introduction to products：
Hot Dip Galvanized (HDG) Plated Hex Flange Bolt DIN6921 (Fully Threaded) are heavy - duty fasteners. They feature a hexagonal head and an integrated flange. The flange helps evenly spread the load, preventing the workpiece from getting damaged and resisting loosening in vibrating situations. Made from carbon steel (grades 4.8–12.9, with higher grades for more strength) or alloy steel for special needs, the HDG coating gives strong corrosion resistance. This makes them perfect for outdoor, wet, or industrial places where rust is a big problem.
Following the DIN 6921 standard, these bolts are fully threaded. This means the threads go all the way along the bolt, giving a secure grip in the mating part. They come in sizes from M5 to M30. You’ll find them used a lot in construction (like building steel structures, bridges), agriculture (on farm machinery, irrigation systems), transportation (for truck frames, trailer hitches), and infrastructure (for power line towers). In these areas, they need to fasten things securely and stand up to bad weather and vibrations.
Instructions for Use：
When putting these bolts in, use a matching hex wrench and tighten them to the torque recommended for their grade. For example, a Grade 10.9 bolt needs more torque than a Grade 4.8 one. The serrated bottom of the flange grabs the workpiece, so it doesn’t spin while you’re tightening.
To take care of them, clean them regularly with a dry cloth to get rid of dirt and rust. If the HDG coating gets scratched, put on zinc - rich paint to keep rust out. Every so often, check if the flange is bent or the threads are damaged. If the threads get stripped or the bolt bends, replace it right away.
| Screw Thread | M5 | M6 | M8 | M10 | M12 | M14 | M16 | M20 | ||||
| d | ||||||||||||
| P | Pitch | Coarse thread | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | ||
| Fine thread-1 | / | / | 1 | 1.25 | 1.5 | 1.5 | 1.5 | 1.5 | ||||
| Fine thread-2 | / | / | / | 1 | 1.25 | / | / | / | ||||
| b | L≤125 | 16 | 18 | 22 | 26 | 30 | 34 | 38 | 46 | |||
| 125＜L≤200 | / | / | 28 | 32 | 36 | 40 | 44 | 52 | ||||
| L＞200 | / | / | / | / | / | / | 57 | 65 | ||||
| c | min | 1 | 1.1 | 1.2 | 1.5 | 1.8 | 2.1 | 2.4 | 3 | |||
| da | Form A | max | 5.7 | 6.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | 22.4 | ||
| Form B | max | 6.2 | 7.4 | 10 | 12.6 | 15.2 | 17.7 | 20.7 | 25.7 | |||
| dc | max | 11.8 | 14.2 | 18 | 22.3 | 26.6 | 30.5 | 35 | 43 | |||
| ds | max | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 20 | |||
| min | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | 19.67 | ||||
| du | max | 5.5 | 6.6 | 9 | 11 | 13.5 | 15.5 | 17.5 | 22 | |||
| dw | min | 9.8 | 12.2 | 15.8 | 19.6 | 23.8 | 27.6 | 31.9 | 39.9 | |||
| e | min | 8.71 | 10.95 | 14.26 | 16.5 | 17.62 | 19.86 | 23.15 | 29.87 | |||
| f | max | 1.4 | 2 | 2 | 2 | 3 | 3 | 3 | 4 | |||
| k | max | 5.4 | 6.6 | 8.1 | 9.2 | 11.5 | 12.8 | 14.4 | 17.1 | |||
| k1 | min | 2 | 2.5 | 3.2 | 3.6 | 4.6 | 5.1 | 5.8 | 6.8 | |||
| r1 | min | 0.25 | 0.4 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | 0.8 | |||
| r2 | max | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.9 | 1 | 1.2 | |||
| r3 | min | 0.1 | 0.1 | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | 0.4 | |||
| r4 | ≈ | 3 | 3.4 | 4.3 | 4.3 | 6.4 | 6.4 | 6.4 | 8.5 | |||
| s | max=nominal size | 8 | 10 | 13 | 15 | 16 | 18 | 21 | 27 | |||
| min | 7.78 | 9.78 | 12.73 | 14.73 | 15.73 | 17.73 | 20.67 | 26.67 | ||||
| t | max | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | 0.45 | 0.5 | 0.65 | |||
| min | 0.05 | 0.05 | 0.1 | 0.15 | 0.15 | 0.2 | 0.25 | 0.3 | ||||
| Length of Thread b | - | - | - | - | - | - | - | - | ||||
Hebei Duojia Metal Products Co., Ltd. was formerly known as Yonghong Expansion Screw Factory. It has over 25 years of professional experience in manufacturing fasteners. The factory is located in the China Standard Room Industrial Base - Yongnan District, Handan City. It conducts online and offline production and manufacturing of fasteners as well as one-stop sales service business.
The factory covers an area of over 5,000 square meters, and the warehouse covers an area of over 2,000 square meters. In 2022, the company carried out industrial upgrading, standardized the production order of the factory, improved the storage capacity, enhanced safety production capacity, and implemented environmental protection measures. The factory has achieved a preliminary green and environmentally friendly production environment.
The company has cold pressing machines, stamping machines, tapping machines, threading machines, forming machines, spring machines, crimping machines, and welding robots. Its main products are a series of expansion screws known as "wall climbers".
It also produces special-shaped hook products such as wood tooth welding sheep eye ring screws and machine tooth sheep eye ring bolts. In addition, the company has expanded new product types from the end of 2024. It focuses on pre-buried products for the construction industry.
The company has a professional sales team and a professional follow-up team to safeguard your products. The company guarantees the quality of the products it offers and can conduct inspections on the grades. If there are any problems, the company can provide professional after-sales service.
Our export countries include Russia, South Korea, Britain, France, Germany, Italy, Canada, Mexico,Brazil, Argentina, Chile, Australia, Indonesia, Thailand, Singapore, Saudi Arabia, Syria, Egypt, Tanzania.Kenya and other countries. Our products will be spread all over the world!
WHY CHOOSE US?
1.As a factory-direct upplier,we eliminate middleman margis to offer you the most competitive pricing for high-quality fasteners.
2.our factory pass the ISO 9001 and AAA certification .we have the hardness testing and the test of zinc coating thickness for galvanized products.
3.with full contrl over production and logistic,we guarantee on-time delivery even for urgnt orders .
4.our engineering team can customize faseners from prototype to mass production , including unique thread designs and anti-corrosion coatings.
5.From carbon steel hex bolts to high-tensile anchor bolts ,we provide a one-stop solution for all your fastener needs.
6.If any defect is found ,we’ll reship replacements within 3weeks of our cost .
