CA1213421A - Method of manufacturing metallic bent pipe - Google Patents
Method of manufacturing metallic bent pipeInfo
- Publication number
- CA1213421A CA1213421A CA000435510A CA435510A CA1213421A CA 1213421 A CA1213421 A CA 1213421A CA 000435510 A CA000435510 A CA 000435510A CA 435510 A CA435510 A CA 435510A CA 1213421 A CA1213421 A CA 1213421A
- Authority
- CA
- Canada
- Prior art keywords
- pipe
- heat
- heating device
- treat
- section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D7/00—Bending rods, profiles, or tubes
- B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
- B21D7/024—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member
- B21D7/025—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member and pulling or pushing the ends of the work
Abstract
ABSTRACT OF THE DISCLOSURE
A method capable of continuously manufacturing at both ends of a bent pipe portion a metallic bent pipe having straight pipe portions which have been subjected to the same heat treatment as that for the bent pipe portion. The method comprises the steps of: inserting the front end portion of a metallic pipe to be bent into a heating device, and advancing the pipe, with the heating device stationary, thereby to heat-treat the pipe;
retracting the heating device and advancing the pipe to heat-treat the same;
terminating the advance of the pipe while retracting the heating device thereby to heat-treat the pipe, and clamping the pipe by a bending apparatus part; terminating the retraction of the heating device, advancing the pipe and applying a bending moment to the pipe thereby to bend it; terminating the advance of the pipe and heat-treating it while retracting the heating device, and releasing the pipe from the bending apparatus part; retracting the heating device and advancing the pipe to heat-treat it; and terminating retraction of the heating device and moving the pipe to heat-treat it.
A method capable of continuously manufacturing at both ends of a bent pipe portion a metallic bent pipe having straight pipe portions which have been subjected to the same heat treatment as that for the bent pipe portion. The method comprises the steps of: inserting the front end portion of a metallic pipe to be bent into a heating device, and advancing the pipe, with the heating device stationary, thereby to heat-treat the pipe;
retracting the heating device and advancing the pipe to heat-treat the same;
terminating the advance of the pipe while retracting the heating device thereby to heat-treat the pipe, and clamping the pipe by a bending apparatus part; terminating the retraction of the heating device, advancing the pipe and applying a bending moment to the pipe thereby to bend it; terminating the advance of the pipe and heat-treating it while retracting the heating device, and releasing the pipe from the bending apparatus part; retracting the heating device and advancing the pipe to heat-treat it; and terminating retraction of the heating device and moving the pipe to heat-treat it.
Description
Lo The present invention relates to a method of continuously manufacturing a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion which have been subjected to the same heat treatment as that for the bent pipe portion.
It is desirable to employ what is called a winged bent pipe, which has straight pipe portions at both ends of a bent pipe portion which have been subjected to the same heat treatment as that for the bent pipe portion, as a metallic pipe required to have a high strength and a high toughness. Such a winged bent pipe may be employed for a bent portion of a pipeline laid in a sea area under severe natural conditions, or in a cold region or in a pipeline required to cope with a transporting pressure that has been raised in order to increase the quantity of transportation or throughout. The reason for this is that in carrying out edge preparation or butt welding, the operation is extremely easy, since the straight pipe portions rather than the bent pipe portions are subjected to such as is necessary to carry out the operation. Moreover, when a welding defect occurs in a welded joint after welding, the defective portion is generally cut off and welding it carried out again. Since the straightened pipe portions are subjected to such operation, the procedure is simplified.
I Further, in paprika used for a nuclear reactor and elsewhere, a stainless steel pipe is generally subjected to heat treatment such as solid solution treatment in order to improve its reliability. In such a case, if the heat treatment can be applied, to not only a bent pipe portion but also straight pipe portions leading thereto, continuously in one step, ... ; ..
I
any discontinuous heat treatment is eliminated, so that it is possible to further improve the reliability.
Hitherto, it has been known that heat treatment permits a steel pipe to be higher in strength and toughness, resulting in the pipe having a high quality level. In a known method of heat-treating a straight steel pipe over its entire length, a heating means such as a high-frequency induction heater is disposed on the longitudinal front end portion of the pipe, and while the pipe is being heated in an annular zone by the heating means, the heater is moved relatively toward the rear end portion of the pipe, thereby to properly cool the heated portion. On the other hand, in a known method of bending a steel pipe such as mentioned above, a portion of the pipe to be bent is annularly and locally heated by the above-mentioned heating means and cooled immediately after heating, and while the heating zone is being relatively moved in the longitudinal direction of the pipe, the pipe is formed by applying a bending moment thereto. The bent pipe portion produced by this method is subjected to heat treatment simultaneously with the bending process.
Thus, a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion, which have been subjected to the same heat I treatment as the bent pipe portion, is conventionally manufactured as follows.
