1. 2018, an Arvedi ESP (Endless Strip Production) line installed in a plant belonging to the Chinese steel producer Rizhao Steel Group Co., Ltd (Rizhao) produced ultra-thin hot rolled strip with a thickness of just 0.6 millimeters for the very first time.
2. Hot rolled strip as thin as this had never before been achieved anywhere in the world.
3. This thin strip can cover more than 80 percent of regular commercial cold-rolled thicknesses.
4. Following on from 10 years of continued development of the endless concept, this latest production record was achieved during a test in which eight coils were produced with strip thicknesses of less than 0.8 millimeters.
5. This production sequence involved first progressively reducing the strip thickness to 0.75, 0.7 and finally 0.6 millimeters, before continuing the sequence with increasing thicknesses.
6. ESP mills are guaranteed to produce strip thicknesses of 0.8 millimeters, which are used industrially and traded on the market for direct applications.
7. Whereas a strip thickness of 0.8 millimeters covers around 50 percent of cold-rolled thicknesses, a strip thickness of 0.6 millimeters can cover more than 80 percent of cold-rolled thicknesses.
8. Conventional hot strip production has a lower thickness limit of 1.8 millimeters, or 1.2 millimeters for special processes.
9. This success was made possible by the familiar properties of the ESP process, such as an extremely high process stability accompanied by constant speeds and temperatures.
10. At the same time, advances were made in technologies that, in their original form, had only been used in cold rolling mills for high-quality products, the process being controlled by “ultra-thin rolling technology” based on the control concepts applied in cold rolling technology.
11. The Arvedi ESP system produces hot strip directly from liquid steel in a continuous, uninterrupted production process in a linked casting and rolling mill.
12. Mills of this type have an energy consumption and associated costs up to 45 percent lower than those of conventional mills with separate casting and rolling processes. They also have substantially reduced CO2 emissions.
13. Furthermore, the dimensions of these mills, with a length of only 155 meters, are considerably more compact than those of conventional casting and rolling mills.
14. The casting and rolling line is controlled by standardized, integrated basic (level 1) and process (level 2) automation, which ensures finely coordinated interaction of the casting and rolling processes.
ARVEDI-ESP (ENDLESS STRIP PRODUCTION) PROCESS
1. They produce high-quality ultrathin hot-rolled strips with widths of up to 1.6 meters and minimal thicknesses as small as 0.8 millimeters.
2. The Arvedi-ESP process requires up to 45 percent less energy than the conventional process, which consists of separate casting and rolling steps. It therefore generates significantly smaller amounts of CO2.
3. The production of steel strips normally requires a great deal of energy and space. Liquid steel is cast in slabs; these are steel plates that are a few centimeters thick, about one to two meters wide, and more than ten meters long.
4. These slab ingots cool off and are processed in the rolling mill into steel strips that in some cases are less than one millimeter thick. Before this can happen, the slabs must be newly loaded and heated up once again. Finally, the steel strips are rolled onto large reels called coils.
5. In total, such a production line is several hundred meters long. The steel strips are processed for use in automobiles, household appliances or construction materials, for example.
6. The special feature of the Arvedi-ESP process is that the casting and rolling processes are performed in a single step. The hot strand of metal is directly rolled in an endless process without having to cut slab ingots beforehand.
7. The steel is processed into a strip in a single run and rolled into coils weighing up to 32 tons each. The entire production line is only 190 meters long.
8. The loading and reheating of the cold slab ingots is no longer necessary, and this saves a great deal of time and energy.
9. The process, which requires only seven minutes to transform liquid steel into a finished coil, is much shorter than conventional processes, which last several hours.
10. What's more, it does not create any scrap material, which is normally generated in the loading process. Thanks to its precise temperature management, the plant produces steel of high and homogeneous quality.
Source:
http://www.worldsteelnews.com/ultra-thin-hot-rolled-strip/
https://phys.org/news/2013-08-steel-endless.html
