SU1537338A1 - Working roll for sheet-rolling mill - Google Patents

Abstract

The invention relates to rolling production and can be used in the production of strips and sheets in broadband hot rolling mills. The purpose of the invention is to increase the flatness of the rolled strips and reduce the consumption of rolls. The concave profile of the barrel of the work roll is carried out along a logarithmic curve, the mathematical expression of which has an exponent in the range 2 ... 8. When rolling strips of different widths in the contact areas, the forming roll slightly changes its concavity, which makes it possible to stabilize the transverse thickness variation with a change in the width of the strips. The smooth nature of the profile profile of the barrel makes it possible to ensure uniform stretching across the width of the strips and a uniform distribution of roll-over pressures along the length of the drums of the working and support rolls, which virtually eliminates the chipping of the working surface of the drums and reduces the thickness of the riveted layer on the adjacent support roll. The economic effectiveness of the invention is made up of reducing the sorting into lower grades by the geometry of the strips and in reducing the consumption of rolls. 2 ill., 4 tab.

Description

I

31537338

solved mapping of roll barrels, mm;

the maximum value of the concavity of the generator in the middle of the roll barrel, mm, the module of the current coordinate of the generator profile from the middle to the edge of the barrel, mm; length of the profiled section - JQ roll, roll, mm; minimum working length

parts of the roll barrel, mm; the amount of concavity forming at

| Y | . -j.- | YI 2

mm;

m is an exponent that determines the nature of the edge profile of the barrel-forming wap, the value of W being set to (0.050.2} W0, the value of 1 equal to (0,, 9) 1, and the value of m is in the range of 2-8.

The roller contains necks 1, a barrel 2 with a length LJ profiled The concave middle section 3 g W ,, (0.05-0.2) W0, 1 (0.4-0.9) 1 ,,, m 2-8. For comparison, the dashed line 4 shows the known roll with the ratio of the length of the parabolic section of the roll barrel to the length of the shaped section, equal to 0.65, and the ratio of the concavity of the hyperbolic weighting to the total value of the roll barrel forming, equal to 0.6

When rolling with different widths using the proposed work roll (FIG. 1), there is little; in comparison with the known roller, the change in the concavity of the forming barrel in the areas of contact with the strip. So, for example, when the width of rolled strips changes from B to B {the value of the concavity of the work roll profiling changes (by D $ significantly less than D,., And when

changing the width of the bands with Ba

on B3 on

& gs less than & 1-2. This indicates the stabilization of the transverse thickness of the strips when their widths change.

The smooth nature of the curve of the profile forming the roll barrel is the same for all the stands of the finishing group along a logarithmic curve with

W, (0.05-0.2) W0, 1 - (0.4-0.9) i "and m 2-8. This allows

Q

uniformity of stretching across the width of the strips with a uniform distribution of the inter-roll pressures along the length of the drums of the workers and support rolls.

By reducing the concentration of specific inter-roll pressures by 10-20%, the cutting of the working surface of the barrels is practically eliminated, and the thickness of the work-hardened Layer on the adjacent support roll is reduced.

Range of change of relations W1:

: Wb 0.05–0.2, 1: ln 0.4–0.9 and magnitude 2–8 ha selected outcome

5 of the rational values of the concavity of the profiles of the work rolls with barrel lengths of 800–2500 mm of wide-strip mills, 0.1-0.8 mm per diameter, and the possible range of the corresponding ratio of the width of the rolled strips to the length of the roll barrel, 0.4- 0.95. The minimum values of the ratio N d: W and the parameter m are obsessive

differently take at the minimum value of W and the maximum ratio

0

five

0

Ln

and the maximum values of the ratio-,: W0 and the parameter m - at

one

Sheni W

the maximum value of W0 and the minimum ratio of 1: 1P. The lower limit of the ratio Wt: W0 0.05, as well as the value of m 2, is set to ensure uniform stretching across the width of the bar, the minimum possible change in the transverse thickness of the strips when changing their width, and a more uniform distribution of rolls pressures along the barrels of the working and support rolls . When W ,,:, 05 and p - 2, the risk of distortion of flatness of thin wide strips in the area of edges appears, the concentration of inter-roll pressures at point a (figure 1) increases and a sharp-pointed profile is formed in the middle of the 5th barrel of the work roll, which leads to local thickening of the middle part of the strip and with further cold rolling to the local flatness. The upper limit of the ratio W 1: W0 0.2 is determined by the lower limit of the range of the ratio of the concavities on the hyperbolic and parabolic sections of the profile of the known working roll. In the case when W,: W0 is 0.2, the ratio of the concavities of the hyperbolic and parabolic sections is 0.2 and the length of the parabolic sections is 1, the point a coincides with the conjugation point of the hyperbolic and para5153

Bolic curve profile of the famous work roll.

