JPH0665403B2 - Setting method of initial reduction amount in Sendzimir mill - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for setting an initial reduction amount in a Sendzimir mill used for cold rolling a steel strip.

[Prior art]

The Sendzimir mill shown in Fig. 1 is often used to cold-roll relatively thin and hard steel strips, etc., which have strict rolling plate thickness accuracy, and as shown in Figs. 3 (a) and 3 (b). Small upper and lower work rolls 4 inside a mill housing 13 with cast steel integrated structure
Starting from the top and bottom, a large number of rolls are arranged in a fan-shaped arrangement so that the steel strip 1 can be reversed in the horizontal direction or can be tandemly moved in one direction for high quality and efficient cold rolling. It's a mill. In such a Sendzimir mill, the number of rolls arranged in the mill housing 13, the roll arrangement, the roll supporting means, the mechanism for rolling down the steel strip 1 and the like are the same as those of a four-stage roll mill schematically shown in FIG. This is a big difference compared to the serially arranged roll mill 20.

That is, this series array roll mill 20 is vertically (vertically)
A small number of rolls such as work roll 21 and backup roll 23 in each direction are work roll chocks.
The structure is arranged and arranged in series while being supported by the 22 and the backup roll chock 24. Therefore, when the steel strip 1 is rolled, the reduction force by the reduction cylinder 25 is transmitted straight to the steel strip 1 via the upper and lower work rolls 21 having a relatively large diameter, and conversely, the reaction force generated against the reduction force is different. The rolls 21 and 23 and the roll chocks 22 and 24 are directly received by the reduction cylinder 25. Moreover, since the reduction force has a linear relationship with the pressure of the working fluid supplied to the reduction cylinder 25, if the pressure of this reduction cylinder 25 is measured, it is transmitted to the steel strip 1 via the upper and lower work rolls 21. The reduction force to be applied is obtained. Then, in setting the reduction amount (work roll gap) for obtaining the desired rolled strip thickness of the steel strip 1 or the rolled strip thickness of the same steel strip 1, even if the upper and lower work rolls 21 are recombined and replaced. Even when incorporating new upper and lower work rolls 21 with different roll diameters, it is easy to directly measure and calculate from the movement amount in the reduction cylinder 25, and the required reduction amount setting accuracy. Is very high. That is, the relationship between the setting of the reduction force and the reduction amount and the reduction cylinder 25 is uniquely determined, and both can be easily and accurately obtained from the pressure of the reduction cylinder 25 and the movement amount of the reduction cylinder 25. .

However, in the case of the Sendzimir mill targeted by the present invention, in order to cold-roll the high-quality steel strip 1 with good rolled plate thickness accuracy, the upper and lower work rolls 4 and other rolls are frequently re-rolled. Since it is replaced, it is necessary to set the initial reduction amount with accuracy each time, but as described above, the number of rolls, roll arrangement, supporting means, reduction mechanism, etc. are different, that is, the model of the mill itself is different. Due to the actual conditions and reasons as mentioned above, the series array roll mill 20 described above is used.
Even in the mill adopting the rolling-down system using the rolling-down cylinder 9 as in the above case, it is not possible to directly measure in the same manner and set the rolling-down force and the rolling-down amount with high accuracy.

B) For example, in the case where the coils of the ordinary steel strip 1 are continuously cold-rolled one after another, the back bearing 7 shown in the figure is every 45 days, the second intermediate roll 6 is every 15 days, and the first intermediate roll is every 15 days. The rolls 5 are changed every 4 hours to 3 days, especially the upper and lower work rolls 4 at most one coil of the steel strip, and the rolls are changed very frequently and the rolls are changed, and the initial reduction amount is changed. The situation is that you have to make settings.

(B) Normally, only the upper and lower work rolls 4 incorporated in the mill housing 13 are not supported at all, and there is a case where the restraint force is not exerted and the work rolls move freely. There are cases where setting is difficult.

