JPS5829165B2 - Pipe rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling large diameter seamless metal tubes.

Conventional rolling methods for large-diameter seamless metal pipes (for example, seamless steel pipes) include pilger mill rolling and rotary expander methods.

Here, large diameter refers to an outer diameter of 16 inches or more, as is generally used in the steel pipe industry.

The Pilger Mill method involves passing a mandrel through a hollow tube,
This is a method in which the material is forged and rolled between a mandrel and a mandrel using a double roll mill with a special caliber, while the rolls push the material back toward the input side.

In this method, the outside diameter of the tube is considerably reduced by rolling, so the outside diameter of the raw tube is required to be considerably larger than the outside diameter of the finished product.

Therefore, when modifying existing medium-diameter pipe manufacturing equipment to enable the production of large-diameter pipes, it is important to It is necessary to increase the size, and of course it is also necessary to increase the size beyond Pilger Mill.

At the current technological level, production by the Pilger mill method is limited to small-scale factories with monthly production of 10,000 tons or less due to the capacity of the Pilger mill. It is undesirable to construct a new line or make major modifications to the line because it increases costs, and even if we try to supply cheap and high-quality pipe materials through continuous casting,
In the case of steel, the current state of the art is limited by the quality of the slab, and from this cross section it can be seen that the Pilger mill rolling method
“It is not possible to obtain larger diameter pipes.

On the other hand, the rotary expander method uses two mushroom-shaped rolls that drive a medium-walled or thin-walled hollow tube.
The tube wall is helically rolled between the non-driven conical plugs placed between the two to create a thin wall with an outer diameter of up to 1.
This is a method of enlarging the image up to about 5 times.

With this method, tubes with an outer diameter of 16 to 24 mm can be rolled, for example, so if you have medium diameter tube manufacturing equipment, you only need to modify or expand the equipment after the rotary expander, and the capital investment is relatively small. It's over.

This method allows mass production compared to the Pilger mill method, but the roll diameter is larger than 1.5 m, and the roll support must be cantilevered due to the structure of the rolling mill. , the mill rigidity is small, and if you want to prevent this, you have no choice but to have a huge rolling mill.

On the other hand, this type of equipment can produce about 30,000 tons per month.

However, if we try to further expand the production scale using this rotary expansion method, the drive source and equipment structure will have to become huge due to the increase in size and speed, or there will be no solution. The drawback is that it has many unresolved problems.

Furthermore, the structure of the rotary expander has a special relationship in that the roll and drive shaft are positioned at an angle of about 600 degrees with respect to the pass center line, and because it is driven from the exit side of the rolling mill, Not only does the area occupied by the equipment become extremely large, but the temperature drop due to the long transportation distance of the rolled tube to the next process becomes significant, making it difficult to maintain the temperature in the next process.

Furthermore, in rotary expanders, the deformation of the tube is not only a simple geometric shape change, but also significant additional shear deformation inside the material, which increases energy consumption, lacks mill rigidity, and causes defects. This contributes to the deterioration of the dimensional accuracy of the pipe.

The drawbacks of this conventional method are largely due to the structure of the large rolling rolls and the rolling mill that supports them, and the fact that the energy necessary to deform the tube is supplied only by the rolling rolls that circumscribe the tube.

The present invention has investigated these drawbacks of the conventional method in detail and has provided a completely new tube rolling method, which has the following advantages over the conventional method.

■Since the pipe is expanded in this step using material for medium diameter, the process before the punching machine can be performed using almost all the equipment for medium diameter.

■The pressure capacity exceeds that of conventional methods.

Additionally, the equipment can be made compact.

■Compared to rotary expanders, the additional shear deformation inside the material is smaller, which reduces the occurrence of defects and requires less energy for deformation.

To explain the invention in detail, in FIG. 1, a tube 1 is pushed into a rolling mill by a pushing device 2 and is kept pressed during rolling.

As shown in FIGS. 1 and 2, the path of the rolling mill is composed of rolling rollers 3-1.3-2, guide rollers 4-1.4-2, and a mandrel 5 placed at the center of the path.

The rolling rollers 3-1, 3-2 and guide rollers 4-1 and 4-2 are housed in a housing 7 that can be rotated and driven along the path center line 6.

The housing 7 has @8 carved along the circumferential direction on the outer periphery, and @10 of the pinion 9 meshes with this @8.

