FR2467643A1 - ROLLER CYLINDER WITH NO PILGRIMS AND IMPLEMENTATION OF SUCH A CYLINDER - Google Patents

Abstract

Cylinder for pilgrim pitch rolling mill, comprising a gauge profile composed of a reduction cone, a polishing gauge and an exit cone. According to the invention, this cylinder is characterized in that the lower part of the reduction cone, adjoining the polishing gauge, follows a substantially linear curve over an angle at the center of 25 degrees, and is extended by a part which extends between 25 degrees and 50 degrees and which obeys a law of the type y = d. (a + be ** c.xn), where a, b, c, d and n are parameters varying according to the diameter of the body of the cylinder, in that the total working area of the cylinder extends over an angle at the center of the order of 210 degrees to 235 degrees, and in that the reduction cone, polishing gauge and exit cone are 'extend over 36%, 28% and 36% of the total work area, respectively. Pilgrim's step cylinder.

Description

The present invention relates to a pilger roller cylinder

  intended to optimize the use of said cylinder. Pilgrim mill rolls are known to have a periphery subdivided into a working zone.

  vail and in a caliber working empty.

  The working area of the cylinder has a reduction cone

  (mouth), a polishing caliber and a cone of

  exit (the flow), these different parts being

  depths, angles in the center and

particular profiles.

  The pilgrim cylinders known to date have a

  total working area corresponding to a center angle

  be of the order of 1800 to 2100, of which from 48% to 54% for the mouth, from 30% to 36% for the polishing caliber and from 12% to 18% for the dispenser. The circular arcs of the cylinder

  Corresponding figures also depend on the total angle,

  influencing the length of work itself.

  The wear of the pilgrim cylinders appears on the

  of working time, in the most marked way

  at a point on the reduction cone and corresponding to

  at the point of attack between the hollow ingot and the cylinder

  dre. This place defines the dirmiensionnement necessary during the mechanical finishing and thus the number of bets

possible implementation of the cylinder.

  we have already thought about moving, in order to avoid

  finishers, said point of attack in the direction of the working caliber. Thus, the fine machining can then

  take place with a small dim-inution of the diameter. How-

  <N. In this arrangement, the output zone -2 is translated in the direction of the vacuum gauge. The material of the rolls does not allow, or difficult to achieve, the desired curve of the exit cone, because of the large opening of the vacuum gauge. An exit cone too abrupt or too short leads to a rapid separation of the cylinder

  and the tube. The rolling pressure, still complete, is

  on too small a surface. The great pressure

  perfective leads to the deterioration of the tube, which exceeds

  tolerance limits, and leads to a number of

high scrap.

  Another way has been proposed, particularly in the patent

  No. 545 843, consisting in constructing the cone of

  output as a reduction cone. This configuration

  should have the advantage that after wear of the first

  no output, the cylinders are ready for use by an easy reversal without additional operation. But the practical use of this proposed means presents

many disadvantages.

  Indeed, the curves of the reduction cone and the exit cone have, because of their different functions,

  a distinctly different evolution.

  In addition, the very steepness of the curve of the reduction cone leads, by transformation of the output cone into a reduction cone, the too fast separation of the cylinders and the tube and the damage, already mentioned.

above, of the tube.

  In addition, during the necessary finishing, the working area

  Cylinders are translated to the empty gauge. In this zone, however, there is not enough

  material to achieve the desired caliber shape.

  In addition, it is known to all that strong stress cracks form in the area of the reduction cone of the cylinder core. By transformation of the exit cone

  in a second reduction cone, this damage appears to be

  The section of the cylinder core is further weakened by about 1,800. By the effect

  notch, this weakening is further increased. Her-

  The difficulty is that the maximum force

  rolling mill is exercised in the area of decrease of section. The reduction in the section of the cylinder causes frequent breaks and therefore has disadvantages

economic order.

  The present invention overcomes these disadvantages and

  circle a cylinder with a pilgrim step to significantly improve the coefficient of use of the pilgrim cylinders, avoiding the negative consequences

on the quality of the pipe.

  For this purpose, according to the invention, the cylinder with no

  rin, having a caliper profile having a reduction cone, a polishing caliber and an exit cone is characterized in that the lower portion of the reduction cone, adjacent to the polishing caliber, follows a substantially linear curve at an angle to center of 25, and is extended by a part, which extends over a center angle between 250 and 500, and which obeys a n cx law of the type y = d. (a + b.e), where a, b, c, d and n are parameters varying according to the diameter of the body

  of the cylinder, in that the total working area of the cylinder

  dre extends over an area corresponding to an angle

  210 to 2350, and in that the areas of the reduction cone, the polishing caliber and the outlet are 36%, 28% and 3690 respectively.

  that of the entire work area.

4-

  The invention also relates to the use of a cylinder

  dre pilgrim, which is characterized in that after

  several commissionings, we proceed each time to the u-

  caliber, while the angles of the different work areas are kept constant for all

  diameters of the cylinder body inside a furnace

  tolerance of plus or minus 30, and that, in the last use (s), the

  exit cone in the usual way.

