Assessment of Cold Resistance of 09G2S Steel Obtained Using 3D Printing Technology by Electric Arc Surfacing at a CNC Machine
The paper presents the results of studies of samples of steel 09G2S at low temperatures, obtained using 3D printing technology by electric arc welding. For comparison, research data on samples obtained from rolled metal are given. To achieve this goal, samples for impact bending were made and tested from 09G2S steel. Samples were printed using 3D printing technology at a CNC machine by layer-by-layer deposition of deposited material from 09G2S wire. The quality and stability of the obtained samples’ material structure were ensured by continuous diagnostics of the stability of the dynamic system “power source - arc - material”. The main diagnostic parameter characterizing the degree of stability was the indicator of the fractal dimension of the attractor of the dynamic system. Samples for research were cut in the longitudinal and transverse directions of surfacing, and samples of rolled metal were similarly made. Studies of the obtained samples were carried out using impact bending tests in a wide range of low temperatures from -80 to + 20 °C. To identify the fracture mechanism features and the temperature of the viscous-brittle transition of metals, fractographic studies of fractures of the samples were performed. In the studies, it was found that the temperature of the viscous-brittle transition of 09G2S steel obtained using 3D printing technology by electric arc welding was about -40 °C. It is slightly higher than the temperature of the viscous-brittle transition of 09G2S steel obtained from sheet metal with subsequent annealing of -47 °C. It should be noted that the samples cut along the surfacing have higher values of impact strength and temperature of viscous-brittle transition. For samples obtained by electric arc welding, the values of impact strength are not more than 20 % lower than the values of impact strength of samples obtained by machining from sheet metal over the entire range of the temperatures studied. The described above technology of computer-controlled electric arc surfacing can be used to manufacture complex products and repairs. When using welding materials with a low temperature of visco-brittle transition, in particular, the steel 09G2S, it is possible to obtain the product’s high performance in a short time, even in Arctic conditions.