Authentic Steel manufactures and exports high-ductility Black Annealed Steel Coils, processed through oxygen-controlled thermal heat treatment of cold-rolled steel substrates. By subjecting cold-worked steel to controlled heating and slow cooling in an anaerobic atmosphere, the internal crystalline stresses are completely relieved while forming a uniform, dark-tinted iron oxide surface layer that provides natural atmospheric rust resistance and superior flexibility.
Black annealed steel coils offer an optimal balance of structural ductility, consistent tensile softness, and aesthetic dark surface quality. Engineered without the need for post-acid pickling or chemical plating, these versatile steel coils serve as an economical, easy-to-form material solution for furniture pipe manufacturing, structural tubing, binding wire production, and light hardware stamping.
Thermal Processing State: Oxygen-Free Bell Annealing / Continuous Black Annealing
Surface Appearance Finish: Uniform Dark Black / Charcoal Grey Oxide Film with Light Protective Oiling
Hardness & Mechanical Softness: Soft Condition, HRB 50 to HRB 65 (High elongation percentage)
Yield & Tensile Elongation: Tensile Strength 290 MPa to 430 MPa;
Thickness Dimension Range: 0.1 mm to 2.50 mm precise thickness tolerance control)
Coil Width Availability: 600 mm, 914 mm, 1000 mm, 1220 mm, 1250 mm
Oiling Protection Status: Light Anti-Rust Oiled, Heavy Dip Oiled, or Dry
Compliance International Standards: ASTM A1008 / A1008M, EN 10130, JIS G3141, GB/T 5213
Furniture & Decorative Steel Tubing: Widely roll-formed and high-frequency welded into round, square, and oval steel tubes for chairs, table frames, clothing racks, and interior metal furniture.
Construction Binding & Industrial Strapping: Slitted into high-tensile narrow strips or drawn into soft binding wires used for heavy cargo packaging, baling, and construction rebar tying.
Electrical Conduit & Cable Channels: Formed into black metal conduit pipes, electrical wire shielding channels, and flexible armoring strips.
Light Stamping & General Hardware: Utilized in door hinges, mounting brackets, curtain rods, and agricultural hand tool fittings requiring deep bending without cracking.
High Ductility & Crack-Free Bending: The specialized bell-annealing cycle restores the grain structure, allowing tight 180-degree bending, flattening, and tube expansion without micro-fissures or weld seam splits.
Uniform Surface Oxide Layer: The dark magnetite layer acts as a barrier against atmospheric moisture while providing excellent adhesion for post-applied black lacquer, oil coatings, or powder coats.
Seaworthy Corrosion-Inhibiting Packaging: Packed with heavy VCI anti-rust paper, PE inner film, steel outer drum shells, edge guards, and high-tensile steel straps on sturdy wooden skids.
