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One of the most effective fastening solutions applied in the automotive industry as well as the construction and heavy engineering industries is hex flange bolts. This design, with a flange inbuilt, eliminates the use of a washer making it better in load distribution. To be able to select and plan correctly, it is necessary to understand the hex flange bolt weight chart in mm and hex flange bolt weight chart in kg.
This guide provides complete technical insight along with extended industrial tables for real-world applications.
What is a Hex Flange Bolt?
A hex flange bolt is basically a bolt with a hexagonal head and a circular flange which is built-in on the bottom side of the bolt. The role of this flange is similar to a washer in that it evenly distributes the clamping force over a larger area thus reducing the chances of surface damage or loosening due to vibration.
Mostly, these bolts are manufactured according to standards such as DIN 6921 and ISO 4162 which ensure both dimensional accuracy and global conformity.
Hex Flange Bolt Dimension Chart (MM)
| Size | Pitch | Head Height | Across Flats | Flange Dia | Thread Dia |
| M6 | 1.0 | 6.0 | 10 | 14.2 | 6 |
| M8 | 1.25 | 8.0 | 13 | 17.9 | 8 |
| M10 | 1.5 | 10.0 | 15 | 21.8 | 10 |
| M12 | 1.75 | 12.0 | 18 | 26.0 | 12 |
| M14 | 2.0 | 14.0 | 21 | 30.0 | 14 |
| M16 | 2.0 | 16.0 | 24 | 33.6 | 16 |
| M18 | 2.5 | 18.0 | 27 | 37.0 | 18 |
| M20 | 2.5 | 20.0 | 30 | 41.6 | 20 |
| M22 | 2.5 | 22.0 | 34 | 45.0 | 22 |
| M24 | 3.0 | 24.0 | 36 | 50.0 | 24 |
Hex Flange Bolt Length Availability Chart
| Size | Standard Length Range (MM) |
| M6 | 10 – 80 |
| M8 | 16 – 100 |
| M10 | 20 – 120 |
| M12 | 25 – 150 |
| M14 | 30 – 180 |
| M16 | 30 – 200 |
| M18 | 40 – 220 |
| M20 | 40 – 250 |
| M22 | 50 – 280 |
| M24 | 60 – 300 |
Hex Flange Bolt Weight Chart (KG)
| Size | Length | Weight/Pc (KG) | Weight/100 PCS (KG) |
| M6 | 20 | 0.007 | 0.7 |
| M6 | 40 | 0.012 | 1.2 |
| M8 | 30 | 0.018 | 1.8 |
| M8 | 60 | 0.030 | 3.0 |
| M10 | 40 | 0.035 | 3.5 |
| M10 | 80 | 0.060 | 6.0 |
| M12 | 50 | 0.065 | 6.5 |
| M12 | 100 | 0.110 | 11 |
| M14 | 80 | 0.120 | 12 |
| M16 | 75 | 0.150 | 15 |
| M16 | 150 | 0.300 | 30 |
| M18 | 100 | 0.250 | 25 |
| M20 | 100 | 0.300 | 30 |
| M20 | 200 | 0.600 | 60 |
| M22 | 150 | 0.550 | 55 |
| M24 | 180 | 0.750 | 75 |
Extended Hex Flange Bolt Weight Chart (Large Sizes)
| Size | Length | Weight/Pc (KG) | Weight/100 PCS (KG) |
| M16 | 200 | 0.400 | 40 |
| M18 | 200 | 0.500 | 50 |
| M20 | 250 | 0.800 | 80 |
| M22 | 250 | 1.000 | 100 |
| M24 | 300 | 1.300 | 130 |
| M27 | 300 | 1.800 | 180 |
| M30 | 350 | 2.500 | 250 |
| M33 | 350 | 3.200 | 320 |
| M36 | 400 | 4.200 | 420 |
Hex Flange Bolt Size & Application Chart
| Size Range | Application |
| M6 – M8 | Automotive panels, light assemblies |
| M10 – M12 | Machinery, fabrication |
| M14 – M18 | Structural connections |
| M20 – M24 | Heavy industrial use |
| M27 – M36 | Bridges, power plants, infrastructure |
Technical Insight: Why Flange Design Matters
The flange of such bolts is a very important element of performance:
- Performs the role of an inbuilt washer.
- Minimizes the stress concentration on surfaces.
- Enhances hand strength and avoids loss.
- Eliminates need for additional components
This renders hex flange bolts more effective than conventional bolt washer combinations.
Strength Grades and Material Options
Hex flange bolts come in a variety of material grades with each being designed for certain environments:
- Grade 8.8: Medium strength, general industrial use
- Grade 10.9: High strength, heavy-duty applications
- Grade 12.9: Very high strength, critical load conditions
- Stainless Steel (SS304/SS316): Corrosion-resistant applications
The choice of material affects not only the performance but also the weight.
Surface Finishes and Their Impact
This is how the different coatings work to improve the durability :
- Zinc Plated: Basic corrosion protection
- Hot Dip Galvanized: High corrosion resistance for outdoor use
- Black Oxide: Minimal protection, used indoors
- PTFE Coated: Chemical resistance
Adding coatings results in just a slight increase in weight but they improve the lifespan by a great deal.
Practical Tips for Using Weight Charts
To use these charts effectively:
- Make sure to always correctly match size and length.
- Calculate exactly with weight per piece
- Bulk estimation multiply by quantity
- Keeping in mind coating and material changes
- Verify with standards (DIN/ISO)
That way, you get precise planning and stay away from expensive errors.
Advantages of Hex Flange Bolts
- Quicker to install (without washer)
- More efficient distribution of load
- Less loosening as a result of vibration
- Great strength and longevity
- Highly economical when used in large quantities
Conclusion
Hex flange bolts are a smart and advanced type of fastening tool. They are designed to provide strength, be efficient, and most of all, reliable. With the help of detailed dimension and weight charts, professionals can reasonably decide on the right size, material estimation, and application suitability.
When one is aware of the physical dimensions and weight properties, industries will be able to guarantee a better performance, less downtime, and the stability of the structure for a long time.