JP2776238B2 - Role operation method of 3-roll reducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, Mannesmann - in the production of seamless pipe by a mandrel mill method, with respect to a roll operating method 3 roll reducer to the outer diameter reducing rolling the stretched rolled mother pipe.

[0002]

2. Description of the Related Art A seamless pipe is manufactured by heating a round or square billet and then drilling the hole, elongating and rolling the drilled hollow shell, and finishing the drawn mother tube by a predetermined process. consisting of a constant径圧rolling step of the outer diameter reducing rolling in size. As a rolling mill in the thinning process, a plug mill, a mandrel mill, an assel mill, a pilga mill and the like are known. Among the seamless pipe manufacturing methods, the Mannesmann-Mandrel Mill method, which has excellent productivity, is to heat a round billet of a material to 1200 to 1260 ° C. in a rotary hearth type heating furnace, and then punch it with a plug and a roll using a drilling machine. Roll into a hollow shell. The hollow shell at this stage has an outer diameter of several sizes and a very large wall thickness as compared with the product.

[0003] In the mandrel mill in the next thinning step, a roll stand incorporating a pair of slotted rolls is rotated 90 ° from each other.
Four to eight rolls are continuously arranged while changing the roll arrangement, and the thickness is reduced to a predetermined thickness and stretched and rolled continuously between the mandrel bar inserted into the hollow shell and the hole-shaped roll. Generally, the reduction in wall thickness in a mandrel mill is generally performed by reducing the thickness by about 7 to 15 mm in order to reduce the roughness of the inner surface. Thinning, stretching rolled mother pipe, the mandrel bar is withdrawn by the scan tripper. Thinning, if the substrate tube temperature to drawing and rolling is too low compared to the degree of processing, if it is heated to 900 to 1100 ° C. The mother pipe in the reheating furnace, which does not cause the temperature drop, the outer diameter After the outer diameter is reduced and the thickness is slightly adjusted by a reduction rolling mill, it is finished to a predetermined finish size.

[0004] A three-roll outer diameter reduction mill such as a three-roll reducer includes a stand provided such that the angle between the respective rolls in the rolling direction is 120 ° in a plane perpendicular to the rolling direction. The rolling direction of the rolls is shifted alternately by 60 ° between adjacent stands, the number of main stands is determined by the degree of working, and continuous drawing rolling of the mother pipe is performed at 5 to 24 stands to reduce the outer diameter and slightly Adjust the wall thickness,
Finish to predetermined product dimensions with finishing 3 to 4 stands.
The three-roll outer diameter reduction mill described above is economical because a high degree of outer diameter working can be obtained, so that the outer diameter setup of the mandrel mill can be consolidated, tools can be omitted, and productivity can be improved. In many cases, a roll gap change mechanism for adjusting the rolling reduction is not provided as compared with a two-roll rolling mill.

[0005] For this reason, a three-roll outer diameter reduction rolling mill without a roll gap changing mechanism requires a stand which has been used when a roll is to be re-cut due to abrasion of the roll, surface roughening, and seizure at an edge portion. Of the roll of the front stand
The amount of roll modification is excessive due to the modification to the hole shape dimensions ,
There is a problem that the roll basic unit deteriorates. The outer diameter reduction ratio per single stand of a three-roll outer diameter reduction mill is about 4 to 7%. For example, in the case of a hole-type roll having an outer diameter of 100 mm, the hole diameter of the stand and the preceding stand is 100 mm. × (0.04 to 0.07 ) = 4 to 7 m
m average renovation is required. The hole rolls of the three-roll outer diameter reduction mill are sequentially re-cut and reused as large hole rolls, but the number of rolling passes in one use is 200.
0 to 5000 passes. Finish outside diameter is 27.2-13
The average roll modification amount of the hole type roll used in the mill for producing seamless pipes of various sizes of 9.8 mm is 2-3 mm.

[0006] Roll modification of a three-roll diameter reduction mill is as follows.
Normally, a method using a special lathe capable of simultaneously cutting three rolls with a circular disk bite, and a method of individually cutting the rolls with an NC lathe are used. The method of simultaneously cutting three rolls with a circular disk bite is shown in FIG.
As shown in FIG. 2, the cutting is performed while rotating the circular disk tool 2 and the roll 1 located at a position where the offset L is taken from the center of the roll 1. At the time of cutting a perfect circular hole, the offset L is set to 0, but by changing the offset L, a hole having an arbitrary ellipticity can be obtained.

