The purpose of heat treatment of carbon steel is
To soften the carbon steel prior to shaping and machining
To relieve the residual stresses from strain hardening that occurs during cold forming
To control dispersion strengthening for achieving the final strength and hardness required in the finished product
All above
The microstructure in annealed carbon steel is
Austenite
Pearlite
Bainite
Martensite
Cooling down austenite by moderate cooling rate forms
Cementite
Carbon steel tempering should take place
Prior to quenching
After quenching
Prior to normalizing
After normalizing
Which of the following microstructures in carbon steel is a two-phased, lamellar (or layered) structure composed of alternating layers of ferrite (88 wt. %) and cementite (12 wt. %)?
When austenite is cooled down at a very high rate by quenching, its FCC structure will transform to Body Centred Tetragonal (BCT) known as
Which of the followings in carbon steel is an extremely hard and brittle phase which lacks toughness so it should be tempered?
Ferrite
List the hardness in ascending order (from low to high) of micro-constitutes in plain carbon steel
❌-❌-❌-❌
In the process of carbon steel normalizing, it is cooled down in
furnace
air
water
Saline water
In process of carbon steel quenching, which cooling medium has the bubbling problem?
Water
Oil
Salt water
What gas should be selected for quenching the carbon steel in the compressed gas quenching process?
O2
Cl2
H2
N2
Surface hardening heat treatment is also called as
Annealing
Quenching
tempering
Case hardening
