Corrugated Metal

Corrugated Metal. Iron and other metals in sheets and plates have communicated to them enormously increased rigidity and power to resist buckling and collapse by being corrugated. The process is merely an application to metallic substances of the old contrivance of 'goffering' or 'piping,' by means of which frills are stiffened and kept in shape. The metal to be corrugated is passed between pairs of rollers with ridged surfaces, the ridges of one fitting into the hollows of the other, and the sheets or plates operated on are bent and compressed into the wavy outline of the rolls. Walls and roofs of light and temporary buildings are extensively made of corrugated galvanised iron—i.e. sheet-iron first corrugated and subsequently coated with zinc by dipping the sheets into a bath of the liquid metal. The most important mechanical application of corrugated metal has been for the flues of large steam-boilers. About 1878 a system of annular corrugated iron flues was introduced, which increased the resistance of the flue to collapse, and saved fuel because of the greater heating surface presented by the corrugations. A spiral corrugated flue gives the greatest amount of strength.