The mechanism of edge cutting machining of rolled iron from oxide scale

A new purifying method of metal surface cleaning from oxide scale using a special rotating edge tool is described, which allows to solve the problem of increasing the extent of surface purification from oxide scale more efficiently, reliably and effectively. The process of the surface cleaning of flat- rolled products used for the manufacture of hollow sheres from oxide scale by mechanical action of a cutting tool on various layers of oxide scale is simulated. The force required to shift an oxide scale and the boundary conditions of the ratio hold-down pressure of the tool to the workpiece, the friction force in the tool support and the impact force of the scale on the tool, at which it is possible to remove the scale from the rolled surface, are determined.

INFLUENCE OF TECHNOLOGICAL FACTORS ON THE EFFICIENCY OF REMOVAL OF SCALE FROM FLATS FOR HOLLOW BALLS

Рассматриваются результаты проведения экспериментальных исследований способа удаления окалины с поверхности стального листового проката. Предложен новый способ и устройство для очистки поверхности листового проката от окалины режущими пластинами, вращающимися вокруг оси, перемещающейся поступательно вдоль обрабатываемой поверхности. Пластины наклонены в направлении вектора вращения на угол до 10 градусов и упруго поджимаются к обрабатываемой поверхности. Это обеспечивает возможность в процессе очистки поверхности воспроизводить макронеровности листового проката. Приведены результаты экспериментальных исследований, построены математические и графические зависимости, описывающие влияние факторов процесса на эффективность очистки поверхности проката. Показано, что наиболее значимое влияние на параметр оптимизации оказывает сила воздействия инструмента на поверхность заготовки. Причем это влияние реализуется в прямо пропорциональной зависимости. Другие исследованные факторы, а именно: угол наклона пластины, скорость ее вращения и подача, оказывают значительно меньшее влияние на степень очистки проката. Эти исследования были необходимы с точки зрения определения конструктивных параметров силовых элементов как технологической оснастки, реализующей указанный способ, так и технологической установки в целом. План эксперимента был принят, исходя из реальных производственных возможностей индустриального партнера, и соответствовал классическим представлениям теории резания. Описанные результаты дают возможность планировать дальнейшие эксперименты по изучению направлений использования данного способа Here we consider the results of experimental studies of the method of removing scale from the surface of steel sheet products. We propose a new method and device for cleaning the surface of rolled sheets from scale by cutting plates rotating around an axis moving translationally along the treated surface. The plates are tilted in the direction of the rotation vector at an angle of up to 10 degrees and are elastically pressed to the treated surface. This makes it possible to reproduce the macro-dimensions of sheet metal during the surface cleaning process. We present the results of experimental studies. We constructed mathematical and graphical dependences describing the influence of process factors on the efficiency of cleaning the rolled surface. We show that the most significant influence on the optimization parameter is exerted by the force of the tool's impact on the surface of the workpiece. Moreover, this influence is realized in a directly proportional relationship. Other factors studied, namely the angle of inclination of the plate, its rotation speed and feed, have a much smaller impact on the degree of cleaning of rolled products. These studies were necessary from the point of view of determining the design parameters of the power elements of both the technological equipment implementing this method and the technological installation as a whole. We adopted the experimental plan based on the real production capabilities of the industrial partner and corresponded to the classical concepts of the cutting theory. The described results make it possible to plan further experiments to study the directions of using the method

Influence of the hydraulic pump unit on the quality of the rolled surface

To ensure the competitiveness of rolled metal in the modern market, the decisive factor is the quality of the rolled surface (defects with a depth of no more than 0.2 mm are allowed without stripping). Rolling processing is a source of formation of small surface defects, most of which are obtained in the process of deformation of a continuously cast billet (hereinafter referred to as CCB, billet) at hot rolling mills in the presence of areas with non-removed furnace scale. This is the main reason for the formation of such types of surface defects as rolled scale, ripple, scale shells, which reduces the quality of the rolled surface and increases the sorting of metal with surface defects. In addition, the scale not removed from the surface of the CCB has a negative impact not only on the quality of metal products, but also on the operation of rolling equipment.One of the directions that allows to achieve high quality of the surface of long products in production conditions is the effective removal of scale from the surface of the initial billet before hot deformation. Scale removal from the surface of the workpiece is carried out on the installation of a hydraulic descaling unit, but not always a satisfactory (complete) scale removal occurs.To determine the cause of poor – quality scale removal before hot deformation, the efficiency of the hydraulic descaling unit and the state of the metal – scale interface surface were investigated.

AUTOMATIC CONTROL OF TEMPERATURE AND POWER CONDITIONS DURING ROUGH GRINDING OF SLABS

The production of high-quality rolled products (slabs), the formation of its surface phase-structural composition, texture, stress state during rough grinding depends on the temperature in the area of contact between the wheel and the slab. During processing, due to geometric errors of the rolled surface, as well as due to local changes in hardness, periodic fluctuations of the instantaneous depth of cut occur, which can be determined indirectly by controlling one of the technological parameters, for example, the power spent on grinding, with subsequent recalculation it to online temperature values. The grinding temperature is described as a control object in the form of an aperiodic link. Computer simulation has confirmed the efficiency of the system for maintaining the specified temperature of slab grinding under various operating conditions that simulate the situations of real production.

Rolls Geometry Calculating Mathematical Model for Rotational Bar Surface Drawing

The problem of round-rolled surface products improving quality by reducing roughness and waviness is solved. Traditionally, grinding is used to improve the surface quality, but at the same time new defects appear in the form of cracks, tinge colours and the abrasive particles in-filtration into the surface layer. Surface pressure processing instead of grinding is not associated with such defects, therefore, it is proposed to use a transverse rolling. Rolling rational profile for transverse rolling on round-rolled surface was theoretically determined. Analytical dependences were obtained for rolls in cage with support rings calibration calculations. Such calibration use ensures uniform deterioration of roll and rings bearing surfaces, as well as the rolls balance with their one-sided load during rolling. A parametric analysis of the deformation conditions effect on the rolls geometry was performed. The conditions under which rolls profile can be limited to a circle or a straight line were considered. The obtained results were used in rolls profiling for drawing the rolling surface in laboratory and industrial conditions.