Issue 37

I. Mazur et alii, Frattura ed Integrità Strutturale, 37 (2016) 287-296; DOI: 10.3221/IGF-ESIS.37.38 288 such discrepancies are detected becomes deeper then the losses caused by rejects are deeper and so the introduction of control systems in all process stages has its logic. A presence of surface defects of steel-smelting and rolling origin is peculiar to the production of hot-rolling mill. That production cloud be a commodity output and pre-rolling. It is not always possible to identify them precisely on the outward signs on the finished commodity. The main methods used for the detection and study of defects of surface of sheet steel, visual – using an external examination without or with the use of special systems [5]. But the speed of the flat bar, its temperature and oxidation of surface complicate the performance of inspection. That is why the rolls are checked for the purpose of presence of defects after a cooling-down as a rule. A volume of insufficient production is increased in that way especially when the defect has a rolling origin (a periodical caused by worker for example). S YSTEM OF QUALITY CONTROL OF SURFACE OF SHEET PRODUCTS oday there are only a limited number of creators of such systems (Codnex, EES, Matra, Parsytec, Siemens-VAI, Sipar and the others) in spite of great need of the enterprises of ferrous metallurgy in the systems of automatic inspection and identification of surface defects. It is explained by the fact that the systems suitable for the rolling are considerably expensive because the surfaces of steels rolled in one company are greatly differ by the outward appearance that leads to the complication of algorithms of detection and classification of surface defects [6-8]. A considerable break-through in the working out and in the introduction of systems of machine check of surface occurred thanks to the creation of highly productive computers and digital video camera of high-resolution that made it possible to obtain and process the image of the moving flat bar in the real time mode. At that time two detections of systems based on the obtaining of primary image from the line scanning video cameras registering the image of surface with the scanning of line by line and matrix fixing the image of surface area had the development. A discussion on the advantages of different systems that took place in different publications is not always constructive because of narrowness of consideration. It is connected, for the most part, with the primary image processing obtained from the cameras. The discussion loses the importance and the criteria for the sake of which these systems are introduced on the metallurgical plants become of current importance on the development and improvement of image processing algorithms, introduction of computers with high data-rate. Namely the accuracy detection and classification of defects, their minimal size and a possibility of use of these results in further technological process stages. C ONTROL OF SURFACE OF HOT ROLLED METAL ON THE CONTINUOUS BROAD - STRIP MILL 2000 system that secures 100 % control of the surface of rolled metal (of the upper and lower side) detects automatically and classifies the defects полосы in the real time mode was mounted in the domestic practice in the first time in 2003 on hot rolling mill 2000 JSC «Novolipetsk Iron & Steel Corporation» (NISC). The companies SYTCO AG, SIEMENS-VAI and the Lipetsk State Technical University (LSTU) took part in the realization of the project together with NISC. The automatic surface inspection system (ASIS) includes two digital line video cameras for the filming of the upper and lower surfaces of the flat bar, block of illumination of the upper and lower surfaces of the flat bar, computer equipment (Fig.1). A resolution of digital video cameras amounts 0,5  1,0 mm. by the width and length of the flat bar correspondingly that defines lower limit size of the fixed surface defect. A graphic presentation of the upper and lower surfaces of the flat bar is received by video cameras and is transmitted to the computer part of the system. The image processing of surface defects occurs in four main stages – preliminary correction of image, determination, segmentation and classification. T A