Position tracking and determination method for skid marks in the finishing mill unit of hot strip continuous rolling

Skid marks are one of the main factors affecting the thickness quality of hot strip continuous rolling. Accurate tracking and determination of the skid mark position during the rolling process are great significance for strip quality control. Based on rolling theory, this paper proposes a method for position tracking and determination of skid marks in the finishing mill unit during hot strip continuous rolling. First, according to the distribution of skid mark positions on slabs of different lengths during heating in the reheating furnace, the start and end positions of each skid mark on the roughing-rolled transfer bar are calculated, and the positions are further determined using the temperature variation curve at the roughing rolling exit. Second, by matching and calibrating the actual length of the roughing-rolled transfer bar with the finished strip length after finishing rolling, the rolling elongation of each finishing stand is predicted, and the start and end positions of the skid marks on the strip exiting each stand are determined. Finally, based on the rolling characteristics of the strip at the skid mark positions in the finishing mill, the accuracy of the calculated skid mark positions from the second step is verified. Experimental results show that the proposed method validates the accuracy of the rolling length tracking in accordance with the actual rolling characteristic variation, and achieves satisfactory results.