An oxygen lance is the operation unit that generates supersonic oxygen jets, controls their behavior, and acts as a vital role in the steelmaking process. It is thought that airflow similar to a tornado may suppress upward splashing because of part of the jet pressure shifting from the axis of the oxygen lance to the tangential direction. Therefore, a new oxygen lance is designed to form a tornado jet, and the numerical simulation consequences are verified by the physical model. The structure of the new oxygen lance is optimized by numerical simulation results, and the comparison of simulation results before and after optimization is analyzed. On this basis, the effect of the cyclone oxygen lance on the upward splashing behavior, penetrating depth, turbulent kinetic energy, turbulent dissipation rate, and rotation of molten bath is investigated. The conclusions present that, compared with the conventional oxygen lance, the upward splashing with the cyclone oxygen lance decreases, and the penetrating depth and reaction area increase. In other words, for obtaining the same penetrating depth, the cyclone lance height can be higher than that of a conventional oxygen lance, which leads to a better protective effect on the refractories of the oxygen lance. Moreover, the average value of the turbulent kinetic energy of the cyclone nozzle is larger than that of the traditional Laval nozzle at the interface between oxygen and slag, which improves the effect of steelmaking.

The technology for obtaining sorbite by isothermal quenching of high-temperature molten salt has been used by more and more factories to produce wires with high tensile strength. In this paper, the controlling cap and bottom pipeline of the original salt bath are redesigned. The mathematical model previously proposed is used to simulate the redesigned salt bath model, and the flow field is analyzed in detail. The redesigned and original controlling cap are compared in detail by applying third-generation vortex identification technology. Then, by using the inverse heat transfer method, the heat transfer coefficient (HTC) during the boiling heat transfer stage of the wire rod in molten salt is calculated by taking advantage of quenching experimental data, on the basis of which the original model is corrected. Finally, a new salt bath design is proposed, which divides the salt bath into two parts. The first salt bath at 515 °C is used to cool the austenitized wire and complete the initial phase transformation. The second salt bath at 560 °C is used to prevent the transformation from retained austenite to bainite, and to induce its transformation from retained austenite to sorbite.

The crucial point for obtaining high-strength wire is controlling the microstructure, and the refinement of the interlamellar spacing between 80 and 150 nm gives sorbite excellent tensile strength and plastic deformation ability. To realize sorbitization, the fastest possible cooling rate should be used to avoid austenite being transformed into coarse pearlite. In this article, the main production processes, advantages, and disadvantages of wire rods for bridges are discussed, and the relationship between microstructure and mechanical characteristics of wire rods is argued. On this basis, the research works of simulation and experiments for heat treatment of wire rods in a salt bath, together with the convection and boiling heat exchange mechanism of wire rods in a salt bath, are discussed and provided. The salt bath quenching course is capable of cooling the wire rapidly from the austenitizing temperature to the sorbite temperature region and also dissipates the latent heat, thus reducing the reheating temperature of the wires. It can realize precise control over the microstructure and characteristics of wire and has advantages in improving the wire strength, hardness, wear, and corrosion resistance. The process parameters are highly adjustable, with strong adaptability and flexibility. To obtain ultra-high-strength sorbite steel wire, the key technical problems to be solved include selecting the suitable coolant, controlling the internal microstructure, and precisely controlling the cooling effect.