Bluing clad steel belt process

Bluing dozen steel belt in steel belt for bluing always wash before and after drying, for & other; Roast basket & throughout; To deal with. Subsequent bluing type steel belt with every other week or so timely analysis of the solution, the content of sodium nitrate, sodium nitrite and sodium hydroxide in order to supplement the relevant component in a timely manner. All solution is generally use half a year later, it must be replaced. ( 1) Take 10 g sodium hydroxide, 4 g sodium carbonate, sodium silicate, 1 g 100 ml of water, as in addition to the oil; Take 50 g ~ 60 g sodium hydroxide, 10 g sodium nitrate, sodium nitrite, 3 g with 100 ml water dissolved into liquid bluing. ( 2) Use iron sand, and then put in a beaker of 20 ml in addition to the oil have, heat to boil after 5 min to 10 min, use tweezers to remove, and then rinse with water. ( 3) The surface of iron after degreasing in cleaning fluid ( 15% of dilute sulphuric acid) The heating ( 60℃～80℃） Derusting, washed out after about 2 min. ( 4) Puts the plate after the degreasing derusting, containing 20 ml bluing liquid in the beaker, about 20 min after heating boiling with forceps, rinse and dry, visible on the plate with a layer of dense black and blue or black oxide film. ( 5) After oxidation treatment of the surface oxide film, although more closely, but there are still a small hole. In order to improve the corrosion resistance, can be processed iron oxide in 3% ~ 5% potassium dichromate solution ( 90℃～95℃） In about 10 min, make loose hole filling or passivation, and then placed in the hot oil ( 105℃～110℃） In about 5 min, will loose hole to fill. ( 6) Will bluing iron after immersion in 2% of the copper sulfate solution, at room temperature keep out after 20 s, wash with water surface, if not appear red contact point, namely bluing qualified.