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ASTM A193 Grade B8 Nuts Manufacturer & Exporter in India

Explore ASTM A193 Grade B8 Nuts 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 B8 Nuts?

ASTM A193 Grade B8 nuts are high-performance stainless steel fasteners manufactured from austenitic stainless steel, specifically Type 304 or its variants, and are designed for use in high-pressure, high-temperature bolting applications. These nuts are solution annealed and strain-hardened to achieve the required mechanical properties, making them suitable for critical service in petrochemical, power generation, and process industries.

Grade B8 nuts are widely specified for bolted flange joints, pressure vessels, and piping systems where corrosion resistance and reliable mechanical strength are essential. They are available in both Class 1 (annealed) and Class 2 (strain-hardened) conditions, conforming to ASTM A194 for nut requirements and are compatible with ASTM A193 Grade B8 bolts and studs.

Quick Specifications

MaterialStainless Steel 304 (AISI 304/304L)
UNS NumberS30400 / S30403
DIN Number1.4301 / 1.4307
Material StandardASTM A193 / ASTM A194
Nut Standard (Metric)DIN 934 / ISO 4032
Nut Standard (Inch)ASME B18.2.2
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 HBW (Class 1) / 321 HBW (Class 2)
? All nuts supplied with full traceability and laboratory certification. Positive Material Identification (PMI) available on request.

Complete the Fastener Set

Other ASTM A193 Grade B8 Fastener Products Available from RealBolt

RealBolt also manufactures the complete ASTM A193 Grade B8 fastener range — ASTM A193 Grade B8 Bolts, ASTM A193 Grade B8 Screws, ASTM A193 Grade B8 Washers, ASTM A193 Grade B8 Studs, ASTM A193 Grade B8 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 B8 Bolts
ASTM A193 Grade B8 Screws
ASTM A193 Grade B8 Washers
ASTM A193 Grade B8 Studs
ASTM A193 Grade B8 Threaded Rods

Technical Data

ASTM A193 Grade B8 Nuts Dimensions, Sizes & Thread Standards

ASTM A193 Grade B8 Nuts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 934 (hex nut) / ISO 4032. Custom thread forms and special dimensions available. Inch sizes per ASME B18.2.2. All ASTM A193 Grade B8 nuts dimensions are verified against applicable DIN, ISO, and ASME

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

Size (M)Pitch (mm)A/F (mm)Height (mm)
M61.0105
M81.25136.5
M101.5178
M121.751910
M162.02413
M202.53016
M243.03619
M303.54624
M364.05529
M424.56534
M485.07538
M565.58545
M646.09551
M726.010558
M806.011565
M1006.014580

Dimensional & Material Standards

StandardCoversThread
DIN 934Hex nutsMetric
ISO 4032Hex nutsMetric
ASME B18.2.2Hex & heavy hex nutsUNC/UNF
ASTM A194Heavy hex nutsUNC/UNF
Material StandardRequirement
ASTM A193B8 bolts, studs, rods
ASTM A194B8 nuts
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

ASTM A193 Grade B8 Chemical Composition

ASTM A193 Grade B8 Nuts 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/A194

ElementComposition (%)
Chromium (Cr)18.0-20.0
Nickel (Ni)8.0-11.0
Carbon (C)0.08 max
Manganese (Mn)2.00 max
Silicon (Si)1.00 max
Phosphorus (P)0.045 max
Sulfur (S)0.030 max
Molybdenum (Mo)0.75 max
Nitrogen (N)0.10 max
Iron (Fe)Balance
? All heats spectro-tested and certified by NABL-accredited laboratory. PMI and chemical analysis available with every batch.

Why ASTM A193 Grade B8 Alloy Composition Matters for Nuts

Cr (18–20%) — Corrosion Resistance
High chromium content ensures excellent resistance to oxidation and corrosion in a wide range of environments, making ASTM A193 Grade B8 nuts ideal for chemical, petrochemical, and marine applications.
Ni (8–11%) — Austenitic Structure
Nickel stabilizes the austenitic structure, providing ductility and toughness even at cryogenic temperatures. This ensures nuts maintain integrity under thermal cycling and vibration.
Low Carbon — Intergranular Corrosion Resistance
Low carbon content (=0.08%) minimizes carbide precipitation during welding or high-temperature service, reducing the risk of intergranular corrosion and ensuring long-term reliability.

