SU984522A1 - Sheet rolling stand rolling roll - Google Patents

Description

The invention relates to sheet rolling production and can be used in the production of stripes on mills which are rolled. Work rolls for rolling wide strips are known, having a barrel shaped along its length with a bulge in the middle part, which gradually decreases towards the edges of the roll. In such rolls, the convexity value is chosen in such a way as to compensate during rolling the elastic deflection of the rolls, their temperature expansion and wear in order to ensure the same thickness of the roll along the width. In this case, the convexity value of the barrel for work rolls with a diameter of 700-1200 mm used on sheet mills is (0.02-0.2) of diameter or 0, 2-2 mm C 1. Rollers are also known for rolling slabs with a bulge in the middle part of the barrel and with shsinder or inclined parts of the barrel along the edges of Г2 3. Closest to the proposed technical essence and achievable. the result of the work rolls of the sheets of the rolled stand with the sections of the cylindrical and curved surface of the expanding barrel. Such rolls form an alternating gap with a variable distance between the forming barrels. At first, the strip is seized by the shredded sections of the barrel, then as the deformation zone is filled, the metal is captured by areas with a curved surface; barrels. After reduction in the said rolls on the upper and lower edges of the roll, longitudinal thickenings are formed, designed to increase the longitudinal stability of the roll in rolls G3 C. The disadvantage of these rolls is that their barrel configuration does not allow the convex front and rear edges of the strip to be formed during its rolling. In addition, subsequent rolling in rolls with a cylindrical barrel of strips leads to the formation of undulating edges and their additional broadening. The purpose of the invention is the formation of the outcrops of the front and rear edges of the strip during its rolling and the reduction of shock loads during the seizure and ejection of the strip by the rollers. The goal is achieved by the fact that in a device having a barrel with sections of cylindrical and curvilinear barrel forming it is made with a grooved convex middle part equal to 1/3 3/4 of the barrel length, the greatest bulge in the middle of the barrel is (0.5 1, 5) - 10 roll diameters and with symmetrical cylindrical sections located along the edges of the barrel and provided with annular grooves. In FIG. 1, for now, the upper and lower working shafts and the profile of the strip in the inter-roll gap; in fig. 2 - produced front and edge of the strip after rolling in the proposed rolls. The work roll 1 consists of a corrugated vtukly the middle part 2 of length t, -, equal to 1/3 - 3/4 of the length L, barrel 3; The largest bulge in the middle of the barrel is (0, 5-1.5) 10 times the diameter D of the roll. The cylindrical sections 4 are provided with annular grooves 5, the proposed roller works as follows. The two rolls 1, installed in 1 slit, form a concave meldaal sh; spruce, concave in the middle. When approaching the rollers of the flat strip 6 with the straight shape of the front and rear edges, the rolls 1 are initially caught by the leading edge of the strip by the convex middle part of the barrel 3, and then by cylindrical sections 4. The force generated during rolling leads to an elastic deflection of the rolls 1 and, thus ; to partially compensate for their cracks in the middle part of the roll, the strength of the c / creates more compression in the middle part of the strip 6, and the corrugated part 2 increases the lead of the metal in the increased reduction zone, as a result of which 6 strips of width 6 are formed on the coids 6 Bbniyyly edges 7 and 8 with a convexity value of l Uf, 3; the presence of annular canals iaoK 5 on cylindrical sections 4 of roll 1 prevents broadening of strip 6. A significant decrease in shock loading: occurs when the convexity value on the front and and the rear end of the strip is not less ICE-30 "4O mm in svESzi with etgol HaiiMenbmaa value convexity in the middle portion of the roll is 0.5 U roll diameter, provides the required minimum value convexity strip edge. When the barrel convexity is greater than 1.510 of the roll diameter, edges with a convexity of more than 15 mm are formed at the front and rear ends of the strip, which leads to an increase in the metal cut on the scissors in front of the finishing stands. The length of the convex part, equal to 1/3 3/4 of the barrel length, is selected taking into account the width range of rolled strips on broadband mills, which is 0.5-O, 9 alins of the roll barrel. In this case, the entire width of the strip is rolled in width proposed valsses both convex and cylindrical sections of the barrel. When the length of the convex part is less than 1/3 of the barrel length, the rolling of wide strips is accompanied by the formation of narrow convex edges that do not significantly reduce the impact loads, and, furthermore, rolling in the following cages may cause the front end of the strip to bend at the exit from rolls and sticking it in the roll table. At. the length of the convex part of more than 3/4 of the length of the roll barrel does not ensure a smooth capture and ejection of the strip, the effect of reducing shock loads drops sharply. The corrugation on the convex part of the roll barrel leads to an increase in the friction of the metal on the rolls and to an increase in the advance of the metal compressed by the convex part, compared to the advance on the cylindrical sections of the barrel, which enhances the effect of the formation of a convex edge at the front and rear end of the strip and the size of its convexity, The creation of a more directional effect in the formation of convex edges on a certain strip width can be applied, for example, on a length of a convex part equal to 1/2 - 3/4 of its length. This increases the steepness of the convexity of the edges at the border of the sections compressed by the grooved and smooth convex part of the barrel. The annular grooves on the cylindrical sections do not change the coefficient of friction along the rolling axis, while along the axis of the roll they significantly increase the friction of the metal on the rolls, as a result of which the metal in the deformation zone does not propagate and this widening does not increase along the compared with rolling rolls with

