JP2012200766A - Caliber roll for stepped steel pipe and method of manufacturing caliber roll for stepped steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a caliber roll for a stepped steel pipe, which has considerably increased life of use and achieves improved production efficiency of the stepped steel pipe.SOLUTION: The caliber roll for a stepped steel pipe has a roll body 11 which is rotated around a roll shaft. Inside a forming groove which is formed on the outside of the roll body 11, projecting parts 20 which are projected from the inner surface of the forming groove are provided. The projecting part 20 has: at least one bar-shaped member 26 which is embedded in the interior of the roll body 11 and also arranged so that a part of the bar-shaped member is projected from the inner surface of the forming groove; and a build-up welded part which is formed so as to cover the part projected from the inner surface of the forming groove, of the bar-shaped member 26.

Description

  The present invention relates to a caliber roll for a stepped steel pipe and a caliber roll for a stepped steel pipe used when manufacturing a stepped steel pipe in which steps such as grooves are formed at a constant pitch on the outer surface of the steel pipe. It is about the method.

2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Documents 1-3, a stepped steel pipe is provided in which stepped portions such as grooves are formed at a constant pitch on the outer surface of the steel pipe.
The stepped steel pipe having such a structure is used as a civil engineering member such as a steel pipe pile. In this stepped steel pipe, the frictional force and the gripping force are increased by the grooves formed on the outer surface, and it becomes possible to improve the adhesion with the formation and the concrete and the supporting force.

Moreover, in a stepped steel pipe, since a surface area becomes large by a step part, heat-transfer efficiency will improve. Furthermore, since the step has a unique appearance, it is also possible to improve the design of the structure using this appearance.
Since it also has the advantages as described above, the use of stepped steel pipes is being studied in applications other than the steel pipe piles described above.

  Here, the above-mentioned stepped steel pipe is stepped by pressing the outer surface of the steel pipe with a pressing means hot or warm in the pipe making line of the steel pipe as disclosed in, for example, Patent Documents 1-3. It is manufactured by molding the part. As a pressing means for forming a stepped portion, a caliber roll for a stepped steel pipe having a forming groove on the outer peripheral surface and having a convex portion protruding from the inner surface of the forming groove is used. A forming hole is defined by arranging the forming grooves of a plurality of stepped steel pipe caliber rolls opposite to each other, and the outer surface of the steel pipe is formed by passing the formed steel pipe through the forming hole. Is pressed to form a stepped portion.

Japanese Patent Laid-Open No. 50-033971 JP 2008-175055 A Japanese Patent No. 4109698

  By the way, as described in Patent Documents 1-3, when a step portion is formed on the outer surface of a steel pipe by a stepped steel pipe caliber roll provided with a convex portion in a forming groove, a stepped steel pipe caliber is used. The convex portion is pressed against the outer surface of the steel pipe while the roll rotates around the roll axis. For this reason, a large load acts on the convex portion in the rotation direction of the caliber roll for the stepped steel pipe, and there is a possibility that the convex portion is deformed or broken so as to fall. In particular, when the rotational speed of the caliber roll for the stepped steel pipe is increased, such a problem becomes remarkable, and it is difficult to improve the manufacturing efficiency of the stepped steel pipe.

  The present invention has been made in view of the above-described situation, and by improving the bonding strength between the convex portion and the roll body, the service life of the stepped steel pipe can be greatly extended and the service life can be greatly extended. It is an object of the present invention to provide a caliber roll for a stepped steel pipe and a method for producing this caliber roll for a stepped steel pipe.

  In order to solve the above problems, a caliber roll for a stepped steel pipe according to the present invention is used for a stepped steel pipe used when manufacturing a stepped steel pipe having stepped portions formed at a constant pitch on the outer surface of the steel pipe. It is a caliber roll, and has a roll body that is rotated around the roll axis, and a forming groove that is brought into contact with the outer surface of the steel pipe is formed on the outer peripheral surface of the roll body. Protrusions that protrude from the inner surface of the forming groove are provided, and the protrusions are embedded in the inside of the roll main body and at least one rod-like member disposed so as to partially protrude from the inner surface of the forming groove. It has a member and a built-up part formed so that the part which protruded from the inner surface of the said shaping | molding groove | channel among this rod-shaped member may be covered.

