Corrosion and stainless steels + heat treatment

Question 1

What does CRES mean?

Answer 1

Corrosion Resistant Stainless Steel

Question 2

What are the 3 categories of stainless steel?

Answer 2

Austenitic
Ferritic
Martinstitic

Question 3

What metals are austenitic made up of?

Answer 3

Chromium / nickel and chromium nickel manganese alloys

Question 4

How much chrome is in Ferritic materials?

Answer 4

15 - 30%

Question 5

What percentage of chromium do martenstitic materials contain?

Answer 5

12 - 18%

Question 6

What does precipitation hardening do to steel?

Answer 6

Makes it harder and more resistant to temperature

Question 7

What are ferrous and titanium alloys susceptible to?

Answer 7

Hydrogen embrittlement

Question 8

How does stress concentration occur?

Answer 8

Misuse of tools

Question 9

What is required for galvanic corrosion to occur?

Answer 9

Annode and Cathode

Question 10

What is galvanic corrosion potential?

Answer 10

A measure is how dissimilar metals will corrode when placed against each other in an assembly

Question 11

What are the 2 methods of case hardening?

Answer 11

Carburising and nitriding

Question 12

Is case hardening used on ferrous or non-ferrous metals?

Answer 12

Ferrous

Question 13

What are the 3 types of carburising?

Answer 13

Gas, pack and liquid

Question 14

What temperatures are components heated to in pack carburising?

Answer 14

1700 degrees Celsius

Question 15

How does liquid carburising work?

Answer 15

Object heated to a suitable temperature and then immersed in a hot, salt bath at 900 degrees C

Question 16

What does nitriding involve?

Answer 16

The introduction of hydrogen