UA8680U - Blooming method - Google Patents

Abstract

A blooming method involves successive rolling of ingot on the smooth body and in the box passes, increase of relative reduction and setting of the coefficients of metal drawing from one pass to another.

Description

Description of the invention

The useful model refers to rolling production, in particular, to the modes of metal deformation during the 2nd rolling of blooms, mainly of square cross-section from ingots obtained from gas-saturated (boiling, pseudo-boiling, semi-quiet) steel, and can be used on reversible crimping mills - bloomings.

Blooming rolling methods are known, which include successive rolling of the ingot on a smooth barrel and in box gauges with relative crimps and metal extraction coefficients that increase from pass to pass until bloom is obtained (1-4). 70 The disadvantage of the known methods is the high probability of formation of defects on blooms due to the opening of subcortical bubbles in the process of deformation of ingots obtained from gas-saturated steel, for example, boiling, pseudo-boiling, semi-quiet. This is due to the lack of "firm" regulation of relative crimps and metal extraction coefficients in the rolling process, which ensure the production of blooms without surface defects at the required level of blooming productivity. Regulation of deformation parameters during rolling of ingots of gas-saturated steel - boiling, pseudo-boiling, semi-quiet - is especially important. This will prevent the formation of defects on blooms due to the opening of subcortical bubbles in the case of intensification of the rolling process without increasing the total number of passes, which reduces the technical and economic performance of blooming.

As a prototype, the blooming method was adopted, which includes successive rolling of the ingot on a smooth barrel and in box gauges with relative compressions and metal extraction coefficients that increase from pass to pass until bloom |b1 is obtained.

The disadvantage of the prototype is a decrease in the quality of blooms due to the lack of regulation of the deformation parameters of rolling, in particular, the relative crimps and coefficients of metal extraction, from pass to pass, established taking into account the deformation characteristics of gas-saturated metal. This, on the one hand, increases the probability of the formation of defects on the finished rolled products - blooms, and, on the other hand, can lead to a decrease in blooming productivity. High degrees of deformation (relative compression) and coefficients of metal extraction during pt) rolling in the first passes can lead to the opening of sub-crustal bubbles in rolling and the formation of defects on the blooms. Low values of the deformation parameters of rolling, in particular, in the last passes, increase their total number, which reduces the productivity of the mill and worsens the technical and economic indicators of its operation.

The problem to be solved consists in the regulation of the deformation parameters of rolling - relative to crimping and metal extraction coefficients during rolling of ingots from gas-saturated steel in such a way that, on the one hand, defects do not form on the blooms due to the opening of subcortical bubbles, and, on the other hand, the total number of passes did not increase, i.e., the required blooming productivity was maintained. eh

The technical result achieved when using a useful model consists in increasing the technical and economic performance indicators of the blooming machine due to the improvement of the rolled quality without reducing the productivity of the blooming machine by 3o during the rolling of steel with increased gas saturation.

The solution to the problem is provided by the fact that in the method of rolling on a blooming, which includes successive rolling of the ingot on a smooth barrel and in box gauges with relative compressions and extraction coefficients of metal that increase from pass to pass, until bloom is obtained, according to a useful model of increase - relative crimps, from pass to pass during rolling on a smooth barrel and in box calibers 740 are set based on the dependence: с в - (0.8...1.23 (15.03 - 1.56 Mo-- 0.201 Mo) , z and the coefficients of metal extraction along the passes are set based on the dependence: w - 0.95 - 1.05 (1.161 - 0.019Мо ж 0.0236 Мо) where is - the value of relative compression, 90, со и - coefficient of metal extraction ,

Mo - passage number

Me. A comparison with the prototype shows that the claimed method of rolling on the blooming differs in that

Go! increase in relative compression, from pass to pass during rolling on a smooth barrel and in box Kcalibres are set based on the dependence: c is - (0.8...1.23 (15.03 - 1.56 Moz - 0.201 Moz) , and the coefficients of metal extraction along the passes are set based on the following dependence: w - 0.95 - 1.05 (1.161 - 0.019Mo and 0.0236 Mo) where is - the value of the relative compression, 90,

WITH; и - coefficient of extraction of metal,

Mo - passage number

A comparison with other technical solutions in this field of technology showed that there is a known method of rolling gas-saturated steel on a blooming, in which the value of the relative crimps, which increase from pass to pass |b), is regulated. However, the relative compression, which is one of the deformation parameters, does not take into account the volume deformation of the metal, in particular the expansion of the metal during rolling. Therefore, the regulation of only the value of the relative crimps during rolling on the blooming of gas-saturated steel without taking into account the non-contact deformation on the free rolling surfaces due to expansion during rolling can lead to the formation of defects on these rolling surfaces. Additional regulation of the coefficient of extraction of metal during rolling of gas-saturated steel, which takes into account the volumetric deformation of the metal, as proposed in the technical solution, allows 65 to prevent the possibility of the formation of defects on the free rolling surfaces as a result of non-contact deformation due to the expansion of the metal during rolling.

