Material Properties

Question 1

What percentage of stainless steel must be chromium for it to be corrosion resistant?

Answer 1

More than 11%

Question 2

What metals are found in stainless steel?

Answer 2

Iron (bulk)
Carbon (for strength 0.25%) more than 2% would make it brittle
Chromium (corrosion resistance) 16-25%
Nickel (7-22% to stabilise the austenite at room temp)

Question 3

What does austenitic stainless steel mean?

Answer 3

It can be cold worked (so s.s can be shaped)
When ss is manipulated above the yield stress the alloy can be shaped and causes a simultaneous increase in strength due to work hardening.

Question 4

What is another type of ss (other than austenitic)?

Answer 4

Martensitic which contains v little/ no nickel and is commonly used for cutting blades.

Question 5

What does 18/8 refer to?

Answer 5

18% chromium (corrosion resistance)
8% nickel (to stabilise austenitic structure at room temp)
Found in dentistry stainless steel and cutlery