Mathematical modeling of relaxation of residual stresses in thin-walled pipelines in the delivery state and after bilateral surface hardening at creep

A mathematical model of reconstruction the fields residual stresses and plastic deformations in thin-walled cylindrical tubes delivery state after bilateral surface hardening was developed. It included a method for identification parameters using example mm made X18N10T steel based on experimental data axial circumferential components stress tensor samples mechanical ultrasonic hardening. The adequacy verified by hardening, taking into account anisotropy distribution deformation directions. calculating two-way relaxation outer inner surfaces under creep conditions developed generalization corresponding unilateral process 08X18N9 (an early analogue steel) thermal exposure, tension, internal pressure combined action tension investigated basis constructed phenomenological theory this steel. detailed analysis kinetics during at different times performed. is shown that these conditions, almost complete technological occurs both within 50 hours.