Metallurgy Fundamentals

Smelting Metals

• Impure metals (ores) need testing before application—variations in properties and appearance.

Refining Crude Oil

• Fractional distillation—heating crude oil separates different hydrocarbons.
• Cracking—breaks down large hydrocarbon molecules into smaller ones.

Metals - Alloys

• Brass—copper and zinc alloy, sonorous, used in locks, gears, door handles, and more.
• Bronze—copper alloy, higher melting point than brass, highly ductile, denser than stainless steel, used in sculptures and bearings.
• Duralumin—aluminum alloy, lightweight, hard, used in aircraft.
• Bauxite—aluminum alloy, low conductivity, hard and abrasive, refined and smelted via electrolysis.

Metals - Ferrous

• Mild steel—tough, ductile, malleable, poor corrosion resistance, used in general construction/cutting tools.
• High carbon steel—wear-resistant, brittle, poor corrosion resistance, used in hand/machine tools.
• Stainless steel—magnetic, ductile, corrosion-resistant, used in cutlery and surgical instruments.
• Cast iron—heavy, rigid, easily machined, used in old lampposts and art pieces.

Metals - Non-Ferrous

• Aluminum—soft, low strength, high conductivity, alloyed easily, used in various metal products.
• Zinc—corrosion-resistant, used to galvanize other metals.
• Tin—corrosion-resistant, used to make tins.
• Copper—pure form is soft, malleable, corrosion-resistant, thermally and electrically conductive, used in wires, etc.
• Tungsten—toughest material, super dense, resistant to corrosion, melting point of 3422°C, used in drill bits and tools.

Woods - Manufactured Boards

• Made from recycled woods, available in large sheets—consistent properties; available pre-finished.
• Engineered boards (cement bonded particle board)
• Laminated (including plywood)—strong, cannot split, marine plywood is water resistant and thinner than regular plywood.
• Compressed (including MDF)—bonded with resin, similar to plywood but larger chunks.
• Wood veneers—stuck on manufactured boards to enhance aesthetics.

Woods - Hardwoods

• Hardwoods—slow-growing, require more land; more expensive but often favored for aesthetics.
• Oak—resistant to rot, long-lasting, strong, durable, corrodes steel—used in construction, furniture, ship building, etc.
• Ash—springy, elastic, shock-resistant—mostly in sports equipment, tool handles.
• Birch—uniform, even texture, low cost, least resilient against insects and rot; used in veneers, plywood, furniture, cabinets, etc.
• Mahogany—endangered species—aesthetically pleasing, stable, highly prized; used in vintage furniture.
• Beech—flexible, tough, odourless, resistant to abrasion, very hard to chip—used in bowls and toys.
• Teak—naturally high in oils—high resistance to acids and alkalis—used mainly in outdoor furniture and chairs.

Woods - Softwoods

• Fast-growth means low cost, mostly lightweight; less seasoning required.
• Douglas Fir—tough, cheap, strong—used in construction, decking, and instruments, etc
• Redwood—grow quickly, great strength-to-weight ratio—used in construction.
• Spruce—great strength-to-weight ratio—used in early aircraft (WWI and II).
• Cedar—high oil content, decay- and insect-resistant—used in outdoor furniture, fencing, decking, etc.
• Larch—high resin content—used in veneers, fence posts, furniture, and boats.

Woods - Random Memorisation

• Rough-sawn timber—cheapest, used most in construction/outdoors.
• Planed timber—made using a planer and thicknesser, smaller and more expensive.
• Natural timbers—most wood sold as boards and square sections—rough sawn or PSE or PAR.
• PSE timber—one square edge.
• PAR timber—square on all sides.
• Wood grain—structure of wood grain affects workability and cost.
• Wood structure—wood like group of straws.
• Anisotropic—material easy to break in one direction, hard in other.

Ceramics

• Used in aerospace, electronics, and biomedicine—made from same ingredients. Superior properties than unrefined ceramics.
• Borosilicate glass—low thermal expansion coefficient.
• Silicon carbide—can be combined with steel, high temp., incredibly hard and hard-wearing.
• Tungsten carbide—high melting point, twice as stiff and dense as steel—very high hardness.

Polymers - Thermosetting

• Cannot be reused, strongly linked monomers. Often hard and durable. Made from crude oil.
• Urea formaldehyde—hard, inexpensive, brittle—used as wood glue.
• Epoxy resin—high strength, stiff, brittle, chemical and electrical resistance, temp. resistance—used as coatings, LEDs, etc
• Phenol formaldehyde—high working temperature, used as laminate sheets, coatings on metals.
• Polyester resin—often bonded with other materials, lower cost than other resins, used in industrial coatings, boat building.

