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

Explore SS 304 / 304L / 304H Nuts 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 Nuts?

SS 304 / 304L / 304H nuts are austenitic stainless steel fasteners manufactured from UNS S30400, S30403, and S30409 bar stock conforming to ASTM A276 and ASTM A479. The 18% chromium and 8% nickel composition delivers reliable corrosion resistance across a broad range of industrial environments, while the three sub-grades address distinct service requirements – standard, low-carbon, and high-carbon stabilised variants.

304L nuts offer superior resistance to sensitisation during welding, making them the preferred choice for fabricated assemblies without post-weld heat treatment. 304H nuts, with a controlled carbon range of 0.04-0.10%, provide enhanced creep strength at elevated temperatures and are specified under ASME Section VIII for pressure vessel and boiler applications above 425°C. All three grades are produced to ASTM A194 Grade 8 / 8M for nut applications.

Quick Specifications

Material	SS 304 / 304L / 304H
UNS Number	S30400 / S30403 / S30409
DIN Number	1.4301 / 1.4307 / 1.4948
Material Standard	ASTM A276 / ASTM A479 / ASTM A182
Nut Standard (Metric)	DIN 934 / DIN 6915 / ISO 4032
Nut Standard (Inch)	ASME B18.2.2 / ASTM A194
Thread Form	ISO Metric / UNC / UNF
Size Range	M3-M100 / #4-4"
Tensile Strength	515 MPa (75 ksi) min
Yield Strength	205 MPa (30 ksi) min
Hardness	Max 35 HRC / 223 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, Screws, Washers, 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 Screws

SS 304 / 304L / 304H Washers

SS 304 / 304L / 304H Studs

SS 304 / 304L / 304H Threaded Rods

Technical Data

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

SS 304 / 304L / 304H Nuts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 934 (hex nuts) / DIN 6915 (heavy hex) / ISO 4032. Custom sizes available. Inch dimensions per ASME B18.2.2 and ASTM A194 Grade 8 / 8M.

Hex Nut Dimensions - Metric (DIN 934 / ISO 4032)

Size (M)	Pitch (mm)	A/F (mm)	Nut Height (mm)	A/C (mm)	Weight (g/pc)
M3	0.5	5.5	2.4	6.01	0.5
M4	0.7	7	3.2	7.66	1.0
M5	0.8	8	4.0	8.79	1.8
M6	1.0	10	5.0	11.05	3.0
M8	1.25	13	6.5	14.38	6.5
M10	1.5	17	8.0	18.90	12.0
M12	1.75	19	10.0	20.03	18.0
M16	2.0	24	13.0	26.75	40.0
M20	2.5	30	16.0	32.95	78.0
M24	3.0	36	19.0	39.55	135.0
M30	3.5	46	24.0	50.85	275.0
M36	4.0	55	29.0	60.79	480.0
M42	4.5	65	34.0	71.30	780.0
M48	5.0	75	38.0	82.60	1150.0
M56	5.5	85	45.0	93.56	1800.0
M64	6.0	95	51.0	104.86	2600.0

Dimensional & Material Standards

Standard	Covers	Thread
DIN 934	Hex nuts, standard height	Metric
DIN 6915	Heavy hex nuts, structural	Metric
ISO 4032	Hex nuts, style 1	Metric
ISO 4033	Hex nuts, style 2 (high)	Metric
ASME B18.2.2	Hex & heavy hex nuts	UNC/UNF
ASTM A194 Gr.8	Nuts for high-temp service	UNC/UNF
ASTM A194 Gr.8M	Nuts for pressure service	UNC/UNF

Material Standard	Requirement
ASTM A276	Bar/rod - UNS S30400/S30403/S30409
ASTM A479	Bar for pressure vessel use
ASTM A182 F304/F304L/F304H	Forged fittings & flanges
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 Nuts 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 A276 / A479

Element	SS 304 (S30400)	SS 304L (S30403)	SS 304H (S30409)
Carbon (C)	0.08% max	0.03% max	0.04-0.10%
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%
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 Nuts

304L — Low Carbon for Weld-Zone Integrity

With carbon capped at 0.03%, 304L nuts resist sensitisation in the heat-affected zone of welded assemblies. Chromium carbide precipitation at grain boundaries is suppressed, preserving corrosion resistance without post-weld annealing — the standard choice for fabricated pressure vessels and piping systems.

304H — Elevated Carbon for Creep Resistance

The controlled carbon range of 0.04–0.10% in 304H provides measurably higher creep and stress-rupture strength above 425°C. ASME Section VIII and Section I boiler codes mandate 304H over standard 304 for high-temperature pressure service, making these nuts essential for superheater and reheater flange connections.

Cr-Ni Balance — Passive Film Stability

The 18% chromium content forms a self-repairing passive oxide film that provides corrosion resistance in atmospheric, freshwater, and mild chemical environments. The 8–10.5% nickel content stabilises the austenitic structure, ensuring non-magnetic behaviour and excellent low-temperature toughness down to cryogenic service.

Fastener Performance

SS 304 / 304L / 304H Nuts Mechanical Properties & Torque Reference

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

Nut Proof Load & Torque Reference - Metric (DIN 934 / ISO 4032)

Nut Size	Proof Load (kN)	Dry Torque (Nm)	Lubricated Torque (Nm)
M6	9.0	8	6
M8	16.5	20	16
M10	26.0	40	32
M12	38.0	70	56
M16	70.0	170	136
M20	110.0	340	272
M24	160.0	590	472
M30	255.0	1170	936
M36	370.0	2050	1640

?? Anti-galling: SS 304 nuts are prone to galling when mated with SS 304 bolts. Use molybdenum disulphide or PTFE-based lubricant. Lubricated values assume K=0.17. Never use copper-based anti-seize on austenitic stainless steel in food-grade or pharmaceutical environments.

