Study of the fatigue strength of steel 09G2S obtained by 3D printing based electric arc welding in a wide range of low temperatures

Abstract

In this work, we consider the issues of obtaining workpieces from cold-resistant steel 09Mn2Si by a promising method of 3D-printing by electric arc surfacing (electric arc additive growing). The task of assessing the mechanical properties of the obtained material and understanding the process of its destruction is urgent. The assessment of the fatigue strength of the obtained material after deposition and after subsequent heat treatment (HT) (normalization) in a wide range of low temperatures is carried out. A fractographic analysis of fatigue fractures of 9Mn2Si steel using scanning electron microscopy was also carried out. Ultimately, this makes it possible to assess the reliability of parts manufactured by 3D-printing arc welding. In the course of the work, the mechanical properties were obtained and the analysis of the curves of low-cycle fatigue of the samples after 3D-printing and after further HT in the temperature range of -60 ... 20 °C was carried out. Metallographic studies have been carried out and structural changes have been established in the process of fatigue loading at different operating time of the sample. A relationship was established between the value of the maximum cycle stress and the operating time corresponding to the onset of the onset of the main crack and the moment of fracture of the sample for steel 9Mn2Si steel. The dependence of the average growth rate of the main crack on the applied stress during fatigue tests is obtained.