After a bent pipe portion is formed by a bending process such as described above straight pipe portions are subjected to heat treatment by the
It is desirable to employ what is called a winged bent pipe, which has straight pipe portions at both ends of a bent pipe portion which have been subjected to the same heat treatment as that for the bent pipe portion, as a metallic pipe required to have a high strength and a high toughness. Such a winged bent pipe may be employed for a bent portion of a pipeline laid in a sea area under severe natural conditions, or in a cold region or in a pipeline required to cope with a transporting pressure that has been raised in order to increase the quantity of transportation or throughout. The reason for this is that in carrying out edge preparation or butt welding, the operation is extremely easy, since the straight pipe portions rather than the bent pipe portions are subjected to such as is necessary to carry out the operation. Moreover, when a welding defect occurs in a welded joint after welding, the defective portion is generally cut off and welding it carried out again. Since the straightened pipe portions are subjected to such operation, the procedure is simplified.
I Further, in paprika used for a nuclear reactor and elsewhere, a stainless steel pipe is generally subjected to heat treatment such as solid solution treatment in order to improve its reliability. In such a case, if the heat treatment can be applied, to not only a bent pipe portion but also straight pipe portions leading thereto, continuously in one step, ... ; ..
I
any discontinuous heat treatment is eliminated, so that it is possible to further improve the reliability.
Hitherto, it has been known that heat treatment permits a steel pipe to be higher in strength and toughness, resulting in the pipe having a high quality level. In a known method of heat-treating a straight steel pipe over its entire length, a heating means such as a high-frequency induction heater is disposed on the longitudinal front end portion of the pipe, and while the pipe is being heated in an annular zone by the heating means, the heater is moved relatively toward the rear end portion of the pipe, thereby to properly cool the heated portion. On the other hand, in a known method of bending a steel pipe such as mentioned above, a portion of the pipe to be bent is annularly and locally heated by the above-mentioned heating means and cooled immediately after heating, and while the heating zone is being relatively moved in the longitudinal direction of the pipe, the pipe is formed by applying a bending moment thereto. The bent pipe portion produced by this method is subjected to heat treatment simultaneously with the bending process.
Thus, a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion, which have been subjected to the same heat I treatment as the bent pipe portion, is conventionally manufactured as follows.
After a bent pipe portion is formed by a bending process such as described above straight pipe portions are subjected to heat treatment by the
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described method. Alternatively, all of the pipe portions except for a portion that is to be bent are previously heat-treated by the above-mentioned method, and then the straight pipe portion that is to be bent is bent by the above-mentioned method. These conventional methods, however, disadvantage require two steps, i.e., the bending process and the heat treatment of the straight pipe portions. Moreover, it is extremely difficult for these conventional methods to achieve uniform heat-trea~ment conditions in the joining portions between the bent pipe portion and the straight pipe portions or the conditions of the advancing heat-treated portion and the subsequent heat-treated portion.
Accordingly, in order to manufacture a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion and which have been subjected to the same heat treatment as the bent pipe portion it is desirable to apply heat treatment to the straight pipe portions while subjecting the pipe to bending processing.
However, although the straight pipe portions can be heat-treated simply by fixing either the pipe or the heating means and moving the other and then cooling the heated portion, the bending processing generates an extremely large bending moment in the pipe, causing a large load to be applied to the clamp support for the pipe. Therefore, since the clamp support for the pipe is constructed as a rigid body capable of bearing this load and has a certain size with respect to the longitudinal direction of the pipe, it is necessary to remove andireposition the pipe clamp in order to shift the heat treatment zone from the straight pipe portions to the bending portion or from the bending portion to the straight pipe portions. Accordingly it is essential to ensure that the variations in load arising from the
described method. Alternatively, all of the pipe portions except for a portion that is to be bent are previously heat-treated by the above-mentioned method, and then the straight pipe portion that is to be bent is bent by the above-mentioned method. These conventional methods, however, disadvantage require two steps, i.e., the bending process and the heat treatment of the straight pipe portions. Moreover, it is extremely difficult for these conventional methods to achieve uniform heat-trea~ment conditions in the joining portions between the bent pipe portion and the straight pipe portions or the conditions of the advancing heat-treated portion and the subsequent heat-treated portion.
Accordingly, in order to manufacture a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion and which have been subjected to the same heat treatment as the bent pipe portion it is desirable to apply heat treatment to the straight pipe portions while subjecting the pipe to bending processing.
However, although the straight pipe portions can be heat-treated simply by fixing either the pipe or the heating means and moving the other and then cooling the heated portion, the bending processing generates an extremely large bending moment in the pipe, causing a large load to be applied to the clamp support for the pipe. Therefore, since the clamp support for the pipe is constructed as a rigid body capable of bearing this load and has a certain size with respect to the longitudinal direction of the pipe, it is necessary to remove andireposition the pipe clamp in order to shift the heat treatment zone from the straight pipe portions to the bending portion or from the bending portion to the straight pipe portions. Accordingly it is essential to ensure that the variations in load arising from the
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removal and remounting of the pipe clamp will not adversely affect the bending processing or the heat treatment. Therefore, there are still many problems to be solved in order to continuously carry out the manufacture of a metallic bent pipe as mentioned above.
However, a method capable of continuously manufacturing a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion, which have been subjected to the same heat treatment as that for the bent pipe portion, would be exceedingly useful from the industrial viewpoint.
