The Effect of Hot Dip Galvanizing Temperature to Corrosion Rate of Steel as the Material for Chopper Machine

Abstract

This study aims to find material steel for animal feed chopper machine which is not easily corroded with method of hot dip galvanizing (HDG). Steel as machinery components or construction often gets broken before the predicted time because of corrosion. The HDG method was begun by pre-treatment process which were polishing, degreasing, rinsing I, pickling, rinsing II, fluxing, and drying. The main process of galvanizing was done by dipping in 98% of zinc solution with temperature variation of 430, 450, 470, and 490°C. The coating thickness measurement was run with Coating thickness NOVOTEST TP-1M. The corrosion was tested with electrochemical method of potentiodynamic polarization with AUTOLAB PGSTAT 128. The highest value of coating thickness was at galvanized temperature of 490°C which was 88.9 ± 3.24%. The value of standard deviation was indicated by how much the coating homogeneity formed. This was in line with the amount of corrosion rate at galvanized temperature of 490°C. The highest corrosion rate values in H2SO4 and NaCl environment were 1.18 and 0.21 mm/year. The highest hardness value of Zn layer is galvanizing temperature of 490°C which rises 41.71% of the base metal. The coating thickness, corrosion and surface hardness test have thee good agreement.