  In the caliber roll for a stepped steel pipe having this configuration, the convex portion that presses the outer surface of the steel pipe has at least one rod-like member partially embedded in the inner surface of the forming groove, so that the roll body It is possible to receive a load in the roll rotation direction applied to the convex portion by the bar-shaped member embedded in the convex portion, and it is possible to prevent the convex portion from being bent or deformed in the roll rotational direction. Therefore, the service life of this stepped steel pipe caliber roll can be greatly extended. Furthermore, the rotational speed of the caliber roll for the stepped steel pipe can be increased, and the production efficiency of the stepped steel pipe can be improved.

Here, the build-up portion includes an underlayer disposed on the inner surface of the forming groove of the roll body, and an outer surface layer disposed on the protruding end side of the convex portion, and the periphery of the rod-shaped member The base layer and the outer surface layer are disposed so as to cover the base layer, the base layer is made of a material having better bonding properties with the roll body than the outer surface layer, and the outer surface layer is It is preferable that the base layer is made of a material superior in wear resistance.
In this case, the convex portion includes an underlayer and an outer surface layer as the build-up portion, and the underlayer disposed on the roll body side has better bondability with the roll body than the outer surface layer. Since it is comprised with the material, the improvement of the joining strength of a convex part and a roll main body can be aimed at. In addition, since the outer surface layer is made of a material having higher wear resistance than the base layer, it is possible to improve the wear resistance of the convex portion and to prevent early deterioration of the convex portion. It becomes.

The underlayer is laminated so as to cover a portion of the rod-shaped member that protrudes from the inner surface of the molding groove, and the outer surface layer is laminated and disposed above the underlayer. The Vickers hardness is preferably 300 Hv or more and 340 Hv or less, and the outer surface layer preferably has a Vickers hardness of 450 Hv or more and 470 Hv or less.
In this case, since the underlayer having a Vickers hardness of 300 Hv or more and 340 Hv or less is formed, the load applied to the convex portion can be absorbed and relaxed by this underlayer. Furthermore, since the outer surface layer having a Vickers hardness of 450 Hv or more and 470 Hv or less is formed above the base layer, it is possible to improve the wear resistance of the protrusions and prevent early deterioration of the protrusions. Is possible.

Furthermore, it is preferable that a diffusion bonding layer formed by mutual diffusion of an element constituting the foundation layer and an element constituting the outer surface layer is provided between the foundation layer and the outer surface layer.
In this case, since the base layer and the outer surface layer are firmly bonded to each other by mutual diffusion, it is possible to prevent cracks and the like from occurring at the interface between the outer surface layer and the base layer.

Moreover, it is preferable that a part of part which protruded from the inner surface of the said shaping | molding groove | channel among the said rod-shaped members is integrated with the said build-up part.
In this case, by integrating the bar-like member embedded in the roll body and the build-up part, it becomes possible to reliably receive the load applied to the convex part by the bar-like member, and in the roll rotation direction of the convex part. It is possible to prevent bending deformation and breakage.

Furthermore, it is preferable that the diameter of the rod-shaped member is 2 mm or more, and the embedding depth of the rod-shaped member is 4 mm or more.
In this case, since the diameter of the rod-shaped member embedded in the roll body and the embedding depth are set within the above-described range, the load applied to the convex portion can be reliably received by the rod-shaped member. Become.

Further, in the cross section including the roll axis of the roll body, with the center of curvature radius of the forming groove as a center point, + 45 ° or more with respect to a reference line connecting the center point and the center point of the forming groove, and It is preferable that a relief portion in which the height of the convex portion is lowered is formed at a portion of −45 ° or less.
In the forming groove, the peripheral speed of the portion located radially outward (end portion of the forming groove) is higher than that of the portion located radially inward (center portion of the forming groove). From this, when pressing the convex part in a shaping | molding groove | channel on the outer surface of a steel pipe, the part located in the radial direction outer side (end part of a shaping | molding groove) will collide ahead. Therefore, the center of the radius of curvature of the molding groove is a center point, and a portion of + 45 ° or more and −45 ° or less with respect to a reference line connecting the center point and the center point of the molding groove (ie, the molding groove) It is possible to reduce the impact on the convex portion by forming a relief portion in which the height of the convex portion is lowered on the outer side in the radial direction (end portion of the forming groove). .

