UNIT 3.1 - HEAT TREATMENTS & ALLOYING

Question 1

HEAT TREATMENTS

Answer 1

• metals are made up of millions of tiny heat grains
• grain structure influences the properties, such as hardness or ductility
• metal properties can be altered by heat treatment (controlled heating and cooling of a metal)

Question 2

HEAT TREATMENTS - HARDENING

Answer 2

• medium and high carbon steels are heated then held at a certain temp for a given time, then quenched in water, oil or salt water baths
• process increases the hardness but also increases brittleness

Question 3

HEAT TREATMENTS - TEMPERING

Answer 3

• reduces some of the excess hardness and brittleness from a hardened metal and increases the toughness and ductility
• metal is heated to below the critical point for a given time then slowly air cooled
• the exact temp the metal is heated to will determine the amount of hardness removed

Question 4

HEAT TREATMENTS - CASE HARDENING

Question 5

HEAT TREATMENTS - ANNEALING

Question 6

HEAT TREATMENTS - NORMALISING

Question 7

ALLOYING