Hex Nuts Manufacturer & Global Supplier

ASME B18.2.2, ASTM A194, ISO 4032 & DIN 934 Standard and Heavy Hex Nuts Engineered in Exotic Nickel Superalloys, Duplex & Titanium

ISO 9001:2015Certified quality management
PED 2014/68/EUApproved by TUV Rheinland
EN 10204 3.1 / 3.2Heat-number traceability
Since 2010Exporting worldwide
Technical Overview

Precision Engineered Hexagonal Nuts for Critical Flange Joints

TorqBolt Inc. specializes in the manufacturing of regular hex nuts, heavy hex nuts, jam nuts, and high-integrity lock nuts crafted for aggressive industrial environments. Mated with our studs and hex bolts across oil & gas, chemical processing, offshore installations, and marine systems, our nuts are produced using precise hot forging, cold heading, and bar-stock CNC turning.

To eliminate galling and catastrophic thread stripping under severe tension, our hex nuts undergo precise pitch verification and mandatory proof-load testing per ASTM F606 and ISO 898-2. Thread tolerances are tightly calibrated to ASME B1.1 Class 2B/3B and ISO 965 Class 6H/4H6H.

Diameter Range
Metric: M6 to M100 | Imperial: 1/4" to 4" (Custom sizes up to 6" on request)
Manufacturing Codes
ASME B18.2.2, ASTM A194, ISO 4032, ISO 4033, ISO 4035, DIN 934, DIN 936, DIN 6915, BS 1768, BS 3692
Thread Profiles
UNC, UNF, 8UN, Metric Coarse, Metric Fine, BSW, Acme (Class 2B, 3B, 6H, 4H6H)
Quality Certification
EN 10204 Type 3.1 & Type 3.2 (Witnessed by TUV, DNV, BV, Lloyd's, SGS), NACE MR0175 / ISO 15156
Precision Heavy Hex Nut in High Nickel Alloy
Nut Configurations

Comprehensive Nut Styles & Standards

TorqBolt engineers standard and custom hexagonal nut profiles to match project load, vibration, and dimensional clearances.

Heavy Hex Nuts

Engineered with increased across-flats and height dimensions (~1.0×D). Designed to develop full tensile proof loads of ASTM A193/A320 studs on ASME B16.5 and B16.47 pressure flanges without thread dilation.

  • ASME B18.2.2 Heavy Pattern
  • ASTM A194 Grades 2H, 7, 8, 8M, 8T
  • ISO 4033 & DIN 6915 High Strength
  • High proof-load proof rating

Finished Regular Hex Nuts

Standard profile (~0.875×D) suitable for structural frameworks, general mechanical assemblies, and non-pressure boundary fixings across industrial plants.

  • ASME B18.2.2 Regular Series
  • ISO 4032 / DIN 934 General Purpose
  • BS 1768 & BS 3692 Unified / Metric
  • Available in full alloy range

Thin / Jam Hex Nuts

Reduced height configuration (~0.5×D) utilized as secondary jam locknuts jammed against primary heavy nuts, or where radial clearances restrict joint thickness.

  • ASME B18.2.2 Jam Pattern
  • ISO 4035 & DIN 936 Low Profile
  • Prevents back-off without lock washers
  • Machined from precision drawn bar

Prevailing Torque Lock Nuts

All-metal distorted-thread style (DIN 980 / ISO 7042) and non-metallic insert lock nuts engineered for cyclic vibration, high shock loads, and high-temperature service.

  • DIN 980 V / ISO 7042 All-Metal
  • Nylon Ring Insert (Nyloc) Style
  • ASME B18.16.6 Top Lock Formats
  • Excellent prevailing torque retention

Flange Serrated Hex Nuts

Integrated circular washer face distributes clamping pressure over a larger surface area while under-head serrations bite into mating faces to prevent dynamic loosening.

  • DIN 6923 / ISO 4161 Flange Pattern
  • Integral washer face eliminates separate washer
  • Anti-vibration ratcheting mechanism
  • Ideal for automated assembly lines

Coupling & Slotted / Castle Nuts

Elongated coupling nuts for connecting threaded bars together, and castle/slotted nuts (DIN 935) drilled to receive cotter pins for positive safety locking.

