Magnetic properties of 09G2S steel, manufactured by selective laser melting and cyclically deformed by tension

Abstract

Low-cycle fatigue tests in the elastic-plastic strain region of 09G2S steel specimens manufactured with a laser 3D printer by selective laser melting method (SLS steel) were carried out. The major hysteresis loops and field dependences of the reversible magnetic permeability were measured. It has been established that normalization at 980 °C (1 hour) reduces the ultimate strength of steel 09G2S in 2 times (502 MPa) and increases the relative elongation almost 6 times (34.6%), bringing this steel closer to cast steel 09G2S. The magnetic properties (Нс, Br, µmax) of cast and SLM normalized steel before and after cyclic tests are similar. The main changes in these properties of both cast and SLM steel are observed at the initial stage of low-cycle tests, a further increase in the number of cycles (up to the destruction of the tested samples) does not lead to their significant change. The nature of the change in the magnetoelastic field Hσ, determined from the experimental field dependences of the reversible magnetic permeability, during low-cycle tests for cast and SLM steels is radically different: for cast 09G2S steel the magnetoelastic field Hσ practically does not change with increasing number of cycles, whereas for SLM 09G2S steel a sharp increase of Hσ value by 30% is observed during the first test cycles, which is most likely associated with an increase in residual mechanical stresses.