SU1135502A2 - Rolling method - Google Patents

Abstract

ROLLING METHOD on auth. No. 869871, characterized in that, in order to improve the quality of the sheets by reducing the anisotropy of the mechanical properties and increasing the efficiency of descaling, the protrusions are formed with a width equal to 0.81, 2 of the height of the workpiece, and the conversion of the depressions instead of the protrusions two stages with the initial deformation of the projections on 0.60, 9 of their height and then on O, 15-0, And the height of the workpiece. g §

Description

This invention relates to rolling production. According to the main author. St. No. 869871, a rolling method for producing wide sheets and strips is known, which consists in the fact that, when receiving a grooved billet with alternating lines and depressions, the latter are formed at the site of the projections, crossing them with ClJ. However, the implementation of the known method does not take into account the intensity of the development of shear deformations that affect the anisotropy of the mechanical properties and the efficiency of the separation of the scale. The purpose of the invention is to improve the quality of the sheets by reducing the anisotropy of the mechanical properties and increasing the removal efficiency of the scale. The aim is achieved by the method of rolling, the protrusions are formed with a width equal to 0.81, 2 of the height of the workpiece, and the conversion of the depressions instead of the protrusions, and vice versa two stages with the initial deformation of the protrusions: 0.6 0.9 of their height and then 0.15-0.4 height of the workpiece. The drawing shows a diagram of the bands with the sequential formation of depressions instead of protrusions on the corrugated blanks. Preheated billet 1 is compressed in profiled rollers to obtain a corrugated billet 2, while the width Bg of the protrusions 3 is 0.8-1.2 heights hj of the corrugated billet 2, which is deformed in two stages with the formation of depressions 4 at the places of the protrusions 3.. Originally ledges 3 wide. b (0.8-1.2) hg and height hj (0.050, 15) h, compressed in rolls with a smooth barrel - 0.6-0.9 height hg and get a corrugated workpiece 5. In the second stage, the workpiece 5 s the partially deformed protrusions 3 are crimped at 0.15-0.40 in height hg of the workpiece 5 in the profiled rolls, ensuring that the newly obtained corrugated workpiece 5 has the width bg of the projections 3 equal to 0.8-1.2 of its height h. Thus, the second stage of the formation of depressions in the place of the protrusions is combined with the initial operation of obtaining the corrugated billet 2 with the alternation of the protrusions and depressions from the original billet 1 forming a larger area of which can be smooth or corrugated. Accordingly, the deformation of the workpiece 5 with the formation of depressions at the site of the projections 3 is carried out in two stages. Such a conversion of the cross-sectional shape of the deformable workpiece is carried out repeatedly, based on the existing number of consecutive rolling mill stands. The last pass of the corrugated billet is made in smooth rollers until the protrusions 3 are completely removed and a wide strip 6 is produced with a constant cross-sectional profile along the length. Ensuring the width bg of the protrusions 3 equal to 0.8-1.2 heights h ,, leads (along with the intensification of the turbulence of metal flows and the development of shear deformations) to the occurrence and prevalence of compressive stresses in the volume of the deformed workpiece, which contribute to the refinement of the dendritic structure of the metal being worked , brewing its internal defects. The formation of depressions at the site of protrusions in two stages allows (by increasing the turbulence of metal flows, intensifying the crushing of the cast structure and working out the metal) to increase the efficiency of the separation and removal of scale in the rolling process, as well as to reduce the amount of tensile stresses produced in the volume of rolled | for uneven compression of its width. Partial, rather than complete crimping of the protrusions, increases the efficiency of descaling and descaling during the rolling process, since at the first stage of the formation of cavities at the places of the protrusions the opening and separation of the scale, and then its natural removal before the second stage takes place. Making the width bg of the protrusions 3 less than 0.8 of height h, the workpiece 2 leads to the appearance and prevalence in the volume of the rolled strip of stretched / unwinding stresses that do not contribute to the compaction of the metal being processed, but loosen it. Making the width bg of the protrusions 3 more than 1.2 of height h, the workpiece 2 limits the possibility of displacing zones with a turbulent flow of metal along the width of the rolled strip, contributes to the development of localized zones with difficult deformation and laminar flow of metal near the flat surface of the projections 3, resulting in a decrease in development the molded structure of the metal being processed and the reduced degree of separation of scale; The squeezing of the projections 3 by an amount less than 0.6 of their height does not allow the penetration of plastic deformation Into the axial zone of the rolled billet, where its dendritic structure develops to the greatest extent, which reduces the development of the metal being processed by grinding its greener. The use of crimping of the projections 3 by an amount greater than 0.9 of their height is accompanied by the development of stresses in the volume of rolled strip, which reduce the ductility of the metal being processed, and the same process of scale rolling, which degrades the quality of finished rolled products. Before the second stage of the crimping of the corrugated billet with the protrusions 3 partially deformed with the height K, the latter, due to the natural heat exchange with the environment and contact with the cooling roll, the water is thickened. In the second stage of the formation of depressions in place of the protrusions with compression of 024 protrusions 3 by 0.15-0.40 in height hg of the workpiece 5, the protrusion protrusions 3 increase the turbulence of the metal flows in the volume of the deformable strip, and hence the intensity of crushing the cast structure of the metal being grinding its grain. The compression at the second stage of the protrusion 3 by an amount less than 0.15 height dB of the workpiece 5 does not ensure the penetration of plastic deformations into the axial zone of the rolled strip, and the greater 0.40 is accompanied by the development of stress strain, with a corresponding decrease in the efficiency of processing the cast structure of the processed metal. In addition, the marked range of conversions in the second stage of converting the protrusions into the valleys is most favorable. From the point of view of providing an optimal range of variation of the width bj of the projections 3 relative to the height hi. billet 2. In table. 1 and 2 show the specific modes of reduction and properties of the resulting rolled products. The use of the proposed method provides improved descaling and reduced anisotropy of the mechanical properties of sheets with a simultaneous increase in their level - strength and ductility. Table 1

130

20

Continued tabl, 1

512

34.9

1 2 3 A 5

0.172 526 37.1 0.129 547 38.7 0.111 539 37.9 0.115 516 35.2 0.187

Known spoobo). 508

33.6

0.193

Local scale injection

Local scale injection

Vkatanna scale.

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Claims (3)

METHOD OF ROLLING No. 869871, characterized in that, in order to improve the quality of the sheets by reducing the anisotropy of the mechanical properties and increase the efficiency of descaling, the protrusions are formed with a width equal to 0.81, 2 heights of the workpiece, and the transformation of depressions instead of protrusions, ή on the contrary, is carried out in two stages with the initial deformation of the protrusions at 0.60.9 of their height and then at 0.15-0.4 of the height of the workpiece. 3 £ § f 1135502