| 摘要 |
The invention relates to metallurgy, namely to a method and a plant for continuous casting a steel billet. The method comprises feeding molten steel into a mold, drawing the billet solidifying in a processing channel of the casting plant, along a trajectory that comprises a vertical section of its lowering, followed by a first curved section, along which the lowering is made with simultaneous bending the billet with decreasing radius of bending from the maximum value in the highest point to the minimum value in the lowest point of motion, a radial section along the arc of constant radius equal to its minimum value, the second curved section with simultaneous lowering the billet and its unbending from the minimum to maximum radius, which corresponds to the straightening the billet with its laying on the horizontal section of the trajectory of its movement provided that limitation of value and rate of deformation on the curved sections of the trajectory of motion is less than their critical values of destruction of a solid shell of the billet, and lowering the billet on the first curvilinear section is carried out along a trajectory, which is described as a continuous function in the form of a relation:y = a arcos (1- x/a) -,where y, x – current coordinates of the trajectory of movement of the billet at its simultaneous drawing and bending, a = (H– H) / (y– y) - scale factor, Hand H- height of the highest and lowest points of the trajectory of movement of the billet on the first curved section relative to the horizontal section, respectively, yand y- ordinates of the highest and lowest points of the trajectory of movement on the first curvilinear section defined by the proposed function, respectively, in the case the increase of bending deformation of the billet along the trajectory of movement at its removal is set by the law of reduction of the radius of curvature of the trajectory as a continuous function R = 2, provided that limitation of the values of deformation of the billet and its speed is less than the critical values at the last point of its bending, where R - radius of curvature of the trajectory of drawing billet at the point of bending, which corresponds to the coordinate x. In the plant that implements the disclosed method, the rollers of sections of bending creating its processing channel are set relative to the axis, which provides its minimal mechanical resistance, the number of rollers and their setting pitch on the section of bending the billet are set in accordance with the rules of increase of accumulated deformation of bending along the trajectory of drawing and subject to limitation of the value of increase of deformation within the allowable value on the last roller of the last section of bending. The invention enhances the quality of the billet obtained by continuous casting, with increasing casting speed, reduction of current loads on the drives of drawing devices and increase of the service life of the roller stand for continuous casting billets. |