The useful model is explained by the drawing, where Fig. 1 and 2 show the dependences of changes in relative compressions and coefficients of metal extraction along the passages, obtained on the basis of the results of experimental studies.

The method is carried out in the following way.

Bloom is obtained from the initial ingot of rectangular cross-section made of gas-saturated steel, heated to the rolling temperature, by rolling on a smooth barrel and in blooming box gauges. Rolling is carried out with several passes in each caliber. In the rolling process, to compensate for the expansion of the metal, the pressing direction is changed by canting the roll. Edgebanding is carried out between two-by-four passes. The crimping mode regulates the deformation parameters of rolling on the blooming, in particular, relative crimping and/or Coefficients of metal extraction in each pass, and the number of canting between passes and during transfer from gauge to gauge.

The values of the specified rolling deformation parameters increase during the technological process - from pass to pass. At the same time, in the case of rolling blooms from ingots of gas-saturated steel, metal deformation on a smooth barrel and in box gauges is carried out with an increase in the relative compression and extraction coefficients /5 of the metal along the passes established based on the dependencies, respectively: there is - (0.8... 1.23 (15.03 - 1.56 Moz - 0.201 Moz), w - 0.95 - 1.05 (1.161 - 0.019 Moz and 0.0236 Moz) where is - the value of the relative compression, 90, and - the coefficient metal hoods,

Mo - passage number

The dependences presented in Fig. 1 and 2 are obtained on the basis of the results of experimental studies carried out in production conditions aimed at optimizing the crimping modes during blooming rolling of gas-saturated steel ingots. In the course of research, the modes of metal crimping and, accordingly, the actual values of the relative crimping and metal extraction coefficients along the passages were varied.

The results of the research were processed using the methods of mathematical statistics. The criteria for optimizing the crimping modes during blooming rolling were the absence of a break on the surface of the blooms after rolling due to the opening of subcortical bubbles with a minimum number of passes.

According to the obtained dependence, the relative compression in the first six passes should not exceed 1595. Starting from the seventh pass, when the metal was worked through, it was sufficiently compacted, and the gas bubbles in the metal were boiled, the relative compression can be increased and reach in the last aisles 30-3495. The indicated change of relative compressions along the passes, on the one hand, will prevent the formation of cracks on the rolling surface during the rolling of gas-saturated metal, especially in the first passes, on the other hand, it will allow maintaining the productivity of the condition during the production of blooms from such metal. co

Thus, the use of the obtained dependence for the calculation of the crimping mode during rolling of blooms from gas-saturated (boiling, pseudo-boiling, semi-quiet) steel allows to prevent the formation of a gap on the rolling surface during the rolling process. At the same time, the values of the relative crimps ensure the optimal number of passes during the rolling of ingots from such steel. Thus, if the relative compressions along the passes are above the curve 71 in Fig. 1, this will lead to the formation of a gap on the rolling surface during rolling from gas-saturated metal, especially in the first passes. If the relative compressions on the passes are below curve 2 in Fig. 1, then an increase in the number of passes will be required, which will reduce the productivity of the state. c An increase in the relative compression along the passes is possible due to the fact that during the rolling process, as a result of "" deformation, the layers of metal are compacted, and the gas bubbles in the metal are welded. This is facilitated by the "soft" mode " of the metal compression in the first passes, which prevents the subcortical opening bubbles As the number of passes increases, it is necessary to increase the relative compressions, because rolling with small relative compressions leads to an excessive increase in the total number of passes, increases the total rolling cycle, which is associated with an increase in energy consumption for rolling and a decrease in state productivity. b Thus, if the values of the relative compressions along the passes will not increase during rolling in accordance with the claimed dependence, then with minimal relative compression in the first passes, this will lead to an unreasonable increase in the number of passes during rolling, with a corresponding decrease in productivity by 20 and by increasing energy consumption for rolling. An increase in the relative compressions in the first passes beyond the tolerance indicated by the dependence will lead to the formation of a gap on the rolling surfaces. Thus, a different regulation of the amount of relative compression along the passages between edging leads to either increased energy consumption for rolling and reduced productivity, or increased formation of a gap on the surface of the roll.

