Question

Consider the following
Assertion (A): Jominy end-quench test is not suitable for evaluating maximum hardness of steel.
Reason (R): The Jominy end-quench test measures hardness variation along the length of a standard specimen

• A. Both A and R are true, and R is the correct explanation of A
• B. Both A and R are true, but R is not the correct explanation of A
• C. A is true, but R is false
• D. A is false, but R is true

Hint:

Jominy test = hardenability test, not hardness test.

Answer 1

The Correct Option is A

Concept: The Jominy end-quench test is used to determine the hardenability of steel, not its maximum hardness.

Step 1: Understand Jominy test.
In this test:
• one end of steel specimen is quenched
• cooling rate varies along length
• hardness is measured at different distances Thus it gives a hardness gradient curve.

Step 2: Evaluate Assertion.
Maximum hardness depends on:
• carbon content
• microstructure (martensite formation) Jominy test does not directly measure maximum hardness, so Assertion is true.

Step 3: Evaluate Reason.
Reason correctly states that hardness varies along specimen length, which is the basis of the test. Final Answer: \[ \boxed{\text{Both A and R are true, and R is the correct explanation of A}} \]