  A method for producing a caliber roll for a stepped steel pipe according to the present invention is a method for producing a caliber roll for a stepped steel pipe for producing the above-described caliber roll for a stepped steel pipe, wherein an insertion hole is formed in the inner surface of the forming groove of the roll body. A piercing step, a burying step of inserting a part of the rod-like member into the pierced insertion hole, and a build-up portion forming step of forming a build-up portion on the inner surface of the molding groove, The convex portion is formed on the inner surface of the forming groove.

  In the method for manufacturing a caliber roll for a stepped steel pipe having this configuration, a drilling step of drilling an insertion hole in the inner surface of the forming groove of the roll body, and an embedding step of inserting the rod-shaped member into the drilled insertion hole; Thus, it is possible to reliably form the convex portion including the rod-shaped member embedded in the roll body.

Here, in the embedding step, it is preferable that the rod-shaped member is formed by screwing a bolt into the insertion hole and removing a head portion of the bolt protruding from the inner surface of the forming groove.
In this case, since a convex part can be shape | molded using a general purpose volt | bolt, it becomes possible to manufacture the caliber roll for stepped steel pipes easily. Further, since the screw portion of the bolt is screwed into the roll main body, the screw portion is engaged with the inner peripheral surface of the insertion hole, and the bolt (rod-like member) can be prevented from coming off. Furthermore, since the contact area between the build-up portion and the bolt (rod-like member) is increased, peeling between the bolt (rod-like member) and the build-up portion can be prevented. Further, by adjusting the screwing amount, it is possible to easily adjust the embedding depth of the bolt (bar-shaped member) and the protruding height of the bolt (bar-shaped member).

In the embedding step, it is preferable that an embedding depth of the rod-shaped member is 4 mm or more, and a protruding height of the rod-shaped member is 0.5 mm or more and 14.5 mm or less.
In this case, since the embedding depth of the bar-shaped member embedded in the roll body is set to 4 mm or more on the inner surface of the forming groove, the load applied to the convex portion can be reliably received by the bar-shaped member. Moreover, since the protrusion height of the rod-shaped member is set within a range of 0.5 mm or more and 14.5 mm or less, the rod-shaped member and the built-up portion can be firmly bonded.

The build-up part forming step includes a base base layer forming step of forming a base base layer serving as a base layer on the inner surface of the molding groove, and an outer surface base layer forming step of forming an outer surface base layer serving as an outer surface layer on the base base layer, It is preferable that the convex portion is formed on the inner surface of the molding groove.
In this case, the method includes: a base base layer forming step for forming a base base layer serving as a base layer on the inner surface of the molding groove; and an outer surface base layer forming step for forming an outer surface base layer serving as an outer surface layer on the base base layer. Therefore, it is possible to reliably form the convex portion including the rod-shaped member embedded in the roll body, the base layer, and the outer surface layer.

Here, the base base layer forming step is configured to form the base base layer by overlay welding a metal on the inner surface of the forming groove, and when welding the metal, On the other hand, it is preferable to perform peening.
In this case, when the base layer is formed by overlay welding, the residual stress is removed from the formed base layer because peening is performed on the metal that has been welded. Therefore, generation | occurrence | production of the crack etc. in the base layer of a convex part can be suppressed.

Moreover, it is preferable to carry out peening after the outer surface base layer forming step. Furthermore, it is preferable to provide a convex portion shaping step for shaping the shape of the convex portion.
In this case, the shape of the convex portion can be accurately formed by the convex portion shaping step, and when the stepped steel pipe is manufactured, the step portion can be formed with high dimensional accuracy. In this convex part shaping process, it is preferable to process the convex part using an NC processing machine. Further, the details may be manually shaped.

Further, in the base base layer forming step, the maximum thickness of the base base layer is set to 0.5 mm or more and 14.5 mm or less, and in the outer surface base layer forming step, the thickness of the outer surface base layer at the tip is set to 0.5 mm or more and 3 mm or less. It is preferable to do.
In this case, since the maximum thickness of the base base layer is 0.5 mm or more and 14.5 mm or less in the base base layer forming step, even if a part of the base base layer diffuses due to heat in the outer base base layer forming step, it is constant. A base layer having a thickness is surely formed. And it becomes possible to absorb reliably the load applied to a convex part by the formed base layer. Further, in the outer surface base layer forming step, since the thickness of the outer surface base layer at the tip is 0.5 mm or more and 3 mm or less, the outer surface layer is disposed at the tip of the manufactured convex portion. The surface layer can improve the wear resistance of the convex portion.

