Diesel heater in the process, due to the impact of air and the environment, the surface will appear a black substance.Do not panic at this time, according to the following methods to deal with:
(1) Firstly, the surface of the metal pipe should be cleaned and kept clean;
(2) surface degreasing: This process can be completely placed in the metal pipe degreasing them. Degumming liquid PH value is best in about 13, the time is not less than half an hour. After degreasing wash with water.
(3) followed by pickling, pickling solution PH value of about 3, the processing time is not longer than ten minutes, washed with water after pickling,
(4) the last blackening treatment, the concentration of the liquid pool PH value between 2-4, the processing time up and down 10 minutes. Be sure to clean after black, the last drying, oiled.