Ensuring the strength of welded joints in laser welding of EP693 heat-resistant dispersion-hardening nickel alloy

Abstract

The paper considers the process of creating a permanent connection from the EP693 heat-resistant alloy of the Ni-Cr-W-Co-Mo system used in the manufacture of components and parts of gas turbine engines by welding on the TruLaser Cell 7020 CO2 complex with pulse-periodic radiation. EP367 filler wire of the Ni—Mo—Cr—Mn system was used to obtain the weld. The influence of heat treatment on the structure and properties of the heat-affected zone and the weld was studied. Based on the research results, the weld structure and kinks obtained by laser welding was studied, weld physical and mechanical properties were identified, the maximum endurance limit for welded joints was determined at 2•106 cycles. The expediency of laser welding of the heat-resistant dispersion-hardening nickel alloy in the manufacture of shells for the turbine support and stator of gas turbine engines was determined. It was found that combined heat treatment (quenching and aging) provides optimal values of strength limits at room and elevated temperatures, as well as short-term strength of welded joints. Based on the strength calculation of the turbine support and stator of gas turbine engines and the obtained experimental data on the strength of welded joints made using laser welding with pulse-periodic radiation, the safety factor was 1.35 to 3.0. This technology is proposed to be introduced into production in the manufacture of parts and assemblies such as shells for the turbine support and stator of gas turbine engines in order to improve the quality of welds by reducing the time of high-temperature heating due to lower heat input.