Release time：2020-01-16 18:44 Browse：
1. **Material Composition and Surface Engineering** Constructed from high-quality carbon steel, these bolts are heat-treated to achieve strength classes of 8.8 to 10.9, ensuring robust tensile and yield strengths suitable for heavy-load applications. The black oxide (blackening) surface treatment is applied through a chemical process that forms a thin, adherent layer of magnetite (Fe₃O₄) on the surface. This coating provides moderate corrosion resistance, reduces light reflection, and minimizes the risk of galling during installation, while maintaining the bolt’s inherent mechanical properties without significantly altering dimensions. 2. **Design Compliance and Structural Features** - **DIN 6291 Standard**: These bolts adhere to the German DIN 6291 specification, which defines requirements for hexagon flange bolts with metric threads, ensuring precision in thread pitch, head dimensions, and overall geometry for interchangeability across industrial systems. - **Hexagon Flange Head**: The integrated flange (wide bearing surface) eliminates the need for separate washers by distributing clamping forces over a larger area, reducing the risk of surface indentation or damage to mating components. - **Anti-Slip Tooth Design**: Serrated teeth on the underside of the flange grip the surface tightly, creating frictional resistance against rotational forces. This feature is critical in vibration-prone environments (e.g., automotive engines, industrial machinery) where traditional bolts might loosen over time. 3. **Metric Threading and Strength Grades** - **Metric Threads**: Designed with ISO metric threads (coarse or fine pitch), these bolts are compatible with standard metric nuts and threaded holes, making them widely usable in European and global manufacturing systems. - **Strength Classes**: - **8.8 Grade**: Offers a minimum tensile strength of 800 MPa and yield strength of 640 MPa, suitable for general industrial applications. - **10.9 Grade**: Provides a higher tensile strength of 1000 MPa and yield strength of 900 MPa, ideal for high-stress applications such as heavy machinery, vehicle chassis, or structural steel connections. 4. **Plain Finish and Environmental Adaptability** The "plain finish" refers to the absence of additional coatings (beyond black oxide), making these bolts suitable for applications where a neutral surface is preferred or where compatibility with specific paints, sealants, or mating materials is required. The black oxide coating offers moderate protection against rust in dry or indoor environments, while still allowing for easy post-installation painting or coating if needed. 5. **Application Scenarios and Installation Benefits** - **Key Uses**: Commonly employed in automotive assembly (e.g., engine mounts, suspension components), industrial equipment (e.g., pumps, gearboxes), agricultural machinery, and structural frameworks where secure, vibration-resistant fastening is essential. - **Installation Advantages**: The combination of a hexagon head (for easy wrench or socket engagement) and anti-slip teeth streamlines installation by reducing the need for additional locking devices (e.g., lock washers). The flange design also ensures quicker alignment and seating, improving assembly efficiency. 6. **Quality Assurance and Performance Testing** Manufactured to meet strict tolerances, these bolts undergo rigorous testing for thread accuracy, hardness, and tensile strength. Compliance with DIN standards ensures consistency in quality, making them reliable for critical applications where failure could lead to safety hazards or equipment downtime. The anti-slip tooth geometry is precision-machined to guarantee uniform grip across all bolts in a batch, further enhancing their performance in high-stakes environments.
