Baking blue packing steel strip process flow

The bake blue packing steel strip must be washed and dried before the bake bake of the bake steel strip before it can be processed into the 'basket'. Subsequent toasted blue packaged steel strip processing is to analyze the content of sodium nitrate, sodium nitrite and sodium hydroxide in the solution on a regular basis every one week or so, so as to replenish relevant ingredients in time. Generally, all the solutions should be replaced after six months of use.
　　 (1) Take 10g of sodium hydroxide, 4g of sodium carbonate, 1g of water glass, add 100mL of water to make a degreasing solution; take 50g～60g of sodium hydroxide, 10g of sodium nitrate, 3g of sodium nitrite, and add 100mL of water Dissolve and mix into baking blue liquid.
　　 (2) Polish the iron sheet with sandpaper, then place it in a beaker containing 20 mL of degreasing liquid, heat and boil for 5 min to 10 min, take it out with tweezers, and rinse with water.
　　 (3) Immerse the iron sheet after degreasing on the surface in a rust removing liquid (15% dilute sulfuric acid) and heat (60℃～80℃) to remove rust, take it out and wash it after about 2min.
　　 (4) Put the degreasing and derusting iron flakes in a beaker containing 20mL roasting blue liquid, heat and boil for about 20 minutes, take it out with tweezers, rinse with water, and wipe dry. It can be seen that there is a layer of black and blue on the iron flakes. Color or black dense oxide film.
　　 (5) Although the surface oxide film after oxidation treatment is relatively compact, there are still tiny pores. In order to improve the corrosion resistance, the oxidized iron sheet can be placed in a 3% to 5% potassium dichromate solution (90°C to 95°C) for about 10 minutes to fill or passivate the pores, and then place it again Fill the loose holes in hot engine oil (105℃～110℃) for about 5 minutes.
　　 (6) Immerse the baked blue iron sheet in a 2% copper sulfate solution, keep it at room temperature for 20s, and then take it out. Wash the surface with water. If there is no red contact point, the baked blue is qualified.