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Galvanizing - hydrogen removal after galvanizing

August 18, 2023

During the galvanizing process of steel parts, in addition to the electrodeposition of zinc, it is often accompanied by the side reaction of hydrogen ion reduction and hydrogen evolution. After hydrogen reduction, part of it becomes gas and escapes, and part of it penetrates into the coating and the substrate in the form of hydrogen atoms. In the lattice of the metal lattice, the lattice is distorted, the internal stress of the part is increased, and the coating and the substrate become brittle, which is called hydrogen embrittlement. Dehydrogenation uses heat to drive the hydrogen out of the part. The hydrogen removal effect is related to the hydrogen removal temperature and holding time. The higher the temperature, the longer the time, the more thorough the hydrogen removal. However, the heating temperature should not be too high. If it exceeds 2500C, the zinc crystal structure will be deformed and become brittle, and the corrosion resistance will decrease significantly. Generally use 190~~230OC, 2~~3h. The dehydrogenation temperature of carburized parts and soldered parts is 140~~160OC, and keep warm for 3h.