C) As shown in the explanatory view of FIG. 4, the steel strip 1 to be rolled is sandwiched in a mill housing 13 of a cast steel integrated structure, and a large number of rolls are arranged in a fan-shaped arrangement symmetrically with respect to each other. As a method, by operating the reduction gear 8 in the vertical (vertical) direction by the reduction cylinder 9, the eccentric shaft supporting the back bearing 7 is rotated, and only the back bearing 7 is pushed out according to the eccentricity based on this rotation. It has a structure that it is retracted and rolled down,
During the cold rolling of the steel strip 1, a reduction cylinder 9 transmits the reduction force to the steel strip 1 from the back bearing 7 through the rolls 6 and 5 one after another and finally through the upper and lower work rolls 4. Then, as shown in the figure, the reaction force generated against such a reduction force is inversely transmitted from the upper and lower work rolls 4 to the respective rolls 5, 6, back bearings 7 and reduction gears 8 while being dispersed. Then, most of the reaction force is finally received by the mill housing 13.
Since the Sendzimir mill has such a unique rolling-down structure, even when only the upper and lower work rolls 4 are recombined and new work rolls 4 with different roll diameters are incorporated, The work roll 4, the rolls 5, 6, the back bearings 7, and the mill housing 13 are all in different positional relations of contact with each other. As a result, not only the upper and lower work rolls 4 but also the rolls cannot be reassembled. Since the respective positional relationships of the rolls and the back bearings 7 in the original state also change, they are generated against the reduction force, and then the upper and lower work rolls 4 pass through the rolls 5, 6 and the back bearings 7 and finally the mill. The dispersion state (direction and magnitude of the reaction force) of the reaction force transmitted while being distributed to the housing 13 and the reduction gear 8 is changed each time.

D) Therefore, even if an attempt is made to measure the reaction force received by the reduction cylinder 9 among the reaction forces generated against the reduction force transmitted to the steel strip 1 via the upper and lower work rolls 4 by the operation of the reduction cylinder 9, the reduction force is received. Even if only the new upper and lower work rolls 4 having different roll diameters are incorporated in the reaction force received by the reduction cylinder 9, the dispersed state of the reaction force, that is, the direction and magnitude of the reaction force change every time. As a result, the reaction force received by the pressure reduction cylinder 9 inevitably follows this change in the dispersed state, and it is meaningless to measure it. Not only the work rolls 4 above and below,
Whenever the rolls 5, 6 and the back bearing 7 are recombined or exchanged with the frequency described in the item a), the reaction force received by the reduction cylinder 9 similarly changes each time. There is no point in measuring the reaction force received.

E) As described above, in the case of the Sendzimir mill which is the object of the present invention, it has a peculiar structure in which a large number of rolls are arranged in a fan shape, and the rolling-down mechanism is completely different from that in the case of the series-arranged roll mill 20 described above. Therefore, most of the reaction force when the steel strip 1 is cold rolled is replaced not by the reduction cylinder 9 but by the mill housing 13 by reassembling the rolls 4, 5, 6 and the back bearings 7. Since it is transmitted while changing to a dispersed state every time, the relationship between the setting of the reduction force and the reduction amount and the reduction cylinder 9 is not uniquely determined as in the case of the series-arranged roll mill 20 described above.

F) Even so, in the past, complicated calculations were made when changing the rolls of the rolls 4, 5, 6 and the back bearing 7, so we attempted to use a computer to set the amount of reduction. Not only the rolls 4, 5, 6 and back bearings 7 are all new, but also some rolls or back bearings are mostly used to change the dimensional diameter, the rigidity condition of the mill housing 13 and its A slight actual deformation state is complicated and difficult to specify, rattling occurs between the back bearing 7 and an eccentric shaft supporting the back bearing 7, and each roll 4 is composed of a roll having a relatively small diameter. Although the flat deformation amount of each of the back bearings 7, 5, 6 and the back bearing 7 is small, the number of them is large and the directions and magnitudes of the rolling force and the reaction force are changed, and thus the totals are added. The like reason that the total flattening deformation of the case becomes a significant amount can not be reliably established,
It was not possible to accurately set the initial reduction amount even if the angle was calculated.

That is, in the case of Sendzimir mill, which is the object of the present invention,
As in the case of the serially arranged roll mill 20 such as a four-stage roll mill, when the rolls 4, 5, 6 and the back bearing 7 are newly installed, the working fluid supplied to both sides of the piston of the reduction cylinder 9 It is not possible to accurately measure the pressure reduction force transmitted to the steel strip 1 through the upper and lower work rolls 4 and the reaction force and the amount of pressure reduction from the pressure difference and the amount of movement of the pressure difference, and to calculate them accurately and easily. It was.

