Stainless Steel and Wrought Alloys Flashcards
how are wrought alloys manipulated
cold working
when are wrought alloys used
ortho wires
partial denture clasps
what is steel made of
iron
carbon
chromium
manganese
what does chromium do
improve tarnish resistance
what are the uses for steel
cutting instruments
forceps
what does it mean that iron is allotropic
it undergoes two solid state phase changes with temperature
where does ferrite exist
at low temperature
where does austenite exist
at high temperature
where does cementite exist
at low temperature
what is pearlite
mix of ferrite and cementite
what is an alloy
two metals which form a common lattice structure, are soluble in one another, and form a solid solution
what are the types of substitutional solid solution
random and ordered
what does the quenching of austenite produce
martensite
what are the properties of martensite
hard and brittle
what does slow cooling of austenite give
pearlite (mix of ferrite and cementite)
if fast cooling of austenite gives martensite how do we change that into pearlite
tempering
what is tempering of martensite
heating followed by quenching
what is the composition of stainless steel
iron
carbon
chromium
nickel
what does chromium do in stainless steel
lowers austenite to martensite temperature and rate
corrosion resistance
what does nickel do in stainless steel
improves fracture strength
improves corrosion resistance
what are the two types of stainless steel
martensitic
austenitic
why does austenitic stainless steel contain sufficient chromium and nickel
to supress austenite to martensite transition
what are the uses of austenitic stainless steel
dental equipment and instruments
ortho wires
denture bases
what are the properties of 18-8 stainless steel
does not heat harden
soft when cast
work hardens rapidly