RU2201825C2 - Universal four-roll stand for shaping tubes - Google Patents

Abstract

FIELD: plastic metal working, namely manufacture of shaped straight-seam steel tubes. SUBSTANCE: stand for shaping tubes with maximum outer diameter d_t includes arranged in one diametrical plane and mounted in chocks with possibility of motion in said plane pairs of idle horizontal and vertical rolls with rectilinear generatrix of working surfaces and with the same diameter equal to (3.2 - 4.0)d_t. Chocks are arranged in four G-shaped supports fastened by means of two rings at inlet and outlet of stand and mounted on supporting plate with possibility of its adjustment motion normal relative to shaping axis in vertical and horizontal directions. Lower horizontal roll may perform such motion only in vertical direction in range Δ = (D-d):2, where D and d - maximum and minimum diameters of roll, respectively. One of vertical rolls is joined by its end face with working surface of above mentioned roll and it may be moved only in horizontal direction. Second vertical roll joined with end face of lower horizontal roll by its working surface and upper horizontal roll may be moved by predetermined distance in vertical and horizontal directions. Upper horizontal roll is joined by its end face and working surface with vertical rolls. EFFECT: lowered labor consumption at making shaped rectangular and square cross section tubes of round welded tubes with the same high quality due to simplified design of rolling stand and decreased roll wear. 2 dwg, 1 ex

Description

 The invention relates to pipe production and can be used in the manufacture of shaped pipes of square and rectangular sections.

 Such pipes are often made by profiling longitudinally welded round pipes in two- or four-roll stands, with the most common four-roll stands, including universal ones. As such stands can be used stands of profile bending mills, described in sufficient detail, for example, in the book. under the editorship of I. S. Trishevsky. The production of bent profiles (equipment and technology. - M.: Metallurgy, 1982, pp. 102-104. The axes of all four rolls (two horizontal and two vertical) universal stands lie in one vertical (diametrical) plane and, thus, the rolls form closed gauge Horizontal rolls of universal roll-forming stands are usually driven.

 The disadvantage of the existing universal roll-forming stands is the relative complexity of their design and, as a result, significant dimensions and increased manufacturing costs.

 Roll forming stands for manufacturing square steel pipes are known, containing four or two rolls (horizontal — drive rolls, and in double roll stands the rolls are asymmetric calibration, and for four roll stands horizontal rolls partially cover the lateral formed edges of the square pipe (see Japan. Application 57- 171518, class B 21 C 37/15, publ. 10/22/82) A device for the continuous production of square tubes is also known which forms a tube stock from strips having thickenings at the locations of the ribs loss (see Japanese application 60-102224, class B 21 C 37/08, B 21 1/08, publ. 06.06.85).

 A disadvantage of the known devices is the inability to obtain rectangular shaped tubes from round pipes with their help, as well as the relative complexity of the design.

 The closest analogue to the claimed object is a universal stand roll forming mill, given in the book of Ya.S. Finkelshtein Guide to rolling and pipe production. - M.: Metallurgy, 1975, p. 247-248 and fig. 2.

 This cage contains two pairs of horizontal and vertical rolls located in the same diametrical plane with a rectilinear generatrix of the working surfaces, mounted in pillows with the ability to move in the specified plane, and is characterized in that the horizontal rolls are driven and the vertical rolls are idle, and the upper roll is balanced by springs and the vertical rolls are mounted in cages and all the roll supports are placed in two open frames.

 The disadvantage of this stand design is its relative complexity, as well as the need to use its own set of rolls for each size of a profile pipe, which increases production costs in the manufacture of these pipes.

 Indeed, since four rolls (more precisely, their barrels) form a square or rectangular closed gauge, each change in the size of the sides of the cross section of the resulting profile pipe also requires the corresponding dimensions of the work rolls, i.e., to switch to another pipe size, it is necessary to remove (topple out) old rolls and install (fill up) new rolls, which is a time-consuming operation. In addition, a fleet of rolls is required that matches the entire range of manufactured profile pipes.

 The technical task of the invention is to reduce labor costs in the production of profile rectangular and square pipes from round welded pipes without compromising their quality by simplifying the design of the universal stand and reducing the consumption of rolls.

