What is hot shortness?

• A. a loss of corrosion resistance when the metal is overheated
• B. a decrease in impact strength upon cooling
• C. a loss of plasticity as the metal reaches its melting temperature
• D. an increase in hardness when the metal is quenched

Answer: (C)

Hot shortness is the loss of plasticity when metal is heated to very high temperatures, close to its melting point. At these temperatures, grain boundaries can become brittle or liquid films can form, which prevents the material from deforming easily and makes it prone to cracking during welding or forming. This is why the description calling out a loss of plasticity as the temperature nears melting best matches the concept. The other statements describe different phenomena—corrosion-related changes from overheating, changes in impact strength on cooling, or increased hardness from quenching—not hot shortness.