Trial 2 (Less important)

Question 1

Air Hardening

Answer 1

If steel has small amounts of Ni and Cr, it can be air hardened
- heated to red hot, cooled in still air = martensitic

Added molybdenum reduces brittleness

Question 2

Austempered Ductile Irons (ADIs)

Answer 2

Cast iron, (spheroidal graphite cast iron)

Good tensile strength
Used where previously steels used instead of cast irons. (lighter, easier cast, less affected by sub-0 temps, work harden under stress and better dampening,

Question 3

Further casting methods:

Answer 3

Centrifugal
Ingot
Continuous

Question 4

Direct vs Indirect Extrusion and Impact

Answer 4

Direct: ram pushes metal into die, cheaper. Used with lower ductility metals.

Indirect: stationary die (uused for alloys with lower ductility): more expensive

Impact extrusion: used for cans, etc.