As shown in FIG. 1 and FIG. 2, when the roll edge radius Ai and the roll groove bottom radius Bi of the roll type roll are determined as shown in FIGS. If the roll diameter is D, DC = Bi−Aicos60 ° + (Ai ² −Bi ² ) / D + (Ai ² sin ² 60 °) / {Bi−Aicos 60 ° + (Ai ² −Bi ² ) / D}. L = {[(D / 2) -Bi] ² -[(D / 2)-(DC / 2)] ² }. Note that i is i
Show the second stand.

[0008]

[SUMMARY OF THE INVENTION] An example of a grooved dimensions of grooved roll when the mother tube with an outer diameter of 151.0mm to the outer diameter reducing rolling to a diameter of 101.6mm in hot Table 1. In the case of the hole type rolls shown in Table 1, the roll phase was shifted by 60 ° at the adjacent stand. No. 1 to 7 main stand. It is incorporated into a finishing stand consisting of 8 to 10 stands. The grooved roll is 3 rolls of the roll outer diameter reducing rolling machine incorporated performs modified cutting If seizure of rough skin and an edge portion of the roll surface occurs. For example, N
o. The roll of 6 stands will be the No. It is cut down to the hole size of a roll of 5 stands. Cutting allowance in this case, a roll groove bottom _{(2B 5 -2B 6) / 2} = (119.0-11
1.5) /2=3.75 mm. Assuming that the number of rolling passes up to the re-cut is N, the basic unit of shaving per roll at the roll groove bottom is 3.75 mm / N in this case. Roll gap adjusting mechanism 3 roll outer diameter reducing mill having no have the disadvantage that the cutting of the inevitably occur.

[0009]

[Table 1]

An object of the present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances, and has been made in consideration of the above circumstances.
In the outer diameter reducing mill is to provide a roll operating method 3 roll reducer rolls intensity can be greatly improved.

[0011]

Means for Solving the Problems The present inventors have intensively studied and studied to achieve the above object. As a result, the cutting reformed grooved roll 3 roll outer diameter reducing mill having no roll gap adjusting mechanism, the grooved rolls in both roll groove bottom portion and the edge portion of the main stand, midway between the stand and front stand By reshaping into a die and using it on the stand, it is possible to greatly improve the basic unit of roll, and if the dimensions of the die roll of the finishing stand are maintained at the standard size, the product seamless pipe after drawing and rolling is reduced. It has been confirmed that there is no particular problem in the outer diameter, ellipticity, and ellipticity, and the present invention has been achieved.

That is, the first invention of the present application is to remodel a grooved roll of a three-roll outer diameter reduction rolling mill without a roll gap adjusting mechanism, by changing a grooved roll of each main stand to a roll groove bottom portion and an edge portion. A method of operating a roll of a three-roll reducer, wherein the roll is cut into an intermediate hole between the stand and a preceding stand and used in the stand.

Further, the second invention of the present application is directed to a reshaping of a grooved roll of a three-roll outer diameter reduction rolling mill having no roll gap adjusting mechanism, wherein the grooved roll of each main stand is fixed to both a roll groove bottom portion and an edge portion. , the stand and then Aratamekezu an intermediate hole type and a previous stand used in the stand, the grooved rolls of the first finishing stand, the edge portion
The amount of reduction at the bottom is half the groove of the regular roll of the final main stand
Regular roll of the first finishing stand from twice the value of the diameter
Exceeding twice the value obtained by subtracting twice the value of the edge radius of
A 3 roll reducer rolls operating method characterized by cutting lest breaks.

Further, the third invention of the present application relates to a reshaping of a grooved roll of a three-roll outer diameter reduction mill having no roll gap adjusting mechanism, wherein the grooved roll of each main stand is fixed to both a roll groove bottom portion and an edge portion. The mill is cut into an intermediate hole between the stand and the previous stand and used for the stand. At least the first finishing stand is provided with a roll gap adjusting mechanism .
The roll gap at the edge of the roll.
From twice the groove bottom radius of the regular roll of the in-stand to 1
2 of the edge radius of the regular roll of the finishing stand
This is a roll operation method for a three-roll reducer, characterized in that adjustment is made so as not to exceed twice the value obtained by subtracting the double value .

[0015]

According to the first aspect of the present invention, the hole type roll of each main stand is rolled at both the roll groove bottom portion and the edge portion.
It is necessary to cut the intermediate roll between the stand and the preceding stand into two holes before using it on the stand to reshape the former roll into the regular roll of the former stand. It can be used in this stand after being remodeled into a hole shape , and the number of rolling passes of each roll until the hole size of the regular roll of the former stand is reworked can be greatly increased, and the basic unit of roll can be greatly improved. . In addition, the effect on the product seamless pipe due to the modification to the intermediate hole type and use in the stand is such that the outer diameter, the ellipticity, and the ellipticity are not particularly problematic.