Summary of the Invention Accordingly, a primary object of the invention is to provide a method capable of continuously manufacturing a metallic bent pipe having at both ends of a bent pipe portion straight pipe portions which have been subjected to the same heat treatment as the bent pipe portion.
The invention provides a method of manufacturing a metallic bent pipe having straight pipe portions at both ends of a bent pipe center portion and having the entire pipe subjected to heat treatment by employing an apparatus which effects bending processing such that a metallic pipe to be bent is locally heated by an annular heating device provided with a cooling device and cooled immediately after the heating, and a bending moment is applied to said center portion of the pipe while said heating device is being relatively moved in the longitudinal direction of said pipe thereby to simultaneously bend and heat-treat said pipe, comprising the steps of:
inserting the front end portion of said pipe into said
removal and remounting of the pipe clamp will not adversely affect the bending processing or the heat treatment. Therefore, there are still many problems to be solved in order to continuously carry out the manufacture of a metallic bent pipe as mentioned above.
However, a method capable of continuously manufacturing a metallic bent pipe having straight pipe portions at both ends of a bent pipe portion, which have been subjected to the same heat treatment as that for the bent pipe portion, would be exceedingly useful from the industrial viewpoint.
Summary of the Invention Accordingly, a primary object of the invention is to provide a method capable of continuously manufacturing a metallic bent pipe having at both ends of a bent pipe portion straight pipe portions which have been subjected to the same heat treatment as the bent pipe portion.
The invention provides a method of manufacturing a metallic bent pipe having straight pipe portions at both ends of a bent pipe center portion and having the entire pipe subjected to heat treatment by employing an apparatus which effects bending processing such that a metallic pipe to be bent is locally heated by an annular heating device provided with a cooling device and cooled immediately after the heating, and a bending moment is applied to said center portion of the pipe while said heating device is being relatively moved in the longitudinal direction of said pipe thereby to simultaneously bend and heat-treat said pipe, comprising the steps of:
inserting the front end portion of said pipe into said
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. . .
I
heating device mounted for travel a predetermined distance forward and rearward in the longitudinal direction of said pipe, and advancing said pipe with the travel of said heating device suspended, thereby to heat-treat a first section of said front end portion of said pipe;
retracting said heating device and advancing said pipe to heat-treat a second section of said front end portion of said pipe;
suspending the advance of said pipe while retracting said heating device thereby to heat-treat a third section of said front portion of said pipe while clamping the leading end of said center portion of said pipe by a bending device;
suspending the retraction owe said heating device and advancing said pipe while applying a bending moment to said center portion thereby to bend the same;
suspending the advance of said pipe while retracting said heating device to thereby heat-treat a first section of the rear portion of said pipe, and releasing said pipe from said bend-in device;
retracting said heating device and advancing said pipe to heat-treat a second section of said rear portion of said pipe;
and suspending the retraction of said heating device and moving said pipe to heat-treat a third section of said rear portion of said pipe, wherein all of the steps are carried out continuously while maintaining substantially constant the ratio between (a) the relative speed of said pipe and heating device and (b) the quantity of heat supplied per unit time in each of the steps.
The invention also provides a method of manufacturing a metallic bent pipe having straight pipe portions on both ends of a bent center portion comprising the steps of:
(a) providing a heat treating device and a bending device;
(b) inserting one end of the pipe into the heating device;
(c) moving the pipe relative to the heating device to 10 heat-treat a first section thereof;
(d) moving the heat treating device relative to the pipe to heat treat a second section thereof while attaching the bending device to the pipe;
(e) moving the pipe relative to the heat treating device to simultaneously heat-treat a third section thereof and bend the third section;
(f) moving the heat treating device relative to the pipe to heat-treat a fourth section thereof while detaching the bending device from the pipe; and (g) moving the pipe relative to the heat treating device to heat-treat a fifth section of the pipe, whereby the entire pipe is heat treated as it is manufactured.
Features of the invention will become apparent from the claims and the following description of a preferred embodiment, when read in conjunction with the accompanying drawings, wherein:-Figure 1 is a schematic diagram showing the state where a metallic bent pipe is bent by a hot pipe-bending apparatus, as an aid for the description of the principle of the method of menu-- pa -. .
lecturing a metallic bent pipe in accordance with the invention;
Figures 2~1) through I show the successive stages of heat treatment and bending processing respectively, in the open-cling sequence, in _ 5b _ I
accordance with an embodiment of the invention employing the apparatus shown in Figure l; and Figure 3 illustrates the condition where the traveling speed of a pipe and that of a heating means are linearly varied with respect to time while the relative speed there between is maintained constant at all times.
An embodiment of the invention will be described herein under.
Referring now to Figure 1, reference numeral 1 denotes a pipe to be bent while 2 designates a bent pipe portion formed by bending the pipe 1.
A heating device H comprises a high-frequency induction heater or the like integrally provided with a cooling device. 3 represents the center of the heating zone, while denotes a bending arm which clamps the front end of the pipe 1 and is rotatable about a bending central point 0. 5 and 6 designate guide rollers for supporting and guiding thy pipe 1.
