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Heavy Hex Bolts

Manufacturer, Exporter & Supplier of Heavy Hex Bolts

Heavy Hex Bolts for Structural & Industrial Applications (ASTM, DIN & ISO Standards)

Heavy hex bolts are high-strength fastening components engineered for critical structural and industrial assemblies where standard hex bolts are not sufficient. Characterized by a larger head size and increased bearing surface, these bolts are widely used in steel structures, bridges, power plants, oil & gas facilities, and heavy machinery installations. Manufactured in compliance with standards such as ASTM A325, ASTM A490, DIN 6914, and ISO specifications, they ensure consistent performance under high axial loads and vibration-intensive environments.

Cupro Nickel Heavy Hex Bolts Manufacturer
Inconel Heavy Hex Bolts Supplier
Stainless Steel Heavy Hex Bolts Exporter

Made from carbon steel, alloy steel, and stainless steel grades like SS 304 and SS 316, heavy hex bolts deliver superior tensile strength, controlled elongation, and enhanced torque resistance. Their geometry improves load distribution, reducing the risk of joint failure in critical assemblies.

KK Fasteners supplies heavy hex bolts to global EPC contractors and industrial OEMs, ensuring full material traceability, dimensional accuracy, and compliance with international bolting standards for safety-critical applications.

Heavy Hex Bolts Technical Specifications

ParameterSpecification
Material GradesCarbon Steel (EN8, EN9), Alloy Steel, Stainless Steel SS 304 / SS 316
Strength Grades8.8, 10.9, 12.9, ASTM A325, ASTM A490
Size RangeM12 – M36 / 1/2” – 1.5”
Thread TypeMetric (ISO), UNC, UNF
StandardsDIN 6914, ASTM A325, ASTM A490, ISO 4014, ISO 4017
Finish OptionsBlack Oxide, Hot Dip Galvanized (HDG), Zinc Plated, PTFE Coated
Head TypeHeavy Hex Head
Tensile Strength800 MPa (8.8), 1000 MPa (10.9), 1200 MPa (12.9)

Heavy Hex Bolts Dimensions

Bolt Diameter D F C H
Body Diameter Width Across Flats Width Across Corners Height
Max Basic Max Min Max Min Basic Max Min
1⁄2 0.515 7⁄8 0.875 0.850 1.010 0.969 11⁄32 0.364 0.302
5⁄8 0.642 11⁄16 1.062 1.031 1.227 1.175 27⁄64 0.444 0.378
3⁄4 0.768 11⁄4 1.250 1.212 1.443 1.383 1⁄2 0.524 0.455
7⁄8 0.895 17⁄16 1.438 1.394 1.660 1.589 37⁄64 0.604 0.531
1 1.022 15⁄8 1.625 1.575 1.876 1.796 43⁄64 0.700 0.591
11⁄8 1.149 113⁄16 1.812 1.756 2.093 2.002 3⁄4 0.780 0.658
11⁄4 1.277 2 2.00 1.938 2.309 2.209 27⁄32 0.876 0.749
13⁄8 1.404 23⁄16 2.188 2.119 2.526 2.416 29⁄32 0.940 0.810
11⁄2 1.531 23⁄8 2.375 2.300 2.742 2.622 1 1.036 0.902
15⁄8 1.658 29⁄16 2.562 2.481 2.959 2.829 13⁄32 1.116 0.978
13⁄4 1.785 23⁄4 2.750 2.662 3.175 3.035 15⁄32 1.196 1.054
17⁄8 1.912 215⁄16 2.938 2.844 3.392 3.242 11⁄4 1.276 1.130
2 2.039 31⁄8 3.125 3.025 3.608 3.449 111⁄32 1.388 1.175
21⁄4 2.305 31⁄2 3.500 3.388 4.041 3.862 11⁄2 1.548 1.327
21⁄2 2.559 37⁄8 3.875 3.750 4.474 4.275 121⁄32 1.708 1.479

Dimensions per ASME B18.2.1

Grades of Stainless Steel Heavy Hex Bolts

  • Stainless Steel 304 Heavy Hex Bolts
  • Stainless Steel 304L Heavy Hex Bolts
  • Stainless Steel 304H Heavy Hex Bolts
  • Stainless Steel 310 Heavy Hex Bolts
  • Stainless Steel 310S Heavy Hex Bolts
  • Stainless Steel 310H Heavy Hex Bolts
  • Stainless Steel 316 Heavy Hex Bolts
  • Stainless Steel 316L Heavy Hex Bolts
  • Stainless Steel 316Ti Heavy Hex Bolts
  • Stainless Steel 317 Heavy Hex Bolts
  • Stainless Steel 317L Heavy Hex Bolts
  • Stainless Steel 321 Heavy Hex Bolts
  • Stainless Steel 321H Heavy Hex Bolts
  • Stainless Steel 347 Heavy Hex Bolts
  • Stainless Steel 347H Heavy Hex Bolts
  • Stainless Steel 904L Heavy Hex Bolts
  • Stainless Steel 410 Heavy Hex Bolts
  • Stainless Steel 446 Heavy Hex Bolts
  • 17-4 PH Stainless Steel Heavy Hex Bolts
  • SMO 254 Heavy Hex Bolts
  • Alloy 20 Heavy Hex Bolts

