JPS6021803B2 - Continuous rolling mill for seamless pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous rolling mill for seamless pipes, and in particular, to a continuous rolling mill for seamless pipes. The present invention relates to an improvement of a continuous rolling mill for seamless pipes having a plurality of slotted roll stands for continuously rolling pipes.

One of the methods for manufacturing seamless pipes such as seamless steel pipes is the first method.
As shown in the figure, first, a solid billet 10 as a material is
For example, heating to a predetermined temperature in a rotary hearth type heating furnace 12,
Next, a hole is punched with a piercer 14 that utilizes the Mannesmann effect to form a thick and short hollow hollow loom 16. Furthermore, after inserting a mandrel bar 18, the hollow hollow loom 16 is passed through a mandrel mill 2 together with a mandrel bar 18.
It is fed into a river mill and stretched and rolled to form a reducer base pipe 22.
After rolling, the mandrel bar 18 is pulled out and the reducer tube 22 is placed in a reheating furnace 2 of a walking beam type, for example.
After being reheated by Step 4, the tube is reduced by a stretch reducer 26 and subjected to outer diameter reduction and slight wall thickness reduction to obtain a finished rolled tube 28 having the required product dimensions, using a mandrel mill rolling method. The stretch reducer 26 is usually composed of 8 to 2 hole-shaped roll stands, and during rolling, a considerably large tensile force (up to 80% of the hot deformation resistance of the material to be rolled) is applied between each stand. (exceeding) so that the wall thickness can be reduced.

The roll rotation speed of each stand is controlled by a DC motor for each stand so that it can be changed freely and independently. This stretch reducer 26 has a 2-roll type and a 3-roll type.
There is a roll type. The two-roll type stretch reducer, as shown in FIG.
Stands incorporating a are consecutively arranged with the arrangement changed by 900 between adjacent stands,
The outer diameter of the reducer tube 22 is gradually reduced at each stand and finished to a predetermined outer diameter at the final stand and at the stand one step before the final stand.

According to this two-roll type stretch reducer, it is possible to change the roll gap during rolling, and the outer diameter of the finished rolled pipe can be maintained constant by tightening the rolls by the amount of wear that occurs as rolling progresses. It has the feature that it can be used as a sizer to control the outside diameter of rolled finished pipes, but because it is a two-roll type, the roll hole shape is deep and the center part of the roll groove bottom is Since the difference in circumferential speed between the roll and the hole-shaped side portion becomes large, there is a problem in that the surface of the tube material and the roll may become phosphorous and cause curls on the surface of the tube material. On the other hand, as a solution to the drawbacks of the two-roll type stretch reducer as described above,
As shown in FIGS. 3 to 5, three stands incorporating three three-roll type hole-type rolls 26b are successively arranged with the arrangement being changed by 600 between adjacent stands.
A roll-type stretch reducer has been put into practical use.

According to this three-roll type stretch reducer, since the roll hole shape is shallow, the difference in roll circumferential speed between the center part of the roll groove bottom and the side part of the hole shape is small, and the tendency of the tube and roll to seize is significantly reduced. It has the characteristic of However, in this three-roll type stretch reducer, the rolls of each stand are cut into hole shapes offline with the three rolls still assembled in the removable housing, and the target hole diameter is It is impossible to adjust the gap. Therefore, once the roll has been finished cutting, fine adjustment of the hole diameter cannot be made when the housing is set online and the roll is used for actual rolling, resulting in errors during roll modification or continuous rolling. The effects of wear and the like due to use remain, and the actual pore diameter changes. Therefore, it has the disadvantage that the frequency of modification of the roll hole shape needs to be significantly increased compared to the two-roll type. Furthermore, in general,
The number of stands arranged for the stretch reducer is selected from 8 to 2 mirrors depending on the outside diameter drawing ratio of the tube, and each stand is a quick change system in which the entire roll housing is reassembled. Generally, this method is used.

In other words, each stand holder with two grooves is equipped with independent gear couplings for transmitting drive, while the roll housings are compatible with each other and can be used with any stand holder. It is now possible to incorporate it into. Therefore, a continuous rolling mill,
In particular, as a stretch reducer, it is desirable that this quick change function is not impaired. The present invention was made to eliminate the drawbacks of the conventional 20-roll type continuous rolling mill and 3-roll type continuous rolling mill. It is an object of the present invention to provide a continuous rolling mill for seamless pipes which is variable, has excellent compatibility and versatility without impairing quick change function, and has excellent compatibility and versatility.

