Iron and Steel

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Chapter 11

• Iron and Steel

Ironmaking Steelmaking
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• The blast furnace is used to convert iron ore
  into pig iron.

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• Elements present in pig iron must be refined to
  allowable amounts to meet steelmaking
  specifications.

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• The microstructure of wrought iron consists of
  ferrite grains incorporating a large quantity of
  silicate slag elongated in the working direction.

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• In the basic oxygen furnace, oxygen is lanced
  into the molten pig iron and scrap steel.

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• The open hearth furnace can make large amounts of
  steel in one heat.

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• The electric-arc furnace is the most common
  furnace used in making many alloys of steel.

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• Each level of deoxidation practice exhibits a
  significant influence on the macrostructure of
  the ingot.

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• A shroud is used to protect the molten steel from
  picking up atmospheric gases as it is poured from
  the ladle into the mold.

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• The four types of semifinished forms (blooms,
  billets, slabs, and rounds) are defined by shape
  and dimensions.

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• The ingot mold is tapered to facilitate its
  removal from the steel ingot after solidification.

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• The macrostructure of a cast ingot consists of a
  chill zone of fine equiaxed grains adjacent to
  the mold wall, columnar grains that grow
  perpendicular to the wall, and equiaxed grains
  toward the center.

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• Primary rolling reduces the ingot to semifinished
  forms of desired cross section.

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• Continuous casting is a direct and continuous
  method of producing blooms, billets, slabs, and
  rounds.

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• Pipe is a shrinkage cavity located in the upper
  portion of the ingot.

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• Heavy press forging is performed in a large
  hydraulic press in order to reduce the size of
  the ingot to a semifinished form larger than a
  standard bloom.

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• Structural shapes are formed in several rolling
  sequences, known as roughing, intermediate
  rolling, and finishing.

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• Wire is drawn in several stages, known as drafts,
  on a wire drawing machine. After each draft the
  wire is coiled.

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• Tubing products may be produced as seamless or
  welded.

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• Inclusions become elongated in the working
  direction of the steel and lead to directional
  mechanical properties, known as anisotropy.

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• The AISI-SAE designation system indicates the
  alloying elements and the partial chemical
  composition.

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• The end use of carbon steel is strongly
  influenced by the carbon content.

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• Generic ASTM specifications indicate common
  characteristics of families of product forms and
  prevent excessive repetition in the individual
  product specifications.

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• Quality descriptors in ASTM standards are used to
  distinguish products well suited to specific
  applications.