Особливості електронно-променевого зварювання магістральних трубопроводів з титанового сплаву

Abstract

Titanium alloys have high strength and satisfactory weldability. They are widely used in the production of aircrafts and other structural elements in the modern aerospace industry. However, due to a high requirement for aviation and rocket-space technology, increasing the reliability and durability of responsible purpose remains an urgent issue. In this study, the results of welding tubular billets with an electron beam are presented. The subject of this article is the features of tubular billets made of complex titanium alloy electron beam welding. The purpose of this work is to ensure that welds of tubular work pieces have a high level of mechanical properties, based on the welding modes experimental testing results. To achieve this goal, the following tasks were set up and solved in this work: to investigate the mechanism of pore formation in welded joints; to study the effect of electron beam welding on the properties of the weld; ensure high indicators of physical and welded joints mechanical properties. The following research results were obtained. It was possible to obtain satisfactory characteristics of the welded joint by welding in the lower position on the substrate and in the horizontal position. The use of heat treatment increases the strength of welded joints to the level of the base metal. Welded seams, regardless of the welding method, have a coarse-grained structure with liquefaction heterogeneity, which is manifested in uneven etching of the seam. Conclusions: Various metallurgical aspects of titanium electron beam welding were studied. During electron beam welding of tubular blanks, pores are formed mainly near the fusion zone and in the seam axis. Edge mechanical processing, speed reduction, work piece rotation, and welded metal remelting dramatically reduce the number of pores in seams welded in the lower position. Crater removal with a stationary work piece avoids root defect formation in the area of annular seam closure. The obtained results have scientific and practical value in the welded joints of tubular blanks mechanical properties improvement.