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The process of the low-span hot steel wire

Process description: line-annealing-slow-cold-pickling-washing-assisting-drying-galvanizing-grinding zinc layer-receiving.


Main process description

       Annealing

       During the drawing process of low carbon steel wire, the stress increases continuously, so it must be annealed before galvanizing. The temperature of returning is about 800-830 °C. Generally, the temperature of the steel wire pulled out by Q195 steel wire is relatively low, and the Q235 steel wire is pulled out. Low carbon steel wire temperatures are relatively high.

       2. Pickling

       Pickling is generally the choice of hydrochloric acid, the ratio of hydrochloric acid is 1:1, there is no temperature limit for pickling, room temperature can be. If the surface of the steel wire is corroded more seriously, the concentration of hydrochloric acid can be slightly increased. If the surface of the steel wire is smooth and intact, the pickling time can be shortened.

       In the pickling process, the ferrous ions will continue to precipitate, and the content is also increasing. When the iron salt reaches 150 g / liter, the pickling speed will be greatly slowed down. At this time, 2/3 can be extracted, and then 2/3 of hydrochloric acid was added, and the concentration of hydrochloric acid added again was 1:1.

       3. Co-plating

       The plating agent is an important process before hot-dip galvanizing. It can activate the surface of steel to avoid oxidation of the surface of the steel wire, improve the quality of galvanizing, and reduce the formation of zinc slag, thereby reducing production costs.

      4. Galvanized

      Hot-dip galvanizing is the key to the whole process. After experimental research, hot-dip galvanizing can achieve the most satisfactory effect when the temperature is 440-460 °C. The lower temperature can reduce the influence of silicon on the galvanized layer, reduce the zinc and The formation of dross. The temperature is too high, the production of zinc slag and zinc ash will increase, and the life of the zinc heating furnace will also be shortened.

       5. Removal of dross

       After hot-dip galvanizing, zinc slag is inevitably produced and is increasing. Zinc slag is mainly an intermetallic compound of iron and zinc, and its specific gravity is greater than that of zinc liquid, so it sinks to the bottom. When the dross accumulates to a certain extent, it may adhere to the surface of the steel wire, affecting the quality of the galvanized layer, and its thermal conductivity is poor, and it will accumulate on the wall of the zinc boiler, affecting the heat conduction, and will Reduce the life of the zinc pot.