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SS 310 / 310S Bolts Manufacturer & Exporter in India

Explore SS 310 / 310S Bolts 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 310 / 310S Bolts?

SS 310 / 310S bolts are austenitic stainless steel fasteners manufactured from UNS S31000 and UNS S31008 bar stock conforming to ASTM A276 and ASTM A479. The alloy’s high chromium content (24-26%) and elevated nickel (19-22%) deliver exceptional resistance to oxidation and carburization at temperatures up to 1150°C, making these bolts the preferred choice for high-temperature structural connections.

The 310S variant limits carbon to 0.08% maximum, reducing carbide precipitation risk during prolonged high-temperature service. SS 310 / 310S bolts are widely specified for furnace hardware, heat treatment equipment, and petrochemical fired heater flanges where standard 304 or 316 stainless steel bolting fails within months due to scaling and thermal fatigue.

Quick Specifications

MaterialSS 310 / 310S
UNS NumberS31000 / S31008
DIN Number1.4841 / 1.4845
Material StandardASTM A276 / ASTM A479
Bolt Standard (Metric)DIN 931 / DIN 933 / ISO 4014
Bolt Standard (Inch)ASME B18.2.1
Thread FormISO Metric / UNC / UNF
Diameter RangeM6-M100 / ¼"-4"
Tensile Strength515 MPa (75 ksi) min
Yield Strength205 MPa (30 ksi) min
HardnessMax 95 HRB / 217 HB
? All material certified by NABL-accredited laboratory. PMI available on request.

Complete the Fastener Set

Other SS 310 / 310S Fastener Products Available from RealBolt

RealBolt also manufactures the complete SS 310 / 310S fastener range — SS 310 / 310S Nuts, SS 310 / 310S Screws, SS 310 / 310S Washers, SS 310 / 310S Studs, SS 310 / 310S Threaded Rods — from certified bar stock per ASTM with full EN 10204 MTC 3.1/3.2 documentation and fast Mumbai dispatch.
SS 310 / 310S Nuts
SS 310 / 310S Screws
SS 310 / 310S Washers
SS 310 / 310S Studs
SS 310 / 310S Threaded Rods

Technical Data

SS 310 / 310S Bolts Dimensions, Sizes & Thread Standards

SS 310 / 310S Bolts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 931 (partial thread) / DIN 933 (full thread) / ISO 4014. Custom lengths in 5mm increments. Inch dimensions available per ASME B18.2.1. All SS 310 / 310S bolts dimensions conform to applicable DIN, ISO, and ASME B18 standards.

Hex Bolt Dimensions - Metric (DIN 931 / ISO 4014)

Size (M)Pitch (mm)A/F (mm)Head Ht (mm)Min L (mm)Max L (mm)
M61.0104.010200
M81.25135.312250
M101.5176.416300
M121.75197.520400
M162.02410.025500
M202.53012.530600
M243.03615.040600
M303.54618.750800
M364.05522.5601000
M424.56526.0801000
M485.07530.01001200
M565.58535.01201500
M646.09540.01402000
M726.010545.01602000
M806.011550.01802500
M1006.014563.02003000

Dimensional & Material Standards

StandardCoversThread
DIN 931Hex bolts, partial threadMetric
DIN 933Hex bolts, full threadMetric
ISO 4014Hex head screws, partialMetric
ISO 4017Hex head screws, fullMetric
ASME B18.2.1Hex & heavy hex boltsUNC/UNF
ASME B16.5Stud bolts for flangesUNC
MSS SP-75Stud bolts, high-pressureUNC
Material StandardRequirement
ASTM A276Bar/rod - UNS S31000 / S31008
ASTM A479Bar for pressure vessels
ASTM F593Fastener mechanical properties
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

SS 310 / 310S Chemical Composition

SS 310 / 310S Bolts 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 / EN 10088-3

ElementSS 310 (%)SS 310S (%)
Carbon (C)0.25% max0.08% max
Chromium (Cr)24.0-26.0%24.0-26.0%
Nickel (Ni)19.0-22.0%19.0-22.0%
Manganese (Mn)2.0% max2.0% max
Silicon (Si)1.5% max1.5% max
Phosphorus (P)0.045% max0.045% max
Sulfur (S)0.030% max0.030% max
Iron (Fe)BalanceBalance
? All heats verified by NABL-accredited spectrometry. PMI available on request.

Why SS 310 / 310S Alloy Composition Matters for Bolts

Cr (24–26%) — High-Temperature Oxidation Resistance
The elevated chromium content forms a dense, adherent Cr2O3 oxide scale that resists spalling under cyclic thermal loading up to 1150°C — critical for furnace door bolts and heat treatment basket fasteners that experience repeated heat-cool cycles.
Ni (19–22%) — Austenite Stability & Carburization Resistance
High nickel content stabilises the fully austenitic structure at all service temperatures, preventing sigma phase embrittlement and providing superior resistance to carburization in carbon-rich furnace atmospheres where lower-nickel grades like 304 and 316 fail rapidly.
310S Low Carbon — Sensitization Prevention
By restricting carbon to 0.08% maximum, 310S avoids chromium carbide precipitation at grain boundaries during prolonged exposure in the 425–870°C sensitization range. This makes 310S bolts the correct choice for welded assemblies and equipment that operates continuously in this temperature band.

