Drying of steel pipes at a hot-dip galvanizing plant by induction heating

Abstract

Abstract In the dry galvanizing process, pipes are subjected to chemical treatment and then dried in a continuous drying furnace which is followed by the galvanizing kettle. However, drying furnaces used in a dry galvanizing process, lead to some problems. The impossibility of achieving a uniform temperature distribution along the pipe in conventional drying furnaces and the negative impacts thereof on the product quality make it inevitable to seek new approaches towards pipe drying. In this study, instead of in a drying furnace, the fluxed pipes were dried at the line by means of induction heating. By using an induction heating system, the pipes were heated up much more uniformly than by the conventional drying method. It is observed that the temperature change along the pipe surface varied by ±5 °C while it was 15–20 °C in the conventional system. In addition, the problem of black spots, seen very frequently at galvanizing plants, was eliminated completely.