Experimental studies of the conditions for the implementation of the claimed method were carried out under the conditions of Blooming 1250

OJSC "Kryvorizhstal" during the rolling of blooms with a section size of 285x285 mm from pseudo-boiling steel. In the course of research, the modes of metal compression during rolling were varied, on the basis of which a dependence was established that determines the relative metal compression values in each pass. During the research, the quality of the surface of the finished rolled products and intermediate rolls was evaluated. The results of the experiments were processed using 60 methods of mathematical statistics, on the basis of which the declared dependence was obtained.

With the use of this dependence, a new mode of rolling bloom with cross-sectional dimensions of 285x285mm from a downwardly expanded ingot with a cross section of 865x750 - 785x66bOmm from steel grades Zns, Z TRns, (curve Z in Fig. 1) was developed and tested on the blooming machine 1250 (curve Z in Fig. 1) instead of the previously obtained cross section of 300xZOOmm.

Some parameters of this mode, illustrating the essence of the claimed method, are presented in the table. b5 The values of the absolute compressions of the DP metal in the passes after edging are established based on the declared dependence, the determining intensity of the increase in the relative compressions in each pass.

The application of a new mode of crimping regulating the degree of increase in relative crimping ensured the absence of a gap on the rolling surfaces during rolling of gas-saturated (boiling, pseudo-boiling, semi-quiet) steel. At the same time, the rolling mode is implemented with the minimum possible number of passes.

This made it possible to improve the quality of blooms due to the exclusion of the formation of a gap on the surface of the deformable workpieces, to reduce their rejection without increasing the energy consumption for rolling and reducing the productivity of the state, to reduce the amount of technological trimming (in absolute value) and to reduce the consumption coefficient of metal due to the rolling of blooms of a reduced cross section (258x285mm). Thus, an increase in the technical and economic indicators of the condition is integrally ensured. from an ingot with a section of 865x750 - 785x660 steel Zns, Z TRns, on blooming 1250, which illustrate the essence of the method that is claimed t mer vno denna 00 5 vovku tvo vyv vvyu 010011 yuyu 0055000oyavo la" in tvo 50000 ml 0000 iz 5 | I am | pvo/zvyu 0086040 pl, 6151) t5o0lvvzh 15005; 000 liv from 2 in vv) vo0javv 95000 BGN ov v v | I am | Yav yuyu 105000 my lyakh about zo z I yav | hu | have | 5 | lyu" | 5 ro so zt she | there is Te zv Te 51 and 17 | this | St howl | lo 313 | about zz so

The implementation of the proposed method on other blooms will make it possible to increase the technical and economic indicators of production due to the reduction of metal consumption coefficients during the production of blooms, from "gas-saturated (boiling, pseudo-boiling, semi-quiet) steel and other steel with increased gas saturation, without increasing the total amount passages, i.e. while maintaining blooming productivity. Out of 20 Sources of information taken into account when making an application. p 1. Patent 2111804 (Russian Federation). MKY B218 1/02, 3/02, 12.09.95, Bull. Mo24, 1997, P. 255. 2. Patent 8259 (Ukraine) MKY" В218 1/02, 29.03.96, Bull. Mo1, 1996, P. 3.1.19. ,» 3. Patent A 13826 (Ukraine). MKY? B218 1/02, 29.06.93, Byul. Mog, 1997, p. 3.1.87. 4. Grudev A.P., Mashkin L.F., Khanyn M.I. Technology of rolling production. Moscow: Metallurgy - 1994. - 656 p., pp. 117-121 (ee) 5. Ilyukovich B. M., Nekhaev N. E. Merkuryev S. E. Rolling and calibration. Volume 1. Reference book. Dnipropetrovsk: bu RIA Dnipro- VAL. - 2002. - P. 238, fig. IM.37 - prototype. 6. Application Mo20041211024 dated 12.31.04. "Method of rolling on a blooming" (ee) at 50

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Claims (1)

The formula of the invention ;" "Blooming rolling method, which includes successive rolling of the ingot on a smooth barrel and in box gauges with relative compressions and coefficients of metal extraction increasing from pass to pass, so 745 to obtain bloom, which differs in that the increase in relative compressions from pass to pass when rolling on a smooth barrel and in box gauges is established based on the dependence: (o) E-(0.8...1.2(15.03-1.56Mo-0.201М0 2), because the coefficients of metal extraction along the passes are set based on the dependence: M-0.95-1.05 (1.161-0.019Mo-0.0236Mo 2), c2 where E is the value of relative compression, 90; M - coefficient of extraction of metal; Mo - passage number. P;o55 Official Bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2005, M 8, 15.08.2005. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. 60 b5