A deformation mode in a cold rolling condition to provide the necessary texture of the Ti-3Al-2.5V alloy

Abstract

Purpose. Providing deformation conditions in order to obtain the required texture of pipes made of Ti-3Al-2.5V alloy based on the choice of rational values of the tool calibration parameters gauges and mandrels during cold pilger rolling of pipes for the required Q-factor distribution along the deformation cone. Methodology. The research methods were based on the existing dependence, which describes the influence of the distribution of the ratio of true reduction along the deformation cone along the wall thickness and along the average diameter, on the distribution of the Q-factor value. The calculation of calibration and all deformation parameters of the Cold Reducing tube process was based on a number of existing theoretical and empirical dependencies included in the generally accepted and adapted methods of their computation. To perform calculations, we created the software product Q-Factor. Cold pilger tube rolling. Findings. The influence of the initial taper of the mandrel with a curvilinear generatrix and the sweep of the groove ridge, the degrees of steepness of the generatrix of the mandrel and the sweep of the groove ridge, the value of the feed on the distribution of the Q-factor along the compression zones and pre-finishing of the deformation cone were investigated by calculation. The use of slope degrees n, equal to 1.5, i.e. less than values of crest slope degree had the most significant effect on obtaining the Q-factor close to equilibrium distribution along the length of wall reduction and pre-finishing zones. A method of multifactor calibration of the tool for cold pilger rolling of pipes is proposed, which makes it possible to select rational values of the initial taper of the mandrel with a curved generatrix, the degree of slope of the sweep of the groove ridge and the mandrel, and to create conditions in the wall compression zone for obtaining the required type of metal texture of cold-rolled pipes made of titanium alloy Ti-3-2.5V. At the same time, in the prefabrication zone, in all investigated cases, there is a drop in the Q-factor values below one. Originality. New knowledge was obtained about the influence of the rolling route and the full complex of tool calibration parameters in the process of cold pilger rolling of pipes on the distribution of the Q-factor along the length of the deformation cone. Practical value. A method for determining the modes of deformation with an extended compression zone and without a pre-finishing zone is proposed and tested with positive results. This method provides a distribution of the Q-factor along the reduction zone of the deformation cone which is close to uniform distribution and with values above one. The results obtained make it possible to select the conditions for obtaining the required type of metal texture of cold-rolled pipes from titanium alloy Ti-3Al-2.5V using the software product Q-Factor. Cold pilger tube rolling.