Influence of Additives on the Mechanical Characteristics of Hardox 450 Steel Welds

Saulius Baskutis; Jolanta Baskutiene; Egidijus Dragašius; Lina Kavaliauskiene; Neringa Keršiene; Yaroslav Kusyi; Vadym Stupnytskyy

doi:10.3390/ma16165593

Influence of Additives on the Mechanical Characteristics of Hardox 450 Steel Welds

Materials (Basel). 2023 Aug 12;16(16):5593. doi: 10.3390/ma16165593.

Authors

Saulius Baskutis¹, Jolanta Baskutiene¹, Egidijus Dragašius¹, Lina Kavaliauskiene¹, Neringa Keršiene², Yaroslav Kusyi³, Vadym Stupnytskyy⁴

Affiliations

¹ Department of Production Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu St. 56, 51424 Kaunas, Lithuania.
² Department of Mechanical Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu St. 56, 51424 Kaunas, Lithuania.
³ Department of Engineering Mechanics and Transport, Lviv Polytechnic National University, Bandera St. 12, 79013 Lviv, Ukraine.
⁴ Department of Robotics and Integrated Mechanical Engineering Technologies, Lviv Polytechnic National University, Bandera St. 12, 79013 Lviv, Ukraine.

Abstract

The aim is to overcome the issues of high-hardness material welding by different additives used to achieve the desired improvements. The research is focused on Hardox 450 steel welding and factors to be considered in order to maintain the required mechanical properties of the weld. The selection of best suited welding materials or additives, including filler metals and shielding gases, are within the important factors to be taken into account. During the welding of Hardox 450 steel, cobalt, nickel, tungsten and titanium additives and cobalt and tungsten mixture additives were used and their influence on the microstructure and mechanical properties of the fusion and heat-affected zones was investigated. The microstructure of the weld zone is related to certain mechanical properties of the weld and heat-affected zone, such as hardness, tensile and bending strength, yield strength, strain at ultimate tensile strength, the Young's modulus and elongation. Research has shown significant differences in the mentioned parameters depending on specific additives used in the welds. It can be concluded that tungsten, used as an additive, increased the hardness of the heat-affected and fusion zones up to 478 HV; the combined presence of cobalt and tungsten additives improves the strength of the seam up to 744 MPa during tensile; and in the case of bending, nickel, when used as an additive, increased ductility (the bending modulus reached the limit of 94 GPa) and at the same time, decreased the risk of cracking. The obtained results highlight the possibilities for strengthening the welded joint of Hardox 450 steel using different additives or their mixtures. The research conclusions and recommendations aim at improving the quality and mechanical properties of welded Hardox 450 steel joints in various applications.

Keywords: Hardox 450 steel; additives; mechanical characteristics; weld zone; welding.

Grants and funding

This research has been conducted as part of ongoing project “Comprehensive system of functional-oriented planning of machining difficult-to-cut materials for the military-industrial complex (Komplekssys)” and has been funded by the Research Council of Lithuania and the Ministry of Education and Science of Ukraine under the Lithuanian–Ukrainian Cooperation Programme in the Fields of Research and Technologies (Grant No. S-LU-22-6).