent rain exposure in non-coastal locations.

Can SS 304L washers be used in food and pharmaceutical applications?

Yes – SS 304L is widely accepted for food contact applications. The grade meets FDA 21 CFR 177.2600 requirements for food contact materials and complies with EU Regulation 10/2011 on plastic materials (as a reference standard for metals). For pharmaceutical clean-room and bioprocessing applications, 304L washers with a 2B or electropolished surface finish are standard. Electropolished washers offer a surface roughness of Ra = 0.8 µm, which minimises bacterial adhesion and facilitates CIP/SIP cleaning. Confirm surface finish and passivation treatment (ASTM A967) requirements with your project specification before ordering.

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Ahmedabad
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