JP2001340903A - Manufacturing method of seamless steel pipe and its manufacturing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply effectively chemical agents and the like to the internal surface of a hollow pipe stock and also prevent flaws on the internal surface of the pipe stock, when manufacturing a seamless steel pipe by a drawing rolling. SOLUTION: (1) A manufacturing method of a seamless steel pipe characterized in that at least one of conditions among injection pressure of carrier gas, a total supply amount of chemical agents and the like, and to total time of the chemical agents and the like is adjusted on the basis of rolling information, when the hollow pipe stock is rolled by a drawing rolling. (2) A manufacturing equipment for the seamless steel pipe characterized in that the equipment is provided with a rolling information recognition portion identifying information for the hollow pipe stock or the chemical agent sand the like, an injection condition determining portion settling conditions for injection pressure, a supply amount and the like, and an injecting condition adjusting portion realizing determined injecting conditions. (3) A manufacturing method and equipment supplying the chemical agents and the like at injection by means of carrier gas, and also carrying it after injection, while rotating the hollow pipe material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a seamless steel pipe for elongating and rolling a hollow shell.
Moreover, a seamless agent that can minimize the amount of an internal lubricant used for that purpose or a chemical for melting or removing the internal scale of the hollow shell (hereinafter, these are collectively referred to simply as “drugs, etc.”) is used. TECHNICAL FIELD The present invention relates to a method for manufacturing a steel pipe and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art As a method for producing a seamless steel pipe by hot working, a Mannesmann plug mill tube method, a Mannesmann pipe mill method, and the like are known.
There are a mandrel mill pipe manufacturing method and a Mannesmann push bench pipe manufacturing method. In these pipe production methods, a step of rolling a hollow shell from a solid round billet as a raw material by hot rolling to produce a seamless steel pipe is employed.

As a specific manufacturing process, 1150 ° C. to 1250
A solid round billet heated to a high temperature of ° C. is used as a rolling material, and the round billet is fed to a piercing and rolling device, and a hole is formed in the axial center thereof to obtain a thick hollow shell. Next, the obtained hollow shell is fed to one or a plurality of types of elongation rolling devices, and is subjected to thickness processing and elongation rolling. Thereafter, it is a process of manufacturing a seamless steel pipe as a product through refinement processing for polishing pipe, shape correction and sizing through a stretch reducer, a reeler, a sizer, and the like.

[0004] As a typical elongation rolling mill adopted in the above-mentioned pipe making method, there is a second drilling machine, a plug mill and a reeler in the Mannesman plug mill making method, and a mandrel mill in the Mannesmann mandrel mill making method. There is. Normally, in these elongation rolling mills, internal flaws such as seizures or scratches due to the scale of the inner surface of the raw tube easily occur between the tool inserted into the inner surface of the hollow raw tube and the inner surface of the raw tube. Therefore, in order to prevent these inner surface flaws, prior to elongation rolling, a chemical agent exhibiting a lubricating action or a function of melting or removing scale, for example, a metal salt such as sodium borate or salt, graphite or the like is subjected to elongation rolling. It may be thrown into the inner surface of the hollow shell used as the material.

Conventionally, various methods have been proposed as a method for introducing a drug or the like into the inner surface of a hollow shell. First,
Japanese Patent Application Laid-Open No. 60-64720 discloses a descaling method in which a descaling agent is supplied by a compressed gas from one end of a hollow shell, and a residual removing agent that spirally moves along the inner surface of the hollow shell from the other end. There has been proposed a method of discharging by suction.

[0006] In the proposed method, it is difficult to uniformly supply the scale removing agent to the inner surface of the base tube. Further, a large amount of chemicals and the like are discharged without being attached to the inner surface of the base tube by suction from the other end. , The amount of use increases significantly. And
Since the drug or the like cannot be completely adhered to the inner surface of the raw tube, the adhesion to the inner surface of the raw tube becomes uneven, and the inner surface flaw is easily generated. Also,
Since the scale removing agent and the like are mixed in the scale removing agent collected on the suction side, a large amount of equipment investment is required to remove these and reuse the scale.

