2. Rinse in hot water at 80 ~ 100℃ for 2 ~ 3min to completely remove the residual lye on the surface of the workpiece.
3. Wash in hot soap solution containing 5% ~ 8% (mass fraction) common laundry soap for 3 ~ 5min at 60 ~ 80℃. Its cleaning functions are as follows: first, it can completely wash off the lye on the workpiece to prevent the lye from corroding the oxide film and the operator's skin; Second, the oxide film of the workpiece treated with soap solution may generate iron stearate, which can increase the strength of the oxide film and the adhesion to steel parts.
4. Hang the workpiece in clean hot water (80 ~ 100℃) for 2 ~ 3min, then take out the replaced hanger (basket) and dry it. If the workpiece with soap solution is immediately immersed in the oil tank of the next working procedure without going through this working procedure, after it is taken out, a milky white shadow will appear under the oil layer on the surface of the workpiece, which is slightly different from the color of the oxide film, and it will gradually disappear after careful wiping.
5. Oil soak5ming: clean the workpiece, dry it with hot water, and soak it in 100 ~ 1 10℃ spindle oil or transformer oil tank for 5 minutes. Its functions are as follows: firstly, it can soak the iron stearate generated by the oxide film in soap solution, further increase the adhesion between the oxide film and steel parts, and improve the strength of the oxide film; Secondly, according to the formation principle of oxide film, it can be inferred that there are countless invisible cracks on the surface of oxide film, and the tiny cracks are filled with oil after oil immersion, which can increase the corrosion resistance of the film and make the workpiece look beautiful.