Grades of Duplex & Super Duplex Steel Heavy Hex Bolts

  • UNS S32205 Heavy Hex Bolts
  • UNS S31803 Heavy Hex Bolts
  • UNS S32750 Heavy Hex Bolts
  • UNS S32760 Heavy Hex Bolts

Grades of Nickel Alloys Heavy Hex Bolts

  • Inconel 600 Heavy Hex Bolts
  • Inconel 601 Heavy Hex Bolts
  • Inconel 625 Heavy Hex Bolts
  • Inconel 718 Heavy Hex Bolts
  • Incoloy 800 Heavy Hex Bolts
  • Incoloy 825 Heavy Hex Bolts
  • Monel 400 Heavy Hex Bolts
  • Monel K500 Heavy Hex Bolts
  • Nickel 200 Heavy Hex Bolts
  • Nickel 201 Heavy Hex Bolts
  • Hastelloy C276 Heavy Hex Bolts
  • Hastelloy C22 Heavy Hex Bolts
  • Hastelloy B2 Heavy Hex Bolts
  • Hastelloy B3 Heavy Hex Bolts
  • Hastelloy X Heavy Hex Bolts

Grades of Titanium Heavy Hex Bolts

  • Titanium Grade 2 Heavy Hex Bolts
  • Titanium Grade 5 Heavy Hex Bolts

Grades of Tantalum Heavy Hex Bolts

  • UNS R05200 Heavy Hex Bolts
  • UNS R05252 Heavy Hex Bolts
  • UNS R05255 Heavy Hex Bolts
  • UNS R05400 Heavy Hex Bolts

Grades of Copper Heavy Hex Bolts

  • UNS C11000 Heavy Hex Bolts
  • UNS C10100 Heavy Hex Bolts
  • UNS C10200 Heavy Hex Bolts
  • UNS C12000 Heavy Hex Bolts
  • UNS C12200 Heavy Hex Bolts

Grades of Cupro Nickel Heavy Hex Bolts

  • CuNi 90/10 Heavy Hex Bolts
  • CuNi 70/30 Heavy Hex Bolts

Grades of Brass Carriage Heavy Hex Bolts

  • UNS C21000 Heavy Hex Bolts
  • UNS C22000 Heavy Hex Bolts
  • UNS C22600 Heavy Hex Bolts
  • UNS C23000 Heavy Hex Bolts
  • UNS C24000 Heavy Hex Bolts
  • UNS C26000 Heavy Hex Bolts
  • UNS C26800 Heavy Hex Bolts
  • UNS C27000 Heavy Hex Bolts
  • UNS C27200 Heavy Hex Bolts
  • UNS C28000 Heavy Hex Bolts
  • UNS C33000 Heavy Hex Bolts
  • UNS C33500 Heavy Hex Bolts
  • UNS C34000 Heavy Hex Bolts
  • UNS C34200 Heavy Hex Bolts
  • UNS C35300 Heavy Hex Bolts
  • UNS C35600 Heavy Hex Bolts

Grades of Aluminium Heavy Hex Bolts

  • Aluminium Alloy 1050 Heavy Hex Bolts
  • Aluminium Alloy 1060 Heavy Hex Bolts
  • Aluminium Alloy 1060 Heavy Hex Bolts
  • Aluminium Alloy 1070 Heavy Hex Bolts
  • Aluminium Alloy 1080 Heavy Hex Bolts
  • Aluminium Alloy 1100 Heavy Hex Bolts
  • Aluminium Alloy 1145 Heavy Hex Bolts
  • Aluminium Alloy 2011 Heavy Hex Bolts
  • Aluminium Alloy 2014 Heavy Hex Bolts
  • Aluminium Alloy 2017 Heavy Hex Bolts
  • Aluminium Alloy 2024 Heavy Hex Bolts
  • Aluminium Alloy 2090 Heavy Hex Bolts
  • Aluminium Alloy 3003 Heavy Hex Bolts
  • Aluminium Alloy 5052 Heavy Hex Bolts
  • Aluminium Alloy 5083 Heavy Hex Bolts
  • Aluminium Alloy 6061 Heavy Hex Bolts
  • Aluminium Alloy 6063 Heavy Hex Bolts
  • Aluminium Alloy 6066 Heavy Hex Bolts
  • Aluminium Alloy 6082 Heavy Hex Bolts
  • Aluminium Alloy 7050 Heavy Hex Bolts
  • Aluminium Alloy 7075 Heavy Hex Bolts