Therefore, in the prior art, as shown in FIG. 2, a magnetic measuring sensor 11 is provided in the reduction cylinder 9, and the piston 10 before the upper and lower work rolls 4 are replaced and before the piston 10 in the reduction cylinder 9 is released. The position of is recorded in advance, and after the upper and lower work rolls 4 are replaced, the actual cold-rolled steel strip 1 moves to the position of the automatic plate thickness measuring machine and the rolled plate thickness can be measured. A method has been adopted in which the piston 10 is fitted to the position of the piston 10 which is recorded in advance, and then cold rolling is performed by re-pressing.

[Problems to be solved by the invention]

However, even if the upper and lower work rolls 4 are used in the same mill, the surface of the work rolls 4 is repeatedly used up to its effective diameter, and therefore the upper and lower work rolls 4 have a diameter of several millimeters to a dozen or more. There is a difference in millimeters, and the position of the piston 10 in the reduction cylinder 9 before replacement of the upper and lower work rolls 4 is recorded in advance, and the new work roll 4 is recorded.
Even if the steel strip 1 is re-pressed after the piston 10 position is moved and adjusted until it matches the recorded piston 10 position after the replacement, the work roll 4 has a small diameter. When it is replaced with a new one, the amount of reduction (work roll gap) becomes larger than the desired value, and when replaced with a new one with a large diameter of the work roll 4, this work roll gap is The value was smaller than the desired value, and the work roll gap could not be accurately formed in the desired state.

As described in detail in the above items (a) to (e), only the upper and lower work rolls 4 having different roll diameters are exchanged because the Sendzimir mill itself has a unique structure and has a special rolling-down mechanism. Even in such a case, the rolling force and the amount of rolling of the rolling cylinder 9 are set in the above-mentioned series array roll mill 20.
It is not uniquely determined as in the case of, and even if the roll diameter changes in this way, it is absorbed without any problems, and the setting of the rolling force and the rolling amount is directly measured and calculated accurately and It couldn't be set easily.

In other words, in the case of Sendzimir mill, a highly accurate method of setting the initial reduction amount (setting the work roll gap) has not been substantially established. Even if AGC (A
Even if the mill is equipped with a Utomatic Gauge Control device, a considerable length of the steel strip 1 is cold-rolled after the upper and lower work rolls 4 are exchanged until the steel strip 1 of the target rolling plate thickness is obtained. Since the rolled strip thickness of the steel strip 1 rolled during this time largely deviates from the target, only cold-rolled products with poor dimensional accuracy can be obtained, or defective parts are unavoidably cut off to reduce the yield of cold-rolled products. There was a problem such as getting worse.

[Means for solving problems]

Therefore, as a result of various studies, the present inventors did not replace the first intermediate roll, the second intermediate roll, and the back bearing with rolls in order to substantially establish a highly accurate and simple method of setting the initial reduction amount. When setting the initial reduction amount when exchanging only the upper and lower work rolls with a new work roll with a different roll diameter, which is performed very frequently with leaving it in the original state, Due to the actual circumstances and reasons explained in detail in the above items (a) to (e), the reduction cylinder receives the reaction force generated against the reduction force transmitted to the steel strip every time the upper and lower work rolls are exchanged. Although the reaction force changes, in the reduction cylinder before and after replacement of the upper and lower work rolls, there is a difference in pressure (differential pressure) of the working fluid generated in the reduction cylinder due to the reduction force and the reaction force. Figure 5 substantially linear correlation as illustrated between the amount of movement of the piston which reciprocates in the pressure cylinder, that was found that the range is present in a proportional relationship. Based on this knowledge, if the material to be rolled (steel strip) is the same in this proportional range, even if the diameter of the work roll changes slightly, the differential pressure generated in the reduction cylinder and the actual cold rolling According to the present invention, the relationship between the rolled steel plate thickness and the rolled steel plate thickness obtained is substantially equal before and after the replacement of the upper and lower work rolls, and the rolled steel plate thickness before and after the replacement can be almost the same. The method of setting the initial reduction amount in Sendzimir mill was completed.

