Structure of Inconel 625 alloy blanks obtained by electric arc surfacing and electron beam surfacing

Introduction. Development of the manufacturing industry has led to the emergence of new methods for manufacturing blanks and parts. One of these new promising methods is additive manufacturing and, in particular, electric arc and electron beam surfacing technologies. The use of these technologies in the production of blanks from heat-resistant materials provides a number of significant advantages. The paper presents the results of a study of the microstructure of Inconel 625 specimens obtained using EBAM and WAAM technologies. The purpose of the work is a comparative analysis of the microstructure of Inconel 625 nickel alloy blanks obtained using EBAM and WAAM technologies. Methods and materials. The paper examined specimens obtained using EBAM and WAAM technologies. The specimens were manufactured using equipment developed at Tomsk Polytechnic University. Metallographic studies, scanning electron microscopy were carried out, and the microhardness of the obtained specimens was determined. Results and discussion. Comparison of specimens obtained by two different additive printing technologies EBAM and WAAM showed general patterns of structure formation that appear when using additive technologies. The specimens have a dendritic microstructure and contain zones rich in Ti, Mo and Nb, which is typical for nonequilibrium cooling. Pores are also observed in the specimens. The grains in the specimens have a predominantly elongated shape and are oriented in the direction of heat removal. The length of the grains reaches 1 mm. Differences in the specimens are observed in the number of formed inclusions of intermetallic compounds, in the number of formed pores, in the size of the grains. The EBAM technology provides more uniform structure. The difference in hardness between EBAM and WAAM is about 3.5 %. At the same time, the speed of specimen production using the WAAM technology is significantly higher.