Designing of technological processes for production of hot-rolled steel products as a semi-finished material

Current metallurgical production is characterized by a wide range of manufactured products. The production process at a metallurgical plant is organized so that the billets obtained in the early stages of the process cycle serve as semi-finished material for subsequent stages of finished article production. This production organization requires the use of specialized approaches to designing process modes to ensure the required level of properties and quality indicators for the semi-finished material at all stages of the complete metal production cycle. Rolled steel products are produced sequentially through hot and then cold rolling mills. The same type of hot-rolled steel can serve as semi-finished material for the production of steel strip for various applications. Therefore, the hot-rolling stage must ensure the properties and microstructure of the hot-rolled product are such that the finished steel strip meets the specified quality standards. Hot-rolling modes are highly variable, allowing them to be adapted to subsequent cold-rolling modes. This article examines options for adapting the quality parameters of the initial billet to control the properties of hot-rolled coiled stock made of grades 50 and 65G steel and low-alloy grades 30G2 and 35G2 steel to ensure the required microstructure. It is shown that adapting hot rolling conditions involves regulating surface cooling in the interstand spaces and on the discharge roller table, taking into account the thickness of the hot-rolled product, or regulating the temperatures at the end of rolling and coiling the strip, as well as the deformation modes of roughing and finishing hot rolling within narrow ranges, taking into account the specific chemical composition of the steel.