Layered synthesis of workpieces by mig-pulse surface method using austenitic metal-cored wire with nitrogen

Abstract

WAAM technology (Wire + Arc Additive Manufacture) is a new method of additive manufacturing using wire as a construction material. The high productivity of the process, the ability to construct large-sized products without the need to use a controlled atmosphere chamber, and the low cost of equipment and construction materials allow using the WAAM technology to built products of simple and medium complexity with the highest economic efficiency. However, WAAM technologies in MIG-Pulse/CMT surfacing processes have a number of disadvantages, such as significant size of the heat-affected zone (HAZ) and large sizes of the build-up layer, which leads to undesirable temperature gradients and the accumulation of residual stresses. A further way to improve WAAM technology is to use metal-cored wires. For the research, metal-cored wire Cr20Mn5Ni4Mo2.5Cu3N0.3 Ø 1.6 mm was developed. It has been established that the use of metal-cored wire allows producing a defect-free surfaced metal with an austenite-ferritic structure (δF ≈ 1–3%), which has high strength and plastic characteristics (σ_B = 810 MPa, σ_0,2 = 500 MPa, δ = 40%). The yield strength of the developed composition is more than 2 times higher than that of the widespread austenitic steel of the Kh18N10T type (σ_0,2 = 206 MPa). Further research will be aimed at improving the impact strength of the surfaced cast metal by optimizing the composition of the metal-cored wire.