Research of Properties of the Metal of the Heat-Affected Zone for Surfacing by Stape Electrode With the Controlled Transfer of the Electrode Metal

Abstract

The quality of the deposited layer is determined by the conditions of its formation, as well as the properties of local zones, due to the parameters of the thermal cycle of surfacing (mechanical, microstructural, chemical, etc.). When surfacing the austenitic layer on pearlitic steels, the properties of the heat-affected zone, along with the resistance of the surface layer to corrosion, largely determine the performance and durability of the deposited product. To reduce the amount of heat input and effectively control the structure and properties of the heat-affected zone when restoring working surfaces by submerged arc surfacing, a method for surfacing with a tape electrode with controlled mechanical transfer of electrode metal is proposed. Studies have shown that the imposition of longitudinal sinusoidal vibrations on the end of the tape electrode can reduce the level of heat input in the heat-affected zone by increasing the efficiency of fusion of the base metal. At the investigated frequency of 50 Hz, the duration of the dots on the boundary of the fusion line and below it in the range 900 ... .1100 °С is less than when surfacing without controlled mechanical transfer. Reducing heat input into the heat-affected zone in the temperature range 900 ... 1100 °С provides a finer-grained structure. The use of forced vibrations of the end of the tape when surfacing a high-alloy austenitic layer on low-carbon steel makes it possible to obtain a finer-grained structure at the fusion boundary in the heat-affected zone. This will increase the resistance of the heat-affected zone to the formation of defects associated with a decrease in its mechanical properties.