Fastener Performance

SS 310 / 310S Bolts Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for SS 310 / 310S Bolts per ASTM. SS 310 / 310S bolts achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Tightening Torque Reference - SS 310 / 310S Hex Bolts

Bolt SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M12554420
M1613510849
M2026521278
M24460368113
M30920736180
M3616001280261
M4225502040358
M4838003040472
?? Anti-galling: SS 310 / 310S bolts are prone to galling under high contact stress. Always use a high-temperature anti-seize compound (Molykote 1000 or equivalent). Lubricated values assume K=0.17. Never assemble dry at elevated temperatures without anti-seize protection.

Industry Applications

SS 310 / 310S Bolts Applications — Industries & End Uses

SS 310 / 310S Bolts 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 310 / 310S hex bolts and stud bolts are the standard fastener specification for industrial furnace door frames, muffle furnace shells, heat treatment basket assemblies, and annealing bell covers. Continuous service temperatures up to 1150°C in oxidizing atmospheres are handled without scaling or bolt seizure that would occur with 304 or 316 stainless steel.
Flange stud bolt sets for fired heater tube support hangers, reformer outlet manifold flanges, and radiant section structural connections where skin temperatures regularly exceed 800°C. SS 310 / 310S bolts maintain adequate clamping force and resist oxidation scaling that causes bolt head embedment and loss of preload in service.
Hex bolts and stud bolts for superheater header flanges, reheater support brackets, and boiler casing structural connections operating in high-temperature steam and flue gas environments. The alloy’s resistance to sulfidation and oxidation in SO2-bearing combustion gases makes it the preferred choice over lower-alloy grades.
Fasteners for kiln shell inspection door frames, burner pipe support brackets, and preheater cyclone structural connections. SS 310 / 310S bolts withstand the combined effects of high temperature, abrasive dust, and cyclic thermal loading that cause rapid failure of carbon steel and standard stainless steel bolting in cement plant environments.

SS 310 / 310S Bolts Standards & International Certifications

SS 310 / 310S Bolts 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, hardness test certificate, ISO 3506 material certification, and NABL-accredited lab reports — available on request for all orders.
Standards
DIN 931 DIN 933 ISO 4014 ISO 4017 ASME B18.2.1 EN ISO 4014 EN ISO 4017 IS 1364 IS 1367
Certifications
ISO 9001:2015PED 2014/68/EUNABL LabMTC 3.1 / 3.2EN 10204

Buy SS 310 / 310S Bolts from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified SS 310 / 310S Bolts — 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.
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Answers for Buyers

SS 310 / 310S Bolts — Frequently Asked Questions

Browse expert answers to common questions about SS 310 / 310S Bolts 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 310 / 310S bolts selection and pricing.
The primary difference is carbon content. SS 310 permits carbon up to 0.25% maximum, while SS 310S restricts carbon to 0.08% maximum. In practice, 310S is specified for applications involving prolonged exposure in the 425-870°C sensitization range, welded assemblies, and equipment that cycles through this temperature band repeatedly. 310 (higher carbon) is acceptable for applications where the fastener remains above 870°C continuously and sensitization is not a concern. For most industrial furnace and heat treatment applications, 310S is the safer and more commonly specified choice.
SS 310 / 310S bolts are rated for continuous service up to 1150°C in oxidizing atmospheres and up to 1035°C in intermittent (cyclic) service. In reducing, sulfidizing, or carburizing atmospheres, the effective maximum temperature is lower – typically 980°C – due to accelerated attack on the protective oxide scale. For applications above 1050°C in cyclic service, consider upgrading to a nickel-based alloy such as Alloy 601 or Inconel 625 for improved spalling resistance.
Use a high-temperature anti-seize compound rated for the service temperature. Molykote 1000 (rated to 1315°C), Jet-Lube SS-30 (rated to 1093°C), or Bostik Never-Seez High-Temperature are all suitable. Apply to threads and the nut bearing face. Reduce torque values by approximately 20% compared to dry assembly values. Never assemble SS 310 / 310S bolts dry in high-temperature service – galling and seizure during disassembly are virtually guaranteed without lubrication, particularly in furnace applications where bolts are repeatedly heated and cooled.
SS 310 / 310S provides good resistance to carburization due to its high nickel content (19-22%), which significantly slows carbon ingress compared to lower-nickel grades. However, in strongly sulfidizing atmospheres (high H2S or SO2 concentrations above 900°C), the protective Cr2O3 scale can be disrupted, leading to accelerated attack. For severe sulfidizing service, alloy 601 or Incoloy 800HT bolts are recommended. For carburizing furnaces operating below 1050°C, SS 310S bolts perform reliably and are widely used in the heat treatment industry.

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