  As described above, according to the present invention, by improving the bonding strength between the convex portion and the roll body, it is possible to greatly extend the service life and improve the manufacturing efficiency of the stepped steel pipe. A caliber roll for a steel pipe and a method for producing the caliber roll for a stepped steel pipe can be provided.

It is explanatory drawing which shows an example of the stepped steel pipe manufactured by the caliber roll for stepped steel pipes which is one Embodiment of this invention. It is a cross-sectional explanatory drawing of the step part (groove part) of the stepped steel pipe shown in FIG. It is explanatory drawing of the steel pipe manufacturing line which manufactures the stepped steel pipe shown in FIG. It is a side view of the caliber roll for stepped steel pipes which is one embodiment of the present invention. It is a front view of the caliber roll for stepped steel pipes which is one embodiment of the present invention. It is an enlarged view of the convex part of the caliber roll for stepped steel pipes shown in FIG. It is AA sectional drawing in FIG. It is a flowchart which shows the manufacturing method of the caliber roll for stepped steel pipes which is one Embodiment of this invention. It is explanatory drawing of the manufacturing method of the caliber roll for stepped steel pipes shown in FIG. It is explanatory drawing of the manufacturing method of the caliber roll for stepped steel pipes shown in FIG. It is explanatory drawing which shows an example of the stepped steel pipe manufactured by the caliber roll for stepped steel pipes which is other embodiment of this invention. It is explanatory drawing of the caliber roll for stepped steel pipes which is other embodiment of this invention.

  Below, the manufacturing method of the caliber roll for stepped steel pipes and the caliber roll for stepped steel pipes which is one Embodiment of this invention is demonstrated with reference to attached drawing.

The caliber roll 10 for a stepped steel pipe according to the present embodiment is used when the stepped steel pipe 8 shown in FIG. 1 is manufactured. The stepped steel pipe 8 shown in FIG. 1 has recesses 9 formed at a constant pitch on the outer surface of the steel pipe.
Cross section perpendicular to the extending direction of the recess 9, as shown in FIG. 2, for example, forms a triangular shape, for example, the depth _{H P} of the recesses _9, H P = 0.6 mm or more 15mm or less, the recess 9 width _{W P} out _are less W P = 2.4 mm or more 300 mm.

Next, a steel pipe production line 1 for producing such a stepped steel pipe 8 will be described with reference to FIG.
The steel pipe manufacturing line 1 shown in FIG. 3 manufactures a so-called forged steel pipe. This steel pipe production line 1 includes a forged roll unit 2 for forming a steel strip 6 into a tubular shape and forging, a drawing roll unit 3 for drawing a formed steel pipe 7, and a stepped steel pipe according to this embodiment. A step processing unit 4 having a caliber roll 10 and a cutting machine 5 are provided.
In this steel pipe production line 1, in the forged forging roll unit 2, the heated steel strip 6 is rounded and formed into a tubular shape, and the ends of the steel strip 6 are joined together to form a steel pipe 7. The steel pipe 7 is drawn by the drawing roll unit 3 and adjusted to a predetermined diameter. And the outer surface of the steel pipe 7 is pressed in the stepped processing unit 4 under hot or warm conditions (for example, 500 to 1350 ° C.), and the above-described recess 9 is formed. Then, it is cut into a predetermined length by the cutting machine 5. Thereby, the above-mentioned stepped steel pipe 8 is manufactured.

Next, the caliber roll 10 for stepped steel pipes which is this embodiment is demonstrated. As shown in FIGS. 4 and 5, the stepped steel pipe caliber roll 10 has a roll body 11 that is rotated about a roll axis O, and the outer peripheral surface of the roll body 11 has a radial direction. A molding groove 12 that is recessed inward is formed. In the present embodiment, the roll body 11 is made of cast iron. A convex portion 20 that protrudes from the inner surface of the molding groove 12 is provided in the molding groove 12.
As shown in FIGS. 4 and 5, in the present embodiment, the forming groove 12 is configured to have a semicircular shape in a cross section including the roll axis O. That is, the two stepped steel pipe caliber rolls 10 are arranged so that the molding grooves 12 face each other, thereby forming a molding hole through which the steel pipe 7 passes. .

