THE DEVELOPMENT OF DUAL WIDTH GAUGES AND HOLE DETECTORS IN CONTINUOUS ANNEALING LINE

摘要

Quality is one of the most important issues for both producers and customers. A system combining width and hole detector was developed by China Steel Corporation to satisfy the increasing demand of strict quality. The system has three main functions, width measurement, edge cracks and holes detection. In this system two high-resolution line-scan cameras configured with a stereoscopic view are used to measure the silhouette of the strip. With this configuration, the influence factors of measurement, such as vibration, tilt and wandering of high speed running strip, are greatly diminished. The accuracy of width measurement is + -0.5mm in the width range 600 to 2000mm. Edge cracks on strip can therefore be detected very effectively, too. Holes with diameter greater than 2mm are detectable at line speed of 500 meters per minute. Many sets of this system have been installed at China Steel Corporation. As a particular case, in the continuous annealing line, two systems were installed, one is before the annealing furnace, and the other one is after the furnace. In this application, the width necking caused by steel grad, temperature and tension variations can be analyzed, so the contingencies can be handled in advance, and consequently to raise the inspection efficiency. By using this system, it not only can lighten the load of the inspectors and acquire on-line measuring data in time but also very helpful for quality and process control.