Flange Bolts
Flange bolts are high-strength fasteners designed with an integrated washer-like flange under the hex head. This wide-bearing surface distributes pressure evenly, reducing the risk of loosening and eliminating the need for separate washers. Flange bolts provide superior resistance to vibration and high-stress applications, making them ideal for automotive, machinery, construction, and structural applications.
At Rajal Industries, we manufacture ISO, ASME, and DIN-compliant flange bolts with precise threading, superior material quality, and corrosion-resistant coatings to meet the demands of industrial and high-performance applications..
Head & Flange Design Specifications
Integrated Flange Head
Acts as a built-in washer, ensuring a larger contact area for better load distribution.
Prevents the loosening of bolts in high-vibration environments such as engines, heavy machinery, and industrial equipment.
Hexagon Head for Easy Torque Application
Compatible with standard wrenches and socket tools, allowing for quick and secure tightening.
Provides high torque resistance, making it ideal for high-load applications.
Smooth or Serrated Flange Options
Smooth Flange Bolts – Designed for general fastening, ensuring even pressure distribution.
Serrated Flange Bolts – Featuring radial teeth to lock onto surfaces, preventing loosening due to vibration or impact.
Thread Specifications & Precision Engineering
| Thread Type | Description | Application |
|---|---|---|
| Coarse Thread (UNC/ISO Metric) | General-purpose, high durability | Heavy machinery, automotive, construction |
| Fine Thread (UNF/Metric Fine) | Increased tensile strength, more thread engagement | Aerospace, high-precision assembly |
| Partially Threaded Bolts | Higher shear strength, better clamping | Structural fastening, automotive |
| Fully Threaded Bolts | Allows maximum adjustability and load distribution | General fastening, repairs, and assemblies |
Thread Fitment & Compatibility
- Metric flange bolts conform to ISO 6g tolerances, ensuring a secure fit in threaded holes and nuts.
- Imperial flange bolts are available in UNC (Coarse) and UNF (Fine) threads, following ASME B1.1.
Corrosion Resistance & Environmental Suitability
Flange bolts are exposed to varying environmental and operational conditions, requiring proper surface protection for long-term durability.
| Coating Type | Corrosion Protection Level | Ideal Applications |
|---|---|---|
| Plain Steel (No Coating) | Low | Indoor use only |
| Zinc Plated (Yellow/Blue/White/Black) | Moderate (48-96 hours SST) | General industrial applications |
| Hot-Dip Galvanized (HDG) | High (600+ hours SST) | Outdoor, marine, bridges, heavy structures |
| Black Oxide Coating | Medium corrosion resistance with a sleek appearance | Automotive, machinery, industrial tools |
| Geomet/PTFE Coatings | Extreme (1000+ hours SST) | Aerospace, chemical, high-performance environments |
Salt Spray Testing (SST) per ASTM B117 & ISO 9227 ensures long-term rust prevention and surface protection.
Sizes & Standards
| Size Range | Standards |
|---|---|
| Diameters: M6 to M36 (Metric) | ISO 7091 – International standard for flange bolts |
| Diameters: 1/4" to 1-1/2" (Imperial) | ASME B18.2.2 – American standard for hex flange bolts |
| Lengths: Variable | ISO 4162 – Metric flange bolts for high-strength applications |
| DIN 6921 – German standard for hex flange bolts |
Material & Strength Grades
| Material Type | Available Strength Grades | Industry Standards |
|---|---|---|
| Mild Steel & Carbon Steel | 4.6, 5.6, 8.8 | ISO 898-1, DIN 603, ASME B18.5 |
| Stainless Steel (Corrosion Resistant) | A2-70 (SS 304), A4-80 (SS 316) | ISO 3506, DIN 603, ISO 8677 |
| High-Tensile Steel | Class 8.8, 10.9 | ISO 898-1, ASME B18.5, DIN 603 |
| Alloy Steel (Heat Treated) | Class 10.9 | ISO 898-1, ASTM A325 |
Common Applications of Flange Bolts
- Automotive & Heavy Vehicles – Used in engine components, suspension systems, and structural assembly.
- Industrial & Construction Equipment – Fastens gearboxes, pumps, and machinery components.
- Structural Engineering – Used in bridge construction, steel structures, and heavy-duty applications.
- Railway & Aerospace – Provides high vibration resistance in locomotives, aircraft, and metro rail systems.
- Renewable Energy & Power Plants – Used in wind turbines, solar panel frames, and power stations.
Why Choose Rajal Industries for Flange Bolts?
Manufactured to International Standards
Ensuring dimensional accuracy, strength, and longevity.
Bulk & Custom Orders Available
Flexible manufacturing to meet your exact specifications.
High-Quality Material Selection
Ensuring long-lasting durability and reliability
Stringent Quality Control
Each bolt undergoes tensile testing, hardness testing, and thread fitment checks
Competitive Pricing & Timely Delivery
Efficient production and supply chain management
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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