Stud Bolt India is an ISO 9001:2015 certified manufacturer and premier exporter of High Tensile Fasteners based in Mumbai, India. We engineer high-strength structural bolts, heavy hex nuts, stud bolts, socket cap screws, and hardened washers designed to withstand severe mechanical loads, high pressure, and fatigue stress across critical offshore, oil & gas, petrochemical, and heavy construction applications.
Our manufacturing plant utilizes advanced cold forging and precision hot forging technology combined with computer-controlled quenching and tempering heat treatment furnaces. Every high tensile fastener is produced in strict compliance with international engineering standards including ASTM, ASME, DIN, ISO, BS, and IS. We offer full material traceability with heat-number embossing and EN 10204 Type 3.1 Material Test Certificates (MTR) provided with all international export packages.
High Strength Fastener Product Portfolio
We stock and manufacture a comprehensive array of high tensile steel fasteners engineered for heavy-duty load-bearing assemblies:
High Tensile Stud Bolts
ASTM A193 B7 / B16 / A320 L7Fully threaded and double-end studs designed for high-pressure valve flanges, pressure vessels, and high-temperature boiler connections.
High Tensile Hex Bolts
ISO 4014 / DIN 931 / DIN 933Precision forged heavy hex bolts available in Property Classes 8.8, 10.9, and 12.9 with rolled threads for enhanced fatigue durability.
High Tensile Heavy Hex Nuts
ASTM A194 2H / 2HM / Grade 8 & 10Proof-load tested heavy hex nuts matched for high tensile stud assemblies, delivering anti-galling performance under high torque settings.
Socket Head Cap Screws
DIN 912 / ISO 4762 Grade 12.9High-strength Allen head socket cap screws engineered for compact machinery, tool manufacturing, and high-vibration equipment.
High Tensile Threaded Rods
DIN 975 / DIN 976 / ASTM A193Continuous threaded bars cut to custom engineering lengths, capable of maintaining clamping load in dynamic structural tie-rod systems.
Hardened Washers
ASTM F436 / DIN 6916 / DIN 125Quenched structural washers providing uniform load distribution and preventing bolt loosening under extreme stress.
Technical Specifications & Property Grade Standards
Our high tensile bolting components are produced from selected alloy steel stock (including 4140, 4140H, 4340, Cr-Mo steels) with full heat-treatment validation. Refer to the standard specification matrix below for global engineering procurement:
| Property Grade / Standard | Tensile Strength (Min) | Yield Strength (Min) | Hardness Range | Common Applications |
|---|---|---|---|---|
| Metric Class 8.8 (ISO 898-1) | 800 N/mm² (116,000 PSI) | 640 N/mm² | 22 to 32 HRC | Automotive framing, general structural steelwork, machinery assembly. |
| Metric Class 10.9 (ISO 898-1) | 1040 N/mm² (150,000 PSI) | 940 N/mm² | 32 to 39 HRC | Heavy construction equipment, engine blocks, high-load bolted joints. |
| Metric Class 12.9 (ISO 898-1) | 1220 N/mm² (176,000 PSI) | 1100 N/mm² | 39 to 44 HRC | Precision tooling, hydraulic pumps, turbine housings, high-stress dies. |
| ASTM A193 Grade B7 | 125 ksi (860 MPa) | 105 ksi (720 MPa) | 32 HRC Max | Refinery flange bolting, high-temperature boilers, pressure vessels. |
| ASTM A193 Grade B16 | 125 ksi (860 MPa) | 105 ksi (720 MPa) | 35 HRC Max | Ultra high-temperature steam turbine headers, power plant piping. |
| ASTM A320 Grade L7 | 125 ksi (860 MPa) | 105 ksi (720 MPa) | Charpy V-Notch Tested | Low-temperature cryogenic valves, subsea gas transport systems. |
Quality Assurance & Testing Rigor
At Stud Bolt India, zero-defect quality control is embedded in every stage of production. Incoming steel billets undergo Positive Material Identification (PMI) chemical verification. Following forging and CNC thread rolling, finished batches pass strict laboratory testing:
Chemical Composition & PMI
Spectrographic alloy verification ensuring correct Carbon, Manganese, Chromium, Molybdenum content.
Mechanical Tensile & Proof Load
Destructive pull-testing to verify ultimate yield strength, elongation, and reduction of area.
Hardness & Microstructure
Rockwell C (HRC) and Brinell hardness testing following controlled oil quenching and tempering.
Non-Destructive Testing (NDT)
Magnetic Particle Inspection (MPI) and Ultrasonic testing for surface and internal micro-crack prevention.
Protective Anti-Corrosion Surface Coatings
High tensile fasteners operating in offshore environments or chemical exposure require robust surface protection to prevent stress corrosion cracking and hydrogen embrittlement. We offer certified surface treatments tailored to EPC specifications:
- PTFE / Xylan Fluoropolymer Coating: Outstanding chemical resistance with low friction coefficient (0.05 - 0.08) for anti-galling flange assembly.
- Hot-Dip Galvanizing (HDG - ASTM A153): Heavy zinc barrier coating for outdoor structural steel and marine infrastructure.
- Electro-Zinc & Zinc-Nickel Plating: Enhanced salt-spray corrosion performance (up to 1,000+ hours to red rust) without compromising thread pitch tolerances.
- Phosphate & Oil Finish: Standard protective coating for oil-immersed engine and internal gear box assemblies.
Global Export Packaging & Seaworthy Logistics
We export high tensile fasteners to over 24 countries across the Middle East, Europe, North America, and Asia-Pacific. Orders are oiled, wrapped in moisture-barrier plastic, packed in heavy-duty corrugated cartons, and secured in ISPM-15 compliant heat-treated wooden crates to ensure zero damage during sea and air transit.
Fastener Availability & Export Destinations
We serve international procurement departments, EPC contract projects, OEMs, and industrial stockists across major global hubs including Saudi Arabia, UAE, Qatar, Kuwait, Oman, United States, United Kingdom, Germany, Singapore, Australia, Canada, and South Korea.