SURFACE HARDENING. A generic term covering several processes applicable to a suitable ferrous alloy that produces, by quench hardening only, a surface layer that is harder or more wear resistant than the core. There is no significant alteration of the chemical composition of the surface layer. The processes commonly used are carbonitriding, carburizing, induction hardening, flame hardening, nitriding, and nitrocarburizing. Use of the applicable specific process name is preferred.
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STRAIN HARDENING. An increase in hardness and strength caused by plastic deformation at temperatures below the recrystallization range.
THERMAL FATIGUE. Fracture resulting from the presence of temperature gradients that vary with time in such a manner as to produce cyclic stresses […]
TEMPERING. Reheating quenched steel to a temperature below the critical range, followed by any desired rate of cooling. Tempering is done to relieve […]
SUPERHEATING. Heating above the temperature at which an equilibrium phase transformation should occur without actually obtaining the transformation.