ARC1414: Building Technology 1, Module 2, Division 5: Metals
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Questions and Answers

What type of aluminum is used mainly for thermal insulation and vapor barriers?

Aluminum foil

Which of the following factors are considered when aluminum is used as a structural material?

  • Aluminum being highly corrosive
  • Aluminum being very weak
  • Aluminum can be extruded economically (correct)
  • Aluminum being very heavy

    • Iron oxidizes rapidly in air and is readily attacked by most acids.

    True

    An impure form of iron that contains 3% to 4% carbon is known as ________ iron.

    <p>pig</p> Signup and view all the answers

    Match the type of aluminum finish with its description:

    <p>Mechanical finishes = Obtained by grinding, polishing, scratching, sandblasting, or other treatment of the surface Chemical finishes = Based on chemical reactions with the aluminum surface to achieve desired results Electrolytic finishes = Anodized finishes based on the ability of aluminum to develop a protective coating of oxide on its surface</p> Signup and view all the answers

    What is cast iron mainly used for in the architectural field?

    <p>Pipes and fittings</p> Signup and view all the answers

    Wrought iron is easily shaped by hammering, rolling, or pressing.

    <p>False</p> Signup and view all the answers

    What elements are present in plain carbon steels besides iron and carbon?

    <p>phosphorus, sulfur, oxygen and nitrogen</p> Signup and view all the answers

    Steel sheet material that is 12” or less wide is called ________.

    <p>strip</p> Signup and view all the answers

    Match the alloy element with its property in alloy steels:

    <p>Manganese = Workability Aluminum = Resistance to corrosion Titanium = Strength Molybdenum = High or low temperature performance</p> Signup and view all the answers

    What are stainless steels mainly used for in architecture?

    <p>Exterior and interior wall finishes</p> Signup and view all the answers

    What are the most important uses of zinc?

    <p>Protective coatings (galvanizing) on iron and steel, die-casting metal, alloying element in brasses</p> Signup and view all the answers

    What are the main characteristics of zinc?

    <p>Readily attacked by acids and alkalis</p> Signup and view all the answers

    Galvanized sheets become defaced and discolored when subjected to dampness and extremes of temperature.

    <p>True</p> Signup and view all the answers

    Brass is fundamentally an alloy of copper and ____.

    <p>zinc</p> Signup and view all the answers

    Match the following metals with their characteristics:

    <p>Nickel = Inert silvery metal that is resistant to strong alkalis and most acids Chromium = Steel-white metal that becomes magnetic at low temperatures Lead = Blue-gray, soft, very heavy metal with good corrosion resistance Bronze = An alloy of copper and tin with a rich golden-brown color</p> Signup and view all the answers

    What method is used to join metals by heating, pressure, and adding molten metal?

    <p>Welding</p> Signup and view all the answers

    Study Notes

    Metals

    Aluminum

    • Types of aluminum:
      • Aluminum sheet and strip: used for roofing, flashing, and gutters
      • Aluminum foil: used for thermal insulation and vapor barriers, rolled to a thickness of 0.005”
      • Corrugated aluminum: rigidized sheet fabricated from special aluminum alloys
      • Structural aluminum: used as a structural material, considering factors such as corrosion resistance, extrudability, and lightweight
      • Aluminum doors and windows: fabricated from extrusions and rolled shapes
      • Aluminum panels and sandwich panels: pre-fabricated units with aluminum exterior facing and cellular core
      • Ornamental aluminum: rods, bars, pipes, railings, fittings, and special shapes for ornamental design

    Finishes of Aluminum

    • Mechanical finishes: obtained by grinding, polishing, scratching, sandblasting, embossing, or other surface treatment
    • Chemical finishes: based on chemical reactions with the aluminum surface, used for etching, cleaning, or polishing
    • Electrolytic finishes (anodized finishes): used for protective and decorative coatings, colored finishes are porous and can be sealed
    • Electroplating: covering aluminum with a protective or decorative film of another metal, usually by electrodeposition
    • Porcelain or Vitreous Enamel: forming a hard, resistant surface with a broad color range
    • Paint: applied to aluminum surfaces with a suitable chemical treatment finish

    Iron

    • Pure iron: tough, malleable, silvery-white metal, soft and ductile, easily magnetized, and oxidizes rapidly in air
    • Characteristics: can be hardened by heating and sudden cooling, and made more pliable by heating and slow cooling

    Types of Iron

    • Cast iron: iron-carbon alloy with more than 1.7% carbon, hard and brittle, used for piping, ornamental ironwork, hardware, and porcelain enameled plumbing fixtures
    • Wrought iron: almost pure iron with less than 0.1% carbon, soft, malleable, tough, and resistant to progressive corrosion, used for genuine wrought iron pipe, chain, sheet, and ornamental ironwork

    Steel

    • Plain carbon steels: alloys of iron and carbon, not containing more than 2% carbon, made in malleable or ingot form
    • Characteristics: iron is always in excess of 95%, phosphorus, sulfur, oxygen, and nitrogen are present, manganese, silicon, aluminum, copper, and nickel may be present as residual impurities or elements deliberately added

