Speed Rate Optimization of the Run-Out Table of a Hot Strip Mill
The existing method of run-out table drive control at the hot strip mill ensures the required strip tension by setting a difference between the speeds of the delivered strip and roller bodies. Such difference results in a higher wear rate of roller bodies and their more frequent replacement entailing high expenses. Thus, a currently important objective is to increase efficiency of run-out table drives on hot strip mills. The research group carried out experimental research of run-out table roller motor torque elements at a hot strip mill, PJSC MMK. The paper uses analytical methods to solve algebraic equations, computer modeling methods and statistical methods to process run-out table motor current variation diagram. As a result of the research performed, the authors offered the methodology to calculate the required run-out table roller drive load torque. They also adjusted the mandatory process requirements for a run-out table roller drive with regard to a decreased wear rate of roller bodies and the improved strip surface quality. The authors developed a method and a functional diagram to control the drive of run-out table rollers ensuring compliance with new process requirements. A special feature of the diagram is a computing block calculating run-out table roller motor torque according to the process requirements and relevant reference motor armature speed. The efficiency of the offered technical solutions was under an experimental evaluation. As a result, for 13 percent of rolled strips the difference between speeds of the run-out table rollers and the strip in a strip head delivery mode decreased by 50% or even more, while providing the necessary tension in the strip.