The upper limit of the parameter m, equal to 8, is limited by the fact that when m 8 is in the middle part of the roll barrel, there appears a straight line segment

promotes the formation of a transverse profile of the bands in the form of a saddle. Such a transverse profile of the strip leads to the deterioration of their flatness during the subsequent cold rolling.

The value of 1 is set to within (O, -0, 9) 1 and the outcome of the possible ratios of WIDTH OF NARROW AND WIDE STRIPS

rolled on the mills for the campaign of work rolls, taking into account the possible amount of displacement of the roll along the roll barrel, reaching 100 mm. With a maximum difference between the width of narrow and wide strips 1, the work rolls rolled over the campaign, i.e. when the minimum width of the bands is 0, L and 1 and L, the value of 1 is 0.4 1, and with the minimum difference between the width of narrow and wide bands - 0.9 l.Bo all cases, the length of the profiled section is determined by the maximum width of strips for the campaign of work rolls and the magnitude of the displacement of strips along the roll barrel.

Example. For the last stand of the finishing group of a wide-strip mill 1700 hot rolling with a barrel length of L 1700 mm, the values of the current concavity of the machine generator are determined, which during the rolling process produces a strip of 900-1000 mm wide with a transverse section bulge in the range of 0.02-0.05 mm . Take 1 equal to the minimum width of the strip, i.e. mm The length of the profiled section is 1P1100 mm and is determined by the maximum width of the strips, taking into account their possible displacement along the roll barrel by an amount of 100 mm.

By calculation, using the known methods, taking into account the proposed ratio W,: WQ, limits of value and condition of flatness of the bands, determine the parameters of the profile forming the roll barrel over the cells of the finishing group (Table 1).

Using Eq. (1) and the parameters given in Table. 1, the current values of the concavity of the profile of the working roll forming along the length of the profiled section 1p are calculated (Table 2).

At the present time, working rolls with a profiling performed at the section of the drum along the hyperbolic (Table 3, option 1) curve when rolling tackle 2, x900 for the tin shop, and with profiling along the parabolic curve, are used at the mill 1700. the entire length of the barrel (option 2), when rolling the remaining strips of the mill gauge with dimensions

(2-12) x (1000-1500) mm.

During industrial testing of the proposed roll, rolling in rolls with a concave profile along a logarithmic curve was performed (Table 3, options 3 and if).

The results of the study (Table 1) indicate an improvement in the flatness of the strip during rolling in the rolls offered. The average deviation from flatness by 1 linear meter of the strip length is reduced from 9.6 mm when rolled into rolls with profiling in options 1 and 2 to 6.8 when rolled into rolls with the proposed profiling (options 3 and C) or by 30%.

At the same time, the thickness of the hardened metal layer of the support rolls due to increased contact loads at the transition points of the curved profile line of the existing rolls (Tables 1 and 2, option 1 and the known work roll) decreases by 0.5 mm. This is 15-25% of the value Removable layer when regrinding the support rolls 2-3 mm, which is due to the hardening of the surface of the barrel support rolls.

After the campaign of the work rolls of the finishing group of the 1700 hot rolling mill, 50 tons of strips measuring 2x1000 mm and 650 tons measuring 2.4x900 mm are rolled after heating the rolls. Figure 2 shows the results of a pilot rolling of which shows that the convexity of the transverse profile for the strips of 2.4 x 900 mm (curve II) and 2 x x 1000 mm (curve I) has approximately the same value within the required range of 0, 02-0.05 mm. This indicates the stability of the transverse profile of the strips when rolling them with different widths using the proposed work roll. In addition, the transverse profile is 71537338

There is a smooth pattern of thickness variation across the strip widths and there are no local thickenings.

The economic efficiency of using the invention adds up from reducing the rejection of the strips into lower grades in terms of geometry and in reducing the consumption of rolls.

Claims (1)

Invention Formula The working roll of the sheet rolling mill containing a roll barrel with a concave generatrix, characterized in that, in order to increase the plane of the rolled strips and reduce the consumption of the rolls., The barrel forming profile is made according to a logarithmic curve According to formula ir, D- (w, / woylm 2 ° T (j where W is the current value of concavity forming profiles along the length- 25 w w0 1- (2 | Y / V P ° five eight roll bar section, mm; W0 is the maximum value of the concavity of the rolls forming in the middle part of the barrel, mm; | Y | - current coordinate module profile forming from the middle to the edges of the barrel, mm; C the length of the profiled section of the roll barrel, mm; 1 - the minimum length of the working part of the roll barrel, mm; W is the magnitude of the concavity of the generatrix at | Y (-1, mm; ha is an exponent from 2 to 8, determines the character of the profi bar forming curve, and the magnitude of the concavity at the current coordinate module is equal to half the minimum length of the working section of the roll barrel is (0.05-0.2) W0, and the minimum working length parts of the roll barrel is (0.4-0.9) lh "I Table 1 Note. The value of m for all the stands of the finishing group is 2, table 2 1537338 y Table 3 Table C §00o / lOAoSuHS strip width, mm Thebes. Z 1