Real Time Crossbow Measurement and Control

• Published in: Corrosion science and technology Vol. 24; no. 3; pp. 184 - 192
• Main Authors: Owen Pearcey, Ivan Marincic, Joel Tham
• Format: Journal Article
• Language: Korean
• Published: 한국부식방식학회 30.06.2025
• Subjects: Correcting roll; Crossbow; Curvature; Passline; Strip shape; Passline; Crossbow; Strip shape; Curvature; Correcting roll
• ISSN: 1598-6462; 2288-6524
• DOI: 10.14773/cst.2025.24.3.184

The transverse curvature of a strip referred to as ‘crossbow’ has always been a factor present in the coated steel production process. Its existence at the galvanizing pot and consequence on coating control need to be managed. Many attempts have been made to reduce its effect. Using an array of sensors across a strip, strip position (passline) and strip shape can be measured just above the air knives. While the passline shift and crossbow are considered separate effects caused by properties of the substrate and pot roll configuration, they are not independent of each other. In the same way, the control of crossbow by adjusting the correcting roll affects both the passline and crossbow. The resulting strip position and curvature measurement can be fed into the coating control air knife and correcting roll positioning systems. This paper presents results from a laser strip profile and passline measurement system employed at the air knives. The use of measurements of strip shape and subsequent development of a crossbow model and control system that can be used to reduce or minimise the crossbow in the steel strip at air knives are also discussed in this paper.