Fastener Performance

ASTM A193 Grade B8 Nuts Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for ASTM A193 Grade B8 Nuts per ASTM. ASTM A193 Grade B8 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 SizeRecommended Torque (Nm)Clamp Load (kN)
M127035
M1617070
M20340110
M24590160
M301200260
M362100380
M423300540
M484800750
?? Anti-galling: Always use a suitable lubricant (such as molybdenum disulfide or PTFE-based) on stainless steel threads to prevent galling. Lubricated values assume K=0.15.

Industry Applications

ASTM A193 Grade B8 Nuts Applications — Industries & End Uses

ASTM A193 Grade B8 Nuts 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 B8 nuts are the default choice for bolted flange joints in refinery piping, heat exchangers, and pressure vessels handling hydrocarbons, acids, and steam. They are compatible with B8 bolts and B8M bolts for critical service in sour and non-sour environments.
Used in turbine casings, HRSG ducting, and steam piping systems where high-temperature oxidation resistance and mechanical strength are required. B8 nuts maintain integrity in thermal cycling and vibration-prone assemblies.
Ideal for reactors, process vessels, and chemical transfer lines exposed to aggressive chemicals, organic acids, and chlorides. The austenitic stainless steel composition ensures long-term corrosion resistance and reliability.
Specified for bolted joints in desalination units, water filtration skids, and brine handling systems where resistance to chloride-induced corrosion is essential for long service life.

ASTM A193 Grade B8 Nuts Standards & International Certifications

ASTM A193 Grade B8 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, hardness test certificate, dimensional inspection report, and proof load test records — available on request for all orders.
Standards
DIN 934 DIN 980 DIN 982 DIN 985 DIN 439 DIN 557 DIN 562 ISO 4032 ISO 7040 ASME B18.2.2 EN ISO 4032 BS EN ISO 4032 IS 1363 IS 1364 IS 6623 IS 3757 SAE J995 SAE J1199 UNI 5588 CSN 021123 PN 82144
Certifications
ISO 9001:2015PED 2014/68/EUNABL LabMTC 3.1 / 3.2

Buy ASTM A193 Grade B8 Nuts from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified ASTM A193 Grade B8 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.
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Answers for Buyers

ASTM A193 Grade B8 Nuts — Frequently Asked Questions

Browse expert answers to common questions about ASTM A193 Grade B8 Nuts 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 B8 nuts selection and pricing.
ASTM A193 Grade B8 nuts are available to DIN 934 (metric hex), ISO 4032, ASME B18.2.2 (inch hex and heavy hex), and ASTM A194 (heavy hex). Custom thread forms such as BSF, BSW, and Whitworth are available on request with short lead times.
Use a high-quality anti-galling lubricant such as molybdenum disulfide (e.g., Molykote 1000) or PTFE-based compounds. Apply to both nut and bolt threads before assembly. Avoid copper-based lubricants to prevent galvanic corrosion with stainless steel.
Yes – ASTM A193 Grade B8 nuts are rated for continuous service up to 870°C (1600°F) and maintain mechanical strength and corrosion resistance at elevated temperatures, making them suitable for steam, refinery, and power plant applications.
No formal MOQ for standard sizes (M8-M36) held in stock – single-piece orders are accepted for urgent requirements. Custom sizes or special coatings may require a minimum batch of 10 kg. Quantity discounts apply at 50, 200, and 500 pieces.

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
  • Canada
  • Mexico
  • Germany
  • UK
  • France
  • Italy
  • Spain
  • Netherlands
  • Belgium
  • Poland
  • Sweden
  • Norway
  • Denmark
  • Turkey
  • UAE
  • Saudi Arabia
  • Qatar
  • Oman
  • Kuwait
  • Bahrain
  • South Africa
  • Egypt
  • Nigeria
  • Australia
  • New Zealand
  • Singapore
  • Malaysia
  • Indonesia
  • Thailand
  • Vietnam
  • South Korea
  • Japan
  • Brazil