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SS 310 / 310S Screws Manufacturer & Exporter in India

Explore SS 310 / 310S Screws 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 Screws?

SS 310 / 310S screws 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 continuous service temperatures up to 1050°C, with intermittent service capability reaching 1150°C.

The combination of high-temperature strength, resistance to sulfidation, and immunity to sigma-phase embrittlement makes SS 310 / 310S screws the preferred fastener choice for furnace construction, heat treatment equipment, and high-temperature chemical processing. These screws are specified under ASTM A193 and ASME B18.3 for critical bolted connections in thermal cycling environments where standard 304 or 316 stainless steel fasteners fail prematurely.

Quick Specifications

MaterialSS 310 / 310S
UNS NumberS31000 / S31008
DIN Number1.4841 / 1.4845
Material StandardASTM A276 / ASTM A479
Screw Standard (Metric)DIN 912 / DIN 933 / ISO 4762
Screw Standard (Inch)ASME B18.3 / ASME B18.6.3
Thread FormISO Metric / UNC / UNF
Diameter RangeM3-M64 / #4-2½"
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 Bolts, SS 310 / 310S Nuts, 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 Bolts
SS 310 / 310S Nuts
SS 310 / 310S Washers
SS 310 / 310S Studs
SS 310 / 310S Threaded Rods

Technical Data

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

SS 310 / 310S Screws are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 912 (socket head cap screws) / DIN 933 (hex screws, full thread) / ISO 4762. Custom lengths in 5mm increments. Inch dimensions available per ASME B18.3 and ASME B18.6.3.

Socket Head Cap Screw Dimensions - Metric (DIN 912 / ISO 4762)

Size (M)Pitch (mm)Head Dia (mm)Head Ht (mm)Socket (mm)Max L (mm)
M30.55.53.02.550
M40.77.04.03.080
M50.88.55.04.0100
M61.010.06.05.0150
M81.2513.08.06.0200
M101.516.010.08.0250
M121.7518.012.010.0300
M162.024.016.014.0400
M202.530.020.017.0500
M243.036.024.019.0600
M303.545.030.022.0800
M364.054.036.027.01000
M424.563.042.032.01000
M485.072.048.036.01200
M565.584.056.041.01500
M646.096.064.046.02000

Dimensional & Material Standards

StandardCoversThread
DIN 912Socket head cap screwsMetric
DIN 933Hex screws, full threadMetric
ISO 4762Socket head cap screwsMetric
ISO 4017Hex head screws, full threadMetric
ASME B18.3Socket head cap screwsUNC/UNF
ASME B18.6.3Machine screwsUNC/UNF
DIN 7984Low head socket cap screwsMetric
Material StandardRequirement
ASTM A276Bar/rod - UNS S31000/S31008
ASTM A479Bar for pressure vessels
ASTM A193Fastener mechanical properties
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

SS 310 / 310S Chemical Composition

SS 310 / 310S Screws 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 / ASTM A479

ElementSS 310 (%)SS 310S (%)
Iron (Fe)BalanceBalance
Chromium (Cr)24.0-26.0%24.0-26.0%
Nickel (Ni)19.0-22.0%19.0-22.0%
Carbon (C)0.25% max0.08% max
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
? All heats verified by NABL-accredited spectrometry. PMI available on request.

Why SS 310 / 310S Alloy Composition Matters for Screws

Cr (24–26%) — High-Temperature Oxidation Resistance
The elevated chromium content forms a dense, adherent Cr2O3 oxide scale that resists spalling during thermal cycling up to 1050°C continuous service. This makes SS 310 / 310S screws far superior to 304 or 316 in furnace and kiln applications where scale adhesion is critical to fastener longevity.
Ni (19–22%) — Carburization & Sigma-Phase Resistance
High nickel content stabilises the austenitic structure at elevated temperatures, suppressing sigma-phase formation that causes embrittlement in lower-nickel grades. It also provides strong resistance to carburization in carbon-rich atmospheres encountered in heat treatment furnaces and petrochemical reformers.
Low Carbon in 310S — Sensitization Prevention
The 310S variant limits carbon to 0.08% maximum, preventing carbide precipitation at grain boundaries during welding or prolonged exposure in the 425–870°C sensitization range. This makes 310S screws the preferred choice for welded assemblies and equipment that operates continuously in the sensitization temperature band.