Throughout this specification, movement of the pipe 1 to the right as seen in the drawings is referred to as "advancing" the pipe, and movement of the heating device to the left as seen in the drawings is referred to as "retracting" the heating device.
Figure 2 shows the states of heat treatment and bending processing, in the operating sequence, while Figure 3 illustrates the state where the traveling speed w of the pipe 1 and the traveling speed vet of the heating device H are linearly varied with respect to time while the relative speed v there between is maintained constant at all times.
In carrying out the invention, in order to apply heat treatment to the straight pipe portion at the front end portion of the pipe 1, the heating device H is previously positioned near the front end of the pipe 1, at a predetermined distance from the intersection between the pipe 1 and a .
~2~3~
perpendicular for the pipe passing through the bending central point O and is retained in this position. The operation is started under this state.
The steps will be described herein under in order:
I The pipe 1 is advanced with the travel of the heating device H
suspended, to effect heat treatment (see Figure I and section a of Figure 3).
In the above-mentioned standby state, the front end portion of the pipe 1 is inserted into the heating device H as shown in Figure I. The heating device H is actuated, and the pipe 1 is advanced at the relative speed v as shown in section a of Figure 3 thereby to heat-treat the pipe 1.
I The pupils advanced while retracting the heating device H, thereby to heat-treat the pipe 1 (see Figure I and section b of Figure 3).
After the pipe 1 has advanced by a proper distance in the previous step I the traveling speed of the pipe 1 is reduced as shown in section b of Figure 3 and at the same time the heating device H is retracted, so that the relative traveling speed of the heater H to the pipe 1 will be v at all times, thereby to heat-treat the pipe 1.
I The travel of the pipe 1 is suspended while retracting the heating device H thereby to heat-treat the pipe 1, the pipe is clamped by the bending processing part, i.e., the bending arm 4 see Figure I and section c of Figure I
When the retracting speed of the heating device H reaches the relative speed v as shown in section c ox Figure 3, the travel of the pipe 1 is suspended, and only the heating device H is moved at the relative speed v to continue the heat treatment. On the other hand, the front portion of the pipe 1 is clamped by the bending arm 4 as indicated by a symbol x in Figure 2~3).
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(4) The travel of the heating device H is suspended, the pipe 1 is advanced and a bending moment is applied thereto to bend the pipe 1 (see Figure 2~4) and sections Go and d of Figure 3).
When the heating device H being retracted in the previous step further travels at the relative speed v thereby to hea1.-treat a desired straight pipe portion 7 and reaches a position near the intersection between the pipe 1 and the perpendicular from the pipe passing through the bending central point 0, the travel of the heating device H is suspended as shown in section Go of Figure 3 and at the same time, the pipe 1 is advanced again at the relative speed v by thrusting force P, in order to apply a bending moment to the pipe 1 to bend the same as shown in Figure 2~4) and section d of Figure 3 thereby to form a desired heat-treated bent pipe portion 2.
. . .
I
heating device mounted for travel a predetermined distance forward and rearward in the longitudinal direction of said pipe, and advancing said pipe with the travel of said heating device suspended, thereby to heat-treat a first section of said front end portion of said pipe;
retracting said heating device and advancing said pipe to heat-treat a second section of said front end portion of said pipe;
suspending the advance of said pipe while retracting said heating device thereby to heat-treat a third section of said front portion of said pipe while clamping the leading end of said center portion of said pipe by a bending device;
suspending the retraction owe said heating device and advancing said pipe while applying a bending moment to said center portion thereby to bend the same;
suspending the advance of said pipe while retracting said heating device to thereby heat-treat a first section of the rear portion of said pipe, and releasing said pipe from said bend-in device;
retracting said heating device and advancing said pipe to heat-treat a second section of said rear portion of said pipe;
and suspending the retraction of said heating device and moving said pipe to heat-treat a third section of said rear portion of said pipe, wherein all of the steps are carried out continuously while maintaining substantially constant the ratio between (a) the relative speed of said pipe and heating device and (b) the quantity of heat supplied per unit time in each of the steps.
The invention also provides a method of manufacturing a metallic bent pipe having straight pipe portions on both ends of a bent center portion comprising the steps of:
(a) providing a heat treating device and a bending device;
(b) inserting one end of the pipe into the heating device;
(c) moving the pipe relative to the heating device to 10 heat-treat a first section thereof;
(d) moving the heat treating device relative to the pipe to heat treat a second section thereof while attaching the bending device to the pipe;
(e) moving the pipe relative to the heat treating device to simultaneously heat-treat a third section thereof and bend the third section;
(f) moving the heat treating device relative to the pipe to heat-treat a fourth section thereof while detaching the bending device from the pipe; and (g) moving the pipe relative to the heat treating device to heat-treat a fifth section of the pipe, whereby the entire pipe is heat treated as it is manufactured.
