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ASTM A193 Grade B7 Washers Manufacturer & Exporter in India

Explore ASTM A193 Grade B7 Washers 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 B7 Washers?

ASTM A193 Grade B7 washers are high-strength alloy steel flat washers manufactured to complement B7 bolts and studs in critical bolted assemblies. Produced from quenched and tempered chromium-molybdenum steel (UNS K21590), these washers provide reliable load distribution and prevent surface damage under high clamping forces. B7 washers are engineered for use in high-pressure, high-temperature, and corrosive environments, including petrochemical, power generation, and oil & gas applications.

Conforming to ASTM F436 and ASTM A194 dimensional and mechanical requirements, ASTM A193 Grade B7 washers are available in both plain and zinc-plated finishes. They are essential for maintaining joint integrity in flange connections, pressure vessels, and structural assemblies where Grade B7 fasteners are specified.

Quick Specifications

MaterialAlloy Steel (Cr-Mo)
UNS NumberK21590
DIN Number1.7225
Material StandardASTM A193 Grade B7
Washer Standard (Metric)DIN 125 / DIN 127 / DIN 7989
Washer Standard (Inch)ASME B18.22.1 / ASTM F436
TypeFlat, Spring, Hardened
Diameter RangeM6-M100 / ¼"-4"
HardnessRockwell C 38-45
FinishPlain, Zinc Plated, Hot Dip Galvanized
? All washers supplied with full traceability and hardness certification. Third-party inspection available.

Complete the Fastener Set

Other ASTM A193 Grade B7 Fastener Products Available from RealBolt

RealBolt also manufactures the complete ASTM A193 Grade B7 fastener range — ASTM A193 Grade B7 Bolts, ASTM A193 Grade B7 Nuts, ASTM A193 Grade B7 Screws, ASTM A193 Grade B7 Studs, ASTM A193 Grade B7 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 B7 Bolts
ASTM A193 Grade B7 Nuts
ASTM A193 Grade B7 Screws
ASTM A193 Grade B7 Studs
ASTM A193 Grade B7 Threaded Rods

Technical Data

ASTM A193 Grade B7 Washers Dimensions, Sizes & Thread Standards

ASTM A193 Grade B7 Washers are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 125 (flat), DIN 127 (spring), DIN 7989 (structural), and ASTM F436 (hardened). Custom OD/ID and thickness available. Inch sizes per ASME B18.22.1. All ASTM A193 Grade B7 washers dimensions conform to applicable DIN, ISO, and ASME B18 standards.

Flat Washer Dimensions - Metric (DIN 125)

Size (M)Inner Ø (mm)Outer Ø (mm)Thickness (mm)
M66.4121.6
M88.4161.6
M1010.5202.0
M1213.0242.5
M1617.0303.0
M2021.0373.0
M2425.0444.0
M3031.0564.0
M3637.0665.0
M4243.0786.0
M4849.0926.0
M5657.01058.0
M6465.01158.0
M7273.013010.0
M8081.014010.0
M100101.018012.0

Dimensional & Material Standards

StandardCoversType
DIN 125Flat washersMetric
DIN 127Spring lock washersMetric
DIN 7989Structural washersMetric
ASME B18.22.1Plain & lock washersInch
ASTM F436Hardened washersInch/Metric
ASTM A194Washer for nutsInch/Metric
Material StandardRequirement
ASTM A193 B7Alloy steel, quenched & tempered
ASTM F436Hardened steel washers
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

ASTM A193 Grade B7 Chemical Composition

ASTM A193 Grade B7 Washers 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 B7

ElementComposition (%)
Carbon (C)0.37-0.49
Manganese (Mn)0.65-1.10
Phosphorus (P)0.035 max
Sulfur (S)0.040 max
Silicon (Si)0.15-0.35
Chromium (Cr)0.75-1.20
Molybdenum (Mo)0.15-0.25
Nickel (Ni)0.25 max
Copper (Cu)0.25 max
? All heats spectro-tested and certified to ASTM A193 B7. Full chemical traceability provided.