To solve this problem in a universal four-roll stand for profiling pipes with a maximum diameter of d _t , containing pairs of horizontal and idle vertical rolls with a rectilinear generatrix of working surfaces located in one diametrical plane and installed in pillows with the possibility of moving in this plane, horizontal rolls are also made idle and the diameter of all the rolls is the same and equal to (3.2 ... 4.0) d _t , while the pillows are placed in four L-shaped supports, fastened by two rings at the entrance and leaving the stand and installed on the base plate with the possibility of its adjusting movement perpendicular to the axis of profiling vertically and horizontally, the lower horizontal roll has the possibility of such movement only vertically within Δ = (Dd): 2, where D and d are respectively the maximum and minimum roll diameters, one of the vertical rolls is connected with its end plane to the working surface of the roll and is made to move only horizontally, and the second vertical roll, conjugated end plane of the lower horizontal roll its working surface, and the upper horizontal roll are movable on predetermined distances vertically and horizontally, and the last one is associated by their end plane and a working surface with vertical rolls.

 The given ratio of the diameters of the rolls and the round pipe is obtained by processing the experimental data and is empirical.

 The essence of the proposed technical solution is to simplify the stand design by using only single rolls of the same diameter (this creates the same deformation conditions in two mutually perpendicular planes), the pillows of which are installed not in the beds (as in the known stand), but in the L-shaped welded bearings, and in the placement of the rolls in such a way that when they move in the diametrical plane of the stand, gauges of different sizes are formed, and the quality of the profile pipes does not deteriorate.

 Indeed, as follows from the diagram in figure 1, the movement of three rolls (two vertical and upper horizontal) allows you to form square and rectangular gauges, the minimum dimensions of which are close to zero, and the maximum are determined by the length of the generatrix of the cylindrical working surface of the rolls. In this case, the displacement of the lower roll will depend only on its diameters D (before regrinding) and d (after regrinding due to wear), and the movement of the entire stand is made so that the axis of profiling (and the longitudinal axis of the round pipe entering the stand) always coincide with the center of the caliber "in the light" (ie in the diametrical plane).

 Since the proposed stand is designed to be installed in the line of a continuous multi-cell pipe-welding mill producing thin-walled pipes, this entire stand can be non-driven, and the movement of the shaped pipe will be carried out due to the "back pressure" created by several stands of the pipe mill, which was confirmed by an experimental verification of the device . The experiments (see below) also made it possible to establish the optimal ratio between the diameter of the rolls and the maximum diameter of the pipe specified in the cage.

 In FIG. 1a, b shows a diagram of the installation of the rolls of the proposed stand, and figure 2 - its device (also - schematically; view from the side of the entrance to the stand).

 With the position of the rolls in the diagram of figa (1 - 4 - respectively the upper and lower horizontal rolls and the left and right vertical; xx and yy - the axis of the rolls; arrows - the possible movement of the rolls to form a caliber of new sizes), they form a caliber of maximum dimensions ABCD , and in the diagram figb - gauge intermediate sizes A'B'C'D '; on both schemes: 5 - end planes, and 6 - the working surfaces of the rolls.

 The axis 7 of the rolls 1-4 of the universal stand (see figure 2) are mounted on bearings (not shown) in pillows 8, which are placed in the windows of horizontal or vertical elements of the L-shaped supports 9. The pillows of the upper horizontal roll 1 move in the windows of the racks along vertically with two pressure screws, and horizontally with a screw 11 mounted on the horizontal surface of the upper right pillar. The left vertical roll 3 is moved vertically (this is necessary when changing the diameter D of the roll) using horizontal screws 12, and vertically by screws 13. Moving the right vertical roll 4 horizontally is carried out by screw 14, which is included in the lower cushion of this roll. Adjusting the position of the lower horizontal roll 2 vertically (when changing its diameter) within the value Δ = (D-d): 2 is done by two screws 14 installed from the bottom of the pillows of this roll.

 The lower L-shaped supports are attached to the base plate 15, which can be moved horizontally and vertically along the foundation plate 16 when changing the size of the caliber formed by the rollers, the center of which, obviously, will move down and to the left (with the fixed plate 15). To create the required rigidity of the stand, all racks are fastened with two rings 17 (shown by a dotted line) - at the entrance and exit of the stand.

