Akademik Veri Yönetim Sistemi
STEEL RESEARCH INTERNATIONAL, 2024 (SCI-Expanded)
This study investigates the relationship between the microstructure and the mechanical properties and the residual stresses of thermomechanically rolled, butt-welded S1100MC ultra high-strength steel plates. Matching metal-cored filler wires are used for metal active gas welding of the plates in horizontal and vertical-up positions. The effect of the heat input on the microstructures of both the weld metal (WM) and the heat-affected zone (HAZ) is studied in detail. The microstructure of the WM consists of different types of ferrite, but the microstructure of the HAZ predominantly consists of fresh martensite at the top and bottom areas. Structure and size of the prior austenite grain boundaries are dependent on the welding positions and affect the impact toughness of the welds. HAZ of the weld produced in vertical-up position is under intensive tensile residual stresses next to the fusion line. Even with matching filler wires, the strength of the welds is insufficient, and fracture of the weld metal occurs because the extended cooling time leads to the formation of acicular ferrite instead of martensite. Metal active gas arc welding is applied to S1100MC ultra high-strength structural steel in flat and vertical-up positions to investigate the effects of welding positions on residual stress, microstructure, and mechanical properties. The research aims to reveal the effect of cooling time, which depends on heat input varying with welding positions, on the joining performance.image (c) 2024 WILEY-VCH GmbH