Which test could be used to indicate an approximation of hardness?

Which test could be used to indicate an approximation of hardness?

• A. tensile test
• B. impact test
• C. radiographic examination
• D. magnetic particle test

Answer: (A)

Hardness can be estimated from how a material behaves under load, because harder materials tend to be stronger. A tensile test pulls the material from its ends until it yields or breaks, giving you data like yield strength and ultimate tensile strength. Those strength values correlate with hardness in many metals, so you can use the results of a tensile test to infer an approximate hardness range.

The other tests don’t relate to hardness. An impact test gauges toughness by measuring how much energy the material absorbs before fracture, not how hard it is. Radiographic examination looks for internal flaws, and magnetic particle testing detects surface defects. Neither provides useful information about hardness, making the tensile test the best choice for an approximate indication.