Hardness and hardenability

For hardening of steel by quenching, the steel is cooled in __________

• Furnace

• Still air

• Water or Oil bath

• Cooling tower

The cooling rate must be _________ the critical cooling rate for hardening of steel by quenching.

• Higher than

• Lower than

• Equal to

• Half to

Phase transformation during hardening transforms

• BCC to FCC

• FCC to BCT

• BCT to HCP

• FCC to HCP

The slip does not occur in martensite due to the presence of _______ in the lattice.

• Silicon

• Germanium

• Carbon

• Tin

The hardening process is carried out on ________ steel.

• No carbon

• Low carbon

• Medium carbon

• High carbon

How does the rate of cooling affect the hardness of steel?

• Faster cooling results in low hardness

• Slow cooling results in high hardness

• Fast cooling results in high hardness

• No changes

How does the size of the specimen affect the hardness of steel?

• Smaller size results are high hardness

• Smaller size results in low hardness

• Larger size results in high hardness

• No change is found

___________ is defined as the ease of forming martensite.

• Hardness

• Hardenability

• Toughness

• Strangth

Hardness readings are taken every ________ after quenching in Jominy end-quench test.

• 0.01 mm

• 0.1 mm

• 1.6 mm

• 2.5 mm

Quenching of the sample in Jominy end-quench method is done at _______

• 0 degree

• 25 degree

• 125 degree

• 200 degree