And this pinion 9 has a speed adjustable motor (
(not shown) is connected, and the housing 7 is rotated and driven by this motor.

The tip 5' of the mandrel is made smaller than the inside diameter of the tube on the entry side and is accommodated inside the tube as the tube advances.

When the tube wall is accommodated in the mandrel 5 and the housing 7 and is pushed in until it is compressed between the rolling rollers 3-1 and 3-2 that rotate together with the housing, the rolling rollers 31.3-2 roll on the outer surface of the tube and the mandrel 5, the tube wall is rolled, the wall thickness decreases and the outer diameter increases.

At this time, the mandrel 50 rotations may be restrained, or the mandrel 50 rotation may be restricted to increase the rolling efficiency.
may be rotated in the opposite direction to the housing 7.

Guide rollers 4-1.42 keep the tube within the path and regulate the outer diameter.

The rolling roller 3-1 is driven by rotation 1 of the housing 7.
．． 3-2 and guide rollers 4-1 and 4-2 roll on the outer surface of the tube and rotate in a driven manner, but during the driven rotation, the rolling roller and guide roller move in the direction in which the frictional force moves so as to push the tube toward the exit side. Leave it tilted.

In other words, if the rotation direction of the housing 10 is clockwise when viewed from the exit side (right side in the figure) as shown in FIG. If the rotation is in the opposite direction, the rotation axes of the rolling roller and the guide roller are also inclined in the opposite direction.

If these inclinations are called a roller inclination angle θ, θ is an angle that is parallel to the path center line 6 and intersects with a plane that includes this.

This angle θ is an element involved in the rotation and advancement of the material to be rolled, but in practice, a value within the range of 4 to 16 degrees can be adopted.

By increasing the distance between the surfaces of the rolling rollers and guide rollers and the path center line 6 toward the exit side, the outer diameter can be easily increased.

Also, it would be easier to deform the tube by increasing the diameter of the acting portion of the roller in accordance with the expansion of the outer diameter of the tube.

Therefore, as shown in FIG. 1, it is preferable to arrange the roller center axis so that it is separated by ψ from the path center line, but φ does not have a direct effect on the advancement effect of the tube.

Here, the angle φ is at the position where the tube and roller contact,
The ratio of rotational angular velocities of the tube and roller is determined to be constant in the tube axis direction, and takes a value of 0° to 30°.

By tilting the roller by an angle φ in this way, twisting of the pipe can be prevented from rain.

The main function of the guide rollers 4-1, 4-2 is to prevent material from flying out of the rolling pass.

That is, rolling is performed by the rolling roller 3-L3-2 and the mandrel 5 while the raw pipe is rotated and advanced in a spiral manner in the state shown in FIG.

However, the mandrel 5 has a cantilevered structure supported at its base end and is easily bent in the vertical direction.

Therefore, if the guide roller 4-1.42 were not present, the material would break away from being held by the rolling rollers 3-1.3-2 and fly out of the rolling path.

Note that the guide rollers 4-1, 4-2 have an inner surface of the raw tube separated from the outer circumference of the mandrel, and do not participate in reducing the wall thickness of the tube.

Further, the guide roller can be replaced with a guide or guide shoe.

As shown in Fig. 3, the diameter of the mandrel 5 increases toward the exit side, and the distance between it and the rolling roller gradually narrows, and as the tube advances in a spiral, the mandrel and the rolling roller move every half turn. Decrease the wall thickness in between and enlarge the outer diameter.

By gradually narrowing the gap between the rolling roller and the mandrel in this way, even if the mandrel diameter increases toward the exit side, the rolled material can still be rolled when it advances in a spiral shape and reaches that position. A gap is created between the inner diameter of the immediately preceding tube and the outer circumferential surface of the tube, resulting in more stable rolling.

The forward force of the tube is determined by the pushing force of the pushing device 2 and the rolling roller 3-
This is caused by the friction generated between the rollers and the tube due to the rolling of the guide rollers 4-1 and 4-2, but sufficient pushing force is applied by the pushing device 2 near the rear end of the tube. Even if 2 is not applied, there are conditions in which the tube can be advanced by the frictional force alone and the rolling can be completed to the final end.

By using the method described above, the outer diameter of the pipe can be increased by 1.2 to 8 times, and even if the manufacturing equipment used before the drilling machine was for manufacturing medium-diameter pipes, it became possible to roll large-diameter pipes. .