  The invention will be better understood in the light of the accompanying drawings.

  Figure 1 shows a cross-section of a cylinder

  dre showing a profile of known type caliber.

  Figure 2 shows a cross section of a cylinder

  having the template profile according to the invention.

  The known type cylinder shown in cross-section in FIG. 1 comprises a working zone (0, III) divided into a reduction cone, a polishing groove and a

exit cone.

  On this section, the different zones are measured angu-

  the stretch, in degrees by angles in the center. Thus, the total work area corresponds to an angle α of the order

from 1800 to 2100.

  The arcs of circles between points 0 and I, I and

  II, II and III respectively correspond to the cone of

  ducting, polishing caliber and exit cone whose angular ratios to the total area of work (0, III) are respectively of the order of 48 to 54%,

  at 36% and 12 to 18%. Point A corresponds to the point of attack

  Only between the hollow ingot and the cylinder. This point defines the dimensionnemnent needed during the mechanical finishing

  and therefore the number of possible implementations of the cylinder.

  However, such cylinders of known type have the disadvantages mentioned above.

  FIG. 2 shows a section of a cylinder according to the invention

and the profile of its caliber.

  The different zones are measured in the same way as

  in FIG. 1, namely by angles in the center and

  perished by points 0,1,11 and III on the circle of

concentric with the cylinder.

  The caliber profile according to the invention is above all

  characterized in that the curves defining the cone of rotation

  ducting and the output cone are optimized to

  allow one type of curve to assume the two functions

  tions. For this purpose, the reduction cone has a

  first part whose curve is defined by a

  hyperbolic, parabolic or exponential

  lower part, contiguous to the polishing caliber and

  finished with a substantially linear curve. The

  first part thus calibrated must correspond to one

  in the center of approximately 250 and shall not be larger than the following limit values Diameter of the cylinder table Depth of gauge on the base circle of the caliber 1200 - 8 50 rm1,5 1,8mmr / 100 840 Au40 0 min 0.8 - 12unm / 100 3190 - 2 50 rmi 0.4 - 0.6mmn / 100 - 6 - The curve of the part contiguous to this part obeys C n to a law of the form: y = d (a + b) ex) on an area corresponding to a center angle of between approximately "and 50 diameter cylinder 1,200

from the table of

  - 850 mm 840 - 400 mm 390 - 250 mm Function y = d. C9,42153.10-2 + 1.344203. 10-3 e61513 (.-) 0 6 d = 14.25 to 20.0 y = d. [1.94049.10-1 + 1.32633.10 3 e6, 4096 (x-O, 6] d = 7.3 to 14, 3 y = d 1.94049.10-1 + 1.32633.10-3

", 4096. (5) 00 6

  d = 4.0 to 7.2 The angle corresponding to the working zone of the cylinder according to the invention is enlarged (relative to the cylinders

  known) to go from 180 - 210 to 210 - 235.

  The different zones constituting the working area (namely the reduction cone, the polishing caliber and the exit cone) occupy respectively 36%, 28% and 36%

of said total work area.

  At the time of machining, the angles of the different work areas kept constant for all the diameters of the body

  cylinder, within a range of plus or minus 3.

  The caliper profile according to the invention makes it possible, in

  minimizing the number of finishing operations and

  both cylinder fractures, a calibration method and a succession of diameters adapted to the diameter of the cylinder.

cylinder body.

  In this regard, the calibration according to the invention is applied

  with two reduction cones in the upper domain of the dia-

  cylinder meter (30% to 40% maximum commissioning)

cited above.

  For the remaining 60% of commissioning,

  in a conventional way with a single cone of

  duction. As a result, voltage cracks in the area of the second reduction cone are eliminated and

  negative effects related to so-called tension creeks.

  In the upper range of the diameter of the cylinder, after six startups, a diameter of larger size is cut to at least the machining rate. This diameter of

  caliber is then kept for 4 to 6 other

  its in use with two reduction cones. Then, a calibration of conventional form is used. The diameter of the calibration chosen must be larger by

minus the machining rate.

ú- 467643

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Claims (2)

R E V E N D I C A T IO N S   1- Cylinder for pilger mill with a caliper profile composed of a reduction cone, a polishing caliper and an exit cone,   characterized in that the lower portion of the cone of   duction, adjacent to the polishing caliber, follows a substantially linear curve at a center angle of 250, and is extended by a portion that extends between 250 and 500 and obeys a law of the type y = d. a + be xn), oa, b, c, d and n are parameters varying with the diameter of the cylinder body, in that the total working area of the cylinder extends over an angle in the center   from 210 to 235, and in that the reduction cone   the polishing caliber and exit cone extends   respectively 36%, 28% and 36% of the total area working.   2- Method of rolling with the cylinder with a pitch of rin according to claim 1,   characterized in that after several uses, it is   assigns each time to the machining of the caliber, the angles of the different work areas being kept constant for all diameters of table-cylinder within a tolerance range of plus or minus 30, and   what, in the last use (s), is   free the exit cone in the usual way.