Metals Flashcards
Ferrous metal
iron is predominantly
wrought iron, cast iron, steel
Non-ferrous
other metals
copper, lead , zinc, aluminium, titanium
Wrought iron
heated ans then worked with tools
Cast iron
melted, poured into a mouls and soldified
Steel
iron-carbon system
Iron, carbon, alloying element
Alloys
micture of metallic elements
- BRASS - copper and zinc
- BRONZE - copper and tin
Carbon steel
as you add more carbon the steel becomes stonger, less ductile and more difficult to work with
cast iron = more than 2% carbon
what does ductility mean?
ability to be deformed under tensile stress without lossing toughness
what does malleability mean?
compressive stress
What would happen if you added chromium to an alloy?
srongly increase hadrenability
improves corrosion resistance
high-temperature strength
Additive vs. impurity
improves strength
adverse impact another property such as ductility, toughness and weldability
The atomic arrangement of alloys
two ways
- substructional (e.g. nickel and chromium) - added elements can take hosts space
- interstitial (e.g. carbon) - occupy space between atoms of the host
types of steel
carbon steel = 90% of total steel production
alloy steel = cheaper
stainless steel = chromium added for corrosion resistance
tool steel = hard and durable
Process of making steel
- blast furnace steelmaking
- electric air furnace steelmaking
1- iron making 2- primary steelmaking 3- secondary steelmaking 4- continuous casting 5 - primary forming 6 - fabrication and finish
Steel process appliances
raw materials blast furnace converter ladle continuous casting slabs / billet / bloom plate/rods and tubes / structural, shape and rails
Oxidation
exposure to water, oxygen, another metallic arrangement
atmospheric corrosion / electrolytic corrosion = coating and good detailing
Rainscreen cladding
double wall system which uses an inner (structural) and outer (non-structural) leaf to create a seal against moisture (ventilated cavity)
Corten Steel
resists the corrosive effects of rain, snow, ice and fog by forming a coating of dark brown oxidation over the metal-stable rust appearance
Benefits of steel
versatile durable strength (strength to weight ratio) ease of manufacture constructability low coat recyclable
Trade-offs of steels
maintenance cost
small fire resistance
cannot be moulded
can lose its ductility - brittle fractures increases
fatigue - large variation in tensile strength aesthetics
Environmental impact of steel
fossil fuels depletion ( coal,oil,gas)
climate atmospheric energy used ( greenhouse gas)
recycled content
electrolytic
durability
ecotoxicity - emission can contaminate the surrounding environment
reduce - reuse - remaunfacture - recylce
