Heat Treatment for Plain Carbon Steels Flashcards
Understand All 4 Heat Treatment Methods in 3 weeks
What does the term “Heat Treatment” mean?
Heat treatment is the term that describes the heating and cooling of a metal or alloy in the solid state to obtain certain desired properties.
Why is a steel’s ability to be heat-treated so important?
To gain wide range of properties such as hardness, strength, ductility and machinability.
These properties can only be achieved by controlling…
Heating and cooling rate
List the 4 types of Annealing
Annealing, Process Annealing, Full Annealing, Spheroidising Annealing
Can Heat treatment process vary the properties of steel?
Yes
What are the Three Stages of Annealing?
Stress relief, Recrystallization, Grain Growth.
What is the purpose of Process Annealing?
To relieve internal stress and soften the material
What is the purpose of Full Annealing?
To improve ductility and machinability in softer steel
What is the purpose of Spheroidising Annealing?
To improve the machinability and ductility of steel
What is meant by “critical cooling rate”?
Critical Cooling rate is the slowest cooling rate for austenite to transform to hard martensite structure.
Explain the effects of quenching medium and mass on the steel to be hardened.
The quenching medium affects the cooling rate and hardness of steel. Faster quenching like water increase hardness but may cause cracks, while slower quenching like oil reduce stress and improve toughness. The mass of the steel also plays a role—thicker sections cool slower, leading to partial hardening, while thinner sections cool faster, achieving full hardness.
What is Grain Refinement?
Grain Refinement is the process that reduces the size of grains to improve its mechanical properties.