That is, the present invention, in the Sendzimir mill used for cold rolling of a steel strip provided with a reduction cylinder to which the working fluid is supplied and discharged, when setting the initial reduction amount and re-reducing after replacement of the work rolls, in the reduction cylinder, Within the range in which the relationship between the amount of piston movement and the pressure difference (differential pressure) of the working fluid that occurs in this reduction cylinder is in a proportional relationship, the thickness of the rolled steel strip in cold rolling before the work roll replacement is performed in advance. And the differential pressure of the working fluid generated in the pressure reduction cylinder, the working fluid is supplied to and discharged from the pressure reduction cylinder until it reaches an arbitrary value among the differential pressure values obtained, and the pressure reduction cylinder reaches the end. The position of the piston in the inside is set as a measurement starting point (zero point) in the reduction cylinder when setting the initial reduction amount. The initial amount of reduction setting method in the mill.

Hereinafter, a method for setting an initial reduction amount in the Sendzimir mill according to the present invention will be described in detail with reference to the drawings.

1 to 5 are drawings relating to a Sendzimir mill, wherein FIG. 1 is a schematic explanatory view showing an example of a Sendzimir mill for implementing an initial reduction amount setting method, and FIG. 2 is a reduction cylinder provided in the Sendzimir mill. FIG. 3 (a) is a perspective view showing the outline of the structure of the Sendzimir mill housing of cast steel integrated structure, and FIG. 3 (b) is FIG. 3 (a).
Fig. 4 is a perspective view showing the state of the steel strip 1 being cold-rolled by the rolls and bearings incorporated in the Sendzimir mill housing, and Fig. 4 shows the reduction force applied to the steel strip being cold-rolled in the Sendzimir mill. FIG. 5 is an explanatory diagram showing a transmission state in which reaction forces generated in opposition are dispersed and transmitted, and FIG. 5 is a relational diagram between the movement amount of the piston in the pressure reduction cylinder and the pressure difference (differential pressure) of the working fluid in the pressure reduction cylinder. Is.

In the drawings, 1 is a cold-rolled steel strip, 2, 2'is a tension reel, 3, 3'is a deflector roll, 4 is a work roll, 5 is a first intermediate roll, 6 is a second intermediate roll, and 7 is A back bearing, 8 is a reduction gear that rotates an eccentric shaft that supports the back bearing 7, and 9 is a piston 10 provided inside by a high-pressure working fluid supplied and discharged from a lateral pressure unit. A reduction cylinder that reciprocates in the direction to move the reduction gear 8 connected to the piston rod 10a, and 11 is provided connected to the end of the cylinder rod 10a of the reduction cylinder 9 to measure the movement amount of the piston 10. The magnetic measuring sensors 11a, 11b, and 11c detect the positions of the magnetic measuring sensors 11, and 11a, 11b, and 11c are coils, scales, and bearings that form the magnetic measuring sensor 11, respectively. Reference numeral 12 is a pressure gauge for measuring the pressure difference (differential pressure) of the working fluid supplied to and discharged from the pressure reducing cylinder 9 from the side pressure unit, 13
Is a Sendzimir mill housing with an integral structure of cast steel.

In order to carry out the method for setting the initial reduction amount in the Sendzimir mill according to the present invention, first, during the cold rolling operation before the upper and lower work rolls 4 are recombined and replaced, the magnetic scale sensor 11 and the pressure gauge 12 Although not shown, a rolling cylinder 9 is preliminarily used by using a plate thickness measuring device for measuring the rolled plate thickness of the steel strip 1 installed on the side of the tension reel 3 or 3'for winding the rolled steel strip 1 of the Sendzimir mill. The relationship between the moving amount of the piston 10 in the inside and the pressure difference (differential thickness) of the working fluid generated in the reduction cylinder 9 and the relationship between the rolled plate thickness of the steel strip 1 and the differential pressure of the working fluid are simultaneously investigated and recorded. Then, after exchanging with new upper and lower work rolls 4 having different roll diameters, the same steel strip 1 (a steel strip of the same size but at least the same material) is re-rolled down. On the occasion,
The relationship between the amount of movement of the piston 10 in the reduction cylinder 9 and the pressure difference (differential pressure) of the working fluid generated in the reduction cylinder 9 is within the range of a comparative relationship, and it is investigated in advance and cold rolling is performed. Until an arbitrary value of the differential pressure values recorded by recording the relationship between the rolled plate thickness of the steel strip 1 and the differential pressure of the working fluid generated in the reduction cylinder 9 is reached while confirming with the pressure gauge 12. The working fluid is supplied and discharged from the lateral pressure unit into the pressure reduction cylinder 9, and the position of the piston 10 in the pressure reduction cylinder 9 that has reached the end is set in the pressure reduction cylinder 9 when the initial reduction amount is set. It is adjusted and set as the measurement start point, that is, the zero point.

