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The development of an environmentally friendly binder can immensely benefit and promote the BF slag fiber industry. Accordingly, in this study, fiber insulation pipes were prepared using water glass, polyvinyl alcohol (PVA), and PVA–glutaraldehyde (GA); moreover, their bulk density, moisture absorption capacity, and thermal conductivity coefficient were measured and compared. The results demonstrated that the values of these three parameters depend on the binder concentration and dosage under certain fiber quality, pipe sizes, and manufacturing process conditions. The best binder composition was proven to be that of PVA–GA, prepared using 3 wt% PVA and 5 wt% GA herein, which facilitated reduction in the bulk density and improvement of the waterproof properties and insulation performance of the slag fiber pipes.

The continuous cooling transformation of 12Cr1MoV perlitic heat-resistant steel was studied by means of ther⁃ mal expansion tester， laser confocal microscope， microhardness tester and scanning electron microscope， the continuous cooling transformation （CCT） curve of experimental steel was drawn， and the effect of cooling rate on the microstructure evolution of phase transformation during cooling process was analyzed. The results show that four transition regions of fer⁃ rite， pearlite， bainite and martensite will appear in the CCT curves of 12Cr1MoV steel at the cooling rates between 0. 5 ℃/ s and 30 ℃/s. At the cooling rates between 0. 5 ℃/s and 1 ℃/s， and the transformation products are composed of ferrite and pearlite. At the cooling rates between 1. 5 ℃/s and 10 ℃/s， and the transition products are mainly composed of upper bainite and ferrite. At the cooling rates between 10 ℃/s and 20 ℃/s， and the transition products are mainly the mixed structure of upper bainite， lower bainite and martensite. At the cooling rate of 30 ℃/s， the transition product is mainly martensite. The transition structure of undercooled austenite appears upper bainite at the cooling rates between 1. 5 ℃/s and 20 ℃/s. The appearance of upper bainite in the structure leads to a decrease in the mechanical properties of the steel， which is prone to crack formation and propagation. Based on the above research results， measures to reduce the cooling rate of 12Cr1MoV steel continuous casting billets and hot rolling lines are proposed to reduce the upper bainite structure The surface cracks of the bars are effectively controlled after adjustment.

Graphitic carbon nitride (g-C3N4, CN) has emerged as a promising photocatalytic material due to its inherent stability, antibacterial properties, and eco-friendliness. However, its tendency to aggregate and limited dispersion hinder its efficacy in practical antibacterial applications. To address these limitations, this study focuses on developing a composite hydrogel coating, in which sodium alginate (SA) molecules interact electrostatically and through hydrogen bonding to anchor CN, thereby significantly improving its dispersion. The optimal CN loading of 35% results in a hydrogel with a tensile strength of 120 MPa and an antibacterial rate of 99.87% within 6 h. The enhanced mechanical properties are attributed to hydrogen bonding between the -NH2 groups of CN and the -OH groups of SA, while the -OH groups of SA facilitate the attraction of photogenerated holes from CN, promoting carrier transfer and separation, thereby strengthening the antibacterial action. Moreover, the hydrogel coating exhibits excellent antibacterial and corrosion resistance capabilities against Pseudomonas aeruginosa on 316L stainless steel (316L SS), laying the foundation for advanced antimicrobial and anticorrosion hydrogel systems. [ABSTRACT FROM AUTHOR]

Converter steelmaking is the primary steelmaking method because of its fast production rhythm and ability to handle molten iron. Despite its benefits, there are some limitations with this method that cannot be ignored. These limitations include excessive loss of iron by evaporation caused by a high-temperature fire spot zone and uneven melting of lump lime, which leads to an increase in steel consumption and a decrease in steelmaking efficiency. In view of these shortcomings, this study tested the approach of mixing a top-blown O2 lance with CO2. The mixture gas (80%O2 + 20%CO2) was used as a carrier gas to blow CaO powder from the top-blown oxygen lance into a molten bath. Based on the standard κ−ε turbulence model and the discrete particle model, the effects of flow rates of carrier gas on the distribution of gas and CaO powder jets were analyzed by numerical simulation. The simulation results show that the velocity of Cao powder increases with the increase in gas flow rate. The distribution area of Cao powder in radial section is more concentrated, and the deviation distance between Cao powder distribution and pore axis is shorter. At the same time, because of the inertia force of Cao powder, the attenuation speed of carrier gas jet in subsonic region slows down. The interaction between mixed carrier gas and powder is beneficial for the mixture gas and powder to participate in metallurgical reaction. [ABSTRACT FROM AUTHOR]

The injection of CO2 during the Rheinstahl-Heraeus (RH) refining process as a lifting gas is a new attempt for the steel industry, and can promote refining effect and realize the utilization of CO2 as a resource. In the present study, the thermodynamic equilibrium of the RH refining process through CO2 injection instead of Ar was calculated using FactSage software. A selective oxidation sequence of [C] and [Al] with CO2 was studied and analyzed under the RH refining temperature and vacuum degree. In addition, the oxidation zones of carbon and aluminum were both defined. Industrial trials were preliminarily conducted to verify the above theory. The results show that CO2 has the potential to be used to refine low-carbon steel in RH, but its refining effect is affected by the [Al] content in steel. By reducing the additive amount of aluminum alloy in the ladle furnace and replenishing the aluminum during the late stage of the RH refining process, CO2 injection can achieve a lower temperature drop of molten steel and a better refining effect than Ar during the RH degassing process. [ABSTRACT FROM AUTHOR]