Features of the invention will become apparent from the claims and the following description of a preferred embodiment, when read in conjunction with the accompanying drawings, wherein:-Figure 1 is a schematic diagram showing the state where a metallic bent pipe is bent by a hot pipe-bending apparatus, as an aid for the description of the principle of the method of menu-- pa -. .
lecturing a metallic bent pipe in accordance with the invention;
Figures 2~1) through I show the successive stages of heat treatment and bending processing respectively, in the open-cling sequence, in _ 5b _ I
accordance with an embodiment of the invention employing the apparatus shown in Figure l; and Figure 3 illustrates the condition where the traveling speed of a pipe and that of a heating means are linearly varied with respect to time while the relative speed there between is maintained constant at all times.
An embodiment of the invention will be described herein under.
Referring now to Figure 1, reference numeral 1 denotes a pipe to be bent while 2 designates a bent pipe portion formed by bending the pipe 1.
A heating device H comprises a high-frequency induction heater or the like integrally provided with a cooling device. 3 represents the center of the heating zone, while denotes a bending arm which clamps the front end of the pipe 1 and is rotatable about a bending central point 0. 5 and 6 designate guide rollers for supporting and guiding thy pipe 1.
Throughout this specification, movement of the pipe 1 to the right as seen in the drawings is referred to as "advancing" the pipe, and movement of the heating device to the left as seen in the drawings is referred to as "retracting" the heating device.
Figure 2 shows the states of heat treatment and bending processing, in the operating sequence, while Figure 3 illustrates the state where the traveling speed w of the pipe 1 and the traveling speed vet of the heating device H are linearly varied with respect to time while the relative speed v there between is maintained constant at all times.
In carrying out the invention, in order to apply heat treatment to the straight pipe portion at the front end portion of the pipe 1, the heating device H is previously positioned near the front end of the pipe 1, at a predetermined distance from the intersection between the pipe 1 and a .
~2~3~
perpendicular for the pipe passing through the bending central point O and is retained in this position. The operation is started under this state.
The steps will be described herein under in order:
I The pipe 1 is advanced with the travel of the heating device H
suspended, to effect heat treatment (see Figure I and section a of Figure 3).
In the above-mentioned standby state, the front end portion of the pipe 1 is inserted into the heating device H as shown in Figure I. The heating device H is actuated, and the pipe 1 is advanced at the relative speed v as shown in section a of Figure 3 thereby to heat-treat the pipe 1.
I The pupils advanced while retracting the heating device H, thereby to heat-treat the pipe 1 (see Figure I and section b of Figure 3).
After the pipe 1 has advanced by a proper distance in the previous step I the traveling speed of the pipe 1 is reduced as shown in section b of Figure 3 and at the same time the heating device H is retracted, so that the relative traveling speed of the heater H to the pipe 1 will be v at all times, thereby to heat-treat the pipe 1.
I The travel of the pipe 1 is suspended while retracting the heating device H thereby to heat-treat the pipe 1, the pipe is clamped by the bending processing part, i.e., the bending arm 4 see Figure I and section c of Figure I
When the retracting speed of the heating device H reaches the relative speed v as shown in section c ox Figure 3, the travel of the pipe 1 is suspended, and only the heating device H is moved at the relative speed v to continue the heat treatment. On the other hand, the front portion of the pipe 1 is clamped by the bending arm 4 as indicated by a symbol x in Figure 2~3).
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(4) The travel of the heating device H is suspended, the pipe 1 is advanced and a bending moment is applied thereto to bend the pipe 1 (see Figure 2~4) and sections Go and d of Figure 3).
When the heating device H being retracted in the previous step further travels at the relative speed v thereby to hea1.-treat a desired straight pipe portion 7 and reaches a position near the intersection between the pipe 1 and the perpendicular from the pipe passing through the bending central point 0, the travel of the heating device H is suspended as shown in section Go of Figure 3 and at the same time, the pipe 1 is advanced again at the relative speed v by thrusting force P, in order to apply a bending moment to the pipe 1 to bend the same as shown in Figure 2~4) and section d of Figure 3 thereby to form a desired heat-treated bent pipe portion 2.
(5) rye travel of the pipe 1 and it is heat-treated while retracting the heating device H and releasing the pipe 1 from the clamp of the bending arm 4 (see Figure 2~5) and sections Go and e of Figure 3).
After the bent pipe portion 2 is formed by the previous step, advance of the pipe 1 is suspended as shown in the section Go of Figure 3 and at the same time, the heating device H is retracted at the relative speed v to continue the heat treatment. On thy other hand, the front end portion of the pipe 1 clamped by the bending arm 4 in step I is released as shown in Figure I.
After the bent pipe portion 2 is formed by the previous step, advance of the pipe 1 is suspended as shown in the section Go of Figure 3 and at the same time, the heating device H is retracted at the relative speed v to continue the heat treatment. On thy other hand, the front end portion of the pipe 1 clamped by the bending arm 4 in step I is released as shown in Figure I.
(6) The heating device H is retracted and the pipe 1 advanced to heat-treat the same (see Figure I and section f of Figure 3).
When a predetermined time has passed after the retraction of the heating device H at the relative speed in the previous step, the traveling speed of the heating device H is reduced as shown in the section f of Figure 3 and at the same time, the pipe 1 is heat-treated while being advanced so ~L213~Z~
that the relative speed between the pipe and the heating device H
will be v at all times, as shown in Figure I.