Grades of Carbon Steel Heavy Hex Bolts

  • Carbon Steel AISI 1018 Heavy Hex Bolts
  • Carbon Steel AISI 1020 Heavy Hex Bolts
  • Carbon Steel AISI 1040 Heavy Hex Bolts
  • Carbon Steel AISI 1045 Heavy Hex Bolts

Grades of Alloy Steel Heavy Hex Bolts

  • Alloy Steel AISI 4130 Heavy Hex Bolts
  • Alloy Steel AISI 4140 Heavy Hex Bolts
  • Alloy Steel AISI 4340 Heavy Hex Bolts
  • Alloy Steel AISI 8620 Heavy Hex Bolts
  • ASTM A193 Alloy Steel Gr B7 Heavy Hex Bolts
  • ASTM A193 Alloy Steel Gr B7M Heavy Hex Bolts
  • ASTM A320 Alloy Steel Gr L7 Heavy Hex Bolts
  • ASTM A320 Alloy Steel Gr L7M Heavy Hex Bolts
  • ASTM A320 Alloy Steel Gr L43 Heavy Hex Bolts
  • ASTM A194 Alloy Steel Gr 2H Heavy Hex Bolts
  • ASTM A194 Alloy Steel Gr 2HM Heavy Hex Bolts
  • ISO 898-1 Alloy Steel Gr 8.8 Heavy Hex Bolts
  • ISO 898-1 Alloy Steel Gr 10.9 Heavy Hex Bolts
  • ISO 898-1 Alloy Steel Gr 12.9 Heavy Hex Bolts

Grades of Silicon Bronze Heavy Hex Bolts

  • UNS C65100 Heavy Hex Bolts
  • UNS C65500 Heavy Hex Bolts
  • UNS C66100 Heavy Hex Bolts

Grades of Phosphor Bronze Heavy Hex Bolts

  • UNS C51000 Heavy Hex Bolts
  • UNS C51900 Heavy Hex Bolts
  • UNS C52100 Heavy Hex Bolts
  • UNS C54400 Heavy Hex Bolts

Grades of Zirconium Heavy Hex Bolts

  • UNS R60700 Heavy Hex Bolts
  • UNS R60702 Heavy Hex Bolts
  • UNS R60704 Heavy Hex Bolts
  • UNS R60705 Heavy Hex Bolts
  • UNS R60706 Heavy Hex Bolts

Grades of Beryllium Copper Heavy Hex Bolts

  • UNS C17200 Heavy Hex Bolts
  • UNS C17300 Heavy Hex Bolts
  • UNS C17500 Heavy Hex Bolts
  • UNS C17510 Heavy Hex Bolts

Grades of High Tensile Heavy Hex Bolts

  • Grade 8.8 Heavy Hex Bolts
  • Grade 10.9 Heavy Hex Bolts
  • Grade 12.9 Heavy Hex Bolts

Grades of Nimonic Heavy Hex Bolts

  • Nimonic Alloy 75 Heavy Hex Bolts
  • Nimonic Alloy 80a Heavy Hex Bolts
  • Nimonic Alloy 90 Heavy Hex Bolts
  • Nimonic Alloy 105 Heavy Hex Bolts
  • Nimonic Alloy 115 Heavy Hex Bolts
  • Nimonic Alloy 236 Heavy Hex Bolts

Grades of Nitronic Heavy Hex Bolts

  • Nitronic 50 Heavy Hex Bolts
  • Nitronic 60 Heavy Hex Bolts

Key Technical Features

  • High Load-Bearing Design: Engineered with an oversized hex head to increase bearing surface area, reducing stress concentration in structural joints.
  • High Tensile Strength Performance: Supports up to 1200 MPa tensile strength, making them suitable for dynamic and heavy-load structural assemblies.
  • Standardized Dimensional Accuracy: Manufactured within tight tolerances to ensure compatibility with ASTM, DIN, and ISO bolting systems.
  • Enhanced Torque Resistance: Optimized geometry minimizes thread stripping and ensures secure tightening under high torque conditions.
  • Corrosion Protection Options: Available in galvanized and stainless steel variants for resistance against marine, chemical, and outdoor environments.
  • Vibration Resistance Stability: Maintains preload integrity in vibrating machinery and steel frameworks, reducing loosening risk.
  • Interchangeable Global Standards: Designed for compatibility with international structural bolting assemblies used across EPC projects.
  • Precision Threading: Ensures smooth engagement and consistent load distribution across threaded joints.

