Abstract
The article discusses the effect of the hybrid-welding process (laser–electric arc MAG Metal Active Gas) on the structure and properties of butt joints (having various thicknesses, i.e., 5 mm and 7 mm) made of steel S960QL. Welding tests were performed in the flat position (PA) and in the horizontal position (PC). Joints made of steel S960QL in the above-presented configuration are present in elements of crane structures (e.g., telescopic crane jibs). The welding tests involved the use of the G Mn4Ni1.5CrMo solid electrode wire and the Ar+18% CO2 shielding gas mixture (M21) (used in the MAG method). Non-destructive visual and radiographic tests did not reveal the presence of any welding imperfections in the joints. The welded joints obtained in the tests represented quality level B in accordance with the requirements of the ISO 12932 standard. Microscopic metallographic tests revealed that the heat-affected zone (HAZ) contained the coarse-grained martensitic structure resulting from the effect of the complex welding thermal cycle on the microstructure of the joints. Destructive tests revealed that the joints were characterised by tensile strength similar to that of the base material. The hybrid welding (laser–MAG) of steel S960QL enabled the obtainment of joints characterised by favourable plastic properties and impact energy exceeding 27 J. The tests revealed the possibility of making hybrid-welded joints satisfying the quality-related requirements specified in the ISO 15614-14 standard.
Highlights
Received: 31 July 2021Accepted: 16 September 2021Published: 20 September 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Presently, the implementation of advanced welding technologies in various industries is considered to be one of the most important trends enabling the modernisation of technological processes [1]
The visual welding tests revealed that hybrid-welded joints no. 1 and 2 (Figure 6)
In accordance with the requirements specified in the ISO 12932 standard, the joints made in the PA and PC positions satisfied related criteria and represented quality level B
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The implementation of advanced welding technologies in various industries is considered to be one of the most important trends enabling the modernisation of technological processes [1]. Laser welding is an advanced, continuously improved, and increasingly common welding process applied in numerous industries (Figure 1). The development of laser radiation sources has led to a situation where the market offer includes lasers having power exceeding 100 kW [2]. The laser-welding process and its variants (remote welding, hybrid welding, etc.) have become primary joining processes used in many industrial sectors [3,4,5]
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