A review on galvanizing coating defects : causes and remedies

Abstract

Hot-dip galvanizing is an efficient technique to control the corrosion of substrates. Producing blemish-free coatings is a challenging task. Continuous work is done on galvanizing technology to achieve excellent surfaces; thus, flaws are encountered at intervals in all continuous galvanizing and galvannealed process. Most of each very small galvanized defect can appear like a draff particle, draff trapped actually a tiny lot of the blemishes found in hot-dipped galvanizing coatings. Also, almost all defects take place due to a roughed or mechanically dented surface, poor bath chemistry management, inadequate washing of the parts, and less maintained apparatus. Thus, the coated products, which are manufactured by galvanizers, have to develop the excellence of the line instrument, the heat treatment management, and the Zn bath in sequence to touching the hard and tough quality essential for automotive uses and applications. This review paper first discusses different types of galvanized coating defects, and then discusses different coating defects like Bare spot, Distortion, Dross, Touch marks, Dents, Rough Coating, Ash Deposit, Mechanical Damage, Blow out, Runs, Uncoated or Ungalvanized Surface, Reactive and Non-reactive steels welded together, Puddling and suggests possible remedial measures to be taken care; at the end, it summarize and concluded.