Hex Flange Bolts M6–M16 Grade 10.9 Carbon Steel Black

Hex Flange Bolts – Grade 10.9 Carbon Steel, Black Finish

Upgrade your fastening projects with these heavy-duty Hexagon Head Flange Bolts. Available in M6, M8, M10, M12, and M16 thread diameters, these bolts are manufactured to Grade 10.9 carbon steel standards — delivering exceptional tensile strength and durability for demanding mechanical, automotive, and construction applications. The integrated flange washer distributes load evenly, eliminating the need for a separate washer and providing a cleaner, more secure assembly.

Made in Mainland China.

Key Features

• Material: Grade 10.9 High-Strength Carbon Steel
• Surface Treatment: Blackening (black oxide finish) for a sleek, corrosion-resistant appearance
• Standard: GB (Chinese National Standard)
• Available Sizes: M6, M8, M10, M12, M16
• Size Guide: e.g. M6×12mm – Full Thread (Thread Diameter = 6mm, Thread Length = 12mm, excluding head length)
• Integrated Flange Washer: Provides wider load distribution without a separate washer
• Hex Drive Head: Compatible with standard hex wrenches and sockets for fast, easy installation
• Packaging: Secure plastic bag/carton packaging to keep fasteners organized and protected
• Quantity: Select your preferred size and quantity from the drop-down menu above

Why Choose Grade 10.9 Flange Bolts?

Grade 10.9 is one of the highest-strength grades available for metric bolts — ideal for high-stress joints in automotive assemblies, machinery, steel structures, and industrial equipment. The black oxide finish adds a professional look while providing a mild layer of corrosion resistance to extend service life.

Applications

• Automotive engine and chassis assembly
• Machinery and industrial equipment
• Steel frame construction
• DIY mechanical and fabrication projects
• Replacement fasteners for existing hardware

Important Notes

• Manual measurement may have a slight tolerance variance — please allow for minor differences.
• Screen color rendering may vary slightly from the actual product; the black oxide finish is the accurate reference.
• Need a quantity or size not listed? Contact us and we'll do our best to accommodate your requirements.

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Frequently Asked Questions

Q: What does Grade 10.9 mean for hex flange bolts?

A: Grade 10.9 is a metric bolt strength classification. It indicates a minimum tensile strength of 1040 MPa and a proof load strength of 940 MPa, making these hex flange bolts suitable for high-stress, heavy-duty mechanical and structural applications where standard bolts may not be adequate.

Q: Do I need a separate washer with hex flange bolts?

A: No — the integrated flange (built-in washer collar) beneath the hex head distributes the clamping load across a wider surface area, eliminating the need for a separate flat washer and simplifying assembly.

Q: What tools do I need to install these bolts?

A: These hex flange bolts are driven with a standard hex (hexagonal) wrench, spanner, or socket set matched to the appropriate bolt size (M6, M8, M10, M12, or M16). No special tools are required.

Q: What does the black oxide (blackening) finish do?

A: The black oxide finish gives the bolts a professional matte-black appearance and provides a basic level of corrosion resistance, helping to extend the service life of the fasteners in typical indoor and sheltered outdoor environments.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.