Polymers - Thermoplastic/Thermoforming

• Can be reused, loosely linked monomers: recyclable, remouldable. Made from crude oil.
• Polyethylene (PE)—120-130°C melting point, flexible, translucent, weatherproof, tough, low cost, food containers, bottles, etc.
• Polyamide (PA)—220-260°C melting point, high wear resistance, high thermal stability, good strength/hardness--textiles, sportswear, automotive parts.
• ABS—good resistance to med. temps, hard, tough, antistatic, good resistance—gardening tools, medical applications, pipes, etc.
• Polypropylene (PP)—poor UV resistance, translucent, rigid, light, excellent chemical resistance—plastic packaging, machinery parts, carpeting, ropes, etc.
• PVC—good UV resistance, excellent chemical resistance, glue-able, weldable, bendable, machinable, stiff—medical tubing, window frames, etc.
• Polyvinyl chloride (PVC)—very light, high tensile strength, hard, stiff—used in bottles, containers and chemical storage, etc
• Acrylic—weather resistant, difficult to recycle, corrosion resistant, electrical insulator—used in lenses, replacements for glass, display products indoor/outdoor signage.

Modern Materials

• E-textiles—materials that eliminate the need for wires and hard electronics, used in sensors, thermochromic displays, etc.
• Super alloys—extreme applications—turbine engines, marine, etc.
• High-Performance Alloys—unique alloys to meet specific needs—used in various industries.
• Bioplastics—plastics from natural sources (fossil fuels, corn, cane, sugar, potatoes).
• Nanocrystalline/Nanocomposites—materials with crystalline properties/added to improve other materials' properties—cutting tools, etc.

Smart Materials

• Respond to external factors (heat change, electrical charge, change in pressure).
• Thermochromic—respond to temp. change (colour change).
• Phosphorescent—respond to light changes (light output change).
• Photochromic—respond to light changes (colour change).
• Electrochromic—respond to current changes (colour change).
• Piezochromic—respond to pressure changes (colour change).
• Solvatochromic—respond to dissolving changes (colour change).
• Shape Memory Alloys—deform when cold, return to original when heated.
• Shape Memory Polymers—deform when heated/pressure applied.

Properties

• Compressive strength—resists being crushed.
• Tensile strength—resists stretching/pulling.
• Stiffness—resists bending.
• Hardness—resists wear/abrasion.
• Durability—resists weathering/damage.
• Impact resistance—absorbs impact without fracture.
• Plasticity—ability to be permanently deformed and retain that shape.
• Elasticity—ability to deform but return to original shape.
• Malleability—ability to be deformed.
• Ductility—ability to be drawn into wires.
• Density—mass per unit volume.
• Strength-to-weight ratio—comparison of strength and weight.
• Flammability—how a material burns after ignition
• Electrical Conductivity—whether it is an electrical conductor/insulator
• Thermal Conductivity—a conductor/insulator of thermal energy flow.
• Corrosion/degradation resistance—material's ability to withstand environmental attack.
• Additives—enhance polymer properties (e.g., fire retardant, antistatic, biodegradability).

Material and Component Considerations

• Materials need testing for profitability; being fit for purpose; desirable characteristics and properties.
• Aesthetics—feel, color, texture, shape, longevity, form, and user selection.
• Reducing costs/higher efficiency—specialized/compatible materials; storage/handling.
• Environmental considerations—social, ethical, economical, and environmental impacts.

Mechanisms

• Efficient mechanisms transfer power without adding or subtracting.
• Efficiency = (Actual Mechanical Efficiency/Ideal Mechanical Advantage) x 100%.
• Efficiency = (Output Power/Input Power) x 100%.
• Actual Mechanical Advantage = (Measured Output Force/Input Force).

Mechanisms - Types

• Motion—rotary, linear, reciprocating, oscillating
• Mechanical Advantage-Load/Effort
• Epicyclic gears—used in cars, engines, gearboxes, drills, motors—three gear ratios.
• Gears—idler gear, mitre, chain & sprocket, belt & pulley, worm drive, screw thread, rack & pinion.

Bearings and Lubrication

• Bearings—components supporting moving parts.
• Planned bearing, tapered bearing, ball bearing, fluid bearing, thrust bearing.
• Drive shaft—requires two contact points.
• Axial loading—force along an axis.
• Radial loads—act at right angles to the shaft.

Systems

• Systems generate/control/change motion.
• Force—often called effort.
• Output force—often called load
• Mechanical advantage = (distance moved by effort / distance moved by load).
• Mechanical advantage = (input arm length / output arm length).

Linkages

• Bell crank
• Crank and slider
• Peg and slot.

Joining Processes

• Joining Woods—difficult with high oil woods.
• Adhesives, joints, and fittings.
• Framing—adding, removing material.
• Laminating—creating curves and increasing surface area.
• Tanalising—prevents insect attack, forces copper sulphate into wood.

Definitions I Didn't Know

• CADD—computer-aided design and drafting (designs converted into technical drawings).

Explore the essential concepts of metallurgy, including smelting, refining, and the properties of different metal alloys. This quiz covers key terms and processes related to ferrous and non-ferrous metals used in various applications. Test your knowledge on the significance of metals in industry and everyday life.