When a predetermined time has passed after the retraction of the heating device H at the relative speed in the previous step, the traveling speed of the heating device H is reduced as shown in the section f of Figure 3 and at the same time, the pipe 1 is heat-treated while being advanced so ~L213~Z~
that the relative speed between the pipe and the heating device H
will be v at all times, as shown in Figure I.
(7) The travel of the heating device H is suspended and the pipe 1 is advanced to heat-treat the same (see Figure I and section g of Figure 3).
When the retraction of the heating device H in the pro-virus step is suspended, the pipe 1 is advanced at the relative speed v as shown in Figure I and section g of Figure 3. When a desired heat-treated straight pipe portion 8 is obtained, the travel of the pipe 1 is suspended and also the operation of the -heating device H is suspended, as shown in Figure I.
husk it is possible to manufacture a metallic bent pipe having the straight pipe portions 7, 8 at each end owe the bent pipe portion 2 which have been subjected to the same heat treatment as the bent pipe portion 2.
It is to be noted that the duration of each of the sections Go, I of Figure 3 is only required to be set so as not to affect the heat treatment in the ordinary bending process, since this duration has an effect on the shifting state of the bonding I radius at each of the boundaries between the straight pipe portions 7, 8 and the bent pipe portion 3. Also in such a case, it is, as a matter of course, necessary to maintain constant the relative speed between the metallic pipe and the heating device.
Moreover, since the straight pipe portions require a smaller force in processing than the bent pipe portion, their pro-cussing speed can be increased. In this case, however, the ratio between the relative speed between the pipe and the heating device ..
~L2~3~
and the quantity of heat supplied per unit time is made constant.
Thus, where the pipe has a large thermal capacity, - pa -` . , .
: , , I 'f such as a pipe having a large wall thickness, and hence has large effects of heat conduction, heat dissipation and heating depth, there are also cases where it is difficult to maintain the heating temperature. Therefore, the change in heating temperature ox an essential part is detected, and control is effected so that the change in heating temperature will be within a range that does not hinder processing.
Although the operation in each of the above-described steps is seemingly complicated, the steps can be simply embodied by effecting a proper control such as program control.
As will be fully understood from the foregoing description, the invention permits manufacture of what is called a winged metallic bent pipe having the whole thereof subjected to a uniform heat treatment continuously, easily as well as at low cost and with high accuracy> which conventionally is difficult. Accordingly, the invention is exceedingly useful from the industrial viewpoint.
Although the invention has been described in specific terms, it is to be noted here that the described embodiment is no exclusive and various changes and modifications may be imparted thereto without departing prom the scope of the invention which is solely limited by the appended claims.
d
When the retraction of the heating device H in the pro-virus step is suspended, the pipe 1 is advanced at the relative speed v as shown in Figure I and section g of Figure 3. When a desired heat-treated straight pipe portion 8 is obtained, the travel of the pipe 1 is suspended and also the operation of the -heating device H is suspended, as shown in Figure I.
husk it is possible to manufacture a metallic bent pipe having the straight pipe portions 7, 8 at each end owe the bent pipe portion 2 which have been subjected to the same heat treatment as the bent pipe portion 2.
It is to be noted that the duration of each of the sections Go, I of Figure 3 is only required to be set so as not to affect the heat treatment in the ordinary bending process, since this duration has an effect on the shifting state of the bonding I radius at each of the boundaries between the straight pipe portions 7, 8 and the bent pipe portion 3. Also in such a case, it is, as a matter of course, necessary to maintain constant the relative speed between the metallic pipe and the heating device.
Moreover, since the straight pipe portions require a smaller force in processing than the bent pipe portion, their pro-cussing speed can be increased. In this case, however, the ratio between the relative speed between the pipe and the heating device ..
~L2~3~
and the quantity of heat supplied per unit time is made constant.
Thus, where the pipe has a large thermal capacity, - pa -` . , .
: , , I 'f such as a pipe having a large wall thickness, and hence has large effects of heat conduction, heat dissipation and heating depth, there are also cases where it is difficult to maintain the heating temperature. Therefore, the change in heating temperature ox an essential part is detected, and control is effected so that the change in heating temperature will be within a range that does not hinder processing.
Although the operation in each of the above-described steps is seemingly complicated, the steps can be simply embodied by effecting a proper control such as program control.
As will be fully understood from the foregoing description, the invention permits manufacture of what is called a winged metallic bent pipe having the whole thereof subjected to a uniform heat treatment continuously, easily as well as at low cost and with high accuracy> which conventionally is difficult. Accordingly, the invention is exceedingly useful from the industrial viewpoint.
