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

OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 apply diff erent technologies of additive manufacturing. Active development of additive technologies (AT) leads to a reduction in the cost of products manufactured with its help. This allows for the rapid production of parts and blanks of not only complex shapes, but also simpler shapes from expensive materials [5, 6]. An example of such parts can be fl anges made of heat-resistant materials. When using AT, there is no need to make a hole and the volume of material removed due to subtractive machining is also reduced. This makes the use of AT in this case economically justifi ed. Also, the use of AT for the production of fl anges allows it to be manufactured to a specifi c size, which provides even greater savings in time and costs compared to the production of a similar part from rolled steel [7–9]. Electron beam (EBAM) and arc printing (WAAM) are the most suitable technologies for the rapid production of simple fl ange-type parts made of heat-resistant materials and, in particular, Inconel [10]. EBAM uses a high-power electron beam to melt a metal wire material, which is surfaced layer by layer to form the desired part. This method can create large size parts with high density and strength [11–14]. One of the key advantages of additive manufacturing is its ability to create complex 3D components with greater speed and fl exibility compared to traditional methods such as milling or casting [15, 16]. 3D printing can reduce the number of manufacturing steps, minimize material waste, and create parts that cannot be made by other methods. This opens up new opportunities for engineers, allowing them to bring their boldest ideas to life [17–20]. Vacuum surfacing of blanks using EBAM technology makes it possible to signifi cantly accelerate the workpiece fabrication process in comparison with SLS (selective laser sintering) technology. However, this is a rather expensive and labor-intensive method of parts manufacturing [21, 22]. A greater reduction in cost and simplifi cation of the workpiece fabrication technology can be achieved using WAAM technology. This technology uses arc welding to surface metal wires layer by layer to form three-dimensional objects. WAAM makes it possible to create large-sized parts much faster than other additive technologies such as electron beam surfacing. WAAM is suitable for producing parts from a variety of metals including steel, titanium and nickel alloys [23–25]. The disadvantages of this technology are the possibility of porosity formation due to printing in a gas environment, as well as worse quality of the printed surface. The features of EBAM and WAAM technologies will aff ect the structure and properties of the resulting blanks. The EBAM technology is currently used quite rarely for printing heat-resistant alloys [26, 27]. This is due to the relatively low prevalence and novelty of this technology. Printing heat-resistant alloys with the help of WAAM technology is also not often used. Printing of heat-resistant alloys by this technology has a number of technological diffi culties. For these reasons, there are very few works devoted to the printing of heat-resistant nickel alloys by EBAM and WAAM technologies [28–31]. The purpose of this work is to conduct a comparative analysis of microstructure of workpieces from nickel alloy Inconel 625 obtained by EBAM and WAAM technologies. Methods and materials Acommon nickel alloy of Inconel 625 was chosen as a material for specimen fabrication. The specimens were printed with a 1.2 mm diameter wire. Printing was carried out on a substrate made of stainless steel with dimensions of 110×110×20 mm. The substrate was placed over the back plate and clamped tightly. The back plate was used to apply molten raw material to the part. It acts as a protection against melt penetration into the substrate and damage to the table. In the printing unit used for printing, it was possible to adjust the position of the wire feeder. The position was adjusted in relation to the electron beam and the workpiece to be printed. This ensured the stability of the material transfer. During the welding process, a bridge of molten metal was created between the fuse and the molten bath [32, 33]. The chemical composition of wire material used for electron beam printing is shown in Table 1. Printing of the fi rst group of specimens was carried out on an electron beam wire surfacing unit manufactured at Tomsk Polytechnic University. The printing of the second group of specimens was carried out on an electric arc wire surfacing unit, also manufactured at Tomsk Polytechnic University.

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