Further, it is necessary to measure the movement of the piston 10 in the reduction cylinder 9 on a scale as described above. For this purpose, a magnetic measurement sensor 11, which has been conventionally abbreviated as a Magnescale, is used for the reduction cylinder. 9 piston rod 10
By operating the magnetic measurement sensor 11 connected to the end of a, the movement amount of the piston 10 in the reduction cylinder 9 can be measured, and its position can be detected and confirmed. Of.

Then, the length is measured from the measurement start point (zero point) adjusted and set as described above, and the new upper and lower work rolls 4
The cold rolling is started in earnest after the initial reduction amount (work roll gap) is set to a desired thickness amount.

[Action]

By setting the initial reduction amount as described in detail above, even if the roll diameter changes from several millimeters to ten and several millimeters before and after the replacement of the upper and lower roll works 4, the measurement before and after the replacement is performed regardless of the change of the roll diameter. Since the starting point, that is, the zero point (reference point for starting the reduction) can be adjusted and set to be almost the same, the setting error generated due to the change in the roll diameter as described above is eliminated, and after the replacement, As in the case before replacement, it is possible to set the initial reduction amount to almost the target amount, and as a result, immediately after the start of cold rolling after setting, the target strip thickness of steel strip 1 remains unchanged from before the replacement. It will be possible to carry out cold rolling. Therefore, it is not necessary to cold-roll until the steel strip 1 as the material to be rolled reaches the target rolling plate thickness after the replacement, while changing the reduction amount one by one, as in the conventional case, until it matches. A cold-rolled product with good dimensional accuracy can be manufactured, and the product yield in the manufacturing can be greatly improved.

〔Example〕

A work roll diameter: 54 mmφ, a first intermediate roll diameter: 102 mmφ, a second intermediate roll: 173 mmφ, using a Sendzimir mill as shown in the schematic explanatory views illustrated in FIGS. 1 to 4.
Back bearing diameter: Includes rolls and back bearings with a diameter of 300 mm, and the material to be rolled is SUS304 (1030 m
(m width) stainless steel strip from 3.0 mm thickness after passing the required number of passes to the target rolling thickness of 1.0 mm while cold rolling while reversing the signal from the magnetic scale sensor The pressure difference (differential pressure) of the working fluid in the pressure reduction cylinder (pressure gauge) is used as the axis and the relationship between the two is recorded over time on the XY recorder while the signal from this magnetic scale sensor is simultaneously recorded. The signal from the plate thickness measuring device for measuring the thickness of the cold-rolled strip on the horizontal axis was plotted on the vertical axis, and the relationship between the two was recorded with time on another XY recorder. as a result,
As shown by the solid line in FIG. 5, the differential pressure of the working fluid is 5 kg / cm ²
55kg / cm that is actually cold rolled from (Point A)
^In the range up to ² (point K), there is a proportional relationship with the signal from the magnetic scale sensor, and this 5 kg / cm ² (point A) is the smallest proportional differential pressure value of the proportional pressure values. It was confirmed that the actual rolled plate thickness was 1.010 mm when the pressure difference was 40.7 kg / cm ² .

Therefore, in this state, the supply of the working fluid is stopped (the differential pressure of the working fluid is set to zero), the roll is reassembled and replaced with a new work roll of 60 mmφ, and the accuracy by the method of the present invention is confirmed. In order to do so, it was decided to try cold rolling the same stainless steel strip as before replacement, and the results were recorded in the same manner.

