SU1600881A1 - Method of preparing working rolls of wide-strip mill for hot rolling - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used in sheet-rolling production, in particular, on wide-strip hot rolling mills in the preparation and profiling of work rolls. The purpose of the invention is to improve the quality of rolled products by reducing defects on corrugations and staleness and stabilizing the shape of the forming surface of the rolls. For this, before grinding the work rolls, the time between transfer and grinding as well as the weighted average width of the work rolls of the strips rolled over the campaign are additionally taken into account. The magnitude of the thermal correction for the calculated profile is determined by the dependencies. Table 3.

Description

The invention relates to the field of metal forming and can be used in the preparation of sheet rolling rolls on broadband hot rolling mills (SHSGGT).

The aim of the invention is to improve the quality of rolling stock by reducing defects on corrugations and warping and stabilizing the shape of the forming surface of the rolls.

The method is carried out as follows.

. For the ShSGP 1700 mill, it is necessary to determine the value of the thermal correction when grinding the work rolls of the stand 10 On these rolls, before the transshipment, stripes with dimensions and volumes presented in Table 1 were rolled. Using these data, as well as the equation, where we take the coefficient 76, we determine the value of the weighted average

strip width mm. Grinding after rolling started after {2 5 h for mill SHSGP 1700. mm, a-2. By measuring the thermocouple found that, then by the formula we find

At9 63 / ri- -7x700 / (1700-700)

Further, taking into account the fact that, about 0.003 mm / s, according to the calculation formulas, we will make the definitions of the amendments to the calculation profiles for the entire length of the work roll barrel according to the following dependencies:

- 26.2% “J, where O mm;

fx, 0.003 X 36, - I2gl where. 500. mm.

The results obtained are summarized in table 2, the control profile of the roll barrel is defined according to

,:

where and - natural profile with

thermal amendment; UV - current thermal correction

along the length of the roll barrel} 6, the initial profile of the roll barrel (with the + sign for the convex forming drum and with the sign r for the concave forming drum). The method was tested under the conditions of SHSGP-1700 in comparison with the known method, according to which the heat correction was determined and applied directly in proportion to the barrel length. From the analysis of the results of comparative data. obtained by rolling the rolled strip, it follows that in the entire rolling range of three assembly lots (software-v1100 tons each), the volumes with the minimum dispersion value with lentil values were larger in the proposed method than in the known Hot parameters of the pre pawning method (table) the proportion of bands with significant values of lentils approaches the known method, and at the maximum values of the parameters of the proposed method - to the minimum values of the lentil, the subsequent rolling of the resulting tackle on a 6-cell steel mill showed that the maximum quality level of the rolled sheet corresponds to the minimum value of the transfer of tin

in second grades, remaining over the entire range of parameters is more preferable than the known method of preparing rolls, /

Basic technical and economic

The indicators of the method are reduced to an improvement in the quality of rolled metal according to the parameters of the cross-section of the hot-rolled strip, which accordingly reduces the second-grade beats, increasing the

 D, h / vx, - -,

quality parameters of the resulting n

Claims (1)

ductions. Formula of gaining The method of preparation of the work rolls of a wide-strip mill for hot rolling, including pouring out of the stand, measuring the temperature along the length of the roll barrel, regrinding the profile with 0 R 25 Q thermal corrections differing from the fact that, in order to improve the quality of rolled metal by reducing defects in the corrugations and warping and stabilizing the shape of the forming surface of the rolls, the thermal correction value is set separately at the section of the barrel corresponding to the weighted average width of rolled metal, and Terminal sections according to SxB 8rut-& teX2XB / B); Sx, ht.t-it,) l - (gb) & tft ut / n-KB / (L-B), the current value of the thermal correction in the section of the barrel length, determined by the weighted average strip width, mm; conditional coefficient of thermal expansion of the barrel, where is 5 H 50 55 k In Sv. at --- temperature difference between the middle and edges of the barrel, C; the current coordinate in the middle section of the barrel, varying from (in the middle of the barrel) to (at the edge of the section defined by, the average strip width), mm; weighted average strip width, mm; the current value of the thermal correction in the section of the barrel length determined by the end sections outside the middle section (B), mm; the current coordinate at the end sections of the barrel varies from (at the edge of the section defined by the weighted average bandwidth) to X, (L – B) / 2 (at the end edge of the barrel); barrel length of the work roll, mm; coefficient taking into account the nature of local heating in the middle of the roll barrel (4 K y-10); time between transshipment and grinding of the roll, h, exponent, which determines the shaping of the thermal convexity (1.56 ab2.5). X. To f but . Table 1 Size of strips Amount - G ;, Assignment of technology - (N; xB;), mm, tical, mm 3,5x1060568 heating rolls 2.5x108019247 Same 2,4x88517204, 3x900771100Taping tin .,Table 2 -f: ™ ° ° ° f 200 30oj400 500 G 60 ° G 70 ° T 800 T eOO Estimated About 0.020.040.07 0.09 0.11 0, amendments, -., . ° -0.14-0.22 0.02 0.04 0.07 0.02 -0.03 -0.09 -0.11 Note. X - the current coordinate from (on the edge of the barrel) to  mm (in the middle of the roll barrel). " Table3  f - - - „,, c I Method 5 Volumes,%, rolled Volumes of rolled,% S Lentil profile of the second grades on the tin rolled strip mm for defects p --- p ------ ------ p ---- .. O- 0.02- 0.04 - Corrugation box 0.02 | 0.04 0.07 Known Go a-- - 5 - "". 2 the guy 11,50,6041,5 5503,381,615,12,45 3 230,7672.0 7002,793 835.030) 6 350,90102.5. 83012,882, 42.9 Compiled by V. Ziselman. Editor L. Gratssho Tehred M. Didyk Proofreader M. Kucher va Order 3234 Circulation 404Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and publishing plant Patent, Uzhgorod, st. Gagarin, 101