抄録
This paper deals with changes in the internal friction at room temperature of Hadfield steel by annealing. The specimen was annealed at various temperatures after quenching in water from 1000°C (solution treatment) to which transversal resonant vibrattion was established by the electro-magnetic method. Then, its internal friction was obtained from the free decay of resonant vibration after the driving electric current was switched off.
Experimental results obtained are as follows:
(1) A specimen annealed after solution treatment or as-solution treated was found to have strain amplitude dependent internal friction, but annealing at 500°∼700°C results in somewhat reduced strain amplitude dependence.
(2) A specimen annealed at the temperature range of 500°∼800°C where the precipitation of carbides and the formamation of needle-likes phase (α, ε) takes places, is low in strain amplitude independent internal friction and high in hardness.