 When profiling, a round pipe of a given diameter is set in the idle rolls of the stand due to the force created by the previous stands of the pipe-welding mill, with the formation of a square or rectangular section of the required size.

 For transshipment (replacement) of the rolls of the stand, one of the coupling rings 17 is disconnected from the supports, providing free removal of pillows with rolls from the stand.

 An experimental verification of the proposed stand was carried out on a pipe welding mill "10-60" LLC "Profile-GP" OJSC "Magnitogorsk Iron and Steel Works".

 In this case, profile pipes of square and rectangular sections of 16 sizes were made of electric-welded straight-seam pipes with an outer diameter of 12 to 60 mm and with a wall thickness of 1 - 3 mm from st. 3. 99.1% of the profile pipes met the technical requirements, and the rejection was due to low-quality welds.

In the experiments, the dependence of the diameter of the rolls d _{in the} stand on the maximum diameter d _{t of the} original pipe was established. When d _in <3,2d _t , the wear of the rolls increased, which reduced their working campaign; in addition, with d _at <2.5d _t, profiling of pipes with d _t <30 mm became impossible, and a reduction in the size of the stand (in order to use rolls of smaller diameter) is impossible due to the dimensions required by the conditions of the strength of the rolling bearings. An increase _in d _in > 4d _t is impractical due to an unjustified increase in the dimensions of the stand and its rise in price.

 Since at the “10-60” continuous mill, cutting of profile pipes to measured lengths is carried out behind the mill, no jamming of pipes in the non-driven stand was observed. Thus, the experiments confirmed the acceptability of the claimed object to obtain high-quality profile pipes.

 A comparison of technical and economic indicators using a known device selected as the closest analogue and the claimed one showed that the cost of the latter is almost three times less. The consumption of rolls when using the proposed stand is reduced (depending on the assortment) by 3-5 times, and labor costs (due to the reduction in the number of transhipments) - not less than 30%. According to the Central Control Laboratory of OJSC MMK, the use of the inventive stand in the production of shaped square and rectangular thin-walled pipes reduces their cost by 10-15% with a corresponding increase in profits.

Concrete example
The universal four-roll stand for profiling straight-seam thin-walled pipes with d _t = 60 mm contains non-driven rolls from st. 9X2 with D = 220 mm and d = 196 mm, which are installed in eight pillows on roller bearings 42206 in four L-shaped bearings (the installation and movement of the rolls is shown in figure 1).

 The lower supports are fixed to the base plate (see figure 2) with the possibility of its movement vertically within 15 mm and horizontally - 30 mm. The lower horizontal roll can be moved horizontally in the windows of the supports within Δ = (D-d): 2 = 12 mm. All rolls are moved using pressure and adjusting screws.

 All supports are fastened with two coupling rings with an external ⌀ = 280 mm and an internal ⌀ = 200 mm at the entrance and exit of the stand. Stand dimensions: N = 560 mm, B = 540 mm, L (along the axis of profiling) = 410 mm; stand weight - about 250 kg; maximum profiling speed - 2 m / s.

Claims (1)

A universal four-roll stand for profiling pipes with a maximum outer diameter d _T , containing pairs of horizontal and idle vertical rolls with a rectilinear generatrix of working surfaces located in one diametrical plane and installed in pillows with the possibility of moving in this plane, characterized in that the horizontal rolls are also single and the diameter of the rollers is the same and is equal to (3,2... 4,0) d _T, when this cushion has four L-shaped supports fastened on two rings WMOs e and leaving the stand and installed on the base plate with the possibility of its adjusting movement perpendicular to the axis of profiling vertically and horizontally, the lower horizontal roll has the possibility of such movement only vertically within Δ = (Dd): 2, where D and d are respectively the maximum and the minimum diameter of the roll, one of the vertical rolls is mated with its end plane to the working surface of the roll and is made with the ability to move only horizontally, and the second vertical roll is mated th with the end plane of the lower horizontal roll with its working surface, and the upper horizontal roll made with the ability to move at specified distances vertically and horizontally, and the last of them is conjugated with its end plane and the working surface with vertical rolls.

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