In Japanese Patent Publication No. 7-74468, as a method of applying a pickling agent to the inner surface of a raw tube, a pickling agent of a predetermined condition is supplied into a pressure vessel and mixed with a gas such as air or nitrogen. , Pressurized, and then guided to a discharge device through an opening valve provided in the pressure vessel and a transport pipe following the same, and applying a pickling agent to the inner surface of the raw pipe while circulating, turbulent, laminar or pulsating. It has been disclosed.

In the method disclosed herein, it is difficult to uniformly mix the pickling agent and the gas in the pressure vessel, and as a result, the adhesion of the pickling agent to the inner surface of the hollow shell becomes uneven. For this reason, similarly to the above-described scale removing method, it is not sufficient to prevent the occurrence of inner surface flaws.

Furthermore, in the device proposed in Japanese Patent Publication No. 7-71689, which supplies a flowable component to the inner surface of a hollow shell, the inner surface of the shell is made uniform in order to uniformly adhere to the inner surface of the shell. A configuration is provided at the tip side of the injection device for imparting a torsion to the flow of the mixture of the flowable component and the carrier gas, and an object is to be achieved by the torsion movement.

However, with the dimensions of the raw material used in the Mannesmann pipe method, it is difficult to maintain the flow of the mixture as a torsional motion over the entire length, and the flowable components are uniformly attached to the inner surface of the raw material. Can not do.
In addition, since a large amount of gas needs to be used, components are easily released from the other end of the raw tube together with the carrier gas. Therefore, even with the proposed apparatus, there is a problem that the generation of internal flaws is not sufficiently prevented, and the production cost increases.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional method and apparatus for introducing a drug or the like into the inner surface of a hollow shell, and allows the drug or the like to be drawn into the hollow shell during elongation rolling. A method of manufacturing a seamless steel pipe that can efficiently supply and uniformly adhere to the inner surface of the pipe, thereby preventing internal flaws caused by elongation rolling, and minimizing the amount of chemicals and the like used for that purpose. And an apparatus for manufacturing the same.

[0012]

