Faculty: Fhysico-metallurgical
Speciality: Metal Pressure
Consumer demand is the evolution of steel products in the direction of further improvement. For the development of modern wire mills characteristic: extensive use of the principle of continuity, the use of wire units with a hard drive group, single rolling at speeds of up to 120 m / s; small diameter working rolls, discs and small mezhkletevym distance. All of the existing wire finishing blocks on the main parameters can be divided into three groups that differ with each other constructively: blocks trehvalkovyh stands, blocks the second and third groups (Double) from the technological point of view which differ slightly. One of the characteristics of the rolled alloy steel is increased resistance to deformation. Resistance to deformation of steel increases with the doping and the austenite is determined as a result of temperature and strain rate. Upper limit temperature deformation, as is known, is determined by temperature perezhoga, which at 100-200 ° C below the melting temperature of metal. In turn, ¬ so the lower the melting temperature, the greater the degree of doping steel, which reduces the upper limit of the temperature deformation and inevitably increases the amount of resistance to deformation. The difference in broadening leads to the fact that for the same profile, for example, the range required ovals of different cross section. For the carbon steel is more oval cross-section than for alloy steel. Reducing the oval cross-section gives rise to additional forces, and tension reduction sectional circle. For rolling circle of the required size must be increased oval cross-section, ie in the case of self-regulation occurs at the expense of growth mezhkletevogo tension. Used in the finishing units, wire sizing mills circle-oval circle is universal and makes it possible to reduce the number of trans-use the same caliber as the exhaust and fair. In addition to the universality and stability of the bands when rolling in the range of sizes, the oval-circle ensured a smooth transition of one profile to another, good preservative metal from the emergence of local stresses. Several methods of calculating the exhaust caliber, which are designed for carbon steel and do not take into account that influence the chemical composition of steel. The latter factor has a significant impact on the size and caliber of compression mode, so in this work were calculated according to, taking into account through the coefficients, the influence of the chemical composition of steel on the broadening, as well as features nepreryvnolitoy structure. The results of the research forming the coefficients for different forms of exhaust sizes and their relationship to allow the power to give preference to a flat oval in the oval exhaust calibers-rib oval. This caliber is usually used in the intermediate group stands wire mills. Flat oval provides a greater ratio between the longitudinal and lateral flow of metal, and therefore provides greater exhaust capacity and efficiency forming. Another positive side of this caliber is a vintage replacement universal calibration and stability of the width of a large size, and hence the square cross section defined in the unit rolled up. It follows that the stability of the area and rolled up upon the stability of wire rod. Using nepreryvnolityh blanks directly on the wire or melkosortnyh machines is an effective way of reducing the cost of production. We know that energy consumption for 1 ton of blanks obtained by continuous casting in 4-5 times less than conventional casting in molds.
Thus, you can draw the following conclusions:
1. Given the high productivity of modern wire mills and the possibility of continuous high-quality elektorostaley come to the unequivocal conclusion that no alternative to the two technologies to obtain competitive final products.
2. A new method of calculating the size of exhaust systems calibers using flat ovals, sensitive indicators of broadening rolled steel.
3. The use of flat ovals instead odnoradiusnyh provides both alignment extracts, and hence the loads of frames, as well as greater durability sizes compared with other systems.
4. Calculated mode-rolled steel of different groups is the basis in the process of rolling cards.