Product Details

Our DIN 6921 Hex Flange Bolts are coated using the genuine Dacromet® process. This advanced surface treatment involves applying a water-based dispersion of zinc and aluminum flakes in a chromate binder. The parts are dip-spun or sprayed, then cured at high temperatures (~300°C / 575°F). This process creates a thin, multi-layered, and completely inorganic metallic silver-gray finish with several key advantages over traditional coatings:

• Exceptional Corrosion Resistance: The overlapping zinc and aluminum flakes create a complex barrier that provides outstanding sacrificial protection, often exceeding 500-1000 hours in salt spray tests (ASTM B117), far surpassing standard zinc plating.
• No Hydrogen Embrittlement: Because Dacromet is a non-electrolytic process, it does not generate hydrogen. This completely eliminates the risk of hydrogen embrittlement, a critical failure mode for high-strength fasteners (Grade 10.9 and above) that can occur with electroplating methods.
• Thin, Uniform Coating: The coating is very thin (typically 5-10 µm) and uniform, ensuring that thread tolerances are maintained. This prevents the fitment issues that can arise with thicker coatings like hot-dip galvanizing, making them perfect for precision assemblies.

These bolts feature an integrated flange that distributes the clamping load over a wider area, preventing damage to the mating surface and eliminating the need for a separate washer. They are available in both fully and partially threaded configurations to suit various clamping and shear-load requirements.

Product Parameters

The technical specifications for our Dacromet Coated DIN 6921 Hex Flange Bolts are detailed below.

Product Features

These high-performance bolts are engineered with a range of features for superior performance and reliability:

• High-Performance Corrosion Protection: The multi-layered Dacromet coating provides a robust barrier against environmental corrosion, chemicals, and salt spray, ensuring long-term durability.
• Eliminates Hydrogen Embrittlement Risk: The non-electrolytic application process makes these bolts the safest choice for high-tensile (Grade 10.9, 12.9) structural and safety-critical applications.
• Thin, Uniform Coating for Precise Fit: Ensures that threads remain within tolerance for smooth, trouble-free assembly without the need for re-tapping nuts.
• Excellent Heat and Abrasion Resistance: The cured metallic coating is resistant to high temperatures and mechanical abrasion, maintaining its protective integrity during installation and operation.
• Integrated Flange for Simplified Assembly: The built-in flange distributes load effectively, resists vibrational loosening, and reduces part count and assembly time.
• High-Strength for Demanding Loads: Manufactured from high-grade carbon steel, these bolts provide the exceptional clamping force and tensile strength required for the most demanding applications.

Product Applications

The unique combination of strength, corrosion resistance, and safety from embrittlement makes our Dacromet Coated Hex Flange Bolts ideal for a wide array of high-tech and heavy-duty industries:

• Automotive Industry: Essential for brake systems, chassis assemblies, engine components, and suspension parts where high strength and corrosion resistance are critical.
• Wind Energy: The preferred fastener for assembling wind turbine towers, nacelles, and blades, where long-term reliability in harsh weather is paramount.
• Construction and Infrastructure: Used in high-tensile structural steel connections, bridges, and other projects requiring durable, high-strength bolting.
• Marine Applications: An excellent alternative to stainless steel for components that require high tensile strength in corrosive marine environments.
• Heavy Machinery & Equipment: Provides secure and long-lasting connections for agricultural, mining, and industrial machinery exposed to wear and the elements.