In the process of using the diesel heater, due to the influence of air and environment, a black substance will appear on the surface of the diesel heater. Do not be alarmed at this time. Dispose of the following method:
(1) The surface of the metal tube is first cleaned and kept clean;
(2) Surface degreasing treatment: This process can completely place the metal tube in the degreasing solution. The PH value of the degreasing solution is preferably around 13 and the time is not less than half an hour. After degreasing, wash with water.
(3) The following can be pickled, the PH value of the pickling solution is about 3, the processing time is not longer than ten minutes, and the water can be washed after pickling.
(4) At the end of the process, the blackening treatment is carried out with a pH value of 2-4 between the bath solution concentration and a treatment time of 10 minutes. After blackening, it must be cleaned, and finally dried and oiled