Ageing: thermal process consisting in heating a met al and causing secondary phase preci pit ation hardening.Annealing: thermal process applied to a metal wit h the aim to influence mat eri al properties by means of diffusional phenomena and/or transf ormations (e. g. st ress relief, recrystallization, normalizati on, etc…)Base Metal Thermocouple: thermocouple whose thermoelements are composed primarily of base met als and their alloys. Examples of base metal thermocouples include E, J, K, N and T .Calibration: the process o f adjusting a n inst rument or compiling a devia tion chart so i ts reading may be correlated to the ac tual v alue being measured.Continuous Furnace: a furnace where product is conveyed continuously f rom the charge area t o the discharge area.