The present invention provides a method for continuously rolling a perforated main pipe.
In a continuous rolling mill for seamless pipes having a plurality of slotted roll stands, the housing of the three-roll slotted roll and the housing of the two-roll slotted roll can be assembled into the same stand holder, and the The roll drive device of the roll stand has two parts that rotate in opposite directions to each other.
The housing of the three-roll perforated roll is equipped with parallel drive shafts, and the housing of the three-roll type hole type roll transmits the driving force inputted by one of the drive shafts to all the rolls by an internal gear built in the housing. The housing of the double-hole type roll achieves the above object by transmitting the driving force inputted by both of the drive shafts to each roll, respectively.

Embodiments of a continuous rolling mill for seamless pipes according to the present invention will be described in detail below with reference to the drawings.

As shown in FIGS. 6 to 10, this embodiment uses a piercer (
A seamless steel pipe stretch reducer having a large number (n) of hole-shaped roll stands for continuously reducing and rolling a reducer base pipe 22 that has been perforated with a mandrel mill (not shown) and stretched and rolled with a mandrel mill (not shown). In 26, 3
The housing of the roll-type perforated roll 26b and the housing of the two-roll perforated roll 26a are made interchangeable, and the two-roll perforated roll 26a is incorporated into the final stand 26-n and its preceding stand 26-n-1. A three-roll perforated roll 26b is installed in the stands 26-1 to 26-n-2 on the more upstream side.

Each of the stands 26-1 to 26-n is equipped with a DC motor 30 as a drive source, as shown in detail in FIG.
, a reducer 32 that reduces the output of the DC motor 30, and a pinion stand 34 that converts the output of the reducer 32 into rotation of two parallel drive shafts 34a and 34b that rotate in opposite directions. A roll drive device 29a (odd numbered stands) or 29b (even numbered stands) is provided.

Therefore, the two drive balls 34 of this pinion stand 34
a, 34b and the housing 44a of the two-roll type perforated roll 26a or the housing 44b of the three-roll type perforated roll 26b are connected via a telescoping spindle 36 and a coupling 38. As shown in FIG. 13, the perforated roll 26a or 26b is driven to rotate. Fig. 11 shows a state in which a two-roll perforated roll is installed, Fig. 12 shows a state in which a three-roll perforated roll is installed in an odd-numbered stand, and Fig. 13 shows a state in which a three-roll perforated roll is installed in an even-numbered stand. The state in which the shaped roll is incorporated is shown in each case. In this embodiment, both a two-roll hole type roll and a three-roll type hole type roll can be incorporated into the same stand holder 42.
In both cases, the rolls can be driven from the same gear spring. Specifically, the 12th
As shown in the figure and FIG.
b is incorporated, as shown in detail in FIG. 14, the driving force input from one drive shaft 34a is transmitted to all rolls by the bevel gear 40 built into the housing 44b. In this case, the other drive shaft 34b is not used. In addition, as shown in FIG. 11, when the two-roll perforated roll 26a is installed, as shown in detail in FIG. Make sure to tell the role. Therefore, for example, among a stand holder with two mirrors, any number of stands (
If the odd-numbered stand and even-numbered stand are integrated, when pipe material is reduced and rolled using any even-numbered stand, if a two-roll type roll housing is incorporated into the final two stands, the finishing stand can be The reduction rolling according to the present invention can be realized regardless of the base number of.

For example, when applying to the stretch reducer 26,
In the upstream three roll stand rows, the hole shape arrangement and roll rotation speed are selected to finish the outer diameter of the pipe material to a value almost equal to that of the product, and for the final two stands, the outer diameter is further increased. It can be used as a finishing stand for precise finishing.

In addition, when adopting a quick change method for each roll housing as a rolling down mechanism for a two-roll stand, a screw rolling down system using an electric motor, which has a simple structure, is easier to handle than a hydraulic rolling down system.

