GB/T 8702-2002 regulates anti-corrosion coating requirements for steel round bars to prevent rust during storage and transportation:
Coating types: Allows oil coating (for short-term storage), phosphate coating (for medium-term), and paint coating (for long-term outdoor storage).
Oil coating: Requires uniform application with no bare spots, with oil film thickness 5–10μm; must be easily cleaned before processing.
Phosphate coating: Specifies coating weight ≥10g/m², with adhesion grade ≥3 (no peeling during bending test).
Paint coating: Mandates dry film thickness ≥60μm, with impact resistance ≥50cm·kg and salt spray resistance ≥240 hours.
This standard ensures steel bars remain rust-free before use, reducing material waste in manufacturing.