After this replacement, maximum proportional differential pressure before replacement: 55 kg / cm ²
The working fluid is supplied into the pressure reduction cylinder until the point (K point) is reached, and the relationship between the amount of movement of the piston in the pressure reduction cylinder and the differential pressure of the working fluid is in a substantially linear proportional relationship during this supply process. After confirming this point, readjust the K point as a measurement start point after replacement, that is, the zero point, including all gauges on the side of the reduction mechanism (reduction operation chamber, etc.), and then reset the initial reduction amount to 1.000. As a result of starting cold rolling after setting to mm, from this recording result, almost the same state as before replacement was obtained as shown by the broken line in FIG. Also, the same differential pressure as before replacement:
At 40.7 kg / cm ² , it was found that the actual rolled plate thickness was 1.008 mm. Further, depending on the AGC device, the conventional method changes the rolling reduction setting until the target rolled plate thickness of 1.110 mm is adjusted to the target rolled plate thickness of 1.000 ± 0.040 mm after restarting cold rolling after roll replacement. The length of the stainless steel strip required to be 20 m during the cold rolling while repeating the above procedure, but at least 0 to 3 m immediately after the cold rolling.
The steel strip length is sufficient, and a factory with a dimensional accuracy of rolled plate thickness of stainless steel strips, and eventually a stainless steel strip with a large number of coils, is manufactured by being sequentially cold-rolled and manufactured. The yield at the factory was greatly improved.

〔The invention's effect〕

As described in detail above, the method for setting the initial reduction amount in the Sendzimir mill according to the present invention is a method that can set the initial reduction amount in the Sendzimir mill very easily and accurately, and as a result, basically the dimensional accuracy can be improved. Since it becomes possible to manufacture a good cold-rolled product and the manufacturing yield due to the cold-rolling can be significantly improved, it is of great industrial value.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of a Sendzimir mill for carrying out a method for setting an initial reduction amount, FIG. 2 is a schematic explanatory view illustrating a reduction cylinder portion provided in the Sendzimir mill, and FIG. 3 (a) is a cast steel. Fig. 3 (b) is a perspective view showing the outline of the structure of the integrated Sendzimir mill housing. Fig. 3 (b) shows the cold rolling of the steel strip by the rolls and bearings incorporated in the Sendzimir mill housing shown in Fig. 3 (a). A perspective view showing a state during rolling,
FIG. 4 is an explanatory view showing a transmission state in which a reaction force generated against a reduction force applied to a steel strip during cold rolling in a Sendzimir mill is dispersed and transmitted, and FIG. 5 is a movement amount of a piston in a reduction cylinder. And FIG. 6 is a diagram showing the relationship between the pressure difference (differential pressure) of the working fluid in the pressure reducing cylinder, and FIG. 1 ... Steel strip 2, 2 '... Tension reel 3, 3' ... Deflector roll 4 ... Work roll 5 ... First intermediate roll 6 ... Second intermediate roll 7 ... Back bearing 8 ... Reduction gear 9 …… Reduction cylinder 10 …… Piston 10a …… Piston rod 11 …… Magnetic scale sensor 11a …… Coil 11b …… Scale 11c …… Bearing 12 …… Pressure gauge 13 …… Mill housing 20 …… Series array roll mill 21 …… Work roll 22 …… Work roll chock 23 …… Backup roll 24 …… Backup roll chock 25 …… Pressing cylinder 26 …… Mill housing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Hashiguchi ed. “Metal Engineering Course 6 Processing ▲ I I ▼ Plastic Working” (S35 issued on January 10, 35) Pages 32-50 Asakura Shoten

Claims (2)

[Claims] 1. A Sendzimir mill used for cold rolling of a steel strip (1) equipped with a reduction cylinder (9) for supplying and discharging a working fluid, wherein an initial reduction amount is set after replacement of a work roll (4). When re-pressing, the relationship between the movement amount of the piston (10) in the reduction cylinder (9) and the pressure difference (differential pressure) of the working fluid generated in this reduction cylinder (9) is within a proportional range. The rolling thickness of the steel strip (1) and the reduction cylinder (9) in cold rolling before replacing the work rolls (4) in advance.
The working fluid is supplied to and discharged from the pressure reducing cylinder (9) until it reaches an arbitrary value among the pressure differential values that have been obtained regarding the relationship with the pressure difference of the working fluid that occurs inside the pressure reducing cylinder. A method for setting an initial reduction amount in a Sendzimir mill, characterized in that the position of the piston (10) in (9) is set as a measurement start point (zero point) in the reduction cylinder (9) when setting the initial reduction amount. . 2. A piston rod (10a) in a reduction cylinder (9).
A magnetic scale sensor (11) connected to the end of the piston is operated to measure the movement amount of the piston (10) in the pressure reduction cylinder (9) and detect its position. A method for setting an initial reduction amount in the Sendzimir mill according to the first item.