No abstract

The technology of flash butt welding of rail frogs with rail ends using an austenitic insert of rolled metal of stainless steel of type 18-10 has found a wide application. In the present paper the experiments on evaluation of possibility of using a shaped casting of steel of type 18-10 as an insert are described. It is shown that fundamental differences in the structure and properties of metal of different zones of welded joints using rolled or cast inserts are not observed. Further increase in efficiency and physical and mechanical properties of welded joints can be realized by optimizing the chemical composition and structure of the insert metal. 8 Ref., 3 Tables, 2 Figures.

The comprehensive mechanical tests of high-strength steel pipe joints produced using flash-butt welding were carried out. The quality of joints completely meets the requirements of the international standard API STANDARD 1104. During tests on impact bending the single dropouts of KCV-40 values lower than the level required by standards DNV-OS-F101 and STO Gazprom 2-3.7-380-2009 were observed. The decrease in KCV-40 was predetermined by formation of zones of 1-2 mm 2 area in the plane of a joint differed by structural heterogeneity, which is characteristic also for base metal and revealed in a sharply distinct anisotropy of its ductile properties. It is shown that the areas with structural heterogeneity do not form colonies, therefore they do not decrease the general serviceability of the welded joint. [3,4] specified the standard values of impact toughness of welded joints of circumferential welds of not less than 37.5 J/cm 2 at the test temperature, which should be 20 °C lower than the design temperature of pipeline service.The aim of the present article is determination of factors, which influence the value and stability of values of impact toughness of high-strength steel pipe joints produced by FBW.The development of welding technology was carried out on the sectors of pipes of 1219 mm diameter with the wall thickness of 27 mm, which are manufactured of sheet steel 10G2FB of X70 strength class, produced by controllable rolling