At present, hot-dip galvanizing is a widely used anti-corrosion and anti-rust treatment method in the field of grating. Because the zinc layer can produce a sealing protective layer on the surface of the grating, and also has excellent practical effect of pipeline cathodic protection. If the zinc layer is accidentally scratched, the cathodic protection effect of the zinc layer itself can also protect the iron flat steel from being eroded by gas. The hot-dip galvanizing solution can reasonably maintain the micro-cracks caused by the wound and cold drawing of the plate and the zinc ablation area near the welding to avoid corrosion.
The secondary electric welding of the grid plate, because the existence of the zinc layer makes the electric welding of the galvanized grid plate difficult, the melting point of zinc is about 420 ℃, and the evaporation temperature is 908 ℃, which is not conducive to electric welding, when the electric Solitary evaporates as soon as it is ignited. Zinc evaporation and air oxidation can cause blowholes, unsoldering and cracks, and even jeopardize the reliability of the electrical isolation, in which welding cracks, blowholes and weld flashes are the key problems.
When the galvanized grid plate is welded by arc welding and electric welding, the zinc layer around the molten pool is oxidized to ZnO and volatilized under the effect of electric isolation, resulting in very large dust. The main component of this type of dust is ZnO, which has a very large stimulating effect on the vocal organs of employees. Therefore, excellent natural ventilation measures must be adopted during electric welding. Under the same welding standard, the amount of dust caused by silicon oxide type welding wire is low, while the amount of dust caused by low hydrogen type welding wire is large.
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