Din 50961 Fe Zn 8b Jun 2026

A brilliant blue surface with a metallic sheen and subtle rainbow iridescence. It is the most visually attractive of all chromate finishes. Corrosion Resistance (Red Rust): According to the standard, Fe Zn 8b must withstand 72 hours in the neutral salt spray test (NSS) before red rust appears (when using Cr(III) based passivations). Electrical Conductivity: The blue film is very thin (approx. 0.1–0.5 µm). Unlike yellow or olive passivations, Fe Zn 8b offers relatively low contact resistance , making it ideal for threaded connections that require electrical grounding (e.g., automotive chassis bolts, electronic enclosures). Weldability: Due to its thin, conductive layer, blue passivated zinc is preferred over thicker coatings for resistance spot welding.

represents the minimum thickness of the zinc layer in micrometers (µm). A thickness of 8µm is considered a standard "medium" coating. It is thick enough to provide significant resistance to red rust in indoor or mildly outdoor environments, but thin enough to avoid interfering with the tolerances of fine-threaded screws or precision machinery. 5. The Chromate Treatment: B The final letter, din 50961 fe zn 8b

At , this coating is considered "moderate" service condition (SC2). It is thin enough to avoid interfering with tight-tolerance threads (like M6 or M8 bolts) but thick enough to provide significant corrosion resistance compared to basic 5-micron flash plating. 2. The "Self-Sacrificing" Layer A brilliant blue surface with a metallic sheen

. Using an electric current, zinc ions are pulled from the solution and bonded to the steel until a uniform 8-micron shield is formed. The "8b" Finishing Touch Electrical Conductivity: The blue film is very thin (approx