The present invention provides the following (1) to (6)
The gist of the present invention is a method for manufacturing a seamless steel pipe and a manufacturing apparatus for a seamless steel pipe described in the following (7) to (10). (1) A method for producing a seamless steel pipe in which, when elongating and rolling a hollow shell, a chemical or the like is injected and injected into the inner surface of the hollow shell with a carrier gas. A seamless steel pipe characterized by adjusting at least one condition among the injection pressure of carrier gas, the total amount of injection of a drug, etc., or the injection time of a drug, etc., based on at least one piece of information among the above types. It is a manufacturing method of. (2) A method of manufacturing a seamless steel pipe in which a drug or the like is injected and injected with a carrier gas onto the inner surface of the hollow shell when elongating and rolling the hollow shell, while the chemical and the like are injected with a carrier gas. And a method of sequentially increasing or decreasing the injection pressure of the carrier gas. (3) A method for producing a seamless steel pipe in which, when elongating and rolling a hollow shell, a chemical or the like is injected and injected into the inner surface of the hollow shell with a carrier gas, while rotating the hollow shell, the inner surface thereof is rotated. A method for producing a seamless steel pipe, wherein a chemical or the like is injected and injected with a carrier gas. (4) A method for producing a seamless steel pipe in which, when elongating and rolling a hollow shell, a chemical or the like is injected and injected by a carrier gas through an injection pipe having an injection port located at one end inner surface of the hollow shell, A method for producing a seamless steel pipe, wherein a chemical or the like is cut into an injection pipe and injected by a carrier gas. (5) A method for producing a seamless steel pipe in which, when elongating and rolling a hollow shell, a chemical or the like is injected and injected by a carrier gas through an injection pipe having an injection port located at one end inner surface of the hollow shell, A method for manufacturing a seamless steel pipe, characterized by injecting a chemical or the like by a carrier gas into an inner surface thereof while rotating a hollow shell. (6) A method for producing a seamless steel pipe wherein, when elongating and rolling a hollow shell, a chemical or the like is injected into the inner surface of the hollow shell with a carrier gas, wherein the carrier or the like is applied to the inner surface of the hollow shell. A method for producing a seamless steel pipe, characterized in that after being injected with gas, the hollow shell is conveyed while rotating around a pipe axis to a start position of the next elongation rolling. (7) An apparatus for producing a seamless steel pipe by injecting a chemical or the like with a carrier gas into the inner surface of the hollow shell when elongating and rolling the hollow shell, the dimensions of the hollow shell, the same material Or, a rolling information recognition unit for recognizing at least one type of information such as a medicine, and an injection for determining at least one condition among a carrier gas injection pressure, a total amount of injection of a drug or the like, or an injection time of the drug or the like An apparatus for manufacturing a seamless steel pipe, comprising: a condition determining unit; and an injection condition adjusting unit that realizes the determined injection condition. (8) A device that manufactures a seamless steel pipe by injecting a chemical or the like with a carrier gas into the inner surface of the hollow shell when elongating and rolling the hollow shell, and is an injection pipe that leads the chemical or the like to an injection port. A rotary vane type cut-out part that cuts directly into the inside,
And a carrier gas input section for inputting a carrier gas into the injection pipe from a position upstream of the cutout section. (9) A device for manufacturing a seamless steel pipe by injecting a chemical or the like with a carrier gas into the inner surface of the hollow shell when elongating the hollow shell, and injecting the chemical or the like with a carrier gas. The present invention provides a seamless steel pipe manufacturing apparatus characterized in that a rotary device for rotating the hollow shell around the pipe axis is provided. (10) A device for manufacturing a seamless steel pipe by injecting a chemical or the like with a carrier gas into the inner surface of the hollow shell when elongating and rolling the hollow shell, wherein the agent or the like is injected and injected into the inner surface of the hollow shell. An apparatus for manufacturing a seamless steel pipe, comprising: an apparatus for conveying a raw pipe while rotating it around a pipe axis to a starting position of elongation rolling.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, in the present invention, chemicals and the like are efficiently supplied to the inner surface of a hollow shell during elongation rolling,
An object of the present invention is to prevent internal flaws generated by rolling by minimizing the amount of chemicals and the like, by uniformly attaching. The term "when elongating and rolling" defined in the present invention means that when elongating before elongating and rolling,
And at the same time.

On the other hand, the drug or the like which is the object of the present invention is applied to hollow shells having various dimensions and materials. The amount and / or type must be selected according to If the amount or type of the drug is different, the specific gravity of the drug or the like, its form (particle diameter, shape of the particle, etc.) and the flowability (for example, the ease of clogging in the pipe, etc.) resulting from these are naturally obtained. Will change.

Therefore, in order to achieve the above object efficiently, it is necessary to set the injection conditions of the carrier gas based on the dimensions of the hollow shell, the material of the hollow shell, and the type of the chemical or the like. Here, the dimensions of the hollow shell indicate the inner diameter of the shell and the length of the shell. The outer diameter of the inner surface tool used for elongation rolling, for example, the outer diameter of a plug or the outer diameter of a mandrel bar can be used as the approximate inner diameter of the raw tube. Alternatively, instead of finely changing the conditions depending on the tube dimensions and tool dimensions, group the tube dimensions in consideration of the representative outer diameter (rolling setup) of the hollow tube, and apply conditions to each group. May be determined. In addition, air, nitrogen gas, or the like is used as the carrier gas.

The injection pressure of the carrier gas must be set to a high pressure because the longer the tube length and the smaller the tube inner diameter, the higher the gas passage resistance. But,
If the set pressure is too high, chemicals and the like contained in the gas will be wastefully discharged from the other end of the raw tube, and the usage amount will increase unnecessarily. On the other hand, if the set pressure is too low, the amount of adhesion to the inner surface of the other end is reduced, and there is a concern that an inner surface flaw may be generated.
Therefore, by setting an appropriate injection pressure according to the dimensions of the hollow shell, the medicine and the like can be uniformly and efficiently attached to the inner surface of the shell.

