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ASTM A193 Grade B8 Screws Manufacturer & Exporter in India

Explore ASTM A193 Grade B8 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 ASTM A193 Grade B8 Screws?

ASTM A193 Grade B8 screws are high-performance fasteners manufactured from austenitic stainless steel, specifically Type 304 (UNS S30400), and are designed for use in high-temperature and high-pressure service. These screws are solution-annealed and strain-hardened to achieve the required mechanical properties, making them ideal for critical bolted joints in petrochemical, power generation, and process industries.

Grade B8 screws offer excellent resistance to corrosion, oxidation, and scaling at elevated temperatures. They are widely specified for pressure vessel flanges, heat exchangers, and piping systems where both strength and corrosion resistance are essential. All fasteners are produced in accordance with ASTM A193 and supplied with full traceability and certification.

Quick Specifications

MaterialStainless Steel 304
UNS NumberS30400
DIN Number1.4301
Material StandardASTM A193 Grade B8
Screw Standard (Metric)DIN 912 / DIN 933 / ISO 4762
Screw Standard (Inch)ASME B18.2.1 / B18.3
Thread FormISO Metric / UNC / UNF
Diameter RangeM6-M64 / ¼"-2½"
Tensile Strength515 MPa (75 ksi) min
Yield Strength205 MPa (30 ksi) min
HardnessMax 223 HB / 95 HRB
? All material certified by NABL-accredited laboratory. PMI and IGC test 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 Nuts, 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 Nuts
ASTM A193 Grade B8 Washers
ASTM A193 Grade B8 Studs
ASTM A193 Grade B8 Threaded Rods

Technical Data

ASTM A193 Grade B8 Screws Dimensions, Sizes & Thread Standards

ASTM A193 Grade B8 Screws are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 912 (socket head), DIN 933 (hex head full thread), ISO 4762, and ASME B18.2.1. Custom lengths available in 5mm increments. Inch dimensions per ASME B18.3 and B18.2.1.

Hex & Socket Head Screw Dimensions - Metric (DIN 912 / DIN 933 / ISO 4762)

Size (M)Pitch (mm)A/F (mm)Head Ht (mm)Min L (mm)Max L (mm)
M61.0106.010120
M81.25138.012150
M101.51710.016200
M121.751912.020250
M162.02416.025300
M202.53020.030350
M243.03624.040400
M303.54630.050500
M364.05536.060600
M424.56542.080700
M485.07548.0100800
M565.58556.0120900
M646.09564.01401000

Dimensional & Material Standards

StandardCoversThread
DIN 912Socket head cap screwsMetric
DIN 933Hex head screws, full threadMetric
ISO 4762Socket head screwsMetric
ASME B18.2.1Hex cap screwsUNC/UNF
ASME B18.3Socket head cap screwsUNC/UNF
Material StandardRequirement
ASTM A193Grade B8, Type 304
ASTM A194Companion 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 Screws 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 Grade B8 (Type 304)

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
Nitrogen (N)0.10 max
Iron (Fe)Balance
? All heats verified by NABL-accredited spectrometry. PMI and IGC test available on request.

Why ASTM A193 Grade B8 Alloy Composition Matters for Screws

Cr (18–20%) — Corrosion Resistance
High chromium content forms a passive oxide layer, giving ASTM A193 Grade B8 screws excellent resistance to atmospheric corrosion, most oxidizing acids, and chloride environments.
Ni (8–11%) — Austenitic Structure
Nickel stabilizes the austenitic structure, ensuring ductility and toughness even at cryogenic temperatures. This makes B8 screws suitable for both high and low temperature service.
Low Carbon — Intergranular Corrosion Resistance
Low carbon content minimizes carbide precipitation during welding, reducing the risk of intergranular corrosion and ensuring long-term reliability in process piping and pressure vessels.

Fastener Performance

ASTM A193 Grade B8 Screws Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for ASTM A193 Grade B8 Screws per ASTM. ASTM A193 Grade B8 screws achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Screw SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M12705628
M1617013657
M2034027289
M24590472128
M301200960206
M3621001680298
M4233002640410
M4848003840550
?? Anti-galling: Use molybdenum-based or PTFE anti-seize. Lubricated values assume K=0.16. Avoid dry assembly for large diameter stainless screws to prevent thread galling.

Industry Applications

ASTM A193 Grade B8 Screws Applications — Industries & End Uses

ASTM A193 Grade B8 Screws 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 screws are widely used for bolting pressure vessel flanges, heat exchanger covers, and reactor closures in refineries and chemical plants. Their corrosion resistance and high-temperature stability make them ideal for process piping and equipment exposed to aggressive media.
Used for turbine casing assembly, boiler manways, and HRSG ductwork, B8 screws provide reliable fastening in high-temperature steam and condensate environments, resisting scaling and oxidation up to 870°C.
Hex and socket head screws for pump assemblies, filter housings, and piping flanges in desalination and water treatment plants, where resistance to chlorides and oxidizing chemicals is essential for long-term service.
B8 screws are specified for hygienic equipment, pressure vessels, and piping in food and beverage plants due to their non-reactive, easy-to-clean surface and compliance with sanitary standards.

ASTM A193 Grade B8 Screws Standards & International Certifications

ASTM A193 Grade B8 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, dimensional inspection report, and proof load test records — available on request for all orders.
Standards
DIN 84 DIN 85 DIN 912 DIN 913 DIN 914 DIN 915 DIN 916 DIN 6912 DIN 7984 DIN 7985 DIN 7991 DIN 965 ISO 4762 ISO 10642 ISO 14579 ASME B18.3 ASME B18.6.3 EN ISO 4762 IS 1363 IS 1367 SAE J933 SAE J1199
Certifications
ISO 9001:2015NABL LabPED 2014/68/EUMTC 3.1 / 3.2

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

Partner with RealBolt — India’s leading manufacturer of certified ASTM A193 Grade B8 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

ASTM A193 Grade B8 Screws — Frequently Asked Questions

Browse expert answers to common questions about ASTM A193 Grade B8 Screws 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 screws selection and pricing.
ASTM A193 Grade B8 screws are available to DIN 912 (socket head), DIN 933 (hex head full thread), ISO 4762, and ASME B18.2.1/B18.3 (inch hex and socket). Custom thread forms (BSW, BSF, Whitworth) and special lengths can be supplied on request with short lead times.
Use molybdenum-based or PTFE anti-seize compound (such as Molykote 1000 or Loctite LB 8014) to prevent galling and seizing. Apply to threads and bearing surfaces. Avoid copper-based anti-seize on stainless steel to prevent galvanic corrosion. Lubricated torque values should be used for assembly.
Yes – ASTM A193 Grade B8 screws are rated for continuous service up to 870°C (1600°F) and maintain their mechanical properties at elevated temperatures. They are commonly used in boilers, heat exchangers, and steam piping in power and process plants.
No formal MOQ for standard sizes (M8-M36) held ex-stock – we supply from single pieces for urgent maintenance. Custom sizes or non-standard threads may require a 10 kg minimum. Quantity price breaks are available 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
  • 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