Metals Sources/ Commercial Manu. Flashcards
Life Cycle Assessment
- Extracting Material
- Manufacturing
- Transporting
- Using
- Recycling or End of life
Step 1- Mining Metals
Metal ores are mined from Earth.
Mined either by surface or underground mining which are energy intensive.
Step 2- Refining Metals
The impure metal needs to be refined
- mined metals aren’t usable in raw state
- smelting chemically alters the raw material
- refining, only purifies the material
Step 3- Smelting Metal
-after ore is mined, waste material must be separated.
- e.g. extracting iron from iron core uses a blast furnace which can reach temperatures of 1,700 degrees Celsius.
- iron melts, liquefies and sinks to the bottom of furnace, known as “pig iron”
- the waste product is known as slag, is tapped off
Step 4- Pig Iron
It runs off the blast furnace into rectangular moulds
- has very high carbon content
- this makes it very brittle
- some of carbon and other impurities are removed to make it into steel
Step 5- Bauxite
Bauxite ore is the primary source of aluminium
- to extract aluminium, the ore must first be chemically refined to produce an intermediate product.
- product is smelted using electrolysis for pure aluminium
Step 6- Duralumin
It is lightweight, but hard alloy of aluminium
- has aluminium and small quantity of copper, magnesium and manganese
- malleable= easily rolled or folded
- high strength
Step 7- Recycling Material
Most metals can be recycled
- can be recycled without altering its properties
- it is then processed, shredded, melted, purified and ready again for use.
Step 8- Dumping Metal
Recycling material is very beneficial to the planet= metals are sustainable
Stainless Steel
Stainless Steel is suitable for a huge range of products
- available in many diff finishes
- costs of different grades varies
- often used for kitchen utensils e.g. saucepans, sinks
Copper Cookware
good for cookware because:
- resistant to microbes
- good at heat distribution
- good conductor
Hardening Steel
Hardening medium- a high carbon steel makes it harder but more brittle
The workpiece is heated to a pre-determined temperature and rapidly quenched in water or special oil.
Tempering Steel
Tempering makes steel tougher and less brittle:
The workplace is reheated again and left to air cool which tempers it
Metals for Hand Tools
- Hand tools need strength and longevity
- be suitable for heavy use
- be hard wearing
be tough
have good tensile and compressive strength
Commercial casting
process of making objects by pouring molten metal into an empty shaped space. The metal then cools and hardens into the form given to it by this shaped mold. Casting is often a less expensive way to manufacture a piece compared with machining the part out of a piece of solid metal.
Milling and Turning
CNC machines are used commercially to mill and turn metal parts. They provide:
- improved accuracy
- versatility and speed
- increased safety
Quality Control
- ensures dimensional accuracy when producing materials
- depth stop may be used to ensure holes are drilled to specific depths
Plastic Dip Coating
a metal workpiece is heated and dipped into powdered plastic that bonds to the surface to protect it.
- provides insulation
- improves ergonomics
- changes functionality and aesthetic
Powder Coating
Electrostatically applied then cured to protect metal surfaces with a tough, even finish
Zinc Galvanising
gives a product a coating of zinc
process is low maintenance, resistant to corrosion and inexpensive
Electro- plating
uses electric current to add a thin layer of another metal to its surface
- adds protection
- improves aesthetics and adds value
Sand or Shot Blasting
Sand or Lead shot is fired at surface under pressure
- it is a surface preparation for another process or aesthetics
5 stages of making:
- Machines could be set up with jigs so that all parts of product are cut to the correct length
- sawing to length with power hacksaw
- sawing to length with power circular/rip/chop/cross cut saw
- held in place by jigs and spot welded/ seem welded by hand or robot arm. For BATCH PRODUCTION traditional Arc, TiG welding
- surface can be spray painted
or electroplating of zinc or tin to protect from rust
Examination LCA for Metals
Steel is made from iron ore. Ores are dug out of the ground by mining but in order to be turned into a metal form that can be used they must be separated from whatever they are mixed with. This process is known as extraction. A mixture of iron ore and coal is then heated in a blast furnace to produce molten iron or pig iron from which steel is made. Molten steel from the furnaces passes through continuous casters and is formed into slabs and billets. The steel is processed and rolled to form tubular steel lengths.
These are transported to manufacturing facility where the steel bar is cut, formed and welded and riveted to form the chassis of the trike. This is then spray painted to protect from rust.
During its life it can be repaired or resprayed if needed.
At the end, steel can be recycled once the painted finish is removed. The wheels would need to be removed and might be reused.
5 stages of making pt2.
POP RIVETS: are used to create a semi permanent fixing between two sheets of metal
requires a rivet gun for pressure
COLD FORM RIVETS: require access to both sides of sheet, they are set with a “snap”
BRAZING: permanent joining method where both parts are heated, spelter is heated and creates a joint. ONLY MELTS THE SPELTER not the metal parts that are being joined (great for bike frames)
WELDING: melts and fuses metals parts using a filler- MIG or TIG
WASTING AND ABRADING- grinding and files can be used to shape metal and remove sharp edges, comes in diff grades and profiles. Emery cloth and wet and dry paper can be used
TURNING- Turning is a machining process where a lathe is used to rotate the metal while a cutting tool moves in a linear motion to remove metal along the diameter, creating a cylindrical shape.
MILLING machines can cut horizontal or vertical to create slots, holes, joints
SANDCASTING- used to create complex shapes like engine parts. molten metal is poured into a sand mold containing a hollow cavity of the desired shape. After a period of time, the casting cools and solidifies. The sand is then broken away and shaken out.
PUNCHING AND BLANKING-
