Metallurgy and Metal Alloys: Properties and Processing

Metallurgy and Metal Processing

Core Concepts

• Process Metallurgy: The extraction of ore deposits through preparation and separation of valuable metals from accompanying materials.
• Metallurgy: The separation of metals from other elements with which they are chemically combined.
• Metal Industries: The production of metals to create useful items.

Minerals and Alloys

A mineral is composed of a rich, usable part called sorts and a non-usable, poor part called bargain.

An alloy is a product obtained from the union of two or more chemical elements (at least one must be a metal) that retains metallic characteristics.

Solidification of Alloys

• Liquid Phase: The alloy remains fluid above the liquidus line.
• Solid + Liquid Phase: The alloy contains a mixture of both solid and liquid phases.
• Solid Phase: The alloy is entirely solid below the solidus line.

Iron and Steel Classification

• Iron: An alloy of iron and carbon with a carbon content of less than 0.03%, valued for its magnetic properties.
• Steel: Alloys of iron with a carbon content between 0.1% and 1.76%.
• Cast Iron: Alloys with a carbon content between 1.76% and 6.67%.

Blast Furnace Production: Produces an alloy containing approximately 4% carbon, 2% silicon, and trace amounts of phosphorus, sulfur, and oxygen.

Thermal Treatment of Steel

Thermal treatment involves subjecting steel to controlled temperature changes to alter its constituent properties.

• Tempering: Applied to achieve high hardness and mechanical strength.
• Tempering (Revingut): Heating to a temperature below 723°C followed by air cooling.
• Annealing: Used to reduce hardness and increase elasticity for easier deformation; involves heating to an elevated temperature followed by slow cooling.
• Normalizing: Heating to the austenitization temperature followed by air cooling.