Metals Polymers & Sustain Flashcards
Chemically metal is…
An element that has positive ions surrounded by a cloud of delocalised electrons
Physically metal is…
A substance that has a bright lustre, good conductivity of heat, good conductivity of electricity, varying degrees of hardness, density, ductility and malleability
2 type of metal
Ferrous
And
Non ferrous
Ferrous metals are
Metals that contain iron and are magnetic
Non ferrous metals are
Metals that do not contain iron and are not magnetic
2 examples of ferrous metals are
Cast iron
And
Steel
2 examples of non ferrous metals are
Aluminium
And
Copper
Alloy metals are
Ferrous or non ferrous metals with an added substance
2 examples of ferrous alloy metals are
Steel + carbon = carbon steel
And
Steel + chromium = stainless steel
An examples of non ferrous alloy metals are
Copper + zinc = brass
Ferrous metals are normally used for
Structural use
Non ferrous metals are usually used for
Non structural use
4 examples of structural metal use in construction are
1) Steel frames - beams and columns
2) Steel flooring - profile metal sheeting
3) Steel roofing - trusses
4) Bridge construction
4 examples of non structural use of metals are
1) Pipework systems
2) Electrical wiring
3) Framing systems for building cladding systems
4) Windows and doors
Raw materials of ferrous metals are (4)
1) Iron ore
2) Coal / coke
3) Limestone
4) Oxygen
Stages of manufacture of pig iron are (6)
1) DIG the iron ore
2) CRUSH the iron ore, coke and limestone
3) WASH out the less heavy impurities
4) HEAT the mix of iron ore, coke and limestone in a blast furnace to breakdown the mineral into its constituent elements
5) DRIVE OFF the volatile impurities (eg sulphur, phosphorous and arsenic from the molten iron mix in the furnace
6) COLLECT the pig iron at the bottom of the furnace
The raw materials for making steel are (3)
1) Pig iron
2) Steel scraps
3) Lime
Steel is produced by (3)
1) REMOVING the impurities from the pig iron
2) REDUCING the carbon content
3) ADDING definite proportions of other elements (eg manganese and silicon)
What is the purpose of the manufacture of secondary steel (4)
1) To improve homogenisation of temperature and composition of steel
2) To allow careful trimming of composition to extract ranges of analysis
3) To remove harmful and unwanted gases such as hydrogen
4) To minimise impurity elements such as sulphur to low levels
The raw material for making secondary steel is…
Molten steel from wither BOF or EAF
BOF stands for
basic oxygen furnace
EAF stands for
Electric arc furnace
Six stages to modern steel manufacture are
1) IRONMAKING - raw materials melted in blast furnace
2) PRIMARY STEEL MAKING - BOS and EAF - oxygen blown through metal at high temperature with scrap steel being added
3) SECONDARY STEEL MAKING - treats molten steel produced from BOS and EAF to adjust composition - adding or removing certain elements
4) CONTINUOUS CASTING - molten steel cast into a cooled mould creating thin steel steel - then cut to desired lengths
5) PRIMARY FORMING - formed into various shapes by hot rolling
6) MANUFACTURING - secondary forming gives steel its final shape - shaping (cold rolling), machining (drilling), joining (welding), coating (galvanising, heat treatment (tempering), surface treatment (carburizing).
Depending on the type of steel required secondary steelmaking can be by (5)
1) stirring
2) ladle furnace
3) ladle injection
4) degassing
5) CAS-OB (composition adjustment by sealed argon bubbling with oxygen blowing
Steel can be described as…
A ferrous alloy metal of iron and carbon containing less than 2% carbon - construction steel typically contains 0.05% - 0.5% carbon as well as additional elements to improve performance.
Objectives of secondary steel making (6)
1) De-oxidation
2) De-sulphurisation
3) Alloying
4) Mirco cleanliness (removals of impurities)
5) Inclusion morphology (change composition of remaining impurities)
6) Superheat control
Blast furnace can be described as….
Large steel vessel lined with refactory brick
Molten iron produced in blast furnace by
1) Raw materials being fed in from top
2) Hot air (between 900degC and 1300degC blasted from bottom
3) Takes 6-8 hours to descend to bottom in form of molten iron and molten slag
Pig iron has a _____ %age of carbon and is therefore very _____________
Higher
Brittle
3 main methods of structural passive fire protection
1) Insulating board
2) Cementitious Sprays
3) Intumescent Paints
Examples (1 - 3 of), Advantages (2 - 2 of) and disadvantages (3 - 1 of) of fire insulating board…
1) Examples - Gypsum, minimal fibre, vermiculite
2) Easy to apply, aesthetically acceptable
3) Difficulties with compels details
Examples (1 - 2 of), Advantages (2 - 1 of) and disadvantages (3 - 3 of) of fire cementitious sprays…
1) Mineral fibre or vermiculite in cement binder
2) Cheap to apply
3) Messy, expensive clean up, poor aesthetically
Advantages (1 - 2 of) and explain what happens when heated (2 - 1 of) of fire insulating board…
1) Aesthetically pleasing, can be used as decorative finishing, can be done off site
2) Expands on being heated to produce insulating layer
2 types of plastics are
1) Thermoplastic - always softens when heated
2) Thermosetting - does not soften when heated
Plastics perform poor in fire - give 4 examples
1) Creep - loss of strength
2) High combustability
3) Toxic fumes from combustion
4) Hazards from melted liquids from plastics
Advantages of using plastic are (5);
1) Relatively Strong
2) Lightweight
3) Durable
4) Low conductivity of heat
5) Low conductivity of electricity
Disadvantages of plastic are (3);
1) Combustable
2) Degrades under direct sunlight
3) Low elasticity
Climate change implications for building design (6);
1) increased extreme weather events
2) increased foundation movement on clay due to drier summers and traumatic flooding
3) Increased summer over heating
4) Disruption of site activities
5) Design loadings - wind
6) Material design - sealants, joining materials, coatings
Sustainable building design priorities;
1) Reduce need for mech systems - use natural vent
2) Thermal performance of materials
3) Renewable energy sources