For example, the pipe making process includes a heating furnace, a drilling machine, an elongator, a plug mill, a pipe expanding machine of the present invention, a diameter diameter machine or a heating furnace, an inclined roll drilling machine, a pipe expanding machine of the present invention, a plug rolling machine, a polishing machine, a Embodiment 2 of the present invention, which may be a diameter machine, is a housing that can be rotated as shown in Figs. With two rolling driven rollers placed inside, two guide driven rollers, and a pushing device, the outer diameter is 180 mm and the wall thickness is 10 r/L.
A good tube of 7IL was obtained.

At this time, the outer diameter of the tube was increased by 1.8 times, and the length was increased by 11 times.

In addition, by changing the adjustment of the rolling mill, it is possible to obtain a good tube with an outer diameter of 150 mm and a wall thickness of 10 m7IL from a raw tube of the same size, and in this case, the outer diameter of the tube is 1. S times, the length was 1.3@.

The outer diameter of the tube can be expanded to about 1.5 times by the conventional method of 1-coatary expansion.

For example, an outer diameter of 100 mm made of plasticine,
Outer diameter 15Qrnm, wall thickness 10M from a 25mm wall thickness raw tube
Only the rIL tube can be obtained.

If the tube is expanded further than this, the shear deformation of the material will increase, making the tube prone to flaws, reducing the smoothness of the surface, and causing work problems such as poor biting and poor bottom shearing. become.

At this time, the rotary expander has rolling rolls 10-1, 10-2 times 4iJ]11-
1.11-2 intersect with the path center line 12 at 60 degrees, and the roll has a mushroom shape as shown.

The tube 1 is rolled between the rolls and the plug 140 while advancing in a helical manner, reducing the wall thickness and increasing the outer diameter.

Plug 14 is held in place by mantle 12 and rotates as the tube rotates.

The rolling rolls 10-1 and 10-2 are rotating and driving,
As shown in FIG. 6, one of the two rotating shafts is higher and the other lower than the path center line 12, and by doing so, the tube is rotated and advanced in a spiral manner.

Therefore, within the portion 13 in contact with the tube, the roll surface speed varies greatly in both direction and magnitude depending on the location, complex forces associated with rolling act on the tube, and the deformation and flow of the material are complicated. When twisted, the inner and outer surface layers undergo large relative displacements in the circumferential and longitudinal directions.

In such rolling equipment, the roll diameter is large and the equipment structure is large and complicated, so it is not easy to adjust the conditions to the optimum condition for each finished rolling dimension of the pipe, and it is difficult to provide an adjustment section.

Therefore, the method of the present invention is superior to the rotary expander method in the following points.

■Since the additional shear deformation inside the material is small, the occurrence of defects is reduced and the energy required for deformation is also small.

■Rolling equipment can be designed compactly.

■There is less work trouble and the rolling capacity can be increased.

To explain the present invention in more detail, with respect to In the invention, (the shape of the mandrel rolling part that corresponds to the change in the inner diameter of the adit and the wall thickness reduction can be selected, [F]) the shape of the rolling roller and the guide roller can be selected from a wide range of shapes that are advantageous for the deformation of the tube; (c) By using a roller bearing in the roller support part, the friction loss of the driven roller bearing part can be reduced; (d) the pipe diameter can be easily expanded by pushing force; and (e) the pushing force can reduce static inside the material. The reason why this method is superior to the conventional method is that the water pressure component is increased and the ratio of tensile stress and shear stress is relatively reduced, thereby preventing the occurrence of flaws.

Regarding (2), as shown in Figures 5 and 6, the conventional method uses a roll (・ma) cantilever support, and the roll rotation axes are each inclined at approximately 60 degrees with respect to the pass line. It has a complicated structure with different heights relative to the center line, and the roll diameter is inevitably large.

In particular, driving the two rolling rolls arranged in this way with a large amount of power and the fact that there is a lot of waste in deforming the tube are the causes of the large size of the apparatus.

In contrast, in the method of the present invention, the rollers are not driven and roll on the outer surface of the tube, so the diameter of the rollers is small and the housing can be designed compactly.

Although the indentation device is provided on the entry side, the indentation stress generated by this device is 0.01 to 1.0 times, preferably o,i to 0.5 times, the yield stress of the rolled material, so it is different from the conventional device. It is smaller compared to a rolling roll drive device.