Although the invention has been described in specific terms, it is to be noted here that the described embodiment is no exclusive and various changes and modifications may be imparted thereto without departing prom the scope of the invention which is solely limited by the appended claims.
d
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacturing a metallic bent pipe having straight pipe portions at both ends of a bent pipe center portion and having the entire pipe subjected to heat treatment by employing an apparatus which effects bending processing such that a metallic pipe to be bent is locally heated by an annular heating device pro-vided with a cooling device and cooled immediately after the heat-ing, and a bending moment is applied to said center portion of the pipe while said heating device is being relatively moved in the longitudinal direction of said pipe thereby to simultaneously bend and heat-treat said pipe, comprising the steps of:
inserting the front end portion of said pipe into said heating device mounted for travel a predetermined distance forward and rearward in the longitudinal direction of said pipe, and advanc-ing said pipe with the travel of said heating device suspended, thereby to heat-treat a first section of said front end portion of said pipe;
retracting said heating device and advancing said pipe to heat-treat a second section of said front end portion of said pipe;
suspending the advance of said pipe while retracting said heating device thereby to heat-treat a third section of said front portion of said pipe while clamping the leading end of said center portion of said pipe by a bending device;
suspending the retraction of said heating device and advancing said pipe while applying a bending moment to said center portion thereby to bend the same;
suspending the advance of said pipe while retracting said heating device to thereby heat-treat a first section of the rear portion of said pipe, and releasing said pipe from said bend-ing device;
retracting said heating device and advancing said pipe to heat-treat a second section of said rear portion of said pipe;
and suspending the retraction of said heating device and moving said pipe to heat-treat a third section of said rear portion of said pipe, wherein all of the steps are carried out continuously while maintaining substantially constant the ratio between (a) the relative speed of said pipe and heating device and (b) the quantity of heat supplied per unit time in each of the steps.
inserting the front end portion of said pipe into said heating device mounted for travel a predetermined distance forward and rearward in the longitudinal direction of said pipe, and advanc-ing said pipe with the travel of said heating device suspended, thereby to heat-treat a first section of said front end portion of said pipe;
retracting said heating device and advancing said pipe to heat-treat a second section of said front end portion of said pipe;
suspending the advance of said pipe while retracting said heating device thereby to heat-treat a third section of said front portion of said pipe while clamping the leading end of said center portion of said pipe by a bending device;
suspending the retraction of said heating device and advancing said pipe while applying a bending moment to said center portion thereby to bend the same;
suspending the advance of said pipe while retracting said heating device to thereby heat-treat a first section of the rear portion of said pipe, and releasing said pipe from said bend-ing device;
retracting said heating device and advancing said pipe to heat-treat a second section of said rear portion of said pipe;
and suspending the retraction of said heating device and moving said pipe to heat-treat a third section of said rear portion of said pipe, wherein all of the steps are carried out continuously while maintaining substantially constant the ratio between (a) the relative speed of said pipe and heating device and (b) the quantity of heat supplied per unit time in each of the steps.
2. A method of manufacturing a metallic bent pipe according to claim 1, wherein the relative speed between said pipe and heat-ing device is maintained substantially constant, and wherein the quantity of heat supplied per unit time is maintained substantially constant.
3. A method of manufacturing a metallic bent pipe according to claim 1 wherein during the traveling of said heating device and pipe, the change in heating temperature is detected, and said change is controlled to be within a predetermined range compatible with both heat treatment and bending.
4. A method of manufacturing a metallic bent pipe having straight pipe portions on both ends of a bent center portion com-prising the steps of:
(a) providing a heat treating device and a bending device;
(b) inserting one end of the pipe into the heating device;
(c) moving the pipe relative to the heating device to heat-treat a first section thereof;
(d) moving the heat treating device relative to the pipe to heat-treat a second section thereof while attaching the bending device to the pipe;
(e) moving the pipe relative to the heat treating device to simultaneously heat-treat a third section thereof and bend the third section;
(f) moving the heat treating device relative to the pipe to heat-treat a fourth section thereof while detaching the bending device from the pipe; and (g) moving the pipe relative to the heat treating device to heat-treat a fifth section of the pipe whereby the entire pipe is heat treated as it is manufactured.
(a) providing a heat treating device and a bending device;
(b) inserting one end of the pipe into the heating device;
(c) moving the pipe relative to the heating device to heat-treat a first section thereof;
(d) moving the heat treating device relative to the pipe to heat-treat a second section thereof while attaching the bending device to the pipe;
(e) moving the pipe relative to the heat treating device to simultaneously heat-treat a third section thereof and bend the third section;
(f) moving the heat treating device relative to the pipe to heat-treat a fourth section thereof while detaching the bending device from the pipe; and (g) moving the pipe relative to the heat treating device to heat-treat a fifth section of the pipe whereby the entire pipe is heat treated as it is manufactured.
5. The method of claim 4 including the step of maintaining a substantially constant ratio between (a) the relative speed between the pipe and the heat treating device and (b) the amount of heat per unit time.
6. The method of claim 5 wherein the relative speed between the pipe and the heat treating device is substantially constant.
7. The method of claim 6 including the further step of maintaining the amount of heat per unit time within a preselected range of values.
8. The method of claim 4 including the further step of maintaining the amount of heat per unit time within a preselected range of values.
9. The method of claim 4 including the further steps of smoothing the transition between steps (c) and (d) and between steps (f) and (g) by moving both the pipe and the heat treating device without substantially changing the relative speed.
