ANTHR 206 LECTURE 15

Technology Pt 2

Overview of Metallurgy

• Main topics: Significance, Basic Concepts, Non-ferrous Metallurgy, Iron Metallurgy

Significance of Metallurgy

• Technological Complexity: Metallurgy marks human advancement.

• Impacts of Metallurgy:

  • Environmental Deterioration: First human impact was resource depletion.

  • Economic Impacts: Promoted long-distance trade and specialization of labor.

  • Social Implications: Contributed to social inequality over time.

  • Political Conflict: Issues over resources led to conflicts and warfare, such as in horse breeding.

• Technological Advancement: Innovations drove progress in various civilizations.

• Comparison of Old World vs. New World:

  • Old World faced resource depletion, while the New World navigated deforestation due to agriculture.

Metallurgy Distribution

• Differences in ore distribution between Metallurgy in Old World and New World.

Chemical Composition of Earth’s Crust

• Major Elements by Weight:

  • Oxygen (O) - 45.20%

  • Silicon (Si) - 27.20%

  • Aluminum (Al) - 8.00%

  • Iron (Fe) - 5.80%

  • Calcium (Ca) - 5.06%

  • Other elements are present in smaller quantities.

• Notably, aluminum's late entry into metallurgy and the scarcity of many metals.

Basic Concepts of Metallurgy

• Key Processes in Metallurgy:

  • Smelting: Reducing metal from its ore.

  • Bloom: Impure metal produced by smelting.

  • Slag: Waste material from smelting.

  • Ingot: Cast metal in a mold.

  • Annealing: Heating and hammering to strengthen metal.

  • Quenching: Rapid cooling to enhance strength but increases brittleness.

Advanced Techniques

• Tempering: Reduces brittleness via reheating.

• Casting Techniques: Open molds, two-piece molds, and lost-wax molds.

• Initial metalwork included hammering and required high temperatures to refine ores into usable metals.

• Unique objects made using lost-wax technique.

Types of Molds in Metallurgy

• Open Mold

• Lost-Wax Mold

• Two-Piece Mold

Fine Metalwork Techniques

• Methods include:

  • Stamping

  • Engraving

  • Repoussé: Embossing technique.

  • Filligré: Thin wires crafted into various shapes.

  • Granulation: Small metal beads for decoration.

  • Plating: Bonding different metals together.

Repoussé Technique

• An overview of repoussé focusing on the method of embossing.

Filligré and Granulation

• Explanation of filligré (thin wires) and granulation (tiny beads) for various decorative applications.

Alloys in Metallurgy

• Common Alloys:

  • Bronze: Copper + Tin (Cu + Sn)

  • Brass: Copper + Zinc (Cu + Zn)

• Alloys are generally stronger and have improved mechanical properties.

• Limited areas in the Old World where metallurgy advancements could lead to political differences due to access to metals.

Non-ferrous Metallurgy

• Key Metals & Their Properties:

  • Copper (Cu): 1083°C, with minerals like Malachite (green) and Azurite (blue).

  • Tin (Sn): 232°C from Cassiterite.

  • Lead (Pb): 327°C from Galena.

  • Zinc (Zn): 420°C from Sphalerite.

  • Silver (Ag) and Gold (Au) also noted for their melting points and color properties.

Copper Minerals

• Discussion of various copper minerals and their properties, leading to the origins of non-ferrous metallurgy.

Other Non-Ferrous Minerals

• Mention of minerals like Lead (Galena), Tin (Cassiterite), and Zinc (Sphalerite).

Iron Metallurgy

• Iron Properties:

  • Smelting at 800°C, with a high melting point (1537°C).

  • Various iron ores include:

    • Magnetite: 72% iron.

    • Hematite: 70% iron.

    • Taconite: 30% iron.

    • Limonite: Low grade.

  • Differences in wrought iron, cast iron, and steel based on carbon content and their applications in tool-making.

Iron Ores

• Description of iron ores including Magnetite, Hematite, and their historical use for pigments.

Impurities in Metallurgy

• Bloom production needs extensive refining, resulting in ingots from shaped blooms meant for distribution.