Structure and mechanical properties of metal 25Kh2V2M2FS, deposited with flux-cored wires with different types of cores

Abstract

The article investigates the influence of the flux-cored wire (FCW) core composition on the structure and mechanical properties of the deposited metal. It is demonstrated that a promising approach to controlling the structure and properties of the deposited metal is the use of chemically pure granulated metallic powders in the FCW core instead of ferroalloy powders. This modification stabilizes the deposition process and enhances the uniformity of the microstructure. The study aims to compare the microstructure and mechanical properties of the deposited metal obtained using FCWs with granulated PG-10R6M5 powder of two different fractions and a conventional ferroalloy-based mixture. Experimental results indicate that specimens produced by deposition with FCW containing granulated powder exhibit a fine-grained structure and greater homogeneity. Metallographic analysis of specimens obtained using ferroalloy-based FCW revealed the presence of large non-metallic inclusions (up to 100 μm) and microdefects, which negatively affect the mechanical properties. Hardness and microstructure analysis demonstrated that the metal deposited using FCW with fine-fraction granulated metallic powder (50–100 μm) exhibits the most favorable combination of mechanical properties, including increased strength and improved ductility compared to the metal obtained with a ferroalloy-core FCW. This improvement is attributed to the reduction in microdefects and the stabilization of the structure during deposition. The chemical composition of the deposited metal in all studied cases corresponds to 25Kh2V2M2FS steel, confirming compliance with established requirements. The research findings validate the feasibility of using granulated metallic powders in the FCW core as an alternative to ferroalloys. This approach ensures a more uniform microstructure, a lower level of non-metallic inclusions, and enhanced mechanical properties, contributing to the increased durability and reliability of deposited components in critical structural applications.