Metals
Ferrous - Metals that contain iron and carbon
Non ferrous - metals that do not contain iron
Ferrous alloy - a mixture of 2 metals that contain iron and carbon
Non ferrous alloy - 2 metals that dont contain iron or carbon
Oxidization - Rusting - Any metal that contains steel will rust.
Mild steel - quite strong, cheap, rusts easily, cant be hardened. USED FOR CAR BODIES.
High carbon steel - harder than mild steel .. rusts.
Cast iron - hard however brittle under impact.
HIGH CONTENT OF CARBON MEANS THE MATERIAL WILL BE BRITTLE!!!
Non ferrous metals
Aluminium - Not as strong as steel - expensive . USED FOR AEROPLANES
BRASS - quite strong corrosion resistant USED FOR DOOR FURNITURE AND ELECTRICAL PARTS.
Copper - soft - conductor of electricity. USED FOR WIRES AND PIPES
Ferrous alloys -
Stainless steel
High speed steel
Non ferrous alloys
Brass
Bronze
25% of earths crust is made up of metal!!!!
ALUMINIUM IS THE MOST COMMON.. FOLLOWED BY IRON.
Iron is extracted, heated up, top layer (the impurities) (slag) are removed. and then cooled to create a greyish metal (purities)
Steel is a mixture of iron and carbon
Alloying with other metals enhance Toughness and resistance to corrosion.
BY DOING THIS YOU CREATE A NEW MATERIAL AND NEW PROPERTIES AND CHARACTERISTICS!!!
Carbon - ORGANIC MATERIALS - like coal and diamond made up purely or carbon.
Thursday 8 October 2009
Casting
Sand Casting
Pouring molten metal into a prepared cavity in a sand mould and allowing it to solidify.
Steel and aluminium are most commonly used in this process.
Ideally suited to manufacture a one off product.
Advantages - Cheap , easy, Hardly any waste and all waste metal can be recast. Even the sand can be reused.
Investment Casting
Create a mould, fill it with sand. Place wax mould of whatever you want too make out of metal into the sand. Pour molten metal through the hole and set.
Wax will dissapear and all impurities will remove themselves through the bottom air hole.
You will then achieve a perfect model of what your wax mould was.
Pouring molten metal into a prepared cavity in a sand mould and allowing it to solidify.
Steel and aluminium are most commonly used in this process.
Ideally suited to manufacture a one off product.
Advantages - Cheap , easy, Hardly any waste and all waste metal can be recast. Even the sand can be reused.
Investment Casting
Create a mould, fill it with sand. Place wax mould of whatever you want too make out of metal into the sand. Pour molten metal through the hole and set.
Wax will dissapear and all impurities will remove themselves through the bottom air hole.
You will then achieve a perfect model of what your wax mould was.
Thursday 1 October 2009
Hard and Soft woods
Natural Timbers
Lumber : When the wood is in natural log form
Timber: is processed material in the form of woods you would purchase from BNQ
Wood: is the material
Hardwoods - deciduous tree (looses leaves in the autumn)
Walnut
Teak
Ash
Oak
Hardwoods are slow growing and therefore aremore expensive
Softwoods: coniferous tree (trees with needles or pine cones)
Doglas Fir
Spruce
Pine
Larch
Softwoods are cheaper because they grow more quickly than hardwoods. They are also not as dense and strong.
The annual rings - show how old the tree is
Light rings on the grain of the wood show that it was summer when the tree was growing
Dark rings show that it was winter when the tree was growing.
You can tell how old a tree is by measuring the distance between the dark rings.
FSC
By seeing the FSC logo marked on products it shows that the wood came from a sustainable maintained source.
Lumber : When the wood is in natural log form
Timber: is processed material in the form of woods you would purchase from BNQ
Wood: is the material
Hardwoods - deciduous tree (looses leaves in the autumn)
Walnut
Teak
Ash
Oak
Hardwoods are slow growing and therefore aremore expensive
Softwoods: coniferous tree (trees with needles or pine cones)
Doglas Fir
Spruce
Pine
Larch
Softwoods are cheaper because they grow more quickly than hardwoods. They are also not as dense and strong.
The annual rings - show how old the tree is
Light rings on the grain of the wood show that it was summer when the tree was growing
Dark rings show that it was winter when the tree was growing.
You can tell how old a tree is by measuring the distance between the dark rings.
FSC
By seeing the FSC logo marked on products it shows that the wood came from a sustainable maintained source.
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