Furthermore, by changing the flow rate and / or the charging time of the drug or the like, the amount of the drug or the like adhered per unit area of the inner surface of the hollow shell is adjusted even under the same injection pressure of the carrier gas. Is possible. Therefore, by appropriately combining the conditions of the injection pressure of the carrier gas, the injection amount of the drug, etc. and the injection time of the drug, etc., it is possible to supply the appropriate amount of the drug, etc., without waste, and to uniformly adhere the inner surface of the pipe. Can be.

FIG. 1 is a diagram illustrating the operation of a rolling information recognition unit, an injection condition determination unit, and an injection condition adjustment unit provided in an example of the apparatus of the present invention. Among the rolling information, the dimensions of the hollow shell 1 are recognized in advance from manufacturing schedule information held by a process computer or the like, or measurement results in a manufacturing line. The material of the hollow shell 1 is also recognized from the production schedule information held by the process computer or the like, and these data are transmitted to the rolling information recognition unit.

On the other hand, information on the type of chemicals used for elongation rolling is also transmitted to the rolling information recognition unit in advance.
Further, if necessary, the type of medicine or the like may be transmitted by an operator in advance by operating the device, or may be automatically selected by a process computer or the like according to the size and material of the hollow shell 1. May be adopted.

The rolling information transmitted to the rolling information recognizing unit is transmitted to the injection condition determining unit, and the injection conditions actually used are determined by a preset value table or a formula for calculating the preset value. More specifically, the injection pressure of the carrier gas, the total input amount of the drug or the like, or the injection time of the drug or the like is determined.

The various injection conditions determined by the injection condition determination unit are transmitted to an injection condition adjustment unit for realizing the injection conditions, and a specific injection operation is performed. As shown in FIG. 1, the injection into the hollow shell 1 is performed by a carrier gas supply device 6.
The medicine or the like is cut out from the supply device 5 for the medicine or the like into the carrier gas supplied to the injection pipe 3 via the valve 4 through the injection pipe 2 provided at the tip of the injection pipe 3.

The injection conditions determined by the injection condition determination unit are as follows:
Carrier gas tank 6a in carrier gas supply device 6
And / or the cut-out speed and cut-out time in the supply device 5 for the medicine and the like, and the actual injection pressure into the hollow shell 1 based on the adjusted injection pressure, the total amount of the medicine and the like, and the time of introduction. Is performed.

Normally, when the injection pressure of the carrier gas is increased, a large amount of chemicals and the like adhere to the distal end side (discharge side) of the raw tube,
When the injection pressure is reduced, a large amount of the drug and the like tends to adhere to the base end side. However, when the medicine or the like is continuously injected at a constant injection pressure, the amount of the medicine or the like attached may vary in the longitudinal direction of the raw tube due to the resistance from the wall surface when the gas passes through the inner surface of the raw tube. Such uneven adhesion in the longitudinal direction of the raw tube can be eliminated by sequentially increasing or decreasing the carrier gas pressure during the injection operation. Since the amount of adhesion in the longitudinal direction can be changed according to the change in the injection pressure, uniform adhesion results.

Further, the fluctuation of the injection pressure during the injection operation is as follows.
It may be sequentially increased and then decreased, or vice versa. However, a fluctuating method involving a rapid pressure change within a short period of time, which is generally called a pulsating flow, should be avoided. This is because a rapid change in pressure hinders a smooth gas flow, and it is difficult to make the adhesion uniform.

In order to inject the medicine or the like and the carrier gas in a homogeneously mixed state, a rotary blade type cutting mechanism is used.
It is efficient to inject and cut out a medicine or the like at a predetermined speed into an injection pipe through which gas flows. By injecting while cutting, the concentration of the drug or the like in the carrier gas can be easily changed, and arbitrarily adjusted from the start to the end of the injection.

In the method of applying a pickling agent disclosed in Japanese Patent Publication No. 7-74468 described above, the concentration variation of the drug or the like due to gravity at the time of mixing in the pressure vessel is inevitable. When the number is increased, it becomes difficult to stabilize the injection easily due to the clogging of the medicine or the like in the pipe.