For example, heated to 1250°C, outer diameter 40Qmm, wall thickness 10
0 mm low carbon steel is rolled to an outer diameter of 600 am and a wall thickness of 20 mm, and the exit material speed at that time is 300 mm/sec.
In this case, if the yield stress of the material is 21<g/rum2 and the indentation stress is t kg/am2, the power required for indentation is as small as about 107 KW.

Regarding (2), whereas the conventional method uses only rolls to apply forward force to the material, the present invention uses the frictional force between the surface of the tube and the rollers and the pushing force to advance the tube.

In other words, in the conventional method, when the tube is rolled between the rolls and the plug as described above, the wall thickness of the tube decreases and the outer diameter expands, but especially when the front end is rolled, the outer diameter expands sufficiently. Instead, if a portion occurs where the inner diameter of the tube is not sufficiently large compared to the diameter of the plug, the advancement of the tube will stop and misroll will occur.

If the pipe does not move forward by a certain amount as it rotates, the amount of wall thickness reduction will be insufficient, and the outer diameter will not expand sufficiently.In this way, the rotation will stop at the same time that the material cannot move forward, and if the material moves forward, Also, the outer diameter varies greatly in the length direction.

In the method of the present invention, the tube diameter is easily expanded by the pushing force and the tube is easily advanced.

Furthermore, in the conventional method, there was a lot of waste in deformation, a lot of energy was spent on additional shear deformation, and the rolling speed was slow.

The present invention has the combined effect of various advantages as described above.
Make the rolling equipment more compact, reduce the power source, and
This made it possible to increase rolling capacity.

As shown in Fig. 1, the method of the present invention consists of a rolling pass made up of a plurality of rolling rollers whose rotating axes are inclined in a specific direction with respect to the pass center line, and a plurality of guide rollers, and the center of the pass is A mandrel whose rotation is restrained from the outlet is placed nearby, and a device for pushing the tube into the rolling mill is placed on the input side, and the pushing force of the pushing device and the rotational drive of the housing cause a gap between the roller and the tube. This is a pipe rolling method in which the pipe is rolled into a spiral shape using the frictional force generated in the pipe.The number of rolling rollers and guide rollers is 2 or 3, respectively, as shown in Figure 2 or 3. Although it is appropriate because the tube diameter is easy to expand and the tube diameter can be expanded, it is also possible to have four or more of each.

The rolling roller rolls the wall thickness of the tube between it and the mandrel, and since its axis of rotation is inclined with respect to the path center line, it is arranged so as to generate a frictional force in the forward direction as it rotates.

The guide roller is arranged so that the distance between the guide roller and the mandrel is larger than the distance between the rolling roller and the mandrel to prevent the tube from jumping out, and as it rotates, a frictional force is generated in the forward direction to move the tube forward. It functions to determine the diameter.

This guide roller can be replaced with a plate-shaped flyout prevention guide.

In this case, the frictional force loses its effect of advancing the tube, but the work is still possible.

By driving the rolling rollers as an auxiliary drive, it becomes easier to roll the rear end of a pipe where insufficient pushing force can be applied, and it is also possible to increase the rolling speed and further reduce additional shear deformation. .

When the mandrel is rotated in a direction opposite to the direction of rotation of the housing, the tube rotates at a slightly slower speed than the mandrel, and the rolling speed of the tube increases.

By rotating the mandrel and the housing simultaneously in this manner, if the rolling speed is the same, the capacity of the electric motor required to rotate the housing can be reduced, and the strength of one drive section can also be reduced.

Note that the guide roller is not auxiliary rotationally driven like the rolling roller.

Examples of the method of the present invention are as follows.

Number of rolling rollers: 2 Number of guide rollers: 2 Rolling roller inclination angle
6゜Guide roller inclination angle
6゜) V/1/Diameter (maximum part) 15
0mm hashing rotation speed 10rpm
Mandrel rotation speed 019m Shortest distance between rolling roller and mandrel 10 order Shortest distance between guide roller and mandrel 20m Door pushing stress
2 g/mff12 Tube material Dimensions of plastidine raw tube (mm
, ) Outer diameter 100 x Wall thickness 25 x Length 500 Dimensions of finished tube (mm) Outer diameter 180 x Wall thickness lO x Length 550 Plastigin is often used for simulating experiments of plastic deformation of metals that can be plastically worked. This allows the deformation of steel during hot rolling to be sufficiently simulated.

