That is, pickling, washing, washing, leaching solvents, drying. The pipe is washed by the crane to the pickling trough (2 tons per crane). 26%% of hydrochloric acid solution for pickling, in order to prevent excessive pickling and acid mist volatilization, in the pickling solution to add 0.5~1.0g/L corrosion inhibitor and fog inhibitor, at ambient temperature to pickling, pickling time is generally 30-60 minutes, in order to make the steel pipe can be evenly pickling, in the pickling process by using a crane to lift the steel pipe 2 ~ 3 times to improve the effect When the acid concentration drops to 100g/L should be supplemented or replaced, iron content reaches 220~260g/L as waste acid emission. The pickling steel pipe is washed by the crane to the washing trough to remove residual acid and ferric salts accumulated in the steel pipe surface after pickling. Then hanging to the washing table with 0.7~0.8Mpa water rinse, when the droplets dry, the steel pipe hanging to solvent trough leaching, dip dip time about one minutes, solvent use of 600~650g/L zinc chloride and 80~100g/L ammonium chloride and 1~2g/L OP-10 surfactants. In order to improve the plating effect of the solvent in the steel pipe, the solvent always keeps the weak alkaline, and then by the crane to the drying furnace rack into the drying oven, drying temperature 100, the time is generally 6-10 minutes.