  • DIN 6334 Coupling Nuts
  • ASME B18.2.2 Extended Coupling
  • DIN 935 / ISO 7035 Slotted Castle Nuts
  • Full length internal thread engagement
Metallurgical Excellence

Exotic Alloys & Corrosion-Resistant Grades

TorqBolt stocks mill-certified round bars and billets to forge and machine hex nuts across high-temperature superalloys, seawater-resistant metals, and sour-gas compatible metallurgies.

Hex Nut Materials & ASTM Specifications
Alloy Family Grade / UNS Applicable Nut Standards Key Performance Advantages Target Applications
Nickel Superalloys Inconel 625 (N06625)
Inconel 718 (N07718)
Incoloy 825 (N08825)		 ASTM B637 / ASTM B446
ASTM A194 Gr. 718 / 625		 High yield strength above 650°C, extreme pitting resistance, NACE sour service compliance Subsea wellheads, gas turbine exhaust, downhole completions
Duplex Stainless Duplex 2205 (S32205)
Super Duplex 2507 (S32750)
Zeron 100 (S32760)		 ASTM A479 / A182 F51 / F53 / F55
ASTM A194 Gr. 8M mod		 PREN > 42, twice the mechanical yield strength of austenitic 316L, chloride SCC immunity Seawater cooling loops, desalination plants, offshore risers
Hastelloy Alloys Hastelloy C276 (N10276)
Hastelloy C22 (N06022)
Hastelloy B2 (N10665)		 ASTM B574 / ASME SB574
ASTM F467		 Exceptional resistance to hot contaminated mineral acids, wet chlorine, and hypochlorites Flue-gas scrubbers, chemical reactors, pickling vessels
Monel & Cu-Ni Monel 400 (N04400)
Monel K500 (N05500)
Cupronickel 70/30 & 90/10		 ASTM B164 / ASTM F467
ASTM B151		 Immunity to rapid biofouling, exceptional resistance to flowing seawater and hydrofluoric acid Marine propeller hardware, submarine hulls, HF alkylation units
Titanium Grade 2 (R50400)
Grade 5 Ti-6Al-4V (R56400)		 ASTM B348 / ASTM F467 High strength-to-weight ratio, total immunity to ambient seawater corrosion Aerospace airframes, motorsport suspensions, subsea sonar housings
Austenitic Stainless AISI 316L (S31603)
AISI 317L (S31703)
AISI 321 / 347 / 904L		 ASTM A194 Gr. 8 / 8M / 8T / 8C
ISO 3506-2 A2 / A4		 Cost-effective general corrosion resistance, cryogenic toughness down to -196°C LNG cryogenic storage, food processing, architectural facades
High-Strength Steels 17-4 PH (S17400)
A286 (S66286)
Nitronic 50 / 60		 ASTM A564 Gr. 630
ASTM A453 Gr. 660		 Age-hardenable high tensile properties combined with galling resistance High-pressure valves, pump drive shafts, aerospace fasteners
Surface Protection

Anti-Corrosion Coatings & Anti-Galling Platings

In aggressive marine and petrochemical services, precision nut platings prevent galvanic cell creation, lower makeup friction, and eliminate thread galling during high-torque tightening.

PTFE Fluoropolymer (Xylan®)

Provides a low coefficient of friction (0.06 to 0.08), ensuring predictable torque-tension transformation during makeup. Outstanding resistance to harsh offshore salt spray and chemical washdowns.

Hot Dip Galvanizing (ASTM A153)

Heavy sacrificial zinc barrier coating applied via molten bath. Internal nut threads are tapped oversize post-galvanizing in accordance with ASTM A563 to ensure clean fitment.

Zinc-Nickel & Electro-Zinc

Precision electroplated zinc-nickel (12-15% Ni) delivering over 1,000 hours salt-spray resistance without red rust, complying with modern automotive and offshore specifications.

Silver & Nickel Plating

High-temperature electrolytic silver plating applied to superalloy hex nuts (Inconel, A286) to provide a solid anti-seize lubricating film in gas turbines operating over 500°C.

Dacromet & Geomet

Non-electrolytic zinc and aluminium flake coatings delivering thin-film corrosion shielding without the hazard of hydrogen embrittlement on high-hardness structural nuts.