FIG. 2 is a view for explaining a configuration of a supply device for medicines and the like provided with a rotary blade type cut-out portion as an example of the device of the present invention. The white arrow in the injection pipe 3 shown in FIG. 3 indicates the flow of only the carrier gas, and the black arrow indicates the flow of the mixture of the carrier gas and the medicine. And
Rotating vane type cut-out part for directly cutting out the medicine 5c in the medicine tank 5a into the injection pipe 3 through which the carrier gas flows.
5b is provided, and a carrier gas supply device (not shown) for introducing a carrier gas into the injection pipe 3 is provided upstream of the cutout portion 5b.

The rotary blade type cut-out portion 5b is a tank for chemicals and the like.
A predetermined amount of the medicine 5c is cut out of the injection pipe 3 by being installed between the injection pipe 3 and the injection pipe 3 and rotating the blades by the attached motor M. In order to adjust the cutout amount of the medicine or the like 5c, it is desirable to install an encoder on the rotating blade in order to accurately detect the rotation speed (angle).

The rotation of the rotary blades causes the medicine 5c in the medicine tank 5a to be cut into the injection pipe 3, and at this time, the carrier gas is supplied from the upstream side of the injection pipe 3 so that the medicine and the carrier gas are kept constant. And the mixture is guided to the injection port. By using the carrier gas in a homogeneous mixed state, stable injection of a drug or the like into the hollow shell becomes possible.

By applying the rotary blade type cut-out portion, the cut-out amount per unit time becomes a constant value, and the supply of the medicine or the like to the injection pipe through which the carrier gas flows can be stabilized. Drug 5c to drug tank 5a
Is supplied through a supply pipe 5e for medicines and the like, and pressure supply to the tank 5a for medicines and the like is performed by a pressurization pipe 5d. Cutout part 5b
In order to prevent the backflow due to the carrier gas pressure in the above, it is desirable to pressurize the tank 5a for the medicine and the like and the operating portion of the cut-out portion 5b supplementarily with a gas of the same type as the carrier gas.

The total amount of the drug or the like is determined from the total number of rotations (angle) of the rotating blades and the individual volume between the rotating blades, and the cutting speed is determined from the rotational speed of the rotating blades and the individual volume between the rotating blades. It is determined. As described above, it is important to adjust the above-described rotation speed and rotation time according to the size, material, type of medicine, and the like of the hollow shell.

By rotating the hollow shell when injecting a drug or the like onto the inner surface of the shell, it is effective to reduce the variation in the amount of adhesion in the circumferential direction of the inner surface of the shell, and to uniformly apply the medicine. is there. That is, even when the injection position of the medicine or the like deviates from the center of the cross section of the raw tube, the rotation of the raw tube averages the adhesion in the circumferential direction, and can also eliminate the influence of the gravity of the medicine and the like. The rotation of the drug or the like adhering to the inner surface of the tube is promoted in the circumferential direction, so that uniform adhering and minimization of the used amount can be further promoted. The rotation of the raw tube may be performed by disposing the raw tube on the rotating roller at the injection position of the medicine or the like.

FIG. 3 is a diagram for explaining a configuration in which a raw tube is arranged on a rotating roller as an example of the apparatus of the present invention. The hollow shell 1 is rotated around the tube axis at the position where the medicine or the like is injected and injected by, for example, a plurality of rotating rollers 1a provided in the tube axis direction during the injection of the medicine or the like. At this time, all of the rotating rollers 1a may be rotationally driven, a part of them may be rotationally driven, and the others may be freely rotated (idle rollers).

As shown in FIG. 3, a medicine or the like is injected from one end of the hollow shell 1 toward the other end. In order to make effective use of the injection pressure, airtightness of the injection end is ensured. In addition, it is desirable that a face plate 2a covering the ejection side end be installed integrally with the ejection port 2.

If the interference with the injection port 2 becomes a problem when the hollow shell 1 is carried into the injection position,
Before the injection is started, the injection port 2 integrated with the face plate 2a is retracted to the side away from the hollow shell 1 (the right side in the figure), is advanced toward the shell just before the injection is started, and is retracted again after the injection is completed. It is possible to adopt a configuration in which At this time, by installing the face plate 2a integrally, the injection port 2 can be positioned at a fixed position with respect to the raw pipe, so that an effect of making the injection condition constant can also be obtained.

