Scientists at Novosibirsk State Technical University (NSTU) are developing a method for the empirical regulation of the technology of layer-by-layer creation of metal parts using an electric arc as a heating source. This will allow you to control the chemical composition of the material during the surfacing process and select the necessary properties, from strength to corrosion resistance.
Functional gradient materials are a class of structural materials with varying composition and properties. This can provide a combination of strength, corrosion resistance, wear resistance and other properties within a single product, which is necessary in modern light and heavy machinery, energy and medicine, including for the manufacture of prosthetics. In recent years, additive technologies have been actively developing, in particular, arc additive Manufacturing (WAAM). Of particular interest is the use of double wire feed, which makes it possible to form multicomponent and gradient structures.
According to Alexey Alimov, head of the youth laboratory of reverse engineering and prototyping at NSTU-NETI, an experimental approach was chosen to determine the optimal surfacing parameters. "For the first trial welding, wire samples of stainless austenitic steel ER308LSi and steel ER70S-6 were selected, while the wire was inserted manually. As a result of the surfacing, a uniform roller was obtained, consisting of layers of dissimilar steels with a transition layer between them," said Alexey Alimov.
In the future, a number of experiments are planned that will allow choosing the optimal surfacing mode. The first selection criterion will be the absence of defects in the deposited layers. Microstructural studies, including studies of the emerging transition layer, will be carried out for samples obtained using the modes selected in this way.
"We will be able to predict the composition of the material during surfacing and, by adjusting the deposition parameters, anticipate and eliminate possible defects. In the future, the method of empirical regulation of the technology of layer—by-layer creation of metal parts will make it possible to weld two, three and even four wires," said Alexey Alimov.
Earlier NSTU-NETI in cooperation with the SB RAS Institute of Hydrodynamics named after M.A. Lavrentiev achieved the connection of heterogeneous materials using a special method. Previously "unfriendly" alloys were combined using a technology based on high-speed impact. The scientists used a strong electromagnetic field to accelerate the workpieces to several hundred meters per second.