SUPERHEATING. Heating above the temperature at which an equilibrium phase transformation should occur without actually obtaining the transformation.
Glossary Terms
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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 […]
TEMPER COLOR. A thin, tightly adhering oxide skin that forms when steel is tempered at a low temperature, or for a short time, in air or a mildly oxidizing atmosphere. The color, which ranges from straw to blue depending on the thickness of the oxide skin, varies with both tempering time […]
TEMPERED MARTENSITE EMBRITTLEMENT. Embrittlement of ultrahigh-strength steels caused by tempering in the temperature range of 205 to 400 degrees C (400 to 750 degrees F); also called 350 degrees C or 500 degrees F embrittlement. Tempered martensite embrittlement is thought to result from the combined effects of cementite precipitation on prior-austenite […]
TEMPERING. Reheating quenched steel to a temperature below the critical range, followed by any desired rate of cooling. Tempering is done to relieve quenching stresses, or to develop desired strength characteristics.
THERMAL FATIGUE. Fracture resulting from the presence of temperature gradients that vary with time in such a manner as to produce cyclic stresses in a structure.
THERMAL SHOCK. The development of a steep temperature gradient and accompanying high stresses within a structure.