Further, in the second invention of the present application, the hole type roll of each main stand is modified at both the roll groove bottom portion and the edge portion into an intermediate hole type between the stand and the preceding stand and used in the stand. by, before Aratamekezu the grooved rolls of the stand grooved <br/> size of regular roll of the front stand, available in the stand by Aratamekezu about twice the intermediate caliber, the pre-stage stand normal Roll hole
The number of rolling passes of each roll before reshaping to the die size is greatly increased, and the basic unit of roll can be greatly improved.
Also, insert the roll of the first finishing stand into the edge
The amount of reduction in the part is the bottom of the regular roll groove of the final main stand
The regular row of the first finishing stand from twice the radius
More than twice the value obtained by subtracting twice the radius of the edge part of the
In order to reduce the rolling load when moving from the final main stand to the first finishing stand when using intermediate rolls at each main stand, it is possible to prevent seizure of the roll edge. it can.

Further, in the third invention of the present application, the hole-type roll of each main stand is modified to have an intermediate hole between the stand and the preceding stand at both the roll groove bottom portion and the edge portion and the stand is formed. By using the hole-type roll of the relevant stand in the hole of the regular roll of the previous stand.
Before remodeling to the mold size, it can be remodeled to the intermediate hole type about twice and can be used on the relevant stand .
The number of rolling passes of each roll before reshaping to a die size is greatly increased, and the basic unit of roll can be greatly improved. In addition, at least the first finishing stand is provided with a roll gap adjusting mechanism, and the hole of the first finishing stand is provided.
Adjust the roll gap of the die roll to minimize the amount of reduction at the edge.
Double the groove bottom radius of the regular roll of the final main stand?
Edge radius of the regular roll of the first finishing stand
By adjusting the value so that it does not exceed twice the value obtained by subtracting the value of twice from the final stand at the time of using the intermediate hole type roll at each main stand, the transition from the final main stand to the first finishing stand is performed. The rolling load is reduced, and seizure of the roll edge can be prevented.

In the present invention, the main stand
Cutting breaks from grooved roll to intermediate pore type, medium Maana roll edge radius Ai × 2, compared to the groove bottom radius Bi × 2 positive Tadashiana type, so as not to exceed 1.5% Design and cut using the same circular disc tool. In addition, the hole type roll of the first finishing stand in the present invention is held at the edge portion.
Is the bottom radius of the regular roll of the final main stand.
Double the value of the regular roll of the first finishing stand
Do not exceed twice the value obtained by subtracting twice the edge radius.
To break-cutting that I will be, for example, of each of the main stand regular
The filtrate Lumpur a twice if you break cutting, and first of finishing the scan
When the roll at the edge of the tando
Twice the groove bottom radius of the regular roll of the stand (2Bi-
From the value of 1) above, the value of the regular roll of the first finishing stand
Twice the value obtained by subtracting the value of twice the edge radius (2Ai)
If the radius Ai of the roll edge portion of the first finishing stand is designed within a range not exceeding the value, the seizure of the roll edge of the first finishing stand poses no practical problem.

Further, if a housing having a gap adjusting mechanism is used for the roll of the first finishing stand,
Even if the regular die roll of each main stand is cut twice ,
The roll gap, pressure under volume at the edge portion is the final Meinsu
Twice the groove bottom radius (2Bi-1) of the regular roll of the tando
Edge of the regular roll of the first finishing stand from the value
Exceeding twice the value obtained by subtracting the value of twice the radius (2Ai)
If the adjustment is made within such a range, the roll edge seizure of the first finishing stand has no practical problem as described above. The gears <br/>-up adjusting mechanism of the roll of the first finishing stands in the present invention, the eccentric ring for supporting the outer periphery of the bearing for supporting the roll axis, the cylinder and worm wheel is rotated by the worm shaft, A method of adjusting a roll reduction amount (Japanese Utility Model Laid-Open No. 4-64406, Japanese Utility Model Laid-Open No. 4-64).
407, JP-A-58-25805, JP-A-60-18208, etc.) or a method in which a screw is rotated by a screw screw-down device (Japanese Patent Application Laid-Open No. H05-5208)
No. 96308).