However, if there are no strict restrictions on the mill stop time for changing rolls, it is also possible to use a hydraulic pressure reduction method with excellent control responsiveness. Control is also possible. In addition, in the above embodiment,
Although the present invention is applied to a stretch reducer, which is a typical reducing rolling mill, the scope of application of the present invention is not limited thereto, and is generally applicable to other products such as sizers with a smaller outer diameter reduction ratio than the stretch reducer. It is also possible to apply the present invention to other continuous rolling mills such as a reduction rolling mill, a multi-stand pipe mill, a mandrel mill, or a roll push bench.

As explained above, according to the present invention, a two-roll slotted roll can be easily incorporated into any slotted roll stand of a continuous rolling mill, regardless of the number of stands selected depending on the material to be rolled. , rolling can be easily carried out using two-roll slotted rolls on the final stand or on the final stand and the preceding stand, providing excellent compatibility and versatility.

That is, the final stand or the final stand and the stand preceding it have a two-roll hole type. By incorporating the
It is now possible to change the amount of roll reduction, which was not possible with a roll-type hole-type roll stand, and the outer diameter of the outlet pipe material can be easily controlled. Therefore, the frequency of roll modification is significantly reduced, productivity is improved, and roll consumption is reduced. In addition, by incorporating a 1-roll, 3-roll hole-shaped stand in which curls occur into the upstream stand, excellent effects such as the ability to significantly reduce curls on the outer surface of the pipe material after rolling can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing the manufacturing process of a seamless steel pipe using a mandrel mill rolling method, and FIG. 2 is a front view showing a conventional stretch reducer having two-roll type grooved rolls.
FIG. 3 is a front view showing a conventional stretch reducer having three rolls of hole-type rolls, FIG. 4 is a sectional view taken along line W-W in FIG. 3, and FIG. V in figure 3
6 is a front view showing an embodiment of a continuous rolling mill for seamless pipes according to the present invention; FIG. 7 is a sectional view taken along the skin line of FIG. 6; FIG. 8 is a sectional view taken along the side dish line in FIG. 6, and FIG. 9 is a cross-sectional view taken along the line K-X in FIG. 6.
10 is a cross-sectional view taken along the line X--X in FIG. 6, and FIG. 11 is a cross-sectional view taken along the line X--X in FIG. 6, and FIG. The front view, FIG. 12, shows the same condition.
FIG. 13 is a front view showing a state in which three-roll type hole-type rolls are installed in an odd-numbered stand; FIG. 14 is a front view showing a state in which three-roll type hole-type rolls are installed in an even-numbered stand. FIG. 15 is a front view showing the drive mechanism of the three-roll type perforated roll used in the embodiment, and FIG. 15 is a front view showing the drive mechanism of the two-roll type perforated roll. 22. ．． ．． ．． ．．・Reducer base tube, 26...Stretch reducer, 26-1 to 26-n...Hole type roll stand, 26a...2 roll type hole type roll, 26b. ．． ．． ...3-roll hole type roll, 29
a, b...・Roll drive mechanism, 30... DC motor, 32... Speed reducer, 34... Pinion stand, 34a, b... Drive shaft, 36...
...Spindle, 38....・Coupling, 40
...Bevel gear, 42...Stand holder, 44a,
b……Housing. Younger brother' drawing Younger brother 2 drawing Younger brother 3 drawing Younger brother 4 drawing 0 drawing 7 drawing Younger brother a drawing Sled box younger brother Yugao Younger brother's drawing Leopard 〃 Younger brother ′2 drawing Younger brother ’3 drawing Younger brother 4 drawing Soge drawing

Claims (1)

[Claims] 1. In a continuous rolling mill for seamless pipes having a plurality of groove roll stands for continuous rolling of perforated main tubes, the housing of the three-roll groove roll and the housing of the two-roll groove roll are The roll drive device of the grooved roll stand is equipped with two parallel drive shafts that rotate in opposite directions, and the three-roll type grooved roll can be assembled into the same stand holder. The housing transmits the driving force input by one of the drive shafts to all the rolls by an internal gear built in the housing, and the housing of the two-roll type perforated roll receives the driving force input by both of the drive shafts. A continuous rolling mill for seamless pipes, characterized in that driving force is transmitted to each roll.