Expansion Bolts
Expansion bolts are specialized fasteners designed for high-load anchoring in concrete, masonry, and brick structures. These bolts feature an expanding sleeve mechanism, which ensures secure gripping by exerting outward pressure when tightened. They are commonly used in heavy-duty construction, structural frameworks, machinery installations, and seismic-resistant applications.
At Rajal Industries, our expansion bolts are engineered to ASTM and DIN standards, offering high pull-out resistance, corrosion protection, and durability for industrial and infrastructure applications.
Sizes & Standards
| Size Range | Standards |
|---|---|
| Diameters: 1/4" to 1" | ASTM E1512 – Standard test method for expansion anchors |
| Lengths: 1" to 6" or more | DIN 529 – German standard for expansion bolts used in concrete & masonry |
Material & Strength Grades
| Material Type | Available Strength Grades | Industry Standards |
|---|---|---|
| Mild Steel & Carbon Steel | 4.6, 5.6, 8.8 | DIN 529, ASTM E1512 |
| Stainless Steel (Corrosion Resistant) | A2-70 (SS 304), A4-80 (SS 316) | ISO 3506, ASTM E1512 |
| High-Tensile Steel | Class 8.8, 10.9 | ISO 898-1, ASTM E1512 |
- Heat-Treated for Enhanced Strength –Expansion bolts undergo quenching & tempering to improve shear resistance and durability.
- Load Capacity Based on Material & Application:
- Carbon Steel Class 8.8 Expansion Bolt : 800-900 MPa tensile strength
- Stainless Steel A4-80 Expansion Bolt : 700-800 MPa corrosion-resistant strength
Head & Expansion Design Specifications
Mechanically Expanding Sleeve for Secure Hold
- As the bolt is tightened, the expanding sleeve grips the surrounding material, preventing movement and pull-out.
- Provides high holding power in concrete, stone, brick, and masonry applications.
Variety of Expansion Mechanisms for Different Applications
- Torque-Controlled Expansion Bolts – Expansion occurs as torque is applied to the nut.
- Displacement-Controlled Expansion Bolts – Expansion is activated when the bolt is hammered into a hole.
- Wedge Expansion Bolts – Provide strong seismic-resistant anchoring by gripping into concrete.
-
High-Precision Threading for Secure Load Transfer
- Threads are engineered for high torque resistance, preventing stripping or loosening under vibration.
- Available in coarse and fine thread profiles for enhanced clamping force and stability.
Thread Specifications & Precision Engineering
| Thread Type | Description | Application |
|---|---|---|
| Coarse Thread (UNC/ISO Metric) | Standard for heavy-load applications | Structural, masonry anchoring |
| Fine Thread (UNF/Metric Fine) | Offers better load distribution and higher tensile strength | Precision anchoring in seismic zones |
| Fully Threaded Expansion Bolts | Allows maximum adjustability and deep embedment | Adjustable base plate connections |
| Partially Threaded Expansion Bolts | Provides higher shear strength and grip stability | Concrete anchoring, bridge supports |
Thread Fitment & Compliance
- Metric threads conform to ISO 6g tolerances, ensuring strong grip and precise fitment.
- Imperial threads meet ASTM and ASME B1.1 standards for high-torque applications.
Corrosion Resistance & Environmental Suitability
Expansion bolts are widely used in outdoor and industrial environments, where corrosion resistance is critical.
| 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) | General construction, industrial use |
| Hot-Dip Galvanized (HDG) | High (600+ hours SST) | Outdoor structures, masonry anchoring, humid conditions |
| Dacromet/Geomet Coating | Extreme (1000+ hours SST) | Aerospace, offshore, and marine applications |
Salt Spray Testing (SST) per ASTM B117 & ISO 9227 ensures long-term rust prevention and durability.
Common Applications of Expansion Bolts
- Concrete & Masonry Anchoring – Used in walls, ceilings, and industrial structures
- Heavy Equipment & Machinery Installation – Provides secure fastening for compressors, turbines, and factory installations.
- Bridges & Infrastructure – Used for steel reinforcement anchoring in roadways, tunnels, and railway projects.
- Power Plants & Renewable Energy – Essential for wind turbines, solar panel mounting, and transmission towers.
- Seismic & Offshore Structures – Ensures structural integrity in high-movement zones.
Why Choose Rajal Industries for Expansion Bolts?
Manufactured to International Standards
Ensuring precision engineering, strength, and compliance.
Customizable Expansion Designs
Available in wedge, sleeve, torque-controlled, and displacement-controlled variants.
Durability & Corrosion Resistance
Engineered with high-quality materials and protective coatings.
Bulk & Custom Orders
Flexible manufacturing capabilities for large-scale and specialized applications.
Stringent Quality Control
Expansion bolts undergo torque testing, pull-out strength verification, and corrosion resistance tests
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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