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ASTM A193 Grade B8M Bolts Manufacturer & Exporter in India

Explore ASTM A193 Grade B8M 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 ASTM A193 Grade B8M Bolts?

ASTM A193 Grade B8M bolts are high-performance fasteners manufactured from austenitic stainless steel alloy 316/316L (UNS S31600/S31603), designed for use in high-pressure, high-temperature, and corrosive environments. These bolts are solution-annealed and strain-hardened to achieve superior mechanical properties, including enhanced tensile and yield strength, while maintaining excellent resistance to pitting, crevice, and general corrosion.

Grade B8M bolts are widely specified for petrochemical, power generation, and marine applications where chloride-induced corrosion is a concern. They are available in both Class 1 (annealed) and Class 2 (strain-hardened) conditions, conforming to ASTM A193 and ASME SA193 standards for critical bolting in flanged joints, pressure vessels, and heat exchangers.

Quick Specifications

MaterialStainless Steel 316/316L
UNS NumberS31600 / S31603
DIN Number1.4401 / 1.4404
Material StandardASTM A193 Grade B8M
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 (Class 1) / 760 MPa (Class 2)
Yield Strength205 MPa (Class 1) / 600 MPa (Class 2)
HardnessMax 223 HB (Class 1) / 321 HB (Class 2)
? All material certified by NABL-accredited laboratory. PMI and ferrite testing available on request.

Complete the Fastener Set

Other ASTM A193 Grade B8M Fastener Products Available from RealBolt

RealBolt also manufactures the complete ASTM A193 Grade B8M fastener range — ASTM A193 Grade B8M Nuts, ASTM A193 Grade B8M Screws, ASTM A193 Grade B8M Washers, ASTM A193 Grade B8M Studs, ASTM A193 Grade B8M Threaded Rods — from certified bar stock per ASTM with full EN 10204 MTC 3.1/3.2 documentation and fast Mumbai dispatch.
ASTM A193 Grade B8M Nuts
ASTM A193 Grade B8M Screws
ASTM A193 Grade B8M Washers
ASTM A193 Grade B8M Studs
ASTM A193 Grade B8M Threaded Rods

Technical Data

ASTM A193 Grade B8M Bolts Dimensions, Sizes & Thread Standards

ASTM A193 Grade B8M 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 ASTM A193 Grade B8M 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 A193Bolting - B8M (316/316L)
ASTM A194Heavy hex nuts - Gr. 8M
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

ASTM A193 Grade B8M Chemical Composition

ASTM A193 Grade B8M Bolts are manufactured from chromium-molybdenum alloy steel with Cr (0.8–1.1%), Mo (0.15–0.65%), and vanadium additions in B16 grades, controlled per ASTM and ASME SA-193. Cr-Mo additions raise hardenability and creep rupture strength for pressure vessel service; vanadium in B16 extends the allowable service temperature to 538°C.

Chemical Composition per ASTM A193 (316/316L)

ElementComposition (%)
Chromium (Cr)16.0-18.0
Nickel (Ni)10.0-14.0
Molybdenum (Mo)2.0-3.0
Carbon (C)0.08 max (316) / 0.03 max (316L)
Manganese (Mn)2.00 max
Silicon (Si)1.00 max
Phosphorus (P)0.045 max
Sulfur (S)0.030 max
Iron (Fe)Balance
? All heats verified by NABL-accredited spectrometry. PMI and ferrite content available on request.

Why ASTM A193 Grade B8M Alloy Composition Matters for Bolts

Mo (2–3%) — Chloride Pitting Resistance
Molybdenum in ASTM A193 Grade B8M bolts provides superior resistance to pitting and crevice corrosion in chloride-rich environments, outperforming standard 304 stainless steel in seawater and chemical process applications.
Low Carbon (316L) — Weldability
The low carbon content in 316L minimizes carbide precipitation during welding, preventing intergranular corrosion and ensuring long-term integrity of bolted joints in pressure vessels and piping systems.
Nickel (10–14%) — Austenitic Structure
Nickel stabilizes the austenitic microstructure, delivering excellent ductility, toughness, and non-magnetic properties even at cryogenic temperatures, making B8M bolts suitable for a wide range of critical applications.

Fastener Performance

ASTM A193 Grade B8M Bolts Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for ASTM A193 Grade B8M Bolts per ASTM. ASTM A193 Grade B8M bolts achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Bolt SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M12705628
M1617013657
M2034027289
M24590472128
M301200960206
M3621001680298
M4233002640420
M4848003840570
?? Anti-galling: Use molybdenum-based or PTFE anti-seize. Lubricated values assume K=0.16. Never assemble stainless bolts dry - galling risk is high.