[0020]

[Embodiment] As shown in Table 2, no. Nos. 1 to 7 and a main stand. 8-10 in 3 roll outer diameter reducing mill consists finishing stands consisting stand, was squeezed rolled to the outer diameter 101.6mm in hot mother tube with an outer diameter of 151.0mm regular roll in Table 2, rolling With 3,200 passes, the roll of the main stand became rough and edge seizure occurred. Then, No. The rolls of the main stand consisting of the stands 1 to 7 were re-cut using the same circular disc tool as the intermediate hole type shown in the column of the intermediate roll (1) in Table 2 and used in the same manner on the stand to obtain the outer diameter. A 151.0 mm mother tube is hot-heated to an outer diameter of 101.6 mm
When the intermediate roll (1) was rolled to 2,800 roll passes, the roll surface became rough and edge seizure occurred. In addition, No. The rolls of the main stand composed of 1 to 7 stands are shown in the column of the intermediate roll (2) in Table 2.
Using the same circular disk bite for the intermediate hole type,
When the mother tube having an outer diameter of 151.0 mm was hot-drawn and squeezed to an outer diameter of 101.6 mm using the same stand,
In the intermediate roll (2), the surface of the roll became rough and edge seizure occurred after 2,700 rolling passes. In the case of using this intermediate roll (2), No. 1 which is the first finishing stand. The roll of No. 8 stand was rolled to the No. 8 roll where the amount of reduction at the edge was the last main stand. 7 is the first finishing stands twice the groove bottom radius B ₇ stand regular roll of No. Double (1.2 m) of the value (0.6 mm) obtained by subtracting twice the edge radius A ₈ of the regular roll of 8 stands.
m) was used after being modified so as not to exceed 0.8 mm. Table 3 shows the results. The roll material used was chilled for both the main stand and the finishing stand.

[0021]

[Table 2]

[0022]

[Table 3]

As shown in Table 3, the surface roughness of each roll of the main stand and the number of rolling passes until edge seizure were 3,200 for the regular roll and 280 for the intermediate roll (1).
0, 2700 passes with intermediate roll (2), 87 total
Rolling was completed up to 00 passes. On the other hand, as compared with the conventional method of cutting the regular roll into the regular roll of the preceding stand at 3,200 passes, 5,500 passes were able to be rolled. As a result, when the conventional roll basic unit is changed from the regular roll of the stand to the regular roll of the preceding stand, the groove bottom average cutting allowance is 6.6 mm, which is 2.06 mm per 1000 passes. 0.76mm per 1000 passes
And it has improved about three times. The obtained seamless tube had an average finish outer diameter, an ellipticity, and an ellipticity which were at a level with no particular problem in use.

[0024]

As described above, according to the present invention, according to the present invention method, 3 basic unit of grooved rolls of the roll outer diameter reducing mill can greatly improve, greatly roll costs in seamless pipe production Can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing a cutting state of a hole type roll by a circular disk tool.

FIG. 2 is a side view showing a cutting state of a hole type roll by a circular disk bite.

[Explanation of symbols]

 1 roll 2 disc tool Ai roll edge radius Bi roll groove bottom radius D roll diameter DC disc tool outer diameter L offset amount

Claims (3)

(57) [Claims] 1. A reshaping machine for a roll of a three-roll outer diameter reduction rolling mill having no roll gap adjusting mechanism, wherein a roll of a roll of each main stand is fixed to both a roll groove bottom part and an edge part of the stand and a preceding stand. Characterized in that it is modified into an intermediate hole type and is used in the stand.
Role operation method of role reducer. 2. The reshaping of a grooved roll of a three-roll outer diameter reduction rolling mill without a roll gap adjusting mechanism, the grooved roll of each main stand is fixed to a roll groove bottom part and an edge part by the said stand and the preceding stand. of was Aratamekezu the intermediate grooved <br/> used in the stand, the first grooved rolls of the finishing stands, rolling reduction at the edge portion is the final main
First from twice the groove bottom radius of the regular roll of the stand
Twice the radius of the edge of the regular roll of the finishing stand
A roll operation method for a three-roll reducer, which is modified so as not to exceed twice the value obtained by subtracting the value . 3. The reshaping of a grooved roll of a three-roll outer diameter reduction mill without a roll gap adjusting mechanism, the grooved rolls of each main stand are rolled together with the roll groove bottom part and the edge part with the stand and the former stand. of was Aratamekezu the intermediate grooved <br/> used in the stand, provided roll gap adjusting mechanism to at least the first finishing stands, No. 1
The roll gap of the hole type roll of the eye finishing stand,
The roll at the edge is the regular roll of the final main stand
From the value of twice the groove bottom radius of the first finishing stand
2 of the value obtained by subtracting twice the value of the radius of the edge of the regular roll
A roll operation method for a three-roll reducer, characterized in that adjustment is made so as not to exceed twice .