The preparation of hot-rolled steel sheets begins with the continuous casting process. Molten steel is formed into solid slabs by a continuous caster; during this stage, the internal temperature of the slab is typically maintained above 1,150 °C. The high-temperature slab is then transferred to a heating furnace for equalization treatment, which aims to eliminate internal temperature gradients and casting stresses, homogenize the austenitic structure, and provide the necessary metallurgical preparation for subsequent deformation. After equalization, the slab is conveyed to the rough rolling unit. The rough rolling process involves multiple passes of high reduction, significantly reducing the slab thickness. Each rolling pass is accompanied by dynamic recrystallization, which breaks the original cast structure and provides preliminary grain refinement. The primary objective of this stage is to obtain an intermediate slab that meets dimensional requirements and to establish the basic shape of the sheet. Upon entering the finish rolling unit, the rolling process parameters undergo critical changes. Finish rolling is typically carried out at higher rolling speeds and within a lower temperature range; the final rolling temperature must be precisely controlled above the critical point for the transformation from austenite to ferrite. The distribution of reduction, the setting of the roll gap, and the cooling rate during the finish rolling stage collectively determine the surface quality, thickness precision, and microstructural morphology of the finished steel sheet. Post-rolling cooling has a decisive influence on the final properties of the material. A laminar cooling system rapidly cools the steel sheet using a specific water flow density and distribution pattern; differences in the cooling path result in different phase transformation products. Rapid cooling can produce high-strength structures such as bainite or martensite, whereas slower cooling favors the formation of ferrite and pearlite. Precise control of the cooling process achieves a balance between the strength and toughness of the steel sheet. After forming, hot-rolled steel sheets undergo multiple surface treatment processes. The descaling process removes surface iron oxide via a high-pressure water jet, while the pickling process further eliminates residual oxides and improves surface cleanliness. Flat rolling is used to correct plate shape defects and enhance surface finish; some products also require oil coating to prevent surface corrosion during storage. In industrial applications, hot-rolled steel plates find diverse uses. In construction engineering, they serve as primary materials for steel structures, meeting the load-bearing requirements of large-span workshops and high-rise buildings. In mechanical manufacturing, their excellent formability enables the fabrication of various equipment frames and structural components through cutting, welding, and bending processes. In the transportation industry, they are utilized for heavy-duty vehicle chassis and container manufacturing, where their high strength and fatigue resistance are fully demonstrated. In energy equipment manufacturing, hot-rolled steel plates are processed into curved segments for wind turbine towers; their low-temperature toughness ensures long-term reliability of the equipment in extremely cold environments. In agricultural machinery manufacturing, these materials are processed via laser cutting and bending to create harvester shells and tractor protective structures, with their wear resistance extending the service life of the equipment. In warehousing and logistics, they are used to produce heavy-duty shelving and automated warehouse steel structures, where load capacity and stability are critical considerations. Material research and development continue to drive the performance enhancement of hot-rolled steel plates. The application of micro-alloying technology involves adding trace elements such as niobium and titanium to the steel; combined with controlled rolling and controlled cooling processes, this achieves fine-grain and precipitation strengthening effects without the need for heat treatment. The intelligent upgrade of next-generation rolling equipment has improved the precision of thickness tolerance and plate shape control, while online inspection systems provide real-time feedback for the adjustment of process parameters. Future trends indicate that the production of hot-rolled steel plates will place greater emphasis on resource efficiency and environmental impact. The optimized design of waste heat recovery systems enables the thermal energy lost during rolling to be reused in production processes, thereby reducing overall energy consumption. The development of short-process technologies aims to minimize processing steps while reducing material loss without compromising performance. The expansion of product specifications includes the use of thinner hot-rolled plates to replace portions of cold-rolled products, as well as the introduction of thicker specifications to meet the requirements of specialized engineering applications. The development of industrial applications will increasingly focus on the precise matching of material properties. Weather resistance requirements under different service environments are driving the research and development of atmospherically corrosion-resistant steel plates, which form a dense protective layer through the adjustment of the content of elements such as copper and chromium. Steel plates used in low-temperature environments require optimized compositional design to enhance impact toughness and prevent brittle fracture. The trend toward lightweighting is driving an increase in the proportion of high-strength steel plate applications, enabling a rational reduction in material consumption under identical load-bearing conditions. These advancements collectively point toward a more efficient and sustainable industrial materials application system.
Null
关闭返回