The Research Of The System Testing High Pressure Descaling Nozzle

During the process of heating in heating-furnace,the iron scale would be formed on the surface of steel slab and billet. Otherwise, secondary iron scale would be formed during the process of hot rolling. By the rolling of roller, a part of iron scale was broken into small pieces and fell from the plant automatically. The other part was pressed into metal surface, forming slag, bug, scars and so on. It will be one of the important factors which would impact the quality of the surface of the slab. In order to improve the quality of the product, high-pressure water descaling system was adopted widely in hot rolling mill. The iron oxide skin will broken into small fragments and disengage quickly from the surface of the plate by the powerful scouring and cooling force which was produced by the high-pressure water, and the shear force which was produced by the different cooling contractibility between steel and oxidation scale, and the expansion of the steam which was produced by the water infiltrating into the substrate and the iron scale. The iron scale will be washed out by the high-pressure water in the setting direction.In the high-pressure water descaling system, the key equipment was the nozzle. The high-pressure water descaling nozzle was studied by some technicians at home and abroad in recent years. The results showed that the effect of descaling and cooling did not only depend on the supply water, but also had a great relation to the type of the nozzles, structure and layout of the nozzles. Developing a testing system for high-pressure descaling nozzle was of great significance to choosing the suitable nozzle for plate production, improving the descaling effectiveness and the quality of slab.In this pape a research had been done on effect of the descaling by the jet impact, and studied various factors which impacted the jet such as spray pressure, flux, jet spray angle, distance and the layout of the spray nozzle. Depending on the research, the high-water descaling testing system was designed. This system mainly consisted three parts, including the water supply systems, electrical controlling system and computer-aided testing system. The paper also discussed the testing method of the jet force and the "zhi" shaped movement testing programme was proposed and done a detailed analysis.The computer-aided testing system in this paper drew the pressure-flow curve and three-dimensional distribution surface of the hitting power by the signal processed by filtering technology combined with least-squares curve, surface fitting algorithm. So that the entire testing system worked effectively and reflected the high-pressure water descaling nozzle accurately. The testing system played an important guiding role on the structure design and installation of the nozzle.