The steel and metal manufacturing industry smelts and/or refines metals for use in many different sectors, especially construction. Companies in this industry also manufacture metal alloys and superalloys by introducing other chemical elements to pure metals. The output of smelting and refining, usually in ingot form, is used in rolling, drawing, and extruding operations to make various types of sheet, strip, bar, rod, and wire metal products, and in molten form to make castings and other basic metal products.