GLEAMING IRON.

Auckland Star, Volume LIX, Issue 198, 22 August 1928, Page 6

GLEAMING IRON.

A city's bridges built of vast spider webs of gleaming silver, chimneys and gasometers and other outdoor ironwork bright and burnished as a corporal's buttons instead of marred with dingy paint—these are some of the possibilities foreseen by Mr. C. J. Brown, who told the recent centennial meeting of the Institution of Civil Engineers in London something of what may be done, of what almost is being done, in industrial applications of the new rustless steels. Our age of iron might equally be called the age of rust. Estimates of what it costs the world to use a metal so easily eaten into by the atmosphere range into many billions annually. Paint is an imperfect device, a confession of metallurgical failure. Mr. Brown is among the optimistic engineers who believe that the end of this age of rust and paiut is almost in sight.

Rustless steels, or "stainless steels," as iney are often called, are iron alloys not unlike ordinary steel, but containing some of the less familiar elements, chiefly chromium and silicon. In these alloys the atoms of iron are protected from disastrous contacts with air and water by filmst. of these other elements which form over the surface. These films are very thin, almost transparent, strongly adherent. If they are scratched or torn away they automatically renew themselves. So simple and familiar a thing as ordinary rust is still not completely understood by the chemists, and the protective action of these foreign films has its similar uncertainties of theory, but it seems probable that these rustless alloys really are merely self-painting metals, the "paint" being this thin, persistent, reproducible film. Just now these alloys are too costly for bridges, nor is their ability to keep their strength known perfectly. These deficiencies Mr. Brown expects that time and research will cure; the more research the less time.

It is not that the Iron Age of the historians is passing. More iron is made to-day than ever before, and more still probably will be made with each decade. What threatens to pass is the exclusive iron age; the age when ordinary iron is the only metal that engineers use and depend on and think about. It would be interesting to discover just how much men's minds have been influenced by the dingy exterior of this metal which has been the world's simile of steadfast strength. Whosoever has deemed himself of ironlike character may have felt it necessary to look tlyit way, to be dull and dingy as well as strong. Now that gleaming rustless steels and delicate silvery aluminium are coming into their own it may be possible to believe that beauty and ,«trei»eth are ,ict incompatible.