We are reputable Flange Bolts Manufacturers in India, and we make high-quality precision fasteners by using quality raw materials and high standards of production methods. Every product is also tested in dimensions, hardness, and tensile strength to guarantee excellent performance. We can also provide custom sizes, coatings, and special requirements for OEM and project-based applications.
The result is an inherent flange that distributes the tightening force across a broader area of the surface, decreasing stress in the area and preventing the use of an extra washer. Due to this design, the flange bolts provide a better, safer, and more stable connection than normal bolts.
They are mostly found in automotive parts, construction work, heavy machinery, and industrial machinery, where vibration resistance and clamping security are critical. The flange is also designed to ensure that the mating surface is not damaged, and hence, it saves time on installation.
The Application of Flange Bolts in Fastening
Loosening in most mechanical joints either occurs through vibrations, temperature changes, or repeated loads. Conventional bolts make use of washers to disperse the load, although their misposition or absence may undermine the joint. The solution to this issue is flange bolts, whereby the washer is incorporated into the bolt.
Major Advantages:
- Even distribution of pressure
- Less deformation of materials
- There is no requirement for a washer
- Improved resistance to sloping
- This results in a reduction of maintenance and installation time
- Better mechanical system safety
A high bearing surface at the flange reduces stress concentration around the hole, extending the bolt's and the component's service life.
| Parameter |
Specification |
| Standard |
DIN 6921 / ISO 4162 |
| Material |
Carbon Steel / Alloy Steel / Stainless Steel (SS 304, SS 316) |
| Size Range |
M5 to M20 |
| Length |
10 mm to 150 mm |
| Thread Type |
Metric / UNC |
| Thread Pitch |
Coarse / Fine |
| Grade |
8.8 / 10.9 |
| Head Type |
Hex Flange Head (Integrated Washer) |
| Flange Type |
Serrated / Non-Serrated |
| Drive Type |
External Hex |
| Tensile Strength |
800 – 1000 MPa |
| Proof Load |
As per ISO standards |
| Hardness |
HRC 20 – 34 |
| Surface Finish |
Zinc Plated / Black Oxide / Hot Dip Galvanized / Plain |
| Coating Thickness |
5 – 25 microns |
| Corrosion Resistance |
Moderate to High |
| Temperature Range |
-40°C to 300°C |
| Application |
Automotive / Construction / Machinery / Structural Assemblies |
| Manufacturing Process |
Cold Forged / Hot Forged |
| Inspection |
Visual / Dimensional / Mechanical Testing |
Types of Flange Bolts
Hex Flange Bolts
The Hex Bolts are characterised by a typical six-sided head flank and an inbuilt flange. They are the most commonly used and can be used in general industrial use.
Common uses:
- Motors and pumps
- Fabricated structures
- Industrial assemblies
- Mechanical equipment
Serrated Flange Bolts
The underside of the flange is serrated (covered with small teeth) with these bolts. The serrations clamp the surface and also keep the bolt tight when vibrated, thus avoiding loosening when tightened.
Common uses:
- Automotive chassis
- Heavy machinery
- Agricultural equipment
- Vibrating installations
12-Point Flange Bolts
Flange bolts are 12-point and require a special socket wrench for tightening. They can be put to use in cramped or limited spaces where a standard spanner cannot turn all the way round.
Common uses:
- Automotive engines
- Aerospace assemblies
- Accurate mechanical systems
Non-Serrated Flange Bolts
The teeth do not undercut these bolts. They are applied in cases where surface protection is necessary and scratching is to be prevented.
Common uses:
- Painted surfaces
- Soft metals
- Sheet metal fabrication
Materials and Grades
The flange bolts are made in various materials depending on their strength and environmental specifications.
Carbon Steel and Alloy Steel
These are the materials that are most employed in heavy-duty applications.
Available grades:
- Grade 8.8 is suitable for general engineering and fabrication purposes.
- Grade 10.9 is designated for use in automobiles and heavy industry equipment.
- Better tensile grades are available for structural and heavy industrial applications.
Stainless Steel
Flange bolts made of stainless steel have a high level of resistance to corrosion.
Available grades:
- SS 304 is suitable for both general outdoor and indoor applications.
- SS 316 is suitable for marine, chemical, and wet conditions.
Special Materials
In special cases, the flange bolts can be produced out of:
- High-strength and lightweight titanium alloys.
- Brass (electrical use and anti-corrosive use)
Surface Finishes
Coats of protection are put on to enhance compliance and resistance to rust and environmental damage.
Available finishes include:
- Zinc plated
- Hot-dip galvanized
- Black oxide coating
- PTFE-coated
Such finishes make them resistant to moisture, chemicals, and exposure to weather, extending their service life.
Sizes and Standards
Flange bolts are manufactured as per international standards:
They exist in both metric and inch series.
Common metric sizes:
Diameters M5, M6, M8, M10, M12, M16, M20 and bigger.
Key dimensions include the following:
Industrial Applications
Automotive Industry: Flange Bolts have been very prevalent in engine parts, transmission units, and exhaust systems, where vibration is constant.
Construction and Structural Engineering
It is used in bridges, buildings, and steel frames to provide a safe structural connection.
Machinery and Equipment
Gearboxes, conveyors, compressors, and manufacturing equipment widely utilise it for continuous load operations.
Plumbing and HVAC Systems
It supports the pipes and duct connections, enabling them to form tight and leakproof joints.
Marine and Aerospace
They are chosen in harsh environments due to their corrosion resistance and strength.
Reputed Flange Bolt Suppliers in India
We are reliable Flange Bolt Suppliers in India who keep ready stocks of all sizes, materials, and grades. We have an inventory system that enables us to dispatch fast to satisfy urgent maintenance and production needs.
Flange Bolt Wholesalers in India
We are trusted Flange Bolt Wholesalers in India at competitive prices in large quantities. It improves the quality and nonstop supply to distributors, hardware stores, and contractors.
Flange Bolt Dealers in India
As knowledgeable Flange Bolt Dealers in India, we are also able to help customers in choosing the right grade of bolts based on the load, environment, and vibration conditions in order to achieve the proper fastening and service life.
Quality Assurance
We use strict quality processes to test all the flange bolts.
- Thread gauge inspection
- Hardness testing
- Tensile strength testing
- The process also includes coating inspection and corrosion inspection.
These checks make it reliable even on heavy-duty and vibration-prone installations.
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Enquire about a specification guide and a quote for the high-end flange bolts. Enlist the services of a reliable manufacturer, supplier, wholesaler, and dealer with reduced prices, quick delivery, and professional advice. Choose Kiran Industries now.
