week 9 final Flashcards
what happens to pure iron when heated to 1538 degrees
it melts
what happens to pure iron when heated to 1394 degrees
it becomes paramagnetic and a bcc structure (a BCC structure 1394 degrees (magnetic but dependant on surrounding conditions)
what happens to pure iron when heated to 912 degrees
becomes (gamma) iron austenite (solid solution of carbon in a non-magnetic form of iron) FCC
becomes soft and ductile (non-magnetic)
what happens to pure iron when heated to 25 degrees
becomes a BCC structure (magnetic)
how is steel formed
it’s formed by dissolving carbon into a Fe (iron)
what is a Fe-Fe3 C phase diagram useful for?
allows understanding of steel properties how to make steel with specific properties and helps to determine phase compositions
what is an interstitial position
small atoms of a non-metal, occupying space between larger atoms of metal
what is a cementite and properties
compound of iron and iron. this is very hard and brittle (used to strength steel)
what do the mechanical properties of steel depend on
depends on the microstructure of the material (how ferrite and cementite are mixed)
what does the microstructure depend on during the formation
it depends on the composition (Carbon content and how it gets heat-treated)
what is a pearlite
the mixture of ferrite and cementite
how is pearlite formed
formed upon slow cooling and a distribution of carbon and cementite
mechanical properties of pearlite
soft, ductile ‘ferrite’ and hard, brittle ‘cementite’
what is a Spheroidie and how is it formed
a mircrostruture consisting of ferrite crystals. its formed by heating bainite or pearlite for a long time
‘fine pearlite or coarse pearlite’ which one is harder and stronger
fine pearlite