    Types of Steel

    • Structural steel: medium carbon steel with controlled carbon content, available in angles, channels, I-beams, H columns, T shapes, Z shapes, plates, round pipe columns, sheet piling, open web joists, and light steel framing shapes

    • Wrought carbon steels:

      • Reinforcement of concrete: deformed bars of varying grades and diameters
      • Sheet and strip: used for fabricated form as decking, galvanized sheet, expanded metal, panels, and sandwich panels, and as a base metal for porcelain enamel

    • Alloy steels: added elements increase properties such as strength, hardness, electrical conductivity, and resistance to corrosion and wear### Types of Metals

    • Steel:

      • High-strength low-alloy steels: improved mechanical properties, resistance to atmospheric corrosion, and used in pre-stressed concrete, high-strength bolts, cables for elevators, etc.
      • Stainless steels: contain >10% chromium, resistant to heat, oxidation, and corrosion, used in exterior and interior wall finishes, doors, windows, etc.

    • Copper:

      • Ductile, malleable, nonmagnetic metal with high electrical and thermal conductivity
      • Resistant to corrosion by air and saltwater, but attacked by alkalis and common acids
      • Forms a protective green patina on exposure
      • Used in minor structural work, alloys, and electrical applications

    • Tin:

      • Soft, ductile, malleable, bluish-white metal
      • Resists corrosion by air, moisture, sulfur dioxide, and hydrogen sulfide due to a thin film of stannic oxide
      • Takes a highly reflective polish
      • Used in protective coatings, alloys, and solders

    • Zinc:

      • Medium hard, bluish-white metal
      • Characterized by brittleness and low strength
      • Readily attacked by acids and alkalis
      • Resistant to corrosion by water, forms a protective film of zinc carbonate or oxide on exposure
      • Used in galvanizing, die-casting, and alloys

    • Brass:

      • An alloy of copper and zinc
      • Less hard and strong than steels but superior in workability and resistance to corrosion
      • Used in various architectural applications

    • Bronze:

      • An alloy of copper and tin
      • Rich golden-brown metal
      • Can refer to alloys of copper with other elements, such as silicon, manganese, or aluminum
      • Used in various architectural applications

    • Chromium:

      • Steel-white metal that takes a brilliant polish
      • Harder than cobalt or nickel
      • Nonmagnetic at ordinary temperatures but becomes magnetic at 13°F
      • Resists oxidation and corrosion
      • Used in ferrous and nonferrous metallurgy, and in chromium plating

    • Nickel:

      • Inert silvery metal
      • Resistant to strong alkalis and most acids
      • Takes a high polish
      • Used in alloys to impart strength, hardness, toughness, and corrosion resistance
      • Used as a protective or decorative coating for other metals

    • Lead:

      • Blue-gray, soft, very heavy metal
      • Extremely workable
      • Has good corrosion resistance
      • Relatively impenetrable to radiation
      • Used in various applications, including radiation shielding

    Methods of Joining Metals

    • Soldering:
      • Joining metals using a lower melting metal or alloy
      • Used to make electrical connections, seal joints, and join metals
      • Soldered joints have little tensile, shear, or impact strength
    • Welding:
      • Process of joining two metals by creating an actual union of interatomic bonds
      • Can be done by close contact, heating, pressure, or adding molten metal
      • Resulting joints are as strong or stronger than the metals joined
    • Rivets:
      • Devices used to join or fasten metals
      • Rivet is inserted through holes in the materials being joined and then flattened to tie the pieces together

    Metals for Concrete Reinforcement

    • Steel Bars:
      • Mostly used for concrete reinforcement
      • Can be plain or deformed (with lugs or projections for better bonding to the concrete)
      • Can be billet-steel or rail-steel bars
    • Wire Fabric:
      • Made of cold-drawn steel wire
      • Widely used for reinforcing concrete slabs and floors, as well as stuccoed work
    • Expanded Mesh:
      • Manufactured from solid steel sheets
      • Sheets are cut or pierced in staggered slots or patterns and then stretched to form an open mesh
      • Forms can include diamond, crimp, herringbone, and Z-rib
      • Used in various applications, including STEELCRETE
    • Laths:
      • Permanent centering or self-centering laths
      • Produced in various forms, including flat or segmental sheets
      • Can be furnished painted or galvanized, and in open-hearth mild steel or special copper-bearing or alloy steels

    Storage and Care for Metal Reinforcement

    • Storage:
      • Metal reinforcement should be stored in racks above the ground and away from moisture and vegetation
      • If stored for an extended period, it's recommended to build a shed over the storage racks
    • Care:
      • Bright-red rust on reinforcement is not detrimental
      • Actual rust scales can indicate a reduction in the effective cross section of the bar
      • Deep scaling should be considered a reason for condemning the use of reinforcement
      • All reinforcement should be kept free from oil to maintain a good bond between concrete and steel

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    Description

    This quiz covers the topics of building technology, specifically module 2, division 5 which focuses on metals. It is designed for students taking ARC1414: Building Technology 1. Test your knowledge of building materials and technology.

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