DANIELI-CQE: System for Controlling Mechanical Properties of Hot-Rolled Coil

Abstract

DANIELI's Coil Quality Estimator (DANIELI-CQE) is an online system meant for estimation of properties of the hot-rolled coil produced in a hot-strip mill. The system predicts the mechanical properties, especially the yield strength (YS), tensile strength (TS), elongation (EL), and hardness (HV) at different locations over the length and through the thickness of the strip as soon as the coil is rolled. The estimation is based on the final ferrite grain size and the volume fraction of the microstructural constituents such as ferrite, pearlite, and bainite. The system is available for different grades of steel such as low, medium, and high carbon steels, and high strength low alloy (HSLA) steels microalloyed with niobium, vanadium, and titanium. The prediction of properties is based on a series of physically based interconnected models. Different models—Thermal Model, Deformation Model, Microstructural Model, Precipitation Model, Phase Transformation Model, and Structure-Property Correlation Model together form the CQE's Mathematical Model Suite. The system traces the thermomechanical histories at different sections of the strip, during reheating, rolling, and cooling operations. The process data are captured from the field devices in real time and are fed through the Danieli Mill Level II Automation System. The uncertainties involved in actual processing in plant are addressed by taking advantage of the state-of-the-art soft computing based models such as artificial neural network (ANN). The CQE system is useful for process control and optimization. The accuracy of prediction for the YS is ± 20 MPa, for UTS, ± 20 MPa, and for EL, ± 5%. The system can generate the user report for the purpose of quality control. The archival of the historical data for the coils gives the opportunity for future process analysis, improvement of product quality. It also helps handle specific customer queries. The savings come from reduction in testing samples, shortening the turnaround time between coil production and delivery, lowering inventory, increasing customer satisfaction through in-time delivery of better quality of product to the customers.

Keywords:

• Coil quality estimator
• Danieli
• Hot rolled coil
• Mechanical properties
• Process control
• Rolling