The effect of nickel on cost and quality in hot dip galvanizing

The corrosion costs of uncoated materials necessitate coating of metals or protection from corrosion in exterior applications exposed to atmospheric corrosion. Different coating systems have been developed to protect against corrosion. Among these systems, hot dip galvanizing is one of the common methods used. In this method, the steel material passes through the pre-treatment steps and is coated by immersing it in the zinc bath which is melted at 450 oC and generally galvanized materials are obtained at coating thicknesses of > 55 μm. The main goal of all galvanizing businesses is to reduce zinc consumption, as the tonnage of zinc cost is over $ 3,000. In this study, The low alloy carbon steel materials having the <%0,03 wt. low silicon content and %0,14-0,25 high silicon content were coated in melted zinc with different Ni concentrations. Samples were examined with <%,0,03 and >0,03 Ni concentrations and the coating thicknesses of the samples were determined. Data gathered during these processes were analyzed by multiple regression analysis and other statistical methods. Not only primarily the effects of Ni analyzed, but also Ni, Pb and Bi correlations on zinc coating thickness investigated. Optimum values were determined by optimization analysis to decrease coating thickness. To be able to compare between the Ni tablet and powder application, XRF tests were carried out to determine the chemical composition of the samples taken from the bottom dross and surface ash formed during zinc immersion and the amount of Ni lost by dross was tried to be determined. According to the analysis, it has been determined that 27,85$/ ton potantial cost saving was calculated when Ni element was used. It has been calculated that a saving from zinc around 50.000-60.000 $ per month can be obtained. Anahtar Kelimeler: Hot dip galvanizing, Nickel, cost-saving, quality