smooth barrel. The dimensions of the annular canals and wok for rolls with a diameter of 70–1200 mm can be, for example, the following: the depth is 0.5–1 mm, the width is 2-3 depths, and the pitch is 3-5 depths.

On the basis of the experimental test on the laboratory mill of lead samples (taking into account the scale factors) in the rolls with the proposed barrel shape, it was established that the convexity value of the front l L, n and the rear L L. of the j edges is proportional to the difference in elongation LD, average compression 4 fi and the average radius of the roll g n can be determined by the formulas

41, - K „-LA - 3b, LC K-LL-L11-g.

- P P - -

where the coefficients K and K influence the influence of the front and rear external zones of the projected band, respectively. According to the experimental rolling data, their average value is equal to O231 mm. K 0.045 1 mm. With this in mind, the amount of convexity at the front end of the strip, the initial thickness of the strip fi is 175 mm, its width is 13OO mm, compression by cylindrical sections with a diameter of 11 mm is 36 mm, and the convexity of the barrel. SL 5.9 mm, the amount of elastic bending of the roll is 0.4 mm, the difference in stretching in the middle part of the strip and along the edges of the strip A 0.111; average compression / 41 mm is L1, -56 mm, in the rear Lj 112 mm. Since the difference in stretching across the width of the strip is proportional to the convexity of the roll, the shape of the leading and trailing edges repeats the form of a roll of rolls, taking into account the corresponding coefficients.

Due to the convex edges formed by the rollers in the subsequent cages of the continuous mill, the shock loads on the work rolls and in the main drive line are significantly reduced compared to the rolling of strips with a straight edge shape, which contributes to an increase in the durability of the mechanical equipment elements. In addition, the influence of gaps in the articulations of the drive line on the magnitude of the impact loads decreases by a factor of 2, 3, and also improves with the condition of the strip being caught by the rollers.

The introduction of the proposed roll, for example, in a draft 17OL continuous broadband mill of the OLOO Karmetkom & shat, in the cells of which, when the strip is captured, systemic Tpexi-four-fold overloads occur, reduces the magnitude of the shock loads 1.5-3 times in all the cells the camp. This in turn leads to a decrease in the number of breaks in the work rolls and elements and to an increase in the mill productivity due to the reduction of unplanned downtime.

During the year, due to dynamic overloads, an average of about eight breakdowns occur in the gearboxes of the roughing stands of the 1700 mill at the Carmetkombinat. This causes unplanned downtime of up to 17 h per year. The implementation of the proposed rolls allows reducing by 2-3 times the magnitude of the dynamic composition of shock loads in the main lines of the stands, which leads to a decrease in the durability of the gearbox elements by 6 times and reducing the downtime by 10 hours by reducing the number of breakdowns.

Claims (3)

1. Author's certificate (ХСР № 194О41, кп. В 21 В 27/02, 1966. 2. USSR author's certificate number 7O92OZ, cl. B 21 B 27 / O2, 1978. 3. The author of the USSR № 572306, cl. B 21 B 27 / O2, 1976. & L (JJU8. Z