Chemical Passivation

Citric or nitric acid chemical passivation per ASTM A967 to dissolve tramp iron particles and promote a robust chromium oxide passive film on stainless and duplex alloys.

Available Alloy Portfolio

Complete Material Grades Manufactured

Explore the full metallurgical matrix supported across our CNC machining and hot forging facilities.

Inconel 625 Hex Nuts Inconel 718 Hex Nuts Inconel 600 Hex Nuts Inconel X750 Hex Nuts Hastelloy C276 Hex Nuts Hastelloy C22 Hex Nuts Hastelloy B2 Hex Nuts Monel 400 Hex Nuts Monel K500 Hex Nuts Duplex 2205 Hex Nuts Super Duplex 2507 Hex Nuts Zeron 100 Hex Nuts Titanium Grade 2 Hex Nuts Titanium Grade 5 Hex Nuts AISI 316L Hex Nuts AISI 304L Hex Nuts AISI 317L Hex Nuts AISI 321H Hex Nuts AISI 347H Hex Nuts AISI 904L Hex Nuts 254 SMO Hex Nuts 17-4 PH Hex Nuts 15-5 PH Hex Nuts A286 Stainless Hex Nuts Nitronic 50 Hex Nuts Nitronic 60 Hex Nuts Alloy 20 Hex Nuts Waspaloy Hex Nuts Nimonic 80A Hex Nuts Cupronickel 70/30 Hex Nuts Cupronickel 90/10 Hex Nuts Aluminium 7075 Hex Nuts Phosphor Bronze Hex Nuts Silicon Bronze Hex Nuts

Need Certified Hex Nuts in Special Alloys?

TorqBolt delivers custom and standard heavy hex nuts with rapid turnaround, third-party inspection, and full EN 10204 3.1/3.2 test certificates. Download our full technical catalog or request an engineering quote today.

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Technical QA

Frequently Asked Questions — Hex Nuts

What is the difference between a Regular Hex Nut and a Heavy Hex Nut?
A Heavy Hex Nut (per ASME B18.2.2 or DIN 6915) is slightly wider across the flats and thicker in height compared to a finished regular hex nut of the same nominal thread diameter. This expanded geometry provides greater thread engagement area and load distribution, allowing heavy hex nuts to develop the full tensile strength of high-strength structural studs (such as ASTM A193 B7, B8M, or high nickel superalloys) without stripping under high hydraulic tensioning forces.
How do you prevent thread galling on stainless and nickel alloy hex nuts?
Stainless steel, titanium, and nickel alloys develop protective oxide films that can cold-weld under friction, leading to severe galling. TorqBolt prevents galling through precision thread flank machining, strict control of mating hardness levels (typically keeping nuts slightly harder or using differing alloys such as Nitronic 60), and by applying dry-film lubricants, PTFE (Xylan) coatings, or electrolytic silver/cadmium platings.
What quality documents and inspection test plans (ITP) are provided?
Every shipment is accompanied by an EN 10204 Type 3.1 Inspection Certificate documenting original melt heat chemistry, proof-load results per ASTM F606 / ISO 898-2, hardness tests (Rockwell/Brinell), and dimensional inspection. When required, EN 10204 3.2 witnessed inspection is performed in conjunction with independent agencies such as TUV Rheinland, Bureau Veritas, DNV, Lloyd's Register, or SGS.
Can you manufacture non-standard or bespoke drawing-based hex nuts?
Yes. In addition to standard metric and imperial tooling, our Rajkot plant operates multi-axis CNC turn-mill centres and dedicated hot forging presses capable of producing non-standard pitch threads (such as ACME or fine pitch), collar nuts, spherical face nuts, extended coupling nuts, and castle nuts strictly to customer engineering drawings.
What are typical production lead times for specialty alloy nuts?
Standard inventory grades (316L, Duplex 2205, Inconel 625/718) are maintained in semi-finished blanks and can be dispatched within 1 to 2 weeks. Custom forged batches or exotic grades (Hastelloy B2, Monel K500, Titanium Gr. 5) typically require 3 to 5 weeks including all mechanical testing and coating processes.
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