Force conditions of pressing light-alloy drill pipes with spiral ribbing

Abstract

The equation for calculating the pressing force of drill pipes with spiral ribbing is proposed from the Perlin procedure based on the balance of active and reactive forces. The cross-section of a spiral pipe is presented in a form of a smooth pipe with a screw arrangement of metal fibers and outer spiral edges. A component taking into account the energy spent for the screw motion of metal is added to the formula. It is shown that the compacting force, which is found according to the modernized formula, is 28% larger than for a smooth pipe with the equal area. It is revealed that an increase in the angle of ascent of the rib spiral leads to an increase in force compared with that for longitudinally edged pipes.