🔍 Key Concepts

• Tempering as a follow-up process to hardening/quenching • Relationship between hardness and brittleness in metals • What heat treatment does to the internal stresses and crystal structure of steel

💭 Think About

• Think about what happens to steel that has been fully hardened and quenched—what is it like in terms of brittleness and toughness? • What is the purpose of reheating (tempering) that already-hardened steel—does it usually make it harder, softer, tougher, or more brittle? • Which choice best matches the idea of "reducing internal stresses" and making the material less likely to crack in service?

✅ Before You Answer

• Remember that hardening and tempering are not the same step—tempering is done after hardening. • Ask: "Does tempering usually make steel more or less likely to snap or crack suddenly?" • Check which option describes an improvement in toughness/ductility rather than increasing the risk of sudden failure.