The hot-dip galvanizing of structural steel sections

Abstract

The transmission of electrical power by overhead systems has involved electrical engineers in yet another branch of engineering, as certain specialists in the structural steelwork industry fabricate the towers which support current-carrying conductors.The initial cost of an electrical scheme embodying an overhead transmission system can be such that a high proportion of outlay is for the transmission of the current, and the deterioration rate of materials used in construction must be kept aslow as possible so that depreciation of capital value and maintenance costs are minimized. Steelwork in an unprotected state, erected in areas where rainfall and atmospheric pollution can be rated even as normal, deteriorates by corrosion quicker than is acceptable.The general method of protecting transmission structures against corrosion is hot-dip galvanizing, detailed examination ofwhich would be of interest only to those engaged in research on the subject. However, a useful working knowledge of the process and the ability to distinguish a good coat from a bad one can be obtained from a reasonably short study.The object of the paper is to give electrical engineers a brief description of the metallurgical construction of a zinc coat, together with some information on its expected life, and to offer a condensed description of the process, certain methods of quality control and to advise on the after-care of the finished product.