钢铁英语课文分段新.doc

Steelmaking Steel is an  HYPERLINK /wiki/Alloy \o Alloy alloy made by combining  HYPERLINK /wiki/Iron \o Iron iron and other elements, and the most common of these are  HYPERLINK /wiki/Carbon \o Carbon carbon. When carbon is used, its content in the steel is between 0.002% and 2.1% by weight, depending on the  HYPERLINK /wiki/Steel_grades \o Steel grades grade. Other alloying elements sometimes used are  HYPERLINK /wiki/Manganese \o Manganese manganese,  HYPERLINK /wiki/Silicon \o Silicon silicon,  HYPERLINK /wiki/Chromium \o Chromium chromium,  HYPERLINK /wiki/Molybdenum \o Molybdenum molybdenum,  HYPERLINK /wiki/Boron \o Boron boron,  HYPERLINK /wiki/Titanium \o Titanium titanium,  HYPERLINK /wiki/Vanadium \o Vanadium vanadium and  HYPERLINK /wiki/Niobium \o Niobium niobium. Carbon and other elements act as a hardening agent, preventing  HYPERLINK /wiki/Dislocation \o Dislocation dislocations in the iron atom  HYPERLINK /wiki/Crystal_lattice \o Crystal lattice crystal lattice from sliding past one another. Varying the amount of alloying elements and the form of their presence in the steel (solute elements, precipitated phase) controls qualities such as the  HYPERLINK /wiki/Hardness_(materials_science) \o Hardness (materials science) hardness,  HYPERLINK /wiki/Ductility \o Ductility ductility, and  HYPERLINK /wiki/Tensile_strength \o Tensile strength tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but such steel is also less  HYPERLINK /wiki/Ductile \o Ductile ductile （韧性、可延伸性） than iron. Alloys with a higher than 2.1% carbon content are known as  HYPERLINK /wiki/Cast_iron \o Cast iron cast iron because of their lower  HYPERLINK /wiki/Melting_point \o Melting point melting point and good  HYPERLINK /wiki/Castability \o Castability castability. Today, steel is one of the most common materials in the world, with more than 1.4 billion