Tempering of steel Flashcards
What is tempering?
reheating of steel below eutectoid temp, holding it and cooling to room temp
What effects does tempering have?
> increases toughness and ductility
decreases hardness and strength
increases dimensional stability
minimizes residual stresses
What effects does increasing tempering temp have?
higher toughness and ductility, lower hardness, lower yield stress and tensile strength
Tempered steel has ____ ___ of work hardening, quenched steel has ___ ___ of work hardening
low rate; high rate
Tempering range 150-200C
> gives modest increase in toughness without big loss in hardness
useful for high strength and fatigue resistance for primarily compressive load
Tempering > 425C
significantly increases toughness, but hardness and strength decrease a lot
Temper embrittlement (260-370C )
decreases toughness, but DOESN’T decrease ductility
> standard tensile test not useful for detecting temper embrittlement