In the production line layout, when it is necessary to transport the pierced and rolled hollow shell by a predetermined distance to the starting position of the elongation rolling in the next step, the hollow pipe into which a chemical or the like has been introduced is transferred. Sometimes rotate around the tube axis. As a result, uniform attachment in the circumferential direction on the inner surface of the raw tube can be further achieved.

Usually, after piercing and rolling, when the raw tube is conveyed to the starting position of elongation rolling, the raw tube is often conveyed sideways. In this case, a plurality of translation claws are provided to convey the raw tube in the lateral direction, and at the same time, the raw tube is conveyed while being in contact with the skid rail, whereby the raw tube is rotated. In order to ensure the above-mentioned effect due to the rotation of the base tube during transfer, for example, perform rotation transfer of 1 second or more to allow the drug or the like to be sufficiently adapted to the inner surface of the hollow base tube or to react sufficiently with the scale of the inner surface. It is desirable to give a proper time.

FIGS. 4 (a) and 4 (b) are diagrams for explaining a configuration in which a plurality of translation claws are provided to convey a raw tube in the lateral direction as an example of the apparatus of the present invention. FIG. 4 (a) is a plan view and FIG. FIG. As shown in the figure, the translation claw 7 and the skid rail 10
Are set in the tube axis direction in parallel with the transport direction of the hollow shell 1. The spacing in the pipe axis direction of the installation of the translation claw 7 and the like is appropriately determined according to the length range of the raw pipe to be transported. In other words, it is necessary to determine an appropriate interval and the number of installed tubes so that the raw tube is not transported obliquely during horizontal transport.

As shown in FIG. 4, the translation claw 7 is mounted on a chain 8 driven by a sprocket 9 which is driven to rotate, moves forward while pressing the side surface of the hollow shell 1, and conveys the shell horizontally. The number of the translation claws 7 is determined as appropriate depending on the transport distance. For example, even if one translation claw 7 is provided for one chain 8, there is no problem in operation, but a reduction in cycle time by shortening the rotation distance of the chain and a failure due to consumption of related equipment are prevented. From a viewpoint, it is desirable to install a plurality of claws on each individual chain 7.

On the other hand, the fixedly mounted skid rail 10
The upper surface is slightly higher than the chain 8 and is in contact with the lower surface of the hollow shell 1 being conveyed to rotate the shell. In order to prevent the occurrence of flaws due to the collision between the surface of the raw tube and the transfer equipment at the start and end of the transfer, it is desirable that the drive speed of the chain be lower at the start and end of the transfer than during the transfer. Also, a guide or the like is effective to prevent the above-mentioned transport flaws in order to reduce the impact on the raw pipe at the transport start position and the transport end position.

Hereinafter, the effects of the present invention will be described based on specific examples. The specific conditions described here do not limit the content of the present invention at all.

[0042]

[Embodiment] (Embodiment 1) Outer diameter: 185.0-426.O with dimensional specifications
mm, wall thickness: 5.0 to 55.0 mm, using a Mannesmann plug mill pipe line capable of manufacturing a seamless steel pipe with a length of 5 to 15 m, after rolling by the second drilling machine, and before elongating and rolling by the plug mill in the next process Next, under various conditions, chemicals and the like were charged into the inner surface of the hollow shell, and the frequency of occurrence of inner surface flaws in the final product was investigated. The chemicals and the like used are a mixture of powdered lubricant containing graphite as a main component and salt.

The supply device for medicines and the like has the structure shown in FIG. 2 and temporarily stores and secures the medicines and the like mixed in advance in the tank, and opens the rotary blade type cut-out portion at the bottom of the tank for the medicines and the like in a predetermined time. Then, a drug or the like is cut out in a pipe leading to the injection port.

