Hot shortness is described as which phenomenon?

• A. Increase in tensile strength
• B. Loss of plasticity as metal approaches melting
• C. Increase in hardness on cooling
• D. Reduction in electrical conductivity

Answer: (B)

Hot shortness is the loss of plasticity (ductility) as metal temperature approaches its melting point. In welding, certain impurities such as sulfur or phosphorus can form low-melting-point compounds at grain boundaries, which soften or partially melt as the metal gets very hot. This causes the material to become brittle and crack under stress while still hot, even though it may be strong at room temperature. That’s why the description “Loss of plasticity as metal approaches melting” is the best fit. Increased tensile strength, increased hardness on cooling, or reduced electrical conductivity do not describe this high-temperature embrittlement phenomenon.