Investigation of the initial stage of hot dip zinc coatings on iron alloys with various silicon contents

In this work tests on the course of zinc coating formation on model iron alloys with diversified silicon additions in molten zinc, with short times of contact at the solid-liquid border have been presented. The experiments were carried out at the temperature of 440°C. The assumed time of contact between solid and liquid phases was: 1, 4, 9, 14, 29, 59 seconds. The test stand was designed. The structure and thickness of coatings obtained on steel with low silicon, on Sandelin steel and on high-silicon steel was defined. Based on the results we may ascertain that in the first stadium of the galvanizing process the impact of silicon upon the intensity of coating growth is small. Increased reactivity of silicon is already observed after about 29-59 seconds of the process.