Hebei Kappa Metal Products Co., Ltd. is one of the most reliable manufacturers and suppliers of grade 4.8 black flange bolt with serrations in China. Welcome to buy bulk high quality grade 4.8 black flange bolt with serrations made in China here from our factory. If you have any enquiry about cooperation, please feel free to email us.
Drywall screws are not priced by quantity alone. Weight per piece has a direct effect on cost, especially for large orders. A small difference in screw weight can change the total tonnage and the final price.
Send us the details, drawing on my factory-floor experience, we can analyze your specific market conditions and store requirements to help you determine the most precise and appropriate pricing.e-no guesswork on weight.
Please specify:
01
- Diameter × length
- Head type (bugle head, countersunk, etc.)
02
- Thread type (fine or coarse)
- Coating (black phosphate, gray phosphate, zinc, etc.)
03
- Target weight per piece (g/pc)
- Order quantity
04
- Packaging (dimensions of the box/outer carton, package weight, and whether the logo style or color can be customized)
Product Specification
| Item | Grade 4.8 black Serrated Hex Flange Bolt |
| Standard | DIN6921 |
| Material | Carbon Steel |
| Grade/Class | 4.8 |
| Finish/Surface treatment | Black Oxide |
| Size | Diameter |
| Thread pitch | 0.8mm/1.5mm/2mm |
| Serration | Yes |
We are a leading fastener manufacturer based in Yongnian, China. With a 10,000-square-meter factory and 180 employees, we specialize in producing high-quality bolts, nuts, and anchor bolts. Utilizing advanced technology and implementing strict quality control, our products have obtained multiple international certifications and are exported to over 30 countries worldwide. We provide durable zinc-plated fasteners suitable for a wide range of applications.
Introduction to Black Oxide Surface Treatment
The black oxide finish gives the bolt a uniform, low-gloss black appearance with minimal change to its dimensions. The thin conversion coating helps retain the original thread fit and can absorb protective oil to improve rust resistance. It is a practical, cost-effective finish for indoor fastening applications where a black surface is preferred. For better corrosion protection, oil sealing and proper storage are recommended.
Application
- General Machinery：For fastening non-critical metal components in machinery and equipment.
- Metal Brackets & Fittings：For securing mounting brackets, plates, and metal fittings.
- Equipment Assembly：For assembling equipment frames and auxiliary components where class 4.8 strength is sufficient.
- Indoor Hardware：For indoor metal fixtures and general hardware connections where a black finish is preferred.
How to Choose the Right Flange Bolt
Consider the Risk of Loosening
Serrated flange bolts provide extra grip against the mating surface and can help resist loosening. Smooth flange bolts are a better choice when the contact surface should remain undamaged.
01
Check the Bearing Surface
The flange spreads the clamping load over a wider area than a standard hex bolt head. This can be useful when fastening thin plates or parts that need a larger bearing surface.
02
Match the Finish to the Application
Yellow zinc plating offers basic corrosion protection for general use. Black oxide bolts are better suited to dry indoor conditions unless additional corrosion protection is applied.
03
Confirm the Bolt Specifications
Check the DIN standard, thread diameter, and bolt length before ordering to make sure the bolt fits your assembly.
04
Custom Packaging&Private Label Available
Choose from bulk cartons, poly bags with branded labels, or retail-ready packaging. Minimum order quantities can be adjusted to support both small contractors and large-scale procurement needs.
We offer custom box/bags printing and labeling services to help you build your own product line.
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