secondary hardening

secondary hardening

[′sek·ən‚der·ē ′härd·ən·iŋ]
(metallurgy)
The hardening of certain alloy steels at moderate temperatures (250-650°C) by the precipitation of carbides; the resultant hardness is greater than that obtained by tempering the steel at some lower temperature for the same time.
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4), whereas on tempering the hardness decreases, and no secondary hardening was not obtained.
Overlay welding of structural steel CT3 with material powders sprayed P6M5 steel chips and melted under the flux AMS1 mixed with the powders of boron carbide layer harden on cooling (64 HRC, primary hardness), whereas on tempering the hardness decreases, and no secondary hardening was obtained.
The diffusion zone in case of other orientations of growth of dendrites in the BJ specimens is more developed (has significant width and contains big amount of secondary hardening phase, in particular acicular [Me.
In tempering of hardened high speed steel secondary hardening takes place in the metal due to precipitation from solid solution of disperse excessive carbides, and in subsequent cooling transformation of residual austenite into martensite occurs.