10. The method of claim 9 including the step of maintaining a substantially constant ratio between (a) the relative speed between the pipe and the heat treating device and (b) the amount of heat per unit time.
11. The method of claim 10 wherein the relative speed between the pipe and the heat treating device is substantially constant.
12. The method of claim 11 including the further step of maintaining the amount of heat per unit time within a preselected range of values.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57/152655 | 1982-09-03 | ||
| JP57152655A JPS6044054B2 (en) | 1982-09-03 | 1982-09-03 | Manufacturing method of metal bent pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1213421A true CA1213421A (en) | 1986-11-04 |
Family
ID=15545175
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000435510A Expired CA1213421A (en) | 1982-09-03 | 1983-08-29 | Method of manufacturing metallic bent pipe |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4479372A (en) |
| EP (1) | EP0102630B1 (en) |
| JP (1) | JPS6044054B2 (en) |
| AU (1) | AU553990B2 (en) |
| CA (1) | CA1213421A (en) |
| DE (1) | DE3376531D1 (en) |
| SU (1) | SU1360576A3 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62192213A (en) * | 1986-02-17 | 1987-08-22 | Hokuriku Kenko Kk | Production of curved shape steel |
| JPH0363151U (en) * | 1989-10-25 | 1991-06-20 | ||
| US6612143B1 (en) * | 2001-04-13 | 2003-09-02 | Orametrix, Inc. | Robot and method for bending orthodontic archwires and other medical devices |
| JP5162102B2 (en) * | 2006-05-10 | 2013-03-13 | 新日鐵住金株式会社 | Bending method of deformed pipe, bending apparatus thereof, and bending product using them |
| EP3150296A4 (en) * | 2014-05-27 | 2018-02-07 | Nippon Steel & Sumitomo Metal Corporation | Manufacturing method for bent member and hot-bending processing apparatus for steel material |
| KR102220417B1 (en) | 2016-10-05 | 2021-02-25 | 닛폰세이테츠 가부시키가이샤 | Press-molded product manufacturing method and manufacturing device |
| CN115815367B (en) * | 2023-02-07 | 2023-05-05 | 江苏新恒基特种装备股份有限公司 | Method and system for predicting wall thickness quality of bent pipe based on forming parameters |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2286893A (en) * | 1937-08-23 | 1942-06-16 | Pont A Mousson Fond | Apparatus and method for bending pipes, bars, plates, and like pieces |
| JPS518159A (en) * | 1974-07-11 | 1976-01-22 | Nippon Steel Corp | Kyokukanno seizoho |
| DE2559694C3 (en) * | 1974-07-23 | 1985-08-01 | Daiichi Koshuha Kogyo K.K., Tokyo | Device for hot bending of metal pipes |
| US3958438A (en) * | 1974-10-04 | 1976-05-25 | Boris Stepanovich Somov | Apparatus for bending pipes with heating of the bending zone |
| US4006621A (en) * | 1975-05-27 | 1977-02-08 | Evgeny Nikolaevich Moshnin | Pipe bending machine |
| DE2546695B2 (en) * | 1975-10-17 | 1979-10-31 | Daiichi Koshuha Kogyo K.K., Tokio | Device for the continuous bending of elongated workpieces |
| NL165667C (en) * | 1976-09-03 | 1981-05-15 | Cojafex | METHOD AND APPARATUS FOR CONTINUOUSLY BENDING OF LONG-LIKE OBJECTS SUCH AS TUBES. |
| SE7805811L (en) * | 1977-05-31 | 1978-12-01 | Prvni Brnenska Strojirna | DEVICE FOR BOOKING OF TUBES |
| NL7806051A (en) * | 1977-06-22 | 1978-12-28 | Daiichi Koshuha Kogyo Kk | METHOD AND DEVICE FOR BENDING LONG PIECES OF METAL. |
| JPS5645220A (en) * | 1979-09-21 | 1981-04-24 | Dai Ichi High Frequency Co Ltd | Bending method for metallic pipe |
-
1982
- 1982-09-03 JP JP57152655A patent/JPS6044054B2/en not_active Expired
-
1983
- 1983-08-12 US US06/522,586 patent/US4479372A/en not_active Expired - Fee Related
- 1983-08-24 AU AU18381/83A patent/AU553990B2/en not_active Ceased
- 1983-08-29 CA CA000435510A patent/CA1213421A/en not_active Expired
- 1983-09-02 SU SU833640893A patent/SU1360576A3/en active
- 1983-09-02 EP EP83108676A patent/EP0102630B1/en not_active Expired
- 1983-09-02 DE DE8383108676T patent/DE3376531D1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU553990B2 (en) | 1986-07-31 |
| EP0102630B1 (en) | 1988-05-11 |
| US4479372A (en) | 1984-10-30 |
| AU1838183A (en) | 1984-03-08 |
| EP0102630A2 (en) | 1984-03-14 |
| DE3376531D1 (en) | 1988-06-16 |
| EP0102630A3 (en) | 1984-04-25 |
| JPS6044054B2 (en) | 1985-10-01 |
| SU1360576A3 (en) | 1987-12-15 |
| JPS5942133A (en) | 1984-03-08 |
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