Machinery and equipment, factories, trains and other modes of transportation all required for producing and delivering goods used iron in their construction. Iron became a major structural material for the framework of train sheds and columns in factories. It was also used
Metals 17 18 Decoration 2 for bridge building and for market halls and other utilitarian buildings. Nineteenth-century commercial buildings used cast-iron columns and beams protected from burning by masonry. Such columns and beams also allowed larger expanses of glass for storefronts. Pressed tin was often used on the interior, mostly for ceilings, but also on the walls. The pressed tin was a “modern” alternative to decorative plaster, chosen for its durability, ease of maintenance, and cost. Today, these metal elements are preserved in place, salvaged, or reproduced for historic buildings. Significant developments in cast-iron decorating include Joseph Paxton’s Crystal Palace (London, 1851) and the world’s tallest building at the time, the Eiffel Tower (Paris, 1889). In 1855 and 1856, Henry Bessemer of the United States developed a process that used a pear-shaped vessel called a converter, which later became known as the Bessemer converter. It enabled the refining of metal at a lower melting point while keeping the carbon content low. The Bessemer process and other innovations allowed inexpensive production of steel, which rapidly replaced iron. The availability of steel for structural components was a significant factor in the development of tall buildings by the turn of the twentieth century. Examples of early use of steel in decorating include Louis Sullivan’s steel-framed, masonry-clad structures in Chicago and Otto Wagner’s Austrian Postal Office Savings Bank (1904-1906) with a roof of metal and glass and columns of steel with exposed rivet heads. Throughout the twentieth century and into the twenty-first century, tall buildings have relied on a structural grid of steel columns, girders, and beams. Steel is cut and drilled in a factory, delivered to the site, and connected with bolts, rivets, and welds. Steel trusses may be used to support roofs. Light-weight steel is made into open web steel joists; indeed, steel studs and joists have become the standard for smaller commercial buildings. Residential construction, although primarily constructed with wood, often incorporates steel as a main floor beam and/or as columns in basements to support the main floor beam. Bauhaus furniture designers turned to steel for its modern, industrial aesthetic. Tubular and flat steel bars were exposed as the framework for furniture by Bauhaus and interna-tional-style architects and designers. Mies van der Rohe and Le Corbusier are among the twentieth-century designers of steel-framed furniture that set a design standard continuing until the present. Aluminum is as important as steel in buildings and interiors. Because it does not occur naturally on its own, the extraction process of aluminum from ore was initially so expensive that aluminum was more precious than gold or silver. Economical extraction methods have made aluminum available commercially for about 100 years.
10 Best Traditional Home Design Ideas Photo Gallery
Metals begin as ore, which is a concentration of the desired raw metal encased in host rock and other materials. Ore is removed from the earth either by surface or underground mining and then converted to raw materials. These raw metals may be combined with other metals before they are formed into usable products.
Mined ore is smelted, a process of separating the desired metal from the surrounding host rock, using the heat of a blast furnace and a source of carbon such as coke from coal. This process removes the oxygen from the ore, leaving metal. The coke introduces a small amount of carbon into steel. Pig iron is a direct product of the blast furnace, which then either is refined to produce steel, wrought iron, or ingot iron, or is melted again into special shapes.
Metal ingots must be shaped to create finished products by working. Working brings metal to its desired shape but also changes its properties, refining its crystalline structure. Worked metal can be either wrought or cast. Wrought metals begin with the solid molded shape of an ingot that is formed into its final shape by either hot or cold working. Hot working simply means that metals are heated to a temperature that is above the melting point of metal before being worked. Cold working methods keep the metal just below the melting point. Wrought, or worked, metals can be rolled, pressed, forged, stamped, drawn, or extruded.