High-Strength Friction Grip (HSFG) Bolts
HSFG (High-Strength Friction Grip) Bolts are specialized structural fasteners designed for high-load, high-stress, and slip-resistant connections in steel structures, bridges, and infrastructure projects. Unlike conventional bolts, HSFG bolts rely on frictional force between clamped surfaces, ensuring greater fatigue resistance and structural stability.
Manufactured to IS, ASTM, and EN standards, our HSFG bolts are heat-treated for high tensile strength, excellent shear resistance, and long-term durability. Rajal Industries provides precision-engineered HSFG bolts for steel-to-steel connections, high-rise buildings, and critical engineering applications.
Sizes & Standards
| Size Range | Standards |
|---|---|
| Diameters: M16 to M36 (Metric) | IS 4000 / IS 3757 – Indian standards for HSFG structural bolts |
| Diameters: 3/4" to 1-1/2" (Imperial) | ASTM A325 / ASTM A490 – American high-strength structural bolt standards |
| Lengths: Variable | EN 14399-4 – European standard for high-strength structural bolts |
Material & Strength Grades
| Material Type | Available Strength Grades | Industry Standards |
|---|---|---|
| Carbon Steel & Alloy Steel | 8.8, 10.9, 12.9 | IS 4000, IS 3757, EN 14399-4 |
| High-Tensile Steel | Class 8.8, 10.9 | ASTM A325, ASTM A490 |
- Heat-Treated for High Performance – HSFG bolts undergo quenching & tempering to enhance their tensile strength, fatigue resistance, and slip resistance.
- Tensile Strength Ratings
- Class 8.8 : 830 MPa
- • Class 10.9 : 1040 MPa
- ASTM A325 : 1220 MPa
- ASTM A490 : 895 MPa
Head & Hex Design Specifications
Hexagonal Head for Secure Load Distribution
- Provides high torque application and uniform stress distribution.
- Designed for slip-resistant and high-strength bolted connections.
Chamfered & Precision-Machined Head
- Ensures proper bolt seating and even load transfer across connected surfaces.
- Manufactured to tight tolerances for precise fitment.
HSFG Bolt Assembly
- HSFG bolts are typically supplied with matching high-strength nuts & washers to achieve the desired tensioning force.
- Available in preloaded and non-preloaded categories for different engineering requirements.
Thread Specifications & Precision Engineering
| Thread Type | Description | Application |
|---|---|---|
| Coarse Thread (UNC/ISO Metric) | Standard thread profile for structural applications | Steel bridges, infrastructure |
| Fine Thread (UNF/Metric Fine) | Offers higher tensile strength and precise load distribution | Seismic-resistant structures |
| Fully Threaded HSFG Bolts | Allows full engagement with mating nuts | Adjustable steel frameworks |
| Partially Threaded HSFG Bolts | Provides higher shear resistance & controlled load transfer | Construction, railways |
Thread Fitment & Compliance
- Metric threads conform to ISO 6g tolerances, ensuring tight and secure fastening.
- Imperial threads adhere to ASTM A325 & A490, ensuring precision-engineered fitment.
Corrosion Resistance & Environmental Suitability
HSFG bolts are used in outdoor structures, heavy engineering, and corrosive environments, requiring protective coatings for durability.
| Coating Type | Corrosion Protection Level | Ideal Applications |
|---|---|---|
| Plain Steel (No Coating) | Low | Indoor applications |
| Zinc Plated (Yellow/Blue/White/Black) | Moderate (48-96 hours SST) | Industrial, mild outdoor use |
| Hot-Dip Galvanized (HDG) | High (600+ hours SST) | Outdoor structures, bridges, wind turbines |
| Black Oxide Coating | Medium corrosion resistance with a sleek appearance | Bridges, steel structures, outdoor frameworks |
| Dacromet/Geomet Coating | Extreme (1000+ hours SST) | Aerospace, offshore, and high-humidity environments |
Salt Spray Testing (SST) per ASTM B117 & ISO 9227 ensures long-term rust prevention and surface protection.
Common Applications of HSFG Bolts
- Steel Structures & Bridge Construction – Ensures high-strength steel-to-steel connections
- High-Rise Buildings & Infrastructure – Used in critical load-bearing frameworks.
- Heavy Engineering & Power Plants – Secures turbines, transmission towers, and machinery bases.
- Railway & Metro Projects – Provides reliable fastenings for railway tracks and stations
- Renewable Energy Installations – Essential for wind turbines, solar panel mounts, and offshore platforms.
Why Choose Rajal Industries for HSFG Bolts?
Manufactured to International Standards
Ensuring dimensional accuracy, strength, and durability.
Engineered for Slip-Resistance & Structural Stability
Designed for friction-grip joints in steel frameworks.
Bulk & Custom Orders Available
Available in various coatings, thread configurations, and tensile strengths.
Stringent Quality Control
Each bolt undergoes load testing, torque verification, and impact resistance checks.
Competitive Pricing & Timely Delivery
Optimized supply chain management for fast order fulfillment.
Keep up to date-get email-updates
Stay tuned for the latest Company news
Our Offices
C-204, Vaibhav Platina, Nr. Kaveri Trishra, S P Ring road, Shilaj, Ahmedabad, Gujarat-380054
Call us
+91-846 036 2030
Email Us
rajalfast@gmail.com sales@rajalindustries.com