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Mechanical vs heat treatment; red shortness

Short answer

Mechanical treatment shapes by force and refines grain (e.g., rolling). Heat treatment alters internal structure without changing shape (e.g., annealing, slow cooling to soften). Red shortness is hot brittleness from sulphur forming low-melting iron sulphide at grain boundaries.

Differentiate between mechanical and heat treatment of steel. How will you define annealing and red shortness of steel?

Mechanical vs heat treatment

PointMechanical treatmentHeat treatment
PrincipleShaping by force: rolling, forging, drawing, pressingHeating, soaking and cooling in a controlled way
ChangeShape/size and grain refinementInternal structure (phases) with the shape unchanged
AimTo get shape, remove defects, strengthen by work-hardeningTo change hardness, strength, ductility, toughness
TemperatureHot or coldSpecific temperatures (150-950 C)
ExamplesHot rolling, cold drawing, forgingAnnealing, normalizing, quenching, tempering

Annealing

Annealing is heating steel above the upper critical temperature, soaking, and cooling very slowly in the furnace to soften it, remove internal stresses and refine the grain.

Red shortness

Red shortness is the brittleness of steel at red-hot temperature (during hot working such as forging and rolling), causing cracks. It is caused by the presence of sulphur (forming low melting iron sulphide at the grain boundaries). It is reduced by adding manganese, which forms manganese sulphide, and by keeping sulphur low.

✓ Answer checked by Claude Opus 5.5 (high effort)

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