Improving the efficiency of welded joints of the “insert pipe-plate” type

Abstract

The article is devoted to the analysis of the causes of damage formation in the transition zone from the seam metal to the base metal of butt welded joints. A method for increasing fatigue strength and improving the properties of compounds of this type is proposed. The analysis of cases of fatigue failures of welded joints operating under repeated static loads indicates that cracks most often originate in the transition zone from the seam to the base metal. For this reason, the geometric parameters of the zone of maximum stress concentration should be taken into account when predicting performance. To analyze the operability of welded joints, which did biaxial loading on a breaking machine test. The operability of welded joints of the "insert pipe-plate" type in the initial state is approximately 4 times lower than the operability of the base metal by remelting the transition zone without electrode oscillations (samples 5 and 6) make up half of the operability of the base metal. By remelting the transition zone with an oscillating electrode with regulation of the linear energy along the width of the seam (samples 7 and 8) are practically not inferior to the operability of the base metal. 1 The design of the installation, which allows for automatic remelting of the transition zone from the seam to the base metal with transverse arc vibrations, providing a coupling radius R = 4 – 6mm. 2 Reduction of stress concentration and regulation of the zone of thermal influence at the junction of the seam with the base metal made it possible to increase the resistance to the origin and development of destruction of welded joints "weld-sheet" to almost similar characteristics of the base metal.