Next, examples of rolling mill rows to which the tube rolling method of the present invention is applied are as follows: (a) Heating furnace → press roll perforator → elongator → plug mill → tube expander of the present invention → diameter diameter machine (b) heating furnace → Press roll perforator → Elongator → Plug mill → Pipe expanding machine of the present invention → Polishing machine → Diameter diameter machine ←) Heating furnace, inclined roll perforator i Pipe expander of the present invention → Diameter diameter machine) Heating furnace → Slant roll perforator Machine → Elongator → Pipe expanding machine of the present invention → Diameter sizing machine ) and (b) rolling mill rows are most preferred.

Further, in the above-mentioned rolling mill row, the tube rolling method of the present invention is all utilized as a tube expanding machine, but it is also possible to perforate the material according to the present invention.

Furthermore, the tube rolling method of the present invention is not limited to hot rolling, but can also be applied to cold rolling.

The present invention is applicable not only to the rolling of large-diameter seamless steel pipes, but also to the expansion rolling of tubular objects that can be plastically worked.

The outer diameter of a rollable tube depends on the torsional strength of the mandrel, and for hot rolling steel, an outer diameter of 16 or more is at the industrial level, and for materials with lower deformation resistance, an even smaller diameter is required. Substitute products can also be industrialized.

[Brief explanation of the drawing]

Figures 1 to 3 show an example of an apparatus for carrying out the method of the present invention, with Figure 1 being a front view and Figure 2 being A-A in Figure 1.
The cross-sectional view along the line and FIG. 3 are cross-sectional views. FIG. 4 is a sectional view showing another embodiment of the above device. Figures 5 and 6 show the rotary ex-bang method, which is a conventional method. It is a diagram. 1...Pipe, 2...Pushing device, 3-1~
3-3... Rolling roller, 4-1 to 4-3...
... Guide roller, 5 ... Mandrel, 7
...Housing.

Claims (1)

[Scope of Claims] 1. The axis of rotation of the tube is inclined in a predetermined direction with respect to the path center line of the tube, and the tube is arranged so as to surround the path center line in a plane perpendicular to the path center line, and the path center line is A rolling pass is formed by two or more rolling rollers housed in a rotatable housing that allows the line to revolve around the line, and a mandrel is placed at or near the center of the rolling pass in a plane perpendicular to the rolling direction. A pipe rolling method characterized by rolling while rotating an oil mud housing. 2 The axis of rotation is inclined in a predetermined direction with respect to the path center line of the pipe, and it is arranged so as to surround the path center line in a plane perpendicular to the path center line, and it revolves around the path center line. A rolling pass is formed by two or more rolling rollers housed in a rotatable housing, and a mandrel is disposed at or near the center of the rolling pass in a plane perpendicular to the rolling direction. A tube rolling method characterized in that a tube pushing device for pushing the tube into the rolling mill is disposed on the side, the housing is rotated, and the material is rolled while being pushed into the rolling mill. 3 The axis of rotation is inclined in a predetermined direction with respect to the pass center line of the pipe, and is arranged so as to surround the pass center line in a plane perpendicular to the pass center line, and when the pass center line is rotated. A rolling pass is formed by two or more rolling rollers housed in a rotatable housing that allows the roll to revolve, and a pop-out prevention guide, and a mandrel is placed at or near the center of the rolling pass perpendicular to the rolling direction. A tube rolling method characterized in that the housing is rolled while rotating the housing. 4. The axis of rotation of the pipe is inclined in a predetermined direction with respect to the pass center line, and is arranged so as to surround the pass center line in a plane perpendicular to the pass center line, and when the pass center line is rotated, A rolling pass is constituted by two or more rolling rollers housed in a rotatable housing that revolves around the rolling pass.
The housing and While rotating the mandrel,
A tube rolling method characterized by rolling the material while pushing it into a rolling mill. 5 The axis of rotation is inclined in a predetermined direction with respect to the pass center line of the pipe, and the pipe is arranged so as to surround the pass center line in a plane perpendicular to the pass center line, and the pipe is arranged around the pass center line. A rolling path is formed by two or more rolling rollers housed in a rotatable housing that allows the rollers to revolve, and a fly-out prevention guide, and the rollers can be rotated at or near the center of the rolling path in a plane perpendicular to the rolling direction. A mandrel is disposed, and a tube pushing device for pushing the tube into the rolling mill is disposed on the entrance side of the rolling pass, so that the housing and the mandrel are rotated, and the material is rolled while being pushed into the rolling mill. Characteristic pipe rolling method.