美国钢铁公司

Developments in third-generation advanced high-strength steels (AHSS) have produced stronger and more formable steels for the automotive industry by controlling chemical composition and mechanical processing. Cracking during cooling after continuous casting has been a prominent problem for these steels and is believed to be influenced by the steel microstructures. In this study, the effects of chemical composition on the mechanical properties are investigated for as-cast steels by performing mechanical tests on steels containing 0.2 wt pct C and 3 wt pct Mn with varying Si and Al concentrations up to 3 wt pct. Tensile tests were performed to measure strength and ductility at temperatures from 200 °C to 600 °C. Si-alloyed steels have the highest yield strength, while combined silicon- and aluminum-alloyed steels have higher ductility. Fracture surfaces were examined and crack paths were found not to propagate along the ferrite in the microstructure.

While rapid development of advanced high strength steels (AHSS) for a safer and lighter vehicle has been a primary focus in the automotive industry, the application of traditional high strength low alloy (HSLA) steel continues to be actively supported and developed. AHSS are often used to replace HSLA steels for downgauging while maintaining similar or better performance in crashworthiness and durability. However, recent developments have enabled the availability of higher strength, cold-rolled HSLA steels that could offer opportunities for a more balanced solution between material cost and material performance. Certain higher strength HSLA steels not only offer a cost-effective way to increase the strength-to-weight ratio but also provide comparable formability and better weldability to AHSS. In this study, cold rolled HSLA grades of CR420LA and CR550LA are evaluated in overall formability and in-use performance when compared to CR590 dual phase (DP) grade. The evaluations performed include both global and local formability tests such as forming limit curve (FLC) testing, true fracture strain, half specimen dome and hole expansion tests. Experimental results indicate that CR550LA tends to have a slightly better local formability but slightly lower global formability than CR590DP. The results demonstrate these higher strength, cold-rolled HSLA steels can potentially be used to replace CR590DP for certain components.

In a twin-slab caster, adjusting the slab width by moving a NF leads to off-center placement of the submerged entry nozzles (SENs), creating a unique mold flow distinct from traditional casters. This study employs CFD simulations to investigate the effects of this asymmetry on temperature distribution and shell formation for twin-slab. A 3D model was established to study three different cases with slab widths of 40, 46, and 50 inches. Solidification was modeled using the enthalpy-porosity approach. A step-by-step approach was adopted, where the simulation was divided into the primary cooling (PC) and secondary cooling (SC) stages. The mold heat transfer was characterized by heat flux, which follows a plant data-driven trend. Slab cooling was defined using an HTC correlation based on real nozzle configurations. Results indicate that at the mold exit and outside the spray-covered region, a reheating trend in temperature is observed. The temperature difference between the loose and fixed sides exceeds 250 degrees C, with the highest variation observed near the corner of CBF. Shell thickness and metallurgical length (ML) are directly influenced by mold heat flux. The 50-inch slab exhibited the highest mold heat flux, resulting in the thickest shell and the shortest ML. Additionally, wider slabs demonstrated greater asymmetry, with the 50-inch slab showing the most significant shell thickness variation in the width direction. These findings provide insights into optimizing secondary cooling strategies to reduce thermal asymmetry and improve solidification uniformity in twin-slab casting.

Mastering crane operation requires precision, yet traditional training methods expose trainees to significant risks and operational constraints. This project demonstrates how virtual technologies and computational modeling enhance operator training by integrating computer-aided design (CAD) modeling, multi-physics analysis, and real-time microcontroller inputs. The developed simulators provide an interactive, physics-based environment that replicates real crane behaviors, enabling trainees to practice critical skills in a controlled setting. By incorporating simulation-driven workflows, this work highlights the role of designing around a particular use case to improve safety, efficiency, and adaptability. Overall, it underscores how even small-scale digital solutions can serve as effective hands-on training tools prior to real-world application.

This presentation will report the rational design and fabrication of NETL's highly permeable non-aging thin film composite (TFC) membranes for CO2 capture from various industrial point sources. This talk will also cover the design, computational fluid dynamic simulation, 3D printing, and permeation testing of plate-and-frame membrane modules for an upcoming field demonstration at U. S. Steel's Edgar Thomson Plant in Braddock, PA. The field test will demonstrate membrane-based CO2 capture from a blast furnace for decarbonization of steel manufacturing for the first time in the U.S. A mobile gas permeation test unit is currently under design and construction for the field test, which is scheduled to take place in 2025.