Explanatory Note
Title: Heat treatment of metals
Includes general heat treatment activities for metals; heat treatment
thermomechanical analysis of metals (e.g. preheating, annealing, hardening, tempering,
cooling, deep freezing of metals) and thermochemical heat treatments of metals
(e.g. carburizing, carbonitruding, nitrucarburizing, nitriding, oxidation, sulfonation,
boronization), generally carried out on a subcontracting basis or on a piecemeal basis.