1. Impacts on Common Subsequent Processing Procedures
| Processing Type | Specific Negative Impacts |
|---|---|
| Laser/Plasma Cutting | 1. Oxide scale has high thermal conductivity, causing uneven heat absorption of the steel surface during cutting-leading to rough edges, burrs, or incomplete penetration.
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| Welding | 1. Oxide scale (mainly FeO, Fe₂O₃) decomposes at high temperatures to produce oxygen, which reacts with molten weld metal to form pores, slag inclusions, and brittle weld joints.
|
| Bending/Stamping | 1. Hard oxide scale is brittle and easy to peel off during plastic deformation, causing scratches or indentations on the steel surface and die.
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| Artificial Patina Acceleration | 1. Loose oxide scale blocks the contact between the chemical accelerator and the base steel, causing uneven patina formation (light spots or no patina in scale-covered areas).
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2. Solutions to Eliminate the Impact of Oxide Scale
Mechanical Removal (Most Common for Industrial Processing)
Sandblasting: Use fine-grained aluminum oxide or steel grit to blast the surface at low pressure (0.2–0.4 MPa). This removes oxide scale and creates a uniform roughness (Ra 3–5 μm) that is beneficial for subsequent patina formation. Suitable for large-batch processing of flat steel.
Wire Brushing: Use a soft stainless steel wire brush to polish the surface-suitable for small-batch, local oxide scale removal (e.g., edge areas). Avoid hard steel wire brushes to prevent surface scratches.
Chemical Removal (Suitable for Precision Components)
Pickling: Immerse the flat steel in a dilute hydrochloric acid solution (5–10%) for 10–20 minutes, then rinse thoroughly with clean water and dry. This method completely removes oxide scale but requires post-treatment to neutralize residual acid and avoid re-rusting.
Note: Do not use strong acids (e.g., concentrated sulfuric acid) to prevent over-corrosion of the base steel.
Combined Removal (For Heavy Oxide Scale)
First use mechanical sandblasting to remove thick, loose oxide scale, then perform light pickling to clean residual fine oxide particles-ideal for weathering flat steel with long-term storage and severe oxidation.