Fastener Performance

SS 310 / 310S Screws Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for SS 310 / 310S Screws per ASTM. SS 310 / 310S screws 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 Screws

Screw SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M6865
M8191511
M10383019
M12665328
M1616012855
M2031525288
M24545436127
M301090872202
?? Anti-galling note: SS 310 / 310S screws are susceptible to galling under high contact stress. Apply nickel-based or molybdenum disulfide anti-seize to threads before assembly. Lubricated torque values assume K=0.15. Reduce torque by 20% when using anti-seize compounds.

Industry Applications

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

SS 310 / 310S Screws 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 socket head cap screws and hex screws are the standard fastener for industrial furnace shell panels, muffle furnace door hinges, retort covers, and heat treatment basket assemblies. Continuous service to 1050°C with resistance to oxidizing and reducing atmospheres makes these screws the only austenitic stainless option for sustained high-temperature structural connections.
Machine screws and hex screws in SS 310 / 310S are specified for catalytic reformer tube support brackets, steam cracker radiant section connections, and fired heater refractory anchor systems. The alloy’s resistance to carburization and sulfidation in hydrocarbon-rich atmospheres at 800-1000°C prevents the premature fastener failure common with 321 or 347 stainless steel.
SS 310 / 310S screws are used in superheater tube support clips, boiler casing panel connections, and steam header insulation cladding fixings where metal temperatures exceed the capability of 304H or 321H stainless. The high chromium-nickel balance maintains adequate creep strength and oxidation resistance at metal temperatures up to 950°C.
Screws and fasteners in SS 310 / 310S are specified for kiln hood inspection door hardware, preheater cyclone access panel fixings, and clinker cooler casing connections. The alloy withstands the combined attack of high temperature, alkali dust, and sulfur compounds present in cement kiln atmospheres where lower-alloy stainless grades suffer rapid scale spalling.

SS 310 / 310S Screws Standards & International Certifications

SS 310 / 310S Screws 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 912 DIN 913 DIN 914 DIN 915 DIN 916 ISO 4762 ISO 10642 ASME B18.3 EN ISO 4762 IS 1367
Certifications
ISO 9001:2015NABL LabPED 2014/68/EUMTC 3.1 / 3.2EN 10204

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

Partner with RealBolt — India’s leading manufacturer of certified SS 310 / 310S Screws — 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 Screws — Frequently Asked Questions

Browse expert answers to common questions about SS 310 / 310S Screws 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 screws selection and pricing.
The primary difference is carbon content. SS 310 permits up to 0.25% carbon, while SS 310S is restricted to 0.08% maximum. Both grades share identical chromium (24-26%) and nickel (19-22%) ranges and deliver the same high-temperature oxidation resistance. SS 310S is preferred for welded assemblies and equipment operating continuously in the 425-870°C sensitization range, as the lower carbon content prevents intergranular carbide precipitation. For non-welded, purely mechanical fastener applications above 900°C, SS 310 is equally suitable and often more cost-effective.
SS 310 / 310S screws are available in socket head cap (DIN 912 / ISO 4762), hex head (DIN 933 / ISO 4017), pan head (DIN 7985), countersunk flat head (DIN 965 / ISO 10642), button head (ISO 7380), and low head socket cap (DIN 7984) configurations. Drive options include hex socket (Allen), Torx, Phillips, slotted, and combination drives. Inch sizes are manufactured per ASME B18.3 and ASME B18.6.3. Custom head styles and non-standard drive configurations are available with 15 working day lead time.
SS 310 / 310S screws are rated for continuous service up to 1050°C and intermittent service up to 1150°C in oxidizing atmospheres. In reducing or carburizing atmospheres, the practical limit is typically 900-950°C due to accelerated carbon absorption at higher temperatures. For applications above 1050°C continuous, Inconel 601 or Incoloy 800HT fasteners should be considered. Always account for thermal cycling frequency – repeated heating and cooling above 900°C can cause scale spalling that exposes fresh metal to further oxidation.
SS 310 / 310S provides moderate resistance to sulfidation, significantly better than 304 or 316 stainless steel, due to its high chromium and nickel content. However, in strongly sulfidizing atmospheres with H2S concentrations above 1% at temperatures exceeding 700°C, alloy degradation accelerates. For severe sulfidation service, Incoloy 800H or Inconel 601 fasteners are recommended. SS 310 / 310S screws perform reliably in mildly sulfur-contaminated combustion gas environments such as those found in cement kilns and industrial boilers operating on sulfur-bearing fuels.

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