Larsen & Toubro Ltd, commonly known as L&T, is an Indian multinational conglomerate company, with business interests in engineering, construction, manufacturing, technology and financial services, headquartered in Mumbai. The company is counted among world's top five construction companies. It was founded by two Danish engineers taking refuge in India. As of 2020, L&T Group comprises 118 subsidiaries, 6 associates, 25 joint-venture and 35 joint operations companies, operating across basic and heavy engineering, construction, realty, manufacturing of capital goods, information technology, and financial services.
Unmanned Aerial Vehicles (UAVs) and high-resolution images are becoming more important for Structural Health Monitoring (SHM) to observe anomalies like cracks in concrete. But cutting-edge object identification methods like YOLOv8 typically have trouble finding extremely thin cracks in large images since they have to down-sample them aggressively during standard inference. This study presents a pipeline that combines YOLOv8 with Slicing Aided Hyper Inference (SAHI) to solve the problem of detecting small objects in civil infrastructure. The study compares the usual full-image inference method with the new sliced inference method. Experimental findings demonstrate that the SAHI-integrated pipeline drastically improves the ability to find weak, fine-grained, and hairline fractures compared to traditional inference. Finally, the sliced images are merged into continuous crack structures using the morphological dilation method, thereby combining multiple overlapping bounding boxes together to form polygonal detection boxes.
In this paper, In this paper, a comparative assessment of 2205 duplex stainless steel (DSS) welded pipes produced using two alternative routes of a hybrid welding process, involving regulated metal deposition (RMD) root pass welding followed by gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) root pass welding followed by GMAW, was undertaken to evaluate the effect of the root pass metal transfer method on metallurgical integrity, mechanical properties, corrosion resistance, and welding rate. Butt joints were fabricated using ER2209 filler metal and a shielding gas mixture of 98% argon and 2% oxygen, with root pass heat inputs of 0.6–0.9 kJ/mm for the RMD process and 0.6–1.76 kJ/mm for the GTAW process. Optical microscopy revealed refined duplex microstructures in RMD + GMAW joints with uniformly distributed grain boundary austenite (γGB), Widmanstätten austenite (γW), and intragranular austenite (γi) morphologies, whereas GTAW + GMAW joints exhibited relatively coarser austenite and a less homogeneous duplex microstructure. Phase balance assessment based on ferrite number measurements indicated a comparatively higher ferrite content in the RMD + GMAW joints (45–49 FN) than in the GTAW + GMAW joints (40–44 FN). Hardness measurements showed average weld metal hardness values in the range of 285–295 HV10 for the RMD + GMAW joints, which were higher than those of the GTAW + GMAW joints (270–275 HV10). Tensile testing further confirmed this trend, as the RMD + GMAW joints exhibited higher strength and ductility, with an ultimate tensile strength of 820–835 MPa compared with 780–800 MPa for the GTAW + GMAW joints and an elongation exceeding 27%. Charpy V-notch impact testing at −40 °C showed higher absorbed energy for the RMD + GMAW weld metal (113.3 J) and heat-affected zone (HAZ) (101.7 J) compared with the GTAW + GMAW weld metal (104.7 J) and HAZ (95.0 J), confirming enhanced cryogenic toughness. Pitting corrosion testing in accordance with ASTM G48 Method A indicated a substantially lower corrosion rate for the RMD + GMAW weld metal (3.09 mdd) compared with the GTAW + GMAW weld metal (12.30 mdd), indicating superior stability of the passive oxide layer. Techno-commercial evaluation showed a shorter total arc time of 7.5 min for RMD + GMAW compared with 12.65 min for GTAW + GMAW, resulting in a productivity improvement of 41%.
This study addresses the productivity and cost limitations of conventional gas tungsten arc welding (GTAW) for root pass welding of 2205 duplex stainless steel (DSS). GTAW, though widely used for its arc stability and weld quality, suffers from low deposition rates and often requires ceramic backing, increasing fabrication time and cost. To overcome these limitations, regulated metal deposition (RMD), a controlled short-circuit GMAW variant, was evaluated as an alternative root pass technique. Two welding routes, RMD + GMAW and GTAW + GMAW, were evaluated through microstructural, mechanical, corrosion, and techno-commercial analyses. RMD + GMAW produced a balanced ferrite - austenite microstructure with refined secondary austenite and higher microhardness (285-295 HV) than GTAW + GMAW (270-275 HV). Superior tensile strength was obtained for RMD + GMAW (821-835 MPa) compared to GTAW + GMAW (773-775 MPa), with comparable elongation (similar to 27-29%). Both joints exhibited >100% efficiency with failure in the base metal. Improved pitting resistance (4.45 mdd) and a 29% reduction in arc time further demonstrate that RMD-based hybrid welding provides a technically and economically efficient alternative to GTAW for DSS fabrication.
This study explores the development of polymer composites that are sustainable and reinforced by natural flax and cotton fibers at different weight fractions (5
This study investigates the tribological and mechanical properties of aluminium matrix composites (AMCs) reinforced with copper chromate (Cu₂Cr₂O₅) nanoparticles, presenting a novel approach to utilizing Cu₂Cr₂O₅ as a reinforcing phase in AA6018 composites fabricated via plasma arc processing. This is the first comprehensive work demonstrating the formation of a nanoscale eutectic structure that significantly enhances tribological performance by refining the microstructure and facilitating a stable lubricating film, thereby reducing wear and friction. The composites were developed with Cu₂Cr₂O₅ weight percentages ranging from 1 to 3 wt