Why ASTM A193 Grade B7 Alloy Composition Matters for Washers

Cr-Mo Alloy — High Strength & Hardness
Chromium and molybdenum additions provide the high tensile strength and hardness required for washers to resist embedding and maintain preload under heavy bolted joints.
Low Phosphorus & Sulfur — Improved Toughness
Strict limits on phosphorus and sulfur ensure toughness and ductility, reducing the risk of brittle fracture in cyclic or impact-loaded assemblies.
Silicon — Enhanced Tempering Response
Silicon content improves the steel’s response to heat treatment, ensuring uniform hardness and mechanical properties across large washer batches.

Fastener Performance

ASTM A193 Grade B7 Washers Mechanical Properties & Hardness Reference

The table below lists mechanical properties and hardness reference for ASTM A193 Grade B7 Washers per ASTM. ASTM A193 Grade B7 washers achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Washer SizeRecommended Hardness (HRC)Max Load (kN)
M1238-4545
M1638-4580
M2038-45125
M2438-45180
M3038-45290
M3638-45410
M4238-45570
M4838-45760
?? Washer hardness must match or exceed nut/bolt hardness for optimal load distribution. Use only certified B7 washers with B7 bolts and nuts.

Industry Applications

ASTM A193 Grade B7 Washers Applications — Industries & End Uses

ASTM A193 Grade B7 Washers 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 B7 washers are specified for use with B7 stud bolts and nuts in ASME B16.5/B16.47 flange assemblies, wellhead equipment, and pressure vessel manways. Their high hardness prevents embedding and maintains gasket compression in high-pressure, high-temperature oil & gas service.
Used in reactor closures, heat exchanger channel covers, and process piping joints where B7 bolting is required. Washers ensure even load distribution and prevent galling or surface damage to flanges and nuts during thermal cycling.
B7 washers are installed in steam turbine casings, HRSG ducting, and boiler manways to maintain bolt preload and prevent joint relaxation under cyclic thermal loads. Suitable for both fossil and combined cycle plants.
Employed in structural bolted joints, anchor assemblies, and heavy machinery where high-strength B7 bolts are used. Washers prevent bolt head/nut embedding and maintain joint integrity under dynamic loads.

ASTM A193 Grade B7 Washers Standards & International Certifications

ASTM A193 Grade B7 Washers 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 125A DIN 126 DIN 127 DIN 128 DIN 433 DIN 434 DIN 436 DIN 440 DIN 6796 DIN 6797 DIN 9021 ISO 7089 ISO 7090 ISO 7091 ISO 7092 ISO 7093 ISO 7094 ASME B18.21.1 EN ISO 7089 BS 4320 IS 5372 IS 1367
Certifications
ISO 9001:2015PED 2014/68/EUNABL LabMTC 3.1 / 3.2

Buy ASTM A193 Grade B7 Washers from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified ASTM A193 Grade B7 Washers — 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 B7 Washers — Frequently Asked Questions

Browse expert answers to common questions about ASTM A193 Grade B7 Washers 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 B7 washers selection and pricing.
ASTM A193 Grade B7 washers are typically supplied to ASTM F436 (hardened steel washers), DIN 125 (flat), DIN 127 (spring), DIN 7989 (structural), and ASME B18.22.1 (inch plain and lock washers). For flange assemblies, ASTM A194 covers compatible nuts and washers. Always match washer hardness and dimensions to the bolt/nut standard for optimal performance.
Yes, ASTM A193 Grade B7 washers can be supplied with hot dip galvanized, zinc plated, or phosphate coatings for enhanced corrosion resistance. When using galvanized washers, ensure compatibility with galvanized B7 bolts and nuts to avoid hydrogen embrittlement and maintain joint integrity.
ASTM A193 Grade B7 washers are suitable for continuous service up to 450°C (840°F), matching the temperature limits of B7 bolts and nuts. For higher temperatures, consider ASTM A193 Grade B16 or stainless steel washers. Always verify application temperature and consult engineering guidelines.
No formal MOQ for standard sizes (M12-M36) held in stock – we supply from single pieces for urgent maintenance. Custom sizes, coatings, or large diameter washers may require a minimum order of 10 kg. Quantity price breaks are available at 100 pcs, 500 pcs, and 1000 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
  • 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