Magyar Aluminiumipari Troszt

Zoltan F Szucs

Ferenc Nagy

Ferenc Szabo

The invention concerns a process and an apparatus for measuring the anisotropy value of form changes in normal direction in sheet metals (the r-value). In course of a standard tensile test, the longitudinal change of dimension of the test piece is measured. When a preselected value of change of dimension in longitudinal direction which is characteristic of the material of the test piece, is reacted during the measuring process, the appertaining change of dimension in lateral direction is measured. Thereafter, an r-value is selected from the r-values corresponding to different changes in dimension in lateral direction at a preselected longitudinal change of dimension, which is closest to the one measured at the change of direction in lateral direction. The apparatus comprises comparator and switching units which are connected to signal transmitters converting changes of dimension in longitudinal direction into electric signals. The comparator and switching units compare the electric input signals with reference signals. After the preselected change of dimension in longitudinal direction is reached in the course of the measuring process, these units send an interlocking signal to a further switching and decoding unit. This further switching unit is connected to a comparator unit which compares the electric signals corresponding to changes of dimension in lateral direction with the reference signals.

Process and apparatus for the measurement of the anisotropy value of

A method of and apparatus for the determination of the standard tensile yield point in which the extension of a test body is monitored, comprises determining in the course of continuous extension within the elastic limit, the ratio of the instantaneous extension and the associated load, storing this ratio and in the course of further continuous extension the ratios of a given residual extension as well as that of the instantaneous extension and the instantaneous load are determined, the stored ratio value is summed with the ratio of the given residual extension and the instantaneous load, and the thus obtained sum is compared with the ratio of the instantaneous load whereby the instantaneous load at which the compared values become substantially equal gives the tensile yield stress at the given residual.

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Szekesfehervar, Hungary

Zoltan F Szucs