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Steel
Strength, ductility, cheapness and machine ability are the four most important industrial and commercial properties of steel. Carbon steel has been known to be the principal product of the steel industry. Besides iron and carbon, it contains small quantities of manganese, phosphorus, sulphur, and silicon. Each of these elements affects the physical properties of steel. The most important influence of carbon is in connection with the hardness, strength, and ductility of the metal.
Manganese comes directly after carbon in importance. It improves rolling and forging qualities of metal and at the same time minimizes the harmful effect of sulpher. Phosphorus acts somewhat like carbon in which it increases tensile strength and hardness while decreasing ductility. Silicon is an excellent deoxidize or cleaner of steel.
When one or more metals are added to plain carbon steel, the steel acquires certain new characteristics. Depending upon the metals added and the amount of each, the steel becomes stronger, tougher, harder, more heat-resisting, more resistant to corrosion, or acquires some other special properties. Such steels are called alloy steels.
Manganese, nickel and silicon make the steel stronger, tougher or more corrosion-resistant. Chromium, molybdenum, and vanadium in combination with carbon make the steel harder and stronger. Silicon, manganese and titanium purify the steel ridding the metal of harmful impurities. Aluminum and zirconium counteract harmful oxides or gases.
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