Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:

G. V. Shimov, Assistant of a Chair “Plastic Metal Working”, e-mail: geosh@bk.ru

JSC “Revda non-ferrous metals processing works”, Revda, Russia:
M. S. Shalaeva, Technologist

JSC “Sredneuralsky Copper Smelter”, Revda, Russia:
M. M. Sladkov, Chief Engineer

Traditionally, copper and brass tubes are supplied in soft condition after annealing, but some copper and brass tubes, such as tube radiators manufactured in accordance with the Standard GOST 529–78, comes in the solid state, that is, without a finish heat treatment. In this case, the tube wall of residual stresses may be considered. These certainly affect the operational durability of tubes. Residual stresses lead to strain and to cracking tubes. Cracking of copper and brass tubes (for example, heat exchanger, tube radiator tubes) during their operation is connected with the corrosion processes and the presence of residual tensile stresses in the tube wall. The proper evaluation of the performance needs to know the value of residual stresses and their distribution in the tube wall. A computer simulation of the process of drawing brass tubes is made. The calculation procedure of residual stresses in the tubes is described. The procedure is based on the calculation of the elastic and thermal discharge after tube dies. There are calculated the residual stresses in the brass tubes 8,00,2 mm made of L96 (Л96) alloy after drawing. The distribution
of residual stresses on the tube wall is also calculated. There are defined the presence and value of the tensile residual stresses on the outer surface of the tube. Using the computer simulation results as primary data, the described technique allows the calculation to establish the value and distribution of residual stresses in the tube wall. Information about the sign and magnitude of the residual stresses in the tube wall is needed to evaluate the corrosion resistance of copper and brass tubes during operation.

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