Crucial Clarifications on Product Specifications

The product page contains several significant errors and misleading statements. The following points provide an accurate description of this product:

• Misleading Application Claim: The product title’s claim of being “Corrosion-Resistant for Outdoor Construction” is highly misleading and incorrect. A black oxide finish provides only very mild corrosion resistance and is primarily intended for dry, indoor applications. When exposed to moisture or outdoor elements, black oxide coated steel will rust quickly. For outdoor construction, a hot-dip galvanized, zinc-plated, or stainless steel bolt is required.
• Finish Contradiction: The summary table lists the finish as both “Zinc Plated” and “Black Oxide Coating.” This is contradictory. The product is a Black Oxide Coated bolt. Black oxide is a chemical conversion coating, not a plating like zinc.
• Material Contradiction: The material is listed as “Stainless Steel/Carbon Steel.” Black oxide is a treatment for ferrous metals like Carbon Steel and Alloy Steel. It is not applied to stainless steel. Therefore, this is a carbon/alloy steel bolt.
• Grade Contradiction: The grade list includes both carbon steel grades (4.8, 8.8, 10.9, 12.9) and stainless steel grades (A2-70, A4-70, etc.). Only the carbon steel grades (4.8, 8.8, 10.9, 12.9) are applicable to this product.
• Incorrect Standard in Title: The title mentions “DIN 913,” which is the standard for a headless set screw. This is incorrect for a hex head bolt. The product is a standard hex bolt, which typically follows standards like DIN 933 (fully threaded) or DIN 931 (partially threaded).

Product Parameters (Corrected)

Black Oxide Finish Explained

Black oxide is a chemical process that creates a magnetite (Fe₃O₄) conversion coating on the surface of the steel.

• Benefits:
  • Aesthetics: Provides a uniform, non-reflective matte black finish.
  • No Dimensional Change: Unlike plating, it does not add any thickness to the part, preserving the original dimensions and tolerances.
  • Reduced Light Glare: The non-reflective surface is beneficial in optical and military applications.
• Limitations:
  • Minimal Corrosion Resistance: On its own, the coating offers very little protection from rust. Its primary anti-corrosion property comes from a supplementary oil or wax treatment that is typically applied after the blackening process. It is only suitable for dry, indoor environments.

Carbon Steel Strength Grades Explained

• Grade 4.8: Low-strength carbon steel for light-duty, non-critical fastening.
• Grade 8.8: Medium-to-high strength, a common choice for automotive and structural applications that require good tensile strength.
• Grade 10.9: High-strength steel for demanding applications requiring high clamping force and load capacity, such as in engines and heavy machinery.
• Grade 12.9: Very high-strength alloy steel, used for the most critical, high-stress applications where fastener failure could be catastrophic.

الميزات الرئيسية

• Aesthetic Black Finish: Offers a clean, professional look for visible components.
• High-Strength Options: Available in grades up to 12.9 for heavy-duty and critical fastening.
• No Dimensional Buildup: The conversion coating does not alter part dimensions, ensuring a perfect fit in tight-tolerance assemblies.
• Ideal for Dry, Indoor Environments: Best suited for machinery, tooling, and industrial equipment that is not exposed to moisture.

Appropriate Applications

• Indoor Machinery and Equipment: Fastening components on industrial machines where aesthetics and strength are needed.
• Automotive Components: Used in engine bays, interiors, and other areas protected from the elements.
• Tooling, Jigs, and Fixtures: Where a dark, non-reflective finish and precise dimensions are important.
• General Industrial Fastening: In any dry, controlled environment.

Installation Guidelines

1. Align the holes of the components to be fastened.
2. Insert the black oxide hex bolt through the hole.
3. Thread a nut onto the bolt or engage the bolt with a pre-tapped hole.
4. Use a correctly sized wrench or socket to tighten the bolt to the appropriate torque specification for its size and grade.
5. Note: To maintain its limited corrosion resistance, it is recommended that black oxide fasteners be kept lightly oiled, especially during storage or in environments with any humidity.