To further improve the internal quality of steel grades that require the continuous casting process, especially thick and extra-thick slabs, Primetals Technologies has developed a single-roll dynamic press down (SRD) sector segment for caster users. Each roll is controlled by a separate hydraulic cylinder. The SRD sector has been specially developed for depressive in the final solidification zone, allowing the upper rollers to be individually pressed onto the solidifying casting stream, enabling precise execution of the final solidification point depressing, thus maximizing the internal quality of the slab (including center porosity and center segregation).
SRD segments are interchangeable with traditional dynamic light pressure sector segments and other types of sector designs, allowing them to be easily integrated into existing casters.
In order to reliably cast steel grades with demanding internal qualities, it is necessary to know exactly where the final freezing point is located and perform light pressure downstrokes accordingly. The SRD sector enables precise final freezing point pressdown, and the individual roll gaps can be dynamically adjusted individually to changes in steel grade, superheat, cooling intensity or drawing speed. Each roller is applied separately, which further increases the amount of pressure in the direction of the thickness of the slab, and effectively improves the central segregation and porosity of the slab.
The design of the SRD sector is characterized by a long service life and easy maintenance. For example, each roll is equipped with its own overload protection to prevent damage to the bearings and roll surfaces. The rolls are built into a functional unit, so they can be replaced either in the workshop or quickly directly on the casting machine with production intermissions. The individual continuous casting roller units can also be tested and calibrated before being installed on the sector.
Cooperation with Anshan Iron and Steel Group
In 2019, Anshan Iron and Steel Group Corporation commissioned Primetals Technologies to modernize a slab continuous casting machine at its Anshan Steel Mill. The goal of the project is to improve the quality of the slabs used in the downstream plate mill and to increase the maximum slab thickness from 300mm to 360mm. In addition, production flexibility is increased by installing SRD sector segments in the horizontal section of the casting flow guide. This is the first time that the SRD sector has been applied to a continuous caster in a Chinese steel mill.
Cooperation with Zhongtian Iron and Steel
In 2021, a 10-flow billet continuous caster upgraded by Primetals Technology for Zhongtian Steel's third converter steelmaking plant in Changzhou was put into operation. It is the world's first billet continuous caster to be fitted with a new SRD tension leveler. In addition, Primetals Technologies' Dynaphase dynamic phase model, Dynacs 3D dynamic secondary cooling model, and Dynagap Sof T Reduction 3D dynamic light pressure model further improve the internal quality of the slab.
This 10-stream billet continuous caster of Zhongtian Iron and Steel has a rated capacity of 2 million tons per year, which can be used at the fastest 2The production speed of 4m min is 160mm 160mm billet. Cast steel grades include low-carbon, medium-carbon, and high-carbon steels, as well as pipeline, spring, cold-heading, and cord steels.