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Hot dip galvanized Double Head Screw

2018-07-13

Most of the hot-dip galvanizing process of steel pipes uses the flux method. In recent years, hydrogen reduction has been developed, which is a new process developed on the basis of continuous hot-dip galvanizing of Sendzimir steel strip. However, due to some technical problems, it has not been promoted so far.
The galvanizing process of the flux steel tube is substantially the same as that of the single steel sheet fluxing method. Since the original tube is generally free of oil and does not require a degreasing process, it directly enters the pickling process. For pickling, the tube bundle is first suspended in the first pickling tank for pre-acid washing. Then, by picking up the second pickling tank for pickling, all the scales can be removed. Hydrochloric acid or sulfuric acid heated to 50 to 60 ° C is usually used. The concentration of the pickling solution is between 10% and 20%, and the effect is good. The pickling time is determined by the condition of the scale of the steel pipe surface. The steel pipe is often strung together to speed up the pickling process. Therefore, the mounting of the protruding strips on the bottom and side walls in the pickling tank facilitates the rolling of the steel tube in the acid solution.
In the normal galvanizing temperature range (445 to 465 ° C), increasing the temperature of the zinc liquid can increase the fluidity of the zinc liquid. Thereby, the surface quality of the zinc layer can be improved and the reflow of the zinc liquid can be improved, and the weight of the plating layer can be reduced. In addition, the galvanizing time can be shortened and the production efficiency of the zinc pot can be improved. However, the galvanizing temperature is too high, which may cause deformation of the steel pipe.

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