Comparison of the strength and structural properties of the specimens made of EOS PH1 stainless steel of additive manufacturing and 30KhGSA hardened steel of traditional production

Abstract

Nowadays, promising and dynamically developing additive manufacturing of complex parts for small-scale production actively succeeds traditional technologies in many industries including aircraft engineering. A method of selective laser fusing also finds effective application along with a well-known methods of additive manufacturing like selective laser sintering, laser metal deposition, plasma-jet hard-facing and electron beam melting etc. The results of comparing the structural, mechanical and tensile strength properties of materials used for manufacturing complex-shaped products by additive and traditional methods revealed the advantage of additive manufacturing which is the basis for their introduction into industry. The goal of the study is a comparative study of the microstructure, mechanical characteristics, fatigue life and fatigue fracture of the specimens made of EOS PH1 stainless steel produced by additive manufacturing and 30KhGSA hardened steel specimens obtained by a traditional technology. Fatigue resistance tests of the specimens were carried out in conditions of uniaxial longitudinal stretching. The microstructural features of the microsections of the cross sections of the samples were studied using stereomicroscope and scanning electron microscopy. Fractographic study of the macro- and micro fracture patterns of the specimens was carried out to identify the structural features of the fractures, fracture nuclei and their correlation with the microstructural imperfections. It is shown that selective laser melting technology used for manufacturing EOS PH1 stainless steel specimens, provides production of the specimens with a rather high tensile strength characteristics comparable to the characteristics of 30KhGSA hardened steel specimens. Therefore, EOS PH1 stainless steel has a great potential as a material for manufacturing parts and products that have high requirements for the strength, hardness and fatigue life.