Online Cooling System and Improved Similar Self-adaptive Strategy for Hot-rolled Seamless Steel Tube

Abstract

In conventional hot-rolled seamless steel tube production, the tube was air cooled to room temperature, and the enhancing of mechanical properties mainly depends on adding alloys elements and additional offline heat treatment. Control cooling was an effective method that can obviously enhance mechanical properties and widely used in hot-rolled strip and plate production lines. To realize control cooling process, an online control cooling equipment was introduced, which can implement the efficient and uniform cooling process for annular seamless tube. Meanwhile, the controller system was built to ensure online continuous cooling process quickly and stably. In order to guarantee precise temperature control, a temperature model based on energy balance and finite difference method was proposed. In addition, a self-adaptive strategy based on improved similar tube was obtained for temperature control, which builds the self-adaptive model combining constrained one pass clustering algorithm and kNN algorithm. Finally, the proposed online control cooling system and temperature model were applied in a PQF460 hot-rolled seamless steel tube production line, which greatly improved qualification rate whilst retaining a good control precision and stability.