Using a nitrogen gas as a carrier gas, a predetermined amount of a drug or the like is cut out in an injection pipe through which the gas flows, and a mixed gas is injected from an injection port. Here, the injection pressure of the carrier gas is adjusted by a proportional valve and an accumulator, and the cut-out time of the medicine or the like can be adjusted by the rotation time of the rotary blade cut-out section. The injection port is provided at the tip of the injection pipe, and has a straight pipe nozzle.

The materials used for the production of seamless steel pipes are as follows:
All were carbon steels having a C content of about 0.2%. The dimensions of the hollow shell pierced and rolled by the second piercing machine are: A: inner diameter 200 mm x length 7000 mm, B: inner diameter 300 mm x length 3000 mm, C: inner diameter 300 mm
X length 7000mm and D: 400mm inner diameter x length 7000mm 4
The number of samples under each condition was 20.

The total amount of the drug or the like charged to the inner surface of the hollow shell was adjusted so as to be 100 g / m ² or 70 g / m ² per unit area with respect to the inner surface area. Table 1 shows the results of investigation of the frequency of occurrence of inner surface flaws in the final product at this time, together with the injection conditions such as chemicals.

[0047]

[Table 1] From the survey results shown in Table 1, in the present invention examples under conditions 5 to 8,
By adjusting the injection pressure of the carrier gas and the injection time of the medicine and the like based on the dimensions (A to D) of the hollow shell, the injection amount of the medicine and the like is smaller, but the inner surface flaw is more excellently suppressed. It is clear that the effect can be obtained. (Example 2) Under condition 4 (conventional example) of Example 1, the injection pressure was 1.5 kg / cm ² at the start of injection and 1.0 O at the end of injection.
When the proportional valve was operated so as to become kg / cm ^2, and the number was sequentially reduced, no internal flaw was generated for 20 rolls.

Similarly, the injection pressure is set to 1.0 kg /
cm ^2, at the time of injection end by operating a proportional valve so that 1.5 kg / cm ^2, was allowed to sequentially increased, occurrence of inner surface flaws was none. From this, it is understood that the effect of suppressing the inner surface flaw is further exhibited by sequentially increasing or decreasing the injection pressure of the carrier gas during the injection operation. (Example 3) Under the condition 1 (conventional example) of Example 1, injection was performed while rotating a hollow shell.
The occurrence of inner surface flaws was reduced to one out of 20. By rotating the hollow shell during injection, the occurrence of internal flaws is further prevented. (Example 4) After injection of a drug or the like under the condition 1 of Example 1, the occurrence of inner surface flaws when the hollow shell was rotated and conveyed was investigated. At this time, the transfer speed was about 1.5 m / sec, and the transfer time was 7 seconds. As a result, the occurrence of inner surface flaws was reduced to one for 20 rolls, and the effect of rotating the hollow shell during transport is clear.

[0049]

According to the method for manufacturing a seamless steel pipe of the present invention and the manufacturing apparatus using the same, chemicals and the like are efficiently supplied to the inner surface of the hollow shell at the time of elongation rolling, and are uniformly adhered. Thereby, the inner surface flaw of the material to be rolled can be prevented. In addition, the amount of chemicals and the like used therefor can be minimized, which is effective in reducing manufacturing costs.

[Brief description of the drawings]

FIG. 1 is a rolling information recognition unit provided in an apparatus example of the present invention;
It is a figure explaining an operation of an injection condition deciding part and an injection condition adjustment part.

FIG. 2 is a diagram illustrating a configuration of a drug or the like supply device provided with a rotary blade type cut-out portion as an example of the device of the present invention.

FIG. 3 is a diagram illustrating a configuration in which a raw tube is arranged on a rotating roller as an example of the apparatus of the present invention.

FIG. 4 is a diagram illustrating a configuration in which a plurality of translation claws are provided and a raw tube is transported in a lateral direction as an example of the apparatus of the present invention.

