SU1342548A1 - Method of shape-forming the rolling mill rolls - 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 in mill stands of the finishing group. The purpose of the invention is to improve the quality of the strips due to the stabilization of the geometrical dimensions of their cross section. The method consists in that the value of the profile of the concavity of the roll barrel is set depending on the cooling temperature. fluid supplied to the rolls. The method allows to increase the amount of hot rolled strips with the highest quality category. 3 tab. i (/

Description

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 in mill stands of the finishing group.

 the invention - the development of a significant variation in the size of its profile. At high coolant temperatures (36-40 C), the difference between the thermal and initial grinding profiles of the work rolls is 0.45-0.15 mm per diameter, respectively, about the first to the last stand of the finishing group, at a low temperature of the strips due to stabilization - hydrating fluid (6-8 С) difference

The geometric dimensions of their cross section.

The method consists in the fact that the value of the concavity of the profile is set

m "ks-

Max

Where

L max

t moss

35

Depending on the temperature of the cooling rolls of 0.25-0.10 mm per diameter of the corresponding liquid supplied to the rolls from the first to the last, the adhesive rolls are determined from the expression of the finishing group.

The exponent j, equal to 0.1-0.9, determines the proportion of change 20 of the size of the initial grinding profile of the work rolls, which is necessary to stabilize the geometric dimensions of the cross section of the finished, hot rolled strips when the temperature of the coolant changes 25 x This exponent depends on the location of the stand in the mill group. For example, for calculating the current value of the grinding profile, 30 l of the work rolls of the first stand of the finishing group of the mill, the value ij 0.1-0.3 is more appropriate, since the temperature of the rolls of the first stand is very high in the group and, therefore, corresponds to a large value of the grinding profile . A further decrease (i.e., at, l) leads to the termination of the regulation of the grinding profile in the first stand in the range of the coolant temperature change from 0.4 t, icDO t, c (Kc, which destabilizes the process of formation geometrical dimensions of the cross section of the finished hot-rolled strip in this coolant temperature range, and therefore to a reduction in quality. The values of the exponent 1, 0.6-0, 9. are acceptable for the last stand of the finishing .50 group, where the temperature of the rolls is minimal in the group, and therefore a smaller grinding profile is required. NC values of 0.9 can lead to a loss of control in the last stand of the group in the range of a coolant temperature change of 0.3-0.1 TD, which also destabilizes the process of forming geometric dimensions over time the value of the grinding profile, mm; the value of the maximum grinding profile at the maximum temperature of the coolant, mm; the current coolant temperature supplied to the mill rolls, C; . maximum temperature. coolant supplied to the mill rolls,

Of ,.

. C - the exponent (O, 1

 1 0.9).

In the process of profiling the work roll under the conditions of the varying temperature of the coolant supplied to the rolls, the actual temperature of the coolant is learned during the formation of the grinding profile. In this case, the grinding profile of the work roll changes from a maximum value at a real maximum coolant temperature to a minimum value at a real minimum coolant temperature, i.e. there is a change in the magnitude of the concavity profile of the work roll, depending on the temperature of the coolant supplied to the mill rolls.

The temperature change of the coolant supplied to the mill rolls, with constant remaining components of the heat balance and elastic deformation of the work roll, is 25482

There is a significant fluctuation in the size of his profile. At high coolant temperature (36-40 C), the difference between the thermal and initial grinding profile of the work rolls is 0.45-0.15 mm per diameter, respectively, from the first to the last stand of the finishing group, at a low temperature ox0, 20-0.05 mm per diameter, respectively, from the first to the last stand of the finishing group, the maximum change in the current profile of the workers

river sections of finished hot rolled strips in this coolant temperature range and to a decrease in the quality of the strips expressed by the required geometrical parameters.

The implementation of the method is carried out in three stages, when the coolant temperature is respectively 4, 16, 34 ° C at the maximum possible coolant temperature under the conditions of the combine to

1c. C. At the same time, the optimum range of indicators for steels is 2-0.8, and the initial grinding concavity corresponds to the value used and is calculated by the proposed method.

The parameters of the grinding concavity of the profile of the rolls, determined by the known and proposed methods, depending on the different ratios of the current (t) and maximum (. Temperatures and the degree of h are given in Table 1.

The following analytical expressions were used to assess the quality of the strips rolled according to the known and proposed methods:

A, (0,1) - fh (0,4) / c / h (0, l);

A L (0.1) - (0.85) j / L (0.1);

Aj.h (0.4) - L (0.85) / L (0.4),

where a

one

Aj and AZ

the relative bandwidth parameters; c / h (0, l) is the transverse difference in the thickness of the strip at t / tMD (1; c h (0,4) is the same, at (.

0.4; t / h (0,85) - the same, with

0.85.

In this case, the value of the transverse thickness thickness is determined according to a known technique, and the strips are rolled on rollers with grinding profiles listed in Table 1, respectively, according to the known and suggested methods.

The results of the evaluation of the strips rolled on the NShSg / n 1700, with different levels of cooling rolls, taking into account their grinding profile, are made

According to the known and proposed method, depending on the temperature, are given in Table 2. The coolant temperature in the magnitude of the exponent t in accordance with the equation

for t / t in cells

m "KS

1.700 and evaluation of the results achieved

 Max

(

Uq

-)

p r

20

Comrades on the strip thickness variation are given in Table 3.

. The values of A,, A, A are determined by the expression 5 d ,, 61.

 - h (0,2) where L (0,2) and c / h (0,6) - transverse

difference in bandwidth obtained at t / t, 2, and 0.6, respectively.

From Table 2 it follows that the proposed method as compared to the known method (according to which the value 5 of the grinding profile of the work rolls remains unchanged with varying coolant temperature) improves the quality by increasing the stability of the geometric dimensions of the cross section of finished hot rolled strips regardless of changes over a wide range of coolant temperature more than 2 times.

From a comparative analysis of the example with the boundary (and h} and optimal (H values of the method (Table 3) in the conditions of mill 1700, it follows that the quality, characterized by the degree of stabilization of the geometric dimensions of the cross section of the finished hot-rolled strips, decreases with boundary values the exponent h, k. this reduces the effect of stabilization to the level of the known method, although it is somewhat higher than by a known method.

The method increases the amount of hot-rolled strips with the highest category is fair.

Claims (1)

Invention Formula 25 thirty The method of prefiltering work rolls, mainly for hot rolling of wide strips, including grinding the roll barrel, shaping it forming by giving it a surface of the concavity and supplying cooling fluid, characterized in that in order to improve the quality of the strips by stabilizing the geometric dimensions of their cross section, the magnitude of the concavity  Max ( Uq -) 51342548 l - the current value of the grinding profile, mm; Ainkc max value grinding profile with a maximum temperature of 5 coolant with tees, mm; t is the current temperature of the cooling fluid supplied to the rolls, ° C; maximum coolant temperature supplied to the rolls, ° C; exponent (0.1 44 0.9). b l and c a 1 Editor N.Rogulich Compiled by V.Vasilyeva Tehred L. Serdyukova Proofreader M. Maksimishinets Order 4545/6 Circulation 480 Subscription VNSHSHI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 . Production and printing company, Uzhgorod, Projecto st., 4 Table 3