The convex part 20 is provided with two or more in the circumferential direction of the roll main body 11, and as shown in FIG. 4, the four convex parts 20 are arrange | positioned at 90 degree intervals in this embodiment.
As shown in FIG. 5, the convex portion 20 extends in the width direction of the roll body 11 along the inner surface of the forming groove 12, and in this embodiment, the roll is viewed from the protruding direction of the convex portion 20. It is configured to extend along the axis O.

Here, in the present embodiment, in the cross section including the roll axis O of the roll body 11, the center of curvature radius of the forming groove 12 is a center point Q as shown in FIG. An escape portion 21 in which the height of the convex portion 20 is lowered is formed at a portion of + 45 ° or more and −45 ° or less with respect to the reference line S connecting the point R. In addition, in this escape part 21, it is comprised so that the width dimension of the convex part 20 may also become thin.
Further, the convex portion 20 includes at least one rod-like member 26 that is embedded toward the inside of the roll main body 11 and that a part thereof protrudes from the inner surface of the molding groove 12. In the present embodiment, as shown in FIG. 6, seven rod-like members 26 are arranged at equiangular intervals (for example, 15 ° intervals) with the center point Q as the center.

When the cross section of the portion of the convex portion 20 where the rod-like member 26 is disposed is viewed, as shown in FIG. 7, the width gradually decreases toward the tip. Here, the width W _R of the convex portion _20, and the height H _R is the width W _P of the recessed portion 9 formed on the outer surface of the steel pipe _7, according to the depth H _P, the wall thickness of the mother tube, strength etc. It is set by.
In this embodiment, W _R = 3 mm to 50 mm and H _R = 1 mm to 15 mm.

And this convex part 20 is laminated | stacked so that the part protruded from the inner surface of the shaping | molding groove | channel 12 among this rod-shaped member 26 and the rod-shaped member 26 with which one part was embedded toward the inside of the roll main body 11 as mentioned above. And a built-up portion.
The build-up portion has a base layer 27 and an outer surface layer 28 that is laminated on the base layer 27, and the base layer 27 is interposed between the base layer 27 and the outer surface layer 28. A diffusion bonding layer 29 formed by mutual diffusion between the constituent elements and the elements constituting the outer surface layer 28 is provided.

The rod-shaped member 26 is made of, for example, general structural steel (SS400 or the like). In this embodiment, as shown in FIG. 9, a bolt 22 made of general structural steel (SS material) is screwed into the roll body 11. It is formed by being. The diameter of the rod-like member 26 (bolt 22) is one in which is changed in accordance with the width W _R of the convex portion 20, in the present embodiment is set to at least 2 mm. Further, the embedding depth h _B of the rod-shaped member 26 is 4 mm or more, and is changed according to the diameter of the rod-shaped member 26.

Here, the base layer 27 is made of a material that has better bondability with the roll body 11 than the material that forms the outer surface layer 28.
Further, the outer surface layer 28 is made of a material that is more excellent in wear resistance than the material constituting the underlayer 27.

The underlayer 27 is made of, for example, a Ni—Fe alloy and has a Vickers hardness of 300 Hv or more and 340 Hv or less. As shown in FIG. 7, the underlayer 27 is formed by overlay welding the above-described Ni—Fe alloy or the like on the inner surface of the forming groove 12 and has a maximum thickness t _S of 0.5 mm or more. It is set to 14.5 mm or less.
Note that a part of the rod-shaped member 26 protruding from the inner surface of the molding groove 12 is melted and integrated with the base layer 27 by heat when the base layer 27 is formed by overlay welding.

The outer surface layer 28 is made of, for example, a Ni—Cr alloy and has a Vickers hardness of 450 Hv or more and 470 Hv or less. As shown in FIG. 7, the outer surface layer 28 is formed by overlay welding the above-described Ni—Cr alloy or the like on the base layer 27, and the thickness t _H at the protruding end portion of the convex portion 20 is , 0.5 mm or more and 3 mm or less.
Note that a part of the base layer 27 and a part of the outer surface layer 28 are diffused to each other by heat when the outer surface layer 28 is formed by overlay welding, and diffused between the base layer 27 and the outer surface layer 28. A bonding layer 29 is formed.

