Samara National Research University named after Academician S. P. Korolev, Samara, Russia¹ ; Prodmash Plant, Samara, Russia²

O. S. Bondareva, Cand. Eng., Associate Prof., Dept. of Metal Technology and Aviation Materials Science¹, Leading Technologist², e-mail: osbond@yandex.ru

Samara National Research University named after Academician S. P. Korolev, Samara, Russia
V. A. Tretyakov, Student, e-mail: tretyakov.vitalick2015@yandex.ru

Prodmash Plant, Samara, Russia
V. V. Chekh, Advisor to the General Director, e-mail: v.cheh@zvpm.ru

The shortage of high-purity zinc leads to the fact that hot-dip galvanizing plants use technical zinc, often of foreign production, with an increased content of impurities. Of particular interest is the study of the effect of copper impurity accumulation in the zinc molten bath and the associated possible remote risks of coating quality deterioration, since such data are absent. Therefore, the purpose of this work was to analyze copper accumulation in the zinc molten bath, in hard zinc, in ashes and in coating phases, and to assess the risk of liquid metal embrittlement and cracking in the weld area with regular use of technical zinc with a copper impurity of about 0.004 wt.%. Using a TESCAN VEGA SB scanning electron microscope with an INCA-act energy-dispersive X-ray spectral microanalysis attachment, data were obtained on changes in the elemental analysis of the melt, hard zinc and ashes for 16 months of using technical zinc produced in Iran at JSC Prodmash Plant. It is shown that over the studied period of time there is an increase in the copper content in all samples. The microstructure of the zinc coating is studied, the coating phase in which copper accumulation occurs is established. It is shown that copper accumulation leads to a decrease in the microhardness of the zinc coating. The microstructure of the zinc coating in the area of welded seams is studied. Cracking of welded seams during galvanizing of products in a melt with an admixture of copper is not detected. It is concluded that copper impurities in the melt do not lead to liquid metal embrittlement of welded structures.

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