Effectiveness of banding pipes and cylindrical shells

Abstract

1. The effect of the stress-state parameter m and the mechanical properties of the material in the pipe wall (coefficients A and n) on banding efficiency E0.2 is demonstrated from the standpoint of metal savings in pipe production. It is established that a specific value of the parameter m, which ensures the attainment of (E0.2)max, exists for each material; in this case, the value of mopt decreases with decreasing indicator n of the extent to which the material has hardened and increasing coefficient A. In this case, (E0.1)max also decreases, and from the standpoint of creation of designs of minimum weight, banding is no longer effective for high-strength steels after quenching and tempering. 2. Relationships are derived for evaluating banding efficiency from the standpoint of a maximum increase in working pressure in a pipe without increasing its wall thickness. It is demonstrated that the maximum increase in working pressure in a pipe subject to banding increases only with increasing indicator n of the degree of hardening of the wall material (with increasing uniform plastic deformation during the testing of specimens of pipe-wall material in axial tension); in this case, an increase of more than a factor of two in the working pressure of a banded pipe is possible when n>0.265.