Industry Applications

ASTM A193 Grade B8M Bolts Applications — Industries & End Uses

ASTM A193 Grade B8M Bolts from RealBolt are specified across oil and gas pressure vessels, power generation, and petrochemical where very good corrosion resistance and 620 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples.
ASTM A193 Grade B8M bolts are specified for flange joints, pressure vessel closures, and heat exchanger assemblies in refineries, offshore platforms, and FPSOs. Their resistance to chloride stress corrosion cracking makes them ideal for sour gas and seawater service.
Used for reactor closures, process piping, and storage tank nozzles in chemical plants handling acids, caustics, and chlorides. B8M bolts outperform 304/304L in aggressive chemical environments and are standard for sulfuric and phosphoric acid service.
Flange bolts for flue gas desulphurisation (FGD) scrubbers, HRSG ducting, and steam turbine exhausts. Grade B8M is preferred for high-temperature, wet, and corrosive flue gas environments where carbon steel or 304 fasteners fail.
Hex bolts and stud bolts for hull penetrations, deck equipment, and seawater piping systems. The molybdenum content ensures long-term resistance to pitting and crevice corrosion in marine atmospheres and submerged conditions.

ASTM A193 Grade B8M Bolts Standards & International Certifications

ASTM A193 Grade B8M 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, dimensional inspection report, and proof load test records — available on request for all orders.
Standards
DIN 931 DIN 933 DIN 960 DIN 961 DIN 6914 ISO 4014 ISO 4017 ISO 8676 ISO 8765 ASME B18.2.1 EN 14399 EN 15048 EN ISO 4014 EN ISO 4017 BS EN ISO 4014 BS 3692 BS 4190 IS 1363 IS 1364 IS 3757 SAE J429 UNI 5737 UNI 5739 CSN 021101 PN 82101
Certifications
ISO 9001:2015PED 2014/68/EUNABL LabEN 10204 3.1 / 3.2

Buy ASTM A193 Grade B8M Bolts from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified ASTM A193 Grade B8M 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

ASTM A193 Grade B8M Bolts — Frequently Asked Questions

Browse expert answers to common questions about ASTM A193 Grade B8M Bolts from RealBolt — covering ASTM A193 grade, proof load, creep ratings, cryogenic L7 limits, coating options, and EN 10204 documentation. Contact our technical team directly for project-specific guidance on ASTM A193 Grade B8M bolts selection and pricing.
ASTM A193 Grade B8M bolts are available to DIN 931 (metric partial thread), DIN 933 (metric full thread), ISO 4014/4017, and ASME B18.2.1 (inch hex and heavy hex). Stud bolts are supplied per ASME B16.5 and MSS SP-75 for flange applications. Custom thread forms (BSW, BSF, Whitworth, BSPP) can be manufactured on request with short lead times.
Use molybdenum-based or PTFE anti-seize compound (such as Molykote 1000 or Loctite LB 8014). Apply to threads and nut bearing face to prevent galling. Lubricated torque values should be used. Never assemble stainless bolts dry – galling risk is high, especially on large diameter fasteners.
Yes – ASTM A193 Grade B8M bolts (316/316L) are specifically designed for marine and seawater applications. The 2-3% molybdenum content provides excellent resistance to pitting and crevice corrosion, making them ideal for submerged and splash zone service without the need for additional coatings.
No formal MOQ for standard sizes (M12-M36) held ex-stock – we supply from single pieces for urgent maintenance. Custom sizes or non-standard threads may require a 10 kg minimum. Flange stud bolt sets are supplied by the set with no minimum. Quantity price breaks at 50 pcs, 200 pcs, and 500 pcs.

Industrial Cities We Serve:

  • Ahmedabad
  • Aurangabad
  • Bengaluru
  • Chennai
  • Coimbatore
  • Faridabad
  • Gandhidham
  • Greater Noida
  • Gurugram
  • Hazira
  • Hosur
  • Hyderabad
  • Jamnagar
  • Jamshedpur
  • Ludhiana
  • Mumbai
  • Mundra
  • Mysuru
  • Nagpur
  • Nashik
  • Navi Mumbai
  • Noida
  • Pune
  • Rajkot
  • Sanand
  • Surat
  • Thane
  • Tiruppur
  • Vadodara
  • Visakhapatnam

Countries We Export To:

  • US
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  • Mexico
  • Germany
  • UK
  • France
  • Italy
  • Spain
  • Netherlands
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  • Poland
  • Sweden
  • Norway
  • Denmark
  • Turkey
  • UAE
  • Saudi Arabia
  • Qatar
  • Oman
  • Kuwait
  • Bahrain
  • South Africa
  • Egypt
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