Industry Applications

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

SS 304 / 304L / 304H Nuts 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.

Chemical & Pharmaceutical Processing

SS 304 hex nuts and heavy hex nuts are the standard fastener specification for flanged connections in chemical reactors, storage tanks, and process pipework handling dilute acids, alkalis, and organic solvents. 304L is preferred for welded assemblies to prevent sensitisation. Compliant with FDA 21 CFR and EHEDG guidelines for food-contact applications.

Water Treatment & Utilities

Hex nuts and coupling nuts in SS 304 are widely used in water treatment plant pipework, pump flanges, filter housings, and municipal infrastructure where atmospheric and freshwater corrosion resistance is required at a cost-effective price point. Suitable for potable water contact per BS 6920 and NSF/ANSI 61.

Pressure Vessels & Boilers (304H)

SS 304H heavy hex nuts are specified under ASME Section VIII Div.1 and Section I for pressure vessel and boiler flange connections operating above 425°C. The elevated carbon content provides superior creep resistance compared to standard 304, making 304H the code-compliant choice for superheater headers, steam drum nozzles, and high-temperature heat exchanger covers.

Food, Dairy & Beverage Equipment

SS 304 nuts are the default fastener material for food processing equipment, dairy plant pipework, beverage filling lines, and brewery vessels. The smooth, non-porous surface resists bacterial adhesion and withstands CIP (clean-in-place) caustic and acid wash cycles without surface degradation.

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

SS 304 / 304L / 304H Nuts 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 934 DIN 980 DIN 982 DIN 985 DIN 439 DIN 315 DIN 1587 DIN 6923 ISO 4032 ISO 7040 ISO 4161 ASME B18.2.2 EN ISO 4032 BS EN ISO 4032 IS 1363 IS 1364 IS 6623 IS 12427 SAE J995 UNI 5588 UNI 6593 CSN 021123 PN 82144

Certifications

ISO 9001:2015PED 2014/68/EUNABL LabMTC 3.1 / 3.2EN 10204

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

Partner with RealBolt — India’s leading manufacturer of certified SS 304 / 304L / 304H Nuts — 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 Nuts — Frequently Asked Questions

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

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

The three grades share the same 18Cr-8Ni base composition but differ in carbon content and resulting performance. SS 304 (UNS S30400) is the general-purpose grade with carbon up to 0.08%, suitable for most ambient and moderate-temperature applications. SS 304L (UNS S30403) has carbon capped at 0.03%, which prevents sensitisation during welding – making it the preferred choice for fabricated assemblies that cannot be post-weld annealed. SS 304H (UNS S30409) has a controlled carbon range of 0.04-0.10%, which provides superior creep and stress-rupture strength above 425°C and is mandated by ASME Section VIII and Section I for high-temperature pressure service. When in doubt for welded assemblies at ambient temperature, specify 304L. For elevated-temperature pressure service, specify 304H.

Which nut standard should I specify - DIN 934, ISO 4032, or ASTM A194?

The choice depends on your application and mating bolt standard. DIN 934 and ISO 4032 are dimensionally equivalent metric hex nuts and are interchangeable for most industrial applications – specify either for metric bolting to DIN 931/933 or ISO 4014/4017. ASTM A194 Grade 8 (for 304) and Grade 8M (for 316, though sometimes cross-referenced for 304 in pressure service) are the correct specifications for inch-thread nuts used on ASME B16.5 flange stud bolt sets and ASME pressure vessel connections. For structural applications using metric heavy hex nuts, specify DIN 6915. Always confirm the mating bolt standard before ordering to ensure thread compatibility and dimensional interchangeability.

Are SS 304 nuts suitable for outdoor and coastal environments?

SS 304 nuts perform well in standard atmospheric and rural outdoor environments, providing reliable corrosion resistance against rain, humidity, and mild industrial pollution. However, in coastal or marine environments with direct salt spray exposure, or in applications involving chloride-bearing process fluids, SS 304 is susceptible to pitting and crevice corrosion – particularly under the nut bearing face where moisture can be trapped. For coastal structural applications, splash-zone installations, or any environment with chloride concentrations above approximately 200 ppm, SS 316 or SS 316L nuts are the recommended upgrade. If SS 304 must be used in borderline environments, applying a PTFE-based thread lubricant and ensuring adequate drainage around the joint will extend service life.

Can SS 304H nuts be used for ASME boiler and pressure vessel code applications?

Yes – SS 304H (UNS S30409) nuts manufactured to ASTM A194 Grade 8 are listed in ASME Section II Part D for use under Section VIII Div.1 and Section I boiler code. The minimum carbon content of 0.04% is required by ASME to qualify for the higher allowable stress values at temperatures above 425°C. Standard 304 or 304L nuts do not meet this requirement and cannot be substituted in code-stamped pressure equipment at elevated temperatures. All 304H nuts supplied for ASME code applications should be accompanied by EN 10204 3.1 or 3.2 mill test certificates confirming the carbon content falls within the 0.04-0.10% range, along with full heat and lot traceability.

Industrial Cities We Serve:

Ahmedabad
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Bengaluru
Chennai
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Faridabad
Gandhidham
Greater Noida
Gurugram
Hazira
Hosur
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Jamnagar
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