EFFECT OF TWIST AND TWIST RATE ON THE RESISTANCE IN TORSION TEST FOR STEEL AND BRASS

In spite of some disadvantages of torsion test as a method for materia l testing, it has advantages such os remarkably high ductility stabili ty of sample geometry and the determination of mean tensile strength f or high degrees of deformation. The present work deals with studying t he effect of twist and twist rate on the resistance in torsion for ste el and brass. Torsion tests were carried out at room temperature on a 200 Nm capacity torsion machine using different values of deformation rate ranging between 0.524 rad/min (30 rpm) to 5.236 rad/min (300 rpm) . Comparison of results of torsion tests on solid cylindrical specimen s with different diameters for the materials tested were conducted. In addition an expression for obtaining the shear stress as a function o f twist angle, twist rate and specimen radius is induced. Good agreeme nt between flow corves determined in tension and torsion has been obta ined.