METALS TEMA 5
METALS CAN BE USED IN INDUSTRIES…
1.1. THE PROPERTIES OF METALS HARD NON ADHESIVE COLD AND SMOOTH SHINY
PROPERTIES - PHYSICAL PROPERTIES - CHEMICAL PROPERTIES - ECOLOGICAL PROPERTIES
✕ PHYSICAL PROPERTIES a) STRONG: they can resist forces and don´t become deformed easily.
b) DUCTIL AND MALLEABLE Can be made into wire or into sheets
c) TOUGH:metals don´t break easily
d) PLASTIC AND ELASTIC: some metals can be bend and return to its original shape.
e) ELECTRICAL, THERMAL AND ACOUSTIC CONDUCTIVITY: metals are good conductors of electricity, heat and sound
f) MAGNETIC: magnets attract some metals
g) FUSIBLE: can be welded to other metallic objects.
h) EXPANSION AND CONTRACTION When the temperature rises, they expand, and when it falls, they contract.
✕ CHEMICAL PROPERTIES OXIDATION: metals react with oxygen in water and air.
✕ ECOLOGICAL PROPERTIES a)RECYCLABLE AND REUSABLE They can be processed to be used again.
b) TOXIC: some metals present a danger to human beings and the environment
1.2.WHERE AND HOW METALS ARE OBTAINED
WHERE ARE METALS OBTAINED? UNDERGROUND MINING SURFACE MINING
HOW ARE METALS OBTAINED? To extract the mineral from the rock we use… EXCAVATOR EXPLOSIVES DRILL
The minerals are separated into ORE and GANGUE ORE GANGUE
The metal is extracted from the ore in an ironworks through physical and chemical processes ORE METAL PHISICAL PROCESSES CHEMICAL PROCESSES
1.3. CLASSIFICATION OF METALS FERROUS (CONTAINING IRON) NON-FERROUS
a) FERROUS (CONTAINING IRON) COMMON INEXPENSIVE NEED PROCESSING TO PRODUCE PURE IRON USED TO MAKE ALLOYS
WHAT IS AN ALLOY? MIXTURE OF TWO OR MORE CHEMICAL ELEMENTS. PRIMARY ELEMENT IS A METAL METAL!!!
WHAT IS AN IRON ALLOY? MIXTURE OF IRON CARBON
WHAT IS AN IRON ALLOY? PURE IRON (CARBON 0,0008%- 0,03%) STEEL (CARBON 0,03%-1,76%) CAST IRON (CARBON 1,76%-6,67%)
WHAT IS AN IRON ALLOY? PURE IRON (CARBON 0,0008%-0,03%) GOOD MAGNETIC PROPERTIES CORRODES EASILY MELTS AT HIGH TEMPERATURES DIFFICULT TO MACHINE USES:ELECTRICAL AND ELECTRONIC COMPONENTS
WHAT IS AN IRON ALLOY? CAST IRON (CARBON 1,76%-6,67%) HARD AND RESISTANT
WHAT IS AN IRON ALLOY? STEEL (CARBON 0,03%-1,76%) VERY HARD AND STRONG
b) NON FERROUS ULTRALIGHT LIGHT HEAVY
LIGHT AND ULTRALIGHT METALS TITANIUM MAGNESIUM ALUMINUM
HEAVY METALS LEAD TIN ZINC COPPER
-Page 69 -Exercises 1, 4, 5, 6
2. SHAPING TECHNIQUES 2.1.SHAPING 2.2.POWDER METALLURGY 2.3.CASTING
2.1.SHAPING Shaping techniques are used to modify the shape of the unprocessed metal (i.e. bending, extrusion, punching or rolling). Extrusion Punching Rolling
2.2.POWDER METALLURGY The process has five stages: 1.-GROUND INTO POWER 2.-PRESSED IN STEEL DIES 3.-HEATED TO A TEMPERATURE 4.-PREASSURE 5.-LEFT TO COOL
2.3.CASTING 1. THE METAL IS HEATED TO MELTING POINT 2.-LIQUID METAL POURED INTO THE MOULD 3.-THE MOULD AND METAL ARE LEFT TO COOL 4.-THE SOLIDIFIED PIECE IS EXTRACTED
-Page 71 -Exercises 15, 20
3. CUTTING, JOINING AND FINISHING TECHNIQUES 1.-MARKING 2.-CUTTING 3.-DRILLING 4.-SHAPING/TURNING 5.-ROUGH FINISHING 6.-PERMANENT JOINTS 7.-JOINTS( PERMANENT AND TEMPORARY) 8.-FINISHES
3.1. MARKING
tools SCRIBERS (punta de trazar) COMPASS ODD-LEG CALLIPERS (compás de trazar)
3.2. CUTTING
tools METAL CUTTERS OR SHEARS GUILLOTINEHACKSAW PUNCH PRESS (troqueladora)
Power tools CIRCULAR SAW (sierra circular) ANGLE GRINDER (amoladora o radial)
3.3. DRILLING
tools AWL DRILL DRILL BITS
3.4. SHAPING/TURNING Turns the metal to the required shape
tools CHISEL (cincel) LATHE (torno)
3.5. ROUGH FINISHING To remove excess material from an object
tools FILE SCRAPER (espátula)
Power tools SANDER GRINDER (amoladora, esmeriladora)
3.6. PERMANENT JOINTS It´s impossible to separate the pieces without damaging them or breaking the joint
RIVETER (remachadora) ADHESIVEWELDING PRESS FIT JOINT
3.7. TEMPORARY JOINTS Can be joined or separated again without breaking the joint
NUT AND BOLTS SCREW
3.8. FINISHES It is used for removing imperfections, polishing or protecting metals from water and corrosion
GRINDING (esmerilado) POLISHING (pulidora) COATING (revestimiento)