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

Explore SS 304 / 304L / 304H Studs 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 Studs?

SS 304 / 304L / 304H studs are austenitic stainless steel threaded 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 a passive oxide layer that resists oxidation, mild acids, and atmospheric corrosion across a broad temperature range without additional coating or treatment.

The three sub-grades serve distinct engineering requirements: standard 304 offers balanced strength and corrosion resistance for general service; 304L with carbon limited to 0.03% max eliminates sensitisation risk in welded assemblies; and 304H with carbon held at 0.04-0.10% provides superior creep strength for elevated-temperature pressure vessel and boiler applications per ASME Section VIII. All three grades are widely specified under ASTM A193, ASME B16.5, and ASME B18.31 for flanged piping, pressure vessels, and structural connections across chemical, food processing, pharmaceutical, and power generation industries.

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 A193 B8
Stud Standard (Metric)	DIN 976-1 / ISO 4032 / DIN 939
Stud Standard (Inch)	ASME B18.31.1 / ASME B16.5
Thread Form	ISO Metric / UNC / UNF
Diameter Range	M6-M100 / ¼"-4"
Tensile Strength	515 MPa (75 ksi) min
Yield Strength	205 MPa (30 ksi) min
Hardness	Max 70 HRB / 187 HB

? All material certified by NABL-accredited laboratory. PMI and heat-specific MTCs 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, Washers, 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 Washers

SS 304 / 304L / 304H Threaded Rods

Technical Data

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

SS 304 / 304L / 304H Studs are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 976-1 (metric studs) / DIN 939 (stud bolts, partial thread) / ISO 4032. Custom lengths in 5 mm increments. Inch dimensions available per ASME B18.31.1 and ASME B16.5.

Stud Bolt Dimensions - Metric (DIN 976-1 / DIN 939)

Size (M)	Pitch (mm)	Thread Length (mm)	Min L (mm)	Max L (mm)	Weight/m (kg)
M6	1.0	18	20	200	0.22
M8	1.25	22	25	250	0.39
M10	1.5	26	30	300	0.62
M12	1.75	30	35	400	0.89
M16	2.0	38	45	500	1.58
M20	2.5	46	55	600	2.47
M24	3.0	54	65	700	3.55
M30	3.5	66	80	800	5.55
M36	4.0	78	100	1000	7.99
M42	4.5	90	120	1200	10.87
M48	5.0	102	140	1500	14.20
M56	5.5	118	160	1500	19.30
M64	6.0	134	180	2000	25.20
M72	6.0	150	200	2000	31.90
M80	6.0	166	220	2500	39.40
M100	6.0	206	260	3000	61.60

Dimensional & Material Standards

Standard	Covers	Thread
DIN 976-1	Metric stud bolts, full thread	Metric
DIN 939	Stud bolts, partial thread (metal end)	Metric
ISO 4032	Hex nuts, style 1	Metric
ASME B18.31.1	Continuous and double-end studs	UNC/UNF
ASME B16.5	Stud bolts for pipe flanges	UNC
MSS SP-75	High-pressure stud bolt sets	UNC
ASME B1.1	Unified inch screw threads	UNC/UNF

Material Standard	Requirement
ASTM A276	Bar/rod - UNS S30400/S30403/S30409
ASTM A479	Bar for pressure vessel use
ASTM A193 B8/B8L/B8H	Fastener mechanical properties
ASTM A194 8/8L/8H	Nuts for high-temperature service
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 Studs 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 (%)	SS 304L (%)	SS 304H (%)
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 and heat-specific MTCs available on request.

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

304L — Low Carbon for Weld-Zone Integrity

Limiting carbon to 0.03% max prevents chromium carbide precipitation at grain boundaries during welding or elevated-temperature exposure. 304L studs maintain full corrosion resistance in the heat-affected zone without post-weld annealing, making them the preferred choice for welded pressure vessel nozzle connections.

304H — Elevated Carbon for Creep Resistance

The controlled carbon range of 0.04–0.10% in 304H significantly improves creep and stress-rupture strength above 425°C. ASME Section VIII and Section I boiler codes mandate 304H over standard 304 for pressure-retaining fasteners in high-temperature service, where long-term bolt load relaxation is a design concern.

Cr-Ni Balance — Passive Layer Stability

The 18–20% chromium content forms a self-repairing passive oxide film that resists oxidation, mild organic acids, and atmospheric corrosion. The 8–10.5% nickel stabilises the austenitic structure, preventing stress corrosion cracking in moderate chloride environments and ensuring non-magnetic behaviour in sensitive instrumentation assemblies.