[Explanation of symbols]

1: hollow shell, 1a: rotating roller 2: injection port, 2a: face plate 3: injection pipe, 4: valve 5: drug supply device, 5a: drug tank 5b: cutout section, 5c: drug, etc. 5d: addition 6e: Carrier gas supply device, 6a: Carrier gas tank 7: Translation claw, 8: Chain 9: Sprocket, 10: Skid rail

Claims (10)

[Claims] When a hollow shell is stretched and rolled, a lubricant (hereinafter referred to as "agent") is melted or removed on the inner surface of the hollow shell to melt or remove scale on the inner surface of the hollow shell. A method of manufacturing a seamless steel pipe to be injected by injection, wherein the injection pressure of a carrier gas, the total injection of chemicals, etc., based on at least one of information on the dimensions of the hollow shell, and also on the type of material or chemicals, etc. A method for manufacturing a seamless steel pipe, comprising adjusting at least one condition among an amount and a charging time of a chemical or the like. 2. A method for producing a seamless steel pipe, wherein a chemical or the like is injected and injected by a carrier gas into an inner surface of the hollow shell when elongating and rolling the hollow shell. The chemical and the like are injected and injected by a carrier gas. A method for producing a seamless steel pipe, wherein the injection pressure of the carrier gas is sequentially increased or decreased. 3. A method for producing a seamless steel pipe, wherein, when elongating and rolling a hollow shell, a chemical or the like is injected into the inner surface of the hollow shell by a carrier gas, wherein the hollow shell is rotated. A method for producing a seamless steel pipe, wherein a chemical or the like is injected and injected into the inner surface thereof by a carrier gas. 4. A method for producing a seamless steel pipe, wherein, during elongation rolling of a hollow shell, a chemical or the like is injected by a carrier gas through an injection pipe having an injection port located at one end inner surface of the hollow shell. A method for manufacturing a seamless steel pipe, wherein a chemical or the like is cut into the injection pipe and injected by a carrier gas. 5. A method for producing a seamless steel pipe, wherein when drawing and rolling a hollow shell, chemicals and the like are injected by a carrier gas through an injection pipe having an injection port located at one end inner surface of the hollow shell. A method for producing a seamless steel pipe, wherein a chemical or the like is injected and injected by a carrier gas into an inner surface thereof while rotating the hollow shell. 6. A method for producing a seamless steel pipe wherein a chemical or the like is injected and injected by a carrier gas into an inner surface of the hollow shell when elongating and rolling the hollow shell. After injecting with carrier gas,
A method for producing a seamless steel pipe, wherein a hollow shell is conveyed while being rotated around a pipe axis to a start position of a next elongation rolling. 7. An apparatus for producing a seamless steel pipe by injecting a chemical or the like with a carrier gas into an inner surface of the hollow shell when elongating and rolling the hollow shell, wherein dimensions of the hollow shell are: Similarly, a rolling information recognition unit for recognizing at least one piece of information, such as a material or a chemical, and determining at least one condition among a carrier gas injection pressure, a total amount of a chemical or the like, or a chemical or the like input time. A seamless steel pipe manufacturing apparatus, comprising: an injection condition determining unit that performs the injection condition; and an injection condition adjusting unit that realizes the determined injection condition. 8. An apparatus for producing a seamless steel pipe by injecting a chemical or the like with a carrier gas into an inner surface of the hollow shell when the hollow shell is stretched and rolled, wherein the chemical or the like is passed through an injection port. A device for manufacturing a seamless steel pipe, comprising: a rotary vane-type cutout section for cutting directly into an injection pipe; and a carrier gas input section for charging a carrier gas into the injection pipe from a position upstream of the cutout section. . 9. An apparatus for producing a seamless steel pipe by injecting a chemical or the like with a carrier gas into the inner surface of the hollow shell when the hollow shell is stretched and rolled. A device for manufacturing a seamless steel pipe, comprising a rotating device for rotating the hollow shell around its pipe axis when injecting. 10. An apparatus for manufacturing a seamless steel pipe by injecting a chemical or the like with a carrier gas into an inner surface of the hollow shell when elongating and rolling the hollow shell, and injecting a chemical or the like into the inner surface. An apparatus for manufacturing a seamless steel pipe, comprising: an apparatus for transporting the hollow hollow tube while rotating it around a pipe axis to a start position of elongation rolling.