The stabilization treatment of rust layers on Q420qNH weathering bridge steel was performed using three different precipitating stabilizers, followed by exposure to a marine atmospheric environment. We investigated the effects of different precipitating stabilizers (CaCl2, Na2MoO4, and Na2HPO4) on the corrosion resistance of the rust layer, as well as the precipitate and evolution of precipitation zone on its surface, and its rust layer evolution under simulated marine atmospheric conditions was investigated via cyclic corrosion tests. The rust microstructure and corrosion resistance of unstabilized and stabilized samples were systematically compared using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses, to reveal their corrosion resistance mechanism, and Pourbaix diagrams of Q420qNH steel at 298 K were drawn. The stabilizers significantly increased α/γ* ratio (by 0.73–1.58), shifted the open-circuit potential positively (by up to 0.06 V initially and 0.09–0.11 V after stabilization), and reduced the corrosion current density (by 0.53–1.42 mA cm−2). Corrosion rates decreased by 39
Phase transformation behavior, solidification structure, microstructural characteristics, strengthening mechanisms, and thermal conductivity of delta-transformation-induced plasticity (δ-TRIP) high-Al steel were systematically investigated. The relationship between thermal conductivity and the solidification coefficient during continuous casting was also analyzed. The macrostructure of the continuous casting slab displayed a typical asymmetric distribution of three crystalline zones along the slab section. The equiaxed zone ratio in the specimen taken from the slab edge reached 26.5
Process data in blast furnace ironmaking often suffer from missing values, deviations, and abrupt mutations due to sensor malfunctions, environmental interference, and drastic changes in operating conditions, with an anomaly rate reaching 5
Efficient phosphorus (P) management is essential for sustainable agriculture. However, global dependence on finite phosphate rock reserves and the environmental impacts of conventional P fertilisers highlight the urgent need for alternative nutrient sources. Steel slag, an abundant by-product of steelmaking, has emerged as a promising secondary P resource with additional agronomic benefits, including liming capacity, silicon provision, and improved soil quality. During iron and steel production, P is transferred from iron ore into slag, accumulating in the dicalcium silicate–tricalcium phosphate (C2S–C3P) phase, which enables targeted P recovery. Recent studies have advanced P enrichment, phase separation, and the development of slag-based fertilisers. Despite these advances, challenges remain in optimising P extraction, understanding nutrient dynamics in various soil types, and ensuring the environmental safety of steel slag application. With growers’ emphasis on sustainable P fertiliser practice, the potential of steel slag as an alternative P source is evaluated. P recovery technologies from the steel industry, agronomic uses of steel slag, and associated environmental concerns are examined to support future research and the development of circular sustainable strategies for enhancing soil health and agricultural productivity.
With increasingly stringent environmental regulations, perfluoroisobutyronitrile (C4F7N/CO2) mixed gas has gained considerable attention as a substitute for sulfur hexafluoride (SF6) in gas circuit breakers. However, the mechanisms underlying its influence on the corrosion behavior of copper-tungsten (CuW) contact materials remain unclear. The corrosion behavior and interfacial reaction mechanisms of CuW contacts in SF6 and 9%C4F7N/91%CO2 environments are systematically compared. Corrosion morphology analysis revealed that, compared to SF6, contacts exposed to the mixed gas exhibited significantly increased surface defects including micro-pores and cracks, enlarged cross-sectional voids, and increased remelted tungsten layer thickness from approximately 69 to 94.6 mu m. Interfacial reaction analysis indicated that complex chemical reactions occurred between the decomposition products of the mixed gas and the contact materials, generating multiple corrosion products including CuO, Cu2O, CuF2, and WO3. To elucidate the physical nature of enhanced corrosion, a temperature field simulation model was established to simulate the phase transformation behaviors of the contact materials, including melting and vaporization processes. Simulation results demonstrated that the mixed gas environment resulted in higher peak surface temperatures and broader high-temperature regions on the contacts, leading to intensified phase transformations, which corroborated the experimentally observed enhanced corrosion phenomena. The coupled mechanisms of enhanced corrosion of CuW contacts in C4F7N/CO2 mixed gas were elucidated, providing theoretical foundation and data support for the optimized design of contact materials, development of surface protection technologies, and reliability assessment in next-generation environmentally friendly gas circuit breakers.
