EFFECT OF DEGREE OF COLD WORK AND ANNEALING TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF COLD DRAWN COPPER WIRES AND TUBES

This work gives the results of influence of temperature and deformatio n degree on changes in the metal grain growth of drawn copper products , because this mutual dependence was observed. Wire samples of O.F.H.C . copper and copper tube samples, chemical content of 99.97% Cu and 0. 024% P, were exposed to recrystallized annealing after drawing. The an nealing was carried out at temperatures of 400, 450, 500, 550 and 600 degrees C, for 30 min, in laboratory conditions. Investigation results show that after drawing with high cold deformation degree (96-99%), t he annealing leads to the changes in the continuous grain growth with increased temperature. The smaller grain size appears at 550 degrees C in comparison with the lower annealing temperature. Annealing has inf luence on mechanical characteristics of tested samples and during draw ing of copper products these characteristics are adequately changed: w ith regard to the annealing at the 500 degrees C, the characteristics of strength and plasticity increase as a result of decreased grain siz e. The increase of annealing temperature to 600 degrees C leads to the increased grain size and decreased values of strength and plasticity characteristics.