Processing method: soaking;
Time: 300s;
Processing temperature: 40-45 ℃;
Purpose: To remove yellow rust or oxide scale from the surface of the workpiece;
Testing method: Visually check whether the surface color of the workpiece presents the natural metallic color and whether the color is consistent. Neutralization method can also be used to detect the total acid in the working solution, using phenolphthalein as an indicator and 0.1mol/L NaOH standard solution.
The content of iron ions is saturated, and the rust removal effect decreases. Regular replacement is necessary;