stainless steel and wrought alloys

Question 1

what is a wrought alloy

Answer 1

an alloy that can be manipulated or shaped by cold working e.g. can be drawn into a wire

Question 2

when does steel become cast iron

Answer 2

when there os more than 2% carbon

Question 3

when does iron have a body centred cubic lattice structure

Answer 3

less than 900 Celsius
more than 1400 Celsius

Question 4

when does iron have a face centred lattice structure

Answer 4

greater than 900 Celsius but less than 1400 Celsius

higher carbon solubility

Question 5

define an alloy

Answer 5

two metals that forma. common lattice structure meaning they are soluble in one another and form a solid solution

Question 6

2 types of solid solution

Answer 6

substitutional solid solution (random or ordered)

interstitial solid solution

Question 7

give 2 advantages and 2 disadvantages of SS as a denture base

Answer 7

a
light
fracture resistant

d
dimensional inaccuracy
difficult to ensure uniform thickness

Question 8

what temmperatures does ferrite and cementite exist

Answer 8

low temperatures

Question 9

what temperature does austenite exist at

Answer 9

720<1500

Question 10

what percentage of chromium is required to make steel stainless

Answer 10

> 12%

Question 11

what component of stainless steel lowers austenite to martensite transition temperature

Answer 11

nickel

Question 12

what are the two types of stainless steel

Answer 12

austenitic
martensitic

Question 13

what type od SS is used for dental instruments and wires

Answer 13

austenitic

Question 14

what is cold working / hard working

Answer 14

work done on a metal at low temperature

causes SLIP

dislocations collect at grain boundaries making material stronger and harder

Question 15

example of a use of wrought alloy

Answer 15

ortho wires
denture clasps

Question 16

what’re the required properties of ortho wire

Answer 16

high YM/EL
stiffness
high ductility
corrosion resistant