Method of continuous casting of ingots

A method of continuous casting of an ingot in a plant provided with a vessel for molten metal, a device for the forced feeding of a molten metal, a radially curved cooled mould, a dummy bar having a through channel in its middle portion along its height, and a secondary cooling device with a radial upcast branch, comprising the steps of:

• (a) introducing the dummy bar into the radially curved cooled mould;
• (b) forced feeding a molten metal from the vessel into the mould from a bottom until the molten metal contacts the dummy bar and simultaneously forces out air through the channel in the dummy bar;
• (c) increasing the pressure of the molten metal applied to an ingot skin being formed and holding the ingot skin being formed to a prescribed thickness;
• (d) reducing the pressure at the end of the holding;
• (e) drawing an ingot from the mould to a value close to, but not exceeding the length of the mould at a rate of drawing that ensures the presence of a molten metal layer on a lower butt portion of the skin;
• (f) forming a hole in the skin of the ingot, made through the channel in the dummy bar during one period of drawing the ingot after reducing the pressure therein;
• (g) supplying a neutral gas to an inner space of the ingot through the channel in the dummy bar and the hole in the ingot skin, in an amount ensuring the equalizing of the level of the molten metal in the mould to a level close to the level of the molten metal in the vessel, as well as forming a gas cushion in an upper portion of the ingot;
• (h) feeding the molten metal into the inner space of the ingot when the ingot is being drawn from the mould and when a pause starts, in an amount that ensures a pressure causing the fitting of the skin of the ingot along the mould;
• (i) decreasing the rate of the ingot drawing until the drawing discontinues completely, the supply of the molten metal continuing;
• (j) returning the ingot to the mould to a distance close to the distance of the longitudinal contraction of a new portion of the ingot being formed;
• (k) continuing the feed of the molten metal in the direction of the ingot drawing until a preset pressure is created on the newly formed portion of the ingot;
• (1) repeating the steps (h)-(k) until formation of an upcast branch of the ingot;
• and (m) straightening and reducing a continuous section of an upper portion of the upcast branch of the ingot, the section being an ingot envelope spaced from the gas cushion to a distance corresponding to the size of a formed lower portion of the ingot, drawn out of the mould.