There are several environmentally friendly and less invasive alternative treatments to pickling for weathering steel plates, which avoid the use of acidic solutions and better preserve the material's surface alloy elements critical for patina formation. These alternatives are suitable for removing oxide scales, loose rust, or surface contaminants, and are categorized by their working principles:
Shot Blasting/Peening: Use low-pressure (0.3–0.5 MPa) soft abrasives (glass beads) to blast the surface physically. Removes oxides without damaging the alloy layer; boosts coating adhesion.
High-Pressure Water Jet Cleaning: 100–200 MPa water (plus rust inhibitor) washes away loose scales. No chemical use; ideal for sensitive applications.
Fine Grinding: 200–400 mesh abrasive belts polish small areas to remove defects; precise and waste-free.
Induction Heating: Rapidly heat the surface to 300–400°C. Oxide scales crack and fall off due to thermal expansion differences; no impact on steel microstructure.
Neutral Salt Descaling: Immerse in 80–90°C sodium sulfate solution for 30–60 mins. Loosens scales via osmosis; no acid waste or neutralization needed.
Chelating Agent Treatment: Organic chelators (e.g., EDTA) dissolve oxides selectively; suitable for precision components but costlier.
