Materials Science and Engineering
Material Properties
Elasticity
Capacity of materials to return to their original form after the force is removed.
Plasticity
Material’s ability to retain its shape once deformed.
Ductility
Ability to stretch the material into wires.
Malleability
Material’s ability to stretch without breaking.
Hardness
Opposition of a material to be penetrated by another material.
Fragility
The material breaks into splinters when impacted by a force.
Toughness
Resistance opposed by a body when subjected to deformation efforts.
Fatigue
Slow deformation of a material subjected to easily variable loads.
Machinability
Ability of a body to be cut by chip removal.
Resilience
Resistance of a body to sudden efforts.
Mechanical Forces
Traction
The force tends to elongate the object and acts perpendicular to the surface it is subjected to.
Compression
The force tends to shorten the object and acts perpendicular to the surface that holds it.
Flexion
The force is parallel to the fastening surface and tends to bend the object.
Torsion
The force tends to twist the object.
Cutting
The force is parallel to the surface that breaks and passes through it.
Buckling
Similar to compression, but occurs in objects with a large section and short length.
Material Testing
Hardness Test
Slowly stretching a standard length and section of material to analyze until it breaks.
Fatigue Test
Quickly rotating a specimen of material to analyze how it is deformed due to constant stress.
Impact Test
Measures resilience by determining the energy needed to break a standardized specimen of material by an impact from a pendulum at a speed of 5-7 m/s.
Metallurgy and Materials Processing
Copper Production
High Content Copper Ore (above 10%)
- The copper ore is introduced into a blender and then passed to a ball mill to pulverize it.
- To separate the gangue, the mineral powder is introduced into a tank full of water and agitated.
- The concentrated ore is carried to an oven where the iron is oxidized.
- The ore is introduced into a reverberatory furnace where it melts.
- Flux is added to form slag.
- Copper is obtained with 40% purity and is electrolytically refined to 99.9%.
Low Content Copper Ore (below 10%)
- The ore is crushed and sulfuric acid is added.
- Electrolysis is performed to obtain copper.
Lead
Characteristics
- Very malleable and soft.
- White color.
- Rusts easily.
- Withstands sulfuric and hydrochloric acid.
Applications
- Pure Lead: Used to produce lead oxide (minio) for paints, pipes, and battery coatings.
- Alloy: Lead and tin-based solder used as filler material.
Aluminum Production
- Bauxite is transported from the mine to the processing location, crushed, and ground into powder.
- Bauxite powder, caustic soda, lime, and hot water are mixed.
- Waste is separated in a decanter.
- The solution is cooled in a heat exchanger and water is added.
- Alumina is precipitated in a precipitation tank.
- A filter separates the alumina from the soda.
- Alumina is heated to 1200°C to eliminate moisture.
- Alumina is cooled to room temperature.
- Alumina is dissolved in molten cryolite at 1000°C and subjected to electrolysis to separate aluminum and oxygen.
Electric Furnace Operation
- The lid is removed, and scrap and flux are inserted.
- The oven is closed, and electrodes are brought close to the scrap to create an electric arc that melts the scrap.
- Oxygen is injected to eliminate undesirable elements.
- The oven is tilted to remove slag.
- Carbon and ferroalloys are added and heated to dissolve and homogenize.
- The oven is tilted to pour the steel into a bucket.
Characteristics
- Lined with firebrick.
- Reaches temperatures up to 3500°C.
- Capacity of 100 tons.
- Each batch takes about an hour.
Blast Furnace Parts
- Bosh: Where the load is entered at the top.
- Crucible: Repository of iron droplets.
- Bigotera: Where slag is drawn every two hours.
- Arrabio Boobies: Where liquid iron is extracted from the crucible.
Converter
Converts pig iron into steel.
Coke
Created artificially from coal combustion. Produces heat for smelting and chemical reactions to transform iron oxide into pig iron. Supports the weight of the raw material to prevent crushing and ensure proper burning at the top of the oven.
Tin Production
- Cassiterite is crushed in a mill.
- It is then placed in a tank with water and stirred.
- Tin ore settles to the bottom and is separated.
- The ore is oxidized in a furnace to remove sulfide.
- Tin oxide is introduced into a reverberatory furnace for reduction.
- Slag is deposited at the top, and tin at the bottom.
- To achieve 99% purity, an electrolytic process is necessary.