engleski

Torsion plastomer results used for determination of degree of softening in steel

Controlled forming of microalloyed steels containing added microalloying elements, such as niobium and vanadium, produces materials with higher yield strenght and ultimate strenght. If the required conditions of thermomechanical treatment are used, high toughness and resistance to low-temperature brittleness is achieved. Owing to lower amount of carbon, the steels have good weldability. To examin the influence of repeated straining, the simulation os performed on plastometers: in this case torsion test was choosen. The results of torsion tests, such as torque and velocity, are converted to values of stress and strain and analysed. The degree of softening X, described by Avrami equation, enables evaluation of yield strenght and peak strains in interrupted tests. The analysis of the softened fraction X included a new method of comparing areas below measured curves.

torsion plastometar; steel; softening

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