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AISI 4340 Nuts Manufacturer & Exporter in India

Explore AISI 4340 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 AISI 4340 Nuts?

AISI 4340 nuts are high-strength alloy steel fasteners manufactured from chromium-nickel-molybdenum steel conforming to ASTM A194 Grade 7 or ASTM A563 Grade DH. This alloy is renowned for its exceptional toughness, fatigue resistance, and ability to maintain high mechanical properties after heat treatment. AISI 4340 nuts are typically quenched and tempered to achieve a minimum tensile strength of 930 MPa, making them ideal for critical bolted joints in demanding environments.

With a balanced alloy composition, AISI 4340 nuts offer superior performance in high-stress, high-temperature, and impact-prone applications such as pressure vessels, heavy machinery, and oilfield equipment. They are widely specified for use with high-strength bolts and studs in the energy, aerospace, and defense sectors.

Quick Specifications

MaterialAISI 4340 Alloy Steel
UNS NumberG43400
DIN Number1.6582
Material StandardASTM A322 / ASTM A29
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 Strength930 MPa (135 ksi) min
Yield Strength785 MPa (114 ksi) min
Hardness24-36 HRC
? All material certified by NABL-accredited laboratory. Heat treatment and mechanical test reports available on request.

Complete the Fastener Set

Other AISI 4340 Fastener Products Available from RealBolt

RealBolt also manufactures the complete AISI 4340 fastener range from certified alloy steel bar stock, including AISI 4340 Bolts, AISI 4340 Screws, AISI 4340 Washers, AISI 4340 Studs, and AISI 4340 Threaded Rods. All AISI 4340 fastener types are produced to ASTM with full EN 10204 MTC 3.1/3.2 documentation.
AISI 4340 Bolts
AISI 4340 Screws
AISI 4340 Washers
AISI 4340 Studs
AISI 4340 Threaded Rods

Technical Data

AISI 4340 Nuts Dimensions, Sizes & Thread Standards

AISI 4340 Nuts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 934 (hex nut) / ISO 4032. Custom thread pitches and heavy hex patterns available. Inch dimensions per ASME B18.2.2. All AISI 4340 nuts dimensions are verified against applicable DIN, ISO, and ASME B18 standards before

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

Size (M)Pitch (mm)A/F (mm)Height (mm)Min L (mm)Max L (mm)
M61.0105.0510
M81.25136.5612
M101.5178.0816
M121.751910.01020
M162.02413.01326
M202.53016.01632
M243.03619.01938
M303.54624.02448
M364.05529.02958
M424.56534.03468
M485.07538.03876
M565.58545.04590
M646.09551.051102
M726.010557.057114
M806.011563.063126
M1006.014580.080160

Dimensional & Material Standards

StandardCoversThread
DIN 934Hex nutsMetric
ISO 4032Hex nutsMetric
ASME B18.2.2Hex & heavy hex nutsUNC/UNF
ASTM A194 Gr. 7Alloy steel nutsUNC/UNF
ASTM A563 Gr. DHHeavy hex nutsUNC/UNF
Material StandardRequirement
ASTM A322Bar/rod - AISI 4340
ASTM A29General alloy steel
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

AISI 4340 Chemical Composition

AISI 4340 Nuts are produced from medium-carbon or alloy steel with carbon (0.15–0.55%), chromium, manganese, and boron additions controlled per ASTM and ISO 898-1. Carbon content and quench-and-temper heat treatment are the primary strength levers, delivering proof loads from 580 MPa (Class 8.8) to 970 MPa (Class 12.9).

Chemical Composition per ASTM A322 / A29

ElementComposition (%)
Carbon (C)0.38-0.43
Manganese (Mn)0.60-0.80
Silicon (Si)0.15-0.30
Nickel (Ni)1.65-2.00
Chromium (Cr)0.70-0.90
Molybdenum (Mo)0.20-0.30
Phosphorus (P)0.035 max
Sulfur (S)0.040 max
Iron (Fe)Balance
? All heats verified by NABL-accredited spectrometry. Full chemical test reports available.

Why AISI 4340 Alloy Composition Matters for Nuts

Ni (1.65–2.00%) — Toughness & Impact Strength
Nickel content in AISI 4340 provides outstanding toughness and resistance to brittle fracture, making these nuts ideal for dynamic and impact-loaded assemblies.
Cr & Mo — Hardenability & Strength
Chromium and molybdenum enhance hardenability and high-temperature strength, ensuring AISI 4340 nuts maintain preload and resist relaxation in severe service.
Low P & S — Clean Steel for Fatigue Life
Strict control of phosphorus and sulfur ensures high fatigue life and resistance to stress corrosion cracking, critical for safety-related bolted joints.

Fastener Performance

AISI 4340 Nuts Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for AISI 4340 Nuts per ASTM. AISI 4340 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)
M1211040
M1627080
M20540125
M24950180
M301950295
M363400430
M425200600
M487600800
?? Lubrication: Use molybdenum disulfide or graphite-based anti-seize for optimal preload and to prevent galling. Torque values assume K=0.18.

Industry Applications

AISI 4340 Nuts Applications — Industries & End Uses

AISI 4340 Nuts from RealBolt are specified across structural engineering, automotive, machinery, and pressure vessels where very good corrosion resistance and 620 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples. Select an industry below to see specific AISI 4340 nuts application details and RealBolt stock availability.
AISI 4340 nuts are specified for high-pressure vessel closures, wellhead assemblies, and BOP stacks where high strength and impact resistance are critical. Used with ASTM A193 B7/B16 studs in sour and non-sour service.
Heavy hex nuts for mining equipment, dragline assemblies, and mill liners where shock loading and fatigue are common. AISI 4340’s toughness ensures reliable performance in harsh environments.
AISI 4340 nuts are used in landing gear, engine mounts, and structural joints requiring high strength-to-weight ratio and resistance to dynamic loads. Supplied to AMS 6415 and MIL-S-5000 standards.
Nuts for steam turbine casings, HRSG flange joints, and boiler manways where elevated temperature strength and relaxation resistance are required. Suitable for both fossil and nuclear applications.

AISI 4340 Nuts Standards & International Certifications

AISI 4340 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 9001:2015NABL LabPED 2014/68/EUMTC 3.1 / 3.2

Buy AISI 4340 Nuts from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified AISI 4340 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.
022-6743-7972
+91 90226 36025
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Answers for Buyers

AISI 4340 Nuts — Frequently Asked Questions

Browse expert answers to common questions about AISI 4340 Nuts from RealBolt — covering property class, tensile and proof load, galvanizing embrittlement risk, surface finishes, and dimensional certification. Contact our technical team directly for project-specific guidance on AISI 4340 nuts selection and pricing.
AISI 4340 nuts are available to DIN 934 (metric hex), ISO 4032, and ASME B18.2.2 (inch hex and heavy hex). For high-pressure and high-temperature service, ASTM A194 Grade 7 and ASTM A563 Grade DH are commonly specified. Custom thread forms and heavy hex patterns are available on request.
Molybdenum disulfide or graphite-based anti-seize is recommended for AISI 4340 nuts, especially in high-load or high-temperature applications. This prevents galling and ensures consistent preload. Avoid copper-based anti-seize in environments prone to galvanic corrosion.
Yes – AISI 4340 nuts, when properly heat treated, maintain impact toughness down to -46°C and are suitable for low-temperature bolted joints in pressure vessels, pipelines, and LNG applications. Always specify Charpy V-notch requirements for critical service.
No MOQ for standard sizes (M12-M36) in stock – single pieces can be supplied for urgent needs. Custom sizes or special coatings may require a 10 kg minimum. Bulk 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