Fastener Performance

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

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

Stud Torque Reference - SS 304 / 304L (Annealed, Class 1)

Stud Size	Dry (Nm)	Lubricated (Nm)	Clamp Load (kN)
M12	52	42	19
M16	125	100	46
M20	245	196	73
M24	425	340	106
M30	850	680	168
M36	1480	1184	244
M42	2360	1888	336
M48	3500	2800	442

?? Anti-galling: SS 304 studs are prone to galling under high torque. Always use molybdenum disulphide or PTFE-based anti-seize. Lubricated values assume K=0.17. Never assemble dry at high torque without lubrication.

Industry Applications

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

SS 304 / 304L / 304H Studs 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 & Petrochemical Processing

SS 304 stud bolt sets are the standard specification for ASME B16.5 flanged connections in chemical reactors, heat exchangers (TEMA Class B/C), and process piping handling dilute acids, alkalis, and organic solvents. 304L is preferred wherever welded nozzle connections are involved to prevent sensitisation in the heat-affected zone.

Food, Beverage & Pharmaceutical

SS 304 studs are widely used in food processing equipment, dairy plant pipework, pharmaceutical reactor vessels, and clean-room structural connections where hygiene, non-reactivity, and ease of cleaning are mandatory. The smooth passive surface resists bacterial adhesion and meets FDA and EU food-contact material requirements.

Water Treatment & Utilities

Stud bolt sets in SS 304 are specified for flanged connections in municipal water treatment plants, desalination pre-treatment systems, and HVAC chilled water pipework. The alloy resists corrosion from treated water, mild chloramines, and atmospheric moisture without coating, reducing long-term maintenance costs.

Power Generation - Boilers & Heat Exchangers

SS 304H studs are mandated by ASME Section I and Section VIII for pressure-retaining bolted connections in boiler drums, superheater headers, and heat recovery steam generator (HRSG) duct flanges operating above 425°C, where the elevated carbon content provides the creep resistance required by code.

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

SS 304 / 304L / 304H Studs 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 938 DIN 939 DIN 976-1 ASME B18.31.2 IS 1364 IS 1367 IS 12427

Certifications

ISO 9001:2015PED 2014/68/EUNABL LabEN 10204 3.1 / 3.2ASME Section VIII

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

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

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

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

The three grades share the same 18Cr-8Ni base composition but differ in carbon content and resulting performance. SS 304 (C = 0.08%) is the general-purpose grade suitable for most ambient and moderate-temperature applications. SS 304L (C = 0.03%) eliminates sensitisation risk in welded assemblies – chromium carbides cannot precipitate at grain boundaries, so corrosion resistance is maintained in the heat-affected zone without post-weld annealing. SS 304H (C 0.04-0.10%) is specified by ASME Section I and Section VIII for pressure-retaining fasteners above 425°C, where the higher carbon content delivers superior creep and stress-rupture strength. For welded pressure vessels at ambient temperature, specify 304L. For high-temperature boiler and HRSG service, specify 304H.

What anti-galling precautions are required when assembling SS 304 studs?

SS 304 is highly susceptible to galling (cold welding of threads) during assembly, particularly in stud-to-nut contact. Always apply a molybdenum disulphide (MoS2) paste, PTFE-based anti-seize, or nickel-based anti-seize compound to all threads and nut bearing faces before assembly. Reduce target torque values by 15-20% compared to dry assembly values. Use a calibrated torque wrench and tighten in a star pattern for multi-bolt flange joints. Never assemble SS 304 studs dry at high torque – thread seizure can occur before the target clamp load is reached, making disassembly destructive.

Are SS 304 studs suitable for chloride-containing environments?

SS 304 provides good resistance to mild atmospheric chloride exposure but is susceptible to pitting and crevice corrosion in concentrated chloride solutions, seawater immersion, and chloride-bearing process streams above 60°C. For seawater-immersed or high-chloride service, SS 316 / 316L studs (with molybdenum addition) or duplex 2205 studs are the correct specification. SS 304 is acceptable for coastal atmospheric exposure, potable water service, and low-chloride process piping where chloride concentration remains below approximately 200 ppm at ambient temperature.

What ASME standard governs SS 304H stud bolts for boiler and pressure vessel service?

SS 304H stud bolts for pressure-retaining applications are governed by ASTM A193 Grade B8H (studs) and ASTM A194 Grade 8H (nuts). ASME Section I (Power Boilers) and Section VIII Division 1 (Pressure Vessels) permit 304H for bolting above 425°C, where the elevated carbon content provides the minimum creep-rupture strength required by the applicable allowable stress tables. Material must be solution-annealed and supplied with EN 10204 3.1 MTC confirming carbon content within the 0.04-0.10% range. Grain size must be ASTM No. 7 or coarser per ASTM A193 requirements for 304H.

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