Processes – Galvanising

Operation and Process Description

The Galvanizing Line entry section comprises of two pay off reels and an overlap seam welder for strip joining. The Hot Dip Galvanising Line utilises a horizontal entry accumulator. The entry accumulator is located directly below the furnace section at floor level and utilises a six strand loop car. Three strip steering units are provided within the accumulator to correct any strip misalignment which may occur. The line includes a horizontal furnace section, consisting of a Non Oxidizing Furnace, gas-fired, to ensure strip cleanliness, an Electrical Heated Furnace, to maintain strip temperature and a Soaking Furnace, also electrically heated, to anneal the strip. The jet cooling section consists of 7 cooling fans to cool the strip down to the required temperature (approximately 460°) for entering the Hot Dip Bath.

The Hot Dip Bath consists of a bath roll system to control strip shape and coating. The air-knife system ensures accurate coating control based on an x-ray gauge moving across the strip measuring the coating on both sides. The composition of the bath is controlled with additions of Aluminium and Antimony. The mill is fitted with a 4 high Skin Pass Mill and a wet temper system that reduces zinc pick – ups and thereby frequent roll changes. A chromating unit applies the passivating agent and an electrostatic oiler is utilised for clients requiring oiled material.

The exit comprises of a multi strand vertical accumulator to facilitate coil removal and continuous processing. Before coiling and splitting coils, the product is visually inspected over the entire length by a dedicated inspector.