Industry Applications

Heavy hex bolts are primarily used in structural and heavy engineering environments where joint integrity under extreme loads is critical.

  • Steel Structure Construction: Used in connecting beams, columns, and gusset plates in high-rise buildings and industrial sheds.
  • Bridge Engineering: Provides secure fastening in load-bearing steel joints subjected to dynamic traffic and wind loads.
  • Oil & Gas Refineries: Applied in pipelines, pressure vessels, and offshore platforms requiring high-strength bolting systems.
  • Power Generation Plants: Used in turbines, boilers, and structural frameworks exposed to thermal and mechanical stress.
  • Heavy Machinery Assembly: Secures critical machine bases and rotating equipment in industrial production lines.
  • Railway Infrastructure: Used in track assemblies, fastening systems, and structural rail components.
  • Shipbuilding Industry: Ensures corrosion-resistant fastening in hull structures and onboard mechanical systems.

Manufacturing & Quality Assurance

Heavy hex bolts are manufactured using precision cold forging and hot forging techniques depending on material grade and strength class. Thread rolling processes ensure superior grain flow continuity, improving fatigue resistance. Heat treatment is applied to achieve required mechanical properties such as hardness and tensile strength.

Each batch undergoes strict quality control including dimensional inspection, tensile testing, hardness verification, and coating thickness evaluation. Traceability is maintained from raw material to finished product through batch coding systems. KK Fasteners follows ISO 9001-certified quality management systems, ensuring compliance with global structural fastening standards and customer-specific engineering requirements.

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Heavy Hex Bolts - FAQs

Heavy hex bolts are high-strength fasteners with a larger hexagonal head and wider bearing surface compared to standard hex bolts. They are designed for structural and industrial applications where higher load distribution, improved torque handling, and enhanced joint stability are required.

Heavy hex bolts are commonly manufactured from carbon steel, alloy steel, and stainless steel grades such as SS 304 and SS 316. Carbon and alloy steels provide high tensile strength, while stainless steel offers superior corrosion resistance in marine and chemical environments.

Heavy hex bolts are produced according to international standards such as ASTM A325, ASTM A490, DIN 6914, ISO 4014, and ISO 4017. These standards define dimensions, mechanical properties, and performance requirements for structural fastening applications.

They are widely used in structural steel construction, bridges, power plants, oil and gas installations, heavy machinery, and marine structures. Their design ensures secure fastening in high-load and vibration-prone environments.

A reliable manufacturer should provide ISO-certified production, full material traceability, compliance with ASTM/DIN standards, and in-house testing capabilities. KK Fasteners supports global buyers with consistent quality, documentation, and export-ready supply.

Heavy Hex Bolts - Export Destination

Heavy Hex Bolts Suppliers in North America
Antigua and Barbuda, Bahamas, Barbados, Belize, Canada, Costa Rica, Cuba, Dominica, Dominican Republic, El Salvador, Grenada, Guatemala, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, United States.
Heavy Hex Bolts Suppliers in South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Falkland Islands, French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay, Venezuela.
Heavy Hex Bolts Suppliers in Europe
Albania, Andorra, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic (Czechia), Denmark, Estonia, Finland, France, Germany, Greece, Holy See, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Moldova, Monaco, Montenegro, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Russia, San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, United Kingdom.
Heavy Hex Bolts Suppliers in Asia
Afghanistan, Armenia, Azerbaijan, Bahrain, Bangladesh, Bhutan, Brunei, Cambodia, Cyprus, Georgia, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kazakhstan, Kuwait, Kyrgyzstan, Laos, Lebanon, Malaysia, Maldives, Mongolia, Myanmar, Nepal, Oman, Pakistan, Palestine, Philippines, Qatar, Saudi Arabia, Singapore, South Korea, Sri Lanka, State of Palestine, Syria, Taiwan, Tajikistan, Thailand, Timor-Leste, Turkey, Turkmenistan, United Arab Emirates, Uzbekistan, Vietnam, Yemen.
Heavy Hex Bolts Suppliers in Australia
Australia, Fiji, Kiribati, Marshall Islands, Micronesia, Nauru, New Zealand, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu, Vanuatu.

Heavy hex bolts are critical components in structural safety and industrial reliability, where failure is not an option. With strict adherence to ASTM, DIN, and ISO standards, they ensure consistent performance in demanding environments. KK Fasteners supports global engineering and EPC projects with precision-manufactured bolting solutions backed by full quality traceability.

For technical specifications, bulk pricing, or custom manufacturing requirements, connect with the engineering team at KK Fasteners to request a quote or datasheet.

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