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The modern ideas about of quality of products are based on the principle of the absolute satisfaction of requirements of recommendations of the buyer. A presence of surface defects of steel-smelting and rolling origin is peculiar to the production of hot-rolling mill. 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. A system that secures 100 % control of the surface of rolled metal (of the upper and lower side) detects automatically and classifies the sheet defects 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 whole assortment of the mill 2000 was divided for the five groups by the outward appearance of the surface. The works on the identification of defects of hot-rolled metal and widening of data base of knowledge of ASIS were continued after the carrying out of guarantee tests. More than 10 thousand images of defects were added to the data base during the year.

SynopsisIn order to search for suitable technological schedule of hot strip mill, there is proposed an economo-mathematical model, in which production cost is a function of technological parameters such as threading speed, thickness of transfer bar and extract temperature from reheating furnace. The optimization of these parameters is performed to produce high quality strip with minimum production cost. The optimization code was applied for a hot strip mill in Bulgaria and also for one in Japan. The economical situation for production of hot strip differs much from each other in these two countries, and the type of hot strip also differs, but the code could output proper solutions. With the use of the code, a new rolling schedule, in which the transfer bar thickness decreased with length of strip, proved the possibility to reduce production cost and improve gage accuracy. I. IntroductionDuring the last 10 15 years the hot strip mill technology, automatization and the equipments have developed very remarkably in all countries especially in Japan. The main subject in the operation hot strip mill today is a production of better quality strip at higher production rate with lower operation cost.3,5) This will be achieved by an effort of energy saving,1 4> because of enormous increase in energy cost,3,5) Surely a very large number of achievements have already been made with the optimization of heating processesl) and by the applications of direct rolling porcess,1-3) of hot and reverse charge,4) and of schedule-free rolling.3) It is important to keep in mind that hot strip mill (HSM) problems are reciprocity contradictory to each other. Moreover, there are many possibilities to realise the rolling technology and to choose the HSM equipment and layout. In such situation, it is necessary to employ optimization technique in order to decide the suitable technology schedules.Some efforts have been done to formulate the approach to choose the controlling method of HSM, considering the reheating furnace, roughing and finishing groups as a united complex and to realise a HSM economo-mathematical model as an instrument to search for the proper technology version. Here, the authors could show that the proposed optimization concept was valid in both cases of Bulgarian and Japanese technological and economical situations, and moreover, they could propose a new rolling schedule where the transfer bar thickness decreases from top to tail end on the basis of the concept.

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Introduction.  Power  parameters  of  the  “rolling  −  equalchannel angular pressing” (ECA) combined process are studied. The work objective is to determine forces of rolling and pressing in the deformation by the combined method.Materials and Methods. The die strength calculation and the experiment on deformation of AISI 6063 aluminum samples were carried out. During the experiment, the force values were recorded using a strain-gauge station.Research Results. The strength analysis results show that this die design is suitable for creating an experimental stand of the “rolling − ECA-pressing” combined process, since the calculated  safety  margin  is  sufficient  to  implement  the  pressing under extreme conditions. The rolling forces at all stages of the  deformation  exceed  the  corresponding  pressing  forces, which is a necessary condition for the combined process. Discussion and Conclusions. The obtained results can be used in the design of experimental stands that implement the investigated combined  process. Herewith, the given  strain-gauge method for studying strength characteristics is suitable for the case of calibrated rolls.