introduction to products：
DIN 6921 Hex Flange Bolts – full Threaded Stainless Steel are high - quality fasteners designed for various applications. These bolts feature a hexagonal head and an integrated flange, which helps in evenly distributing the load and preventing loosening, especially in applications subject to vibrations.
Crafted from stainless steel, commonly in grades like SS304 (offering good general - purpose corrosion resistance for a wide range of environments) and SS316 (providing enhanced resistance to saltwater and harsh chemicals, ideal for marine and industrial settings). Their fully threaded design allows for maximum engagement with the mating component, ensuring a secure connection.
Compliant with the DIN 6921 standard, they come in a variety of sizes, typically ranging from M5 to M30. They are widely used in marine engineering (shipbuilding, offshore platforms), food processing equipment (where corrosion resistance and hygiene are crucial), chemical plants (exposed to corrosive substances), and outdoor architectural structures (resisting weathering), where reliable and corrosion - resistant fastening is essential.
Instructions for Use：
When installing, use a matching hex wrench to tighten the bolts to the recommended torque value. The appropriate torque depends on the specific stainless steel grade and the application requirements. The serrated underside of the flange helps to grip the workpiece firmly, preventing it from rotating during tightening.
For maintenance, clean the bolts regularly with a soft cloth and mild detergent to remove dirt and any potential corrosive substances. Stainless steel has a passive oxide layer that resists rust, but in case of scratches, the oxide layer can self - repair in air. However, for deeper scratches or in more corrosive environments, applying a stainless - steel - specific protective coating can enhance its longevity. Periodically inspect the bolts for any signs of damage, such as thread stripping or flange deformation, and replace them if necessary.
| 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 .