Next, the manufacturing method of the caliber roll 10 for a stepped steel pipe having such a configuration will be described with reference to FIGS.
First, as shown in FIG. 9, an insertion hole 24 for filling the rod-like member 26 is drilled in the inner surface of the forming groove 12 of the roll body 11 (piercing step S01). At this time, a female screw portion (not shown) is formed on the inner peripheral surface of the insertion hole 24 by a drill tap. In the present embodiment, as shown in FIG. 6, since seven rod-shaped members 26 are arranged for one convex portion 20, the insertion holes 24 are formed so as to correspond to the respective rod-shaped members 26. become.

Next, the rod-like member 26 is embedded in the insertion hole 24 (embedding step S02). In the present embodiment, the bolt 22 is screwed into the insertion hole 24 (screwing step S21), and the head 23 of the bolt 22 is removed by a grinder or the like (head removing step S22). Thereby, the above-mentioned rod-shaped member 26 is formed. In screwing step S21, screw-in depth _{h B} of the bolt 22 is adjusted to be above 4 mm. Further, in the screwing step S21 and the head removing step S22, the protrusion height h _P of the bolt 22 is adjusted to be 0.5 mm or more and 14.5 mm or less. It is preferable that the protrusion height h _P of the bolt 22 is approximately the same as the height of the target base layer 27a.

  Next, as shown in FIG. 10, Ni—Fe alloy is build-up welded to the inner surface of the forming groove 12 to form the base base layer 27a (base base layer forming step S03). At this time, the overlay welding is performed in a plurality of times to form the base base layer 27 a so as to cover the protruding end of the rod-shaped member 26.

  Moreover, in this foundation | substrate base layer formation process S03, when carrying out overlay welding of Ni-Fe alloy, peening process is performed with respect to the welded metal with an air hammer. By this peening process, the welded Ni—Fe alloy is quickly cooled, and the tensile stress generated when the Ni—Fe alloy solidifies is removed. Thereby, the residual stress is reduced in the underlying layer 27 (underlying base layer 27a) to be formed.

In the base base layer forming step S03, a part of the rod-shaped member 26 protruding from the inner surface of the molding groove 12 is melted and integrated with the base base layer 27a to be formed.
Next, the ground base layer 27a is shaped by performing grinder processing or the like on the formed ground base layer 27a (ground base layer shaping step S04). At this time, the height of the base base layer 27a is adjusted to a predetermined height.

Then, the outer surface base layer 28a is formed on the base layer 27a by overlay welding a Ni—Cr alloy (outer surface base layer forming step S05). At this time, the thickness of the outer surface base layer 28a is adjusted by performing overlay welding in a plurality of times. Peening may be performed when forming the outer surface base layer 28a.
In the outer surface base layer forming step S05, a part of the base layer 27a and a part of the outer surface layer 28a are diffused to each other, and a diffusion bonding layer 29 is formed between the base layer 27a and the outer surface layer 28a. Will be.

Next, in order to shape the shape of the convex portion 20 obtained in this way, machining is performed with an NC processing machine and manual operation (convex portion shaping step S06). Thereby, the width dimension and height dimension of the convex part 20 are set as mentioned above. At this time, the convex part 20 is shaped so that the thickness at the protruding end of the convex part 20 in the outer surface base layer 28a is 0.5 mm or more and 3 mm or less.
Moreover, in this convex part shaping | molding process S06, in the cross section containing the roll axis line O of the roll main body 11, the curvature-radius center of the shaping | molding groove 12 is made into the center point Q, and this center point Q and the center point R of the shaping | molding groove 12 are made into. A relief portion 21 is formed in the portion of + 45 ° or more and −45 ° or less with respect to the connected reference line S, with the height of the convex portion 20 being low and the width being narrowed.

  As described above, the caliber roll 10 for a stepped steel pipe according to the present embodiment is manufactured.

  According to the caliber roll 10 for a stepped steel pipe according to the present embodiment, the convex portion 20 is formed on the inner surface of the forming groove 12, and the convex portion 20 is partially embedded toward the inside of the roll body 11. Since it has the rod-shaped member 26, and the build-up part provided with the outer surface layer 28 laminated | stacked on the base layer 27 and the base layer 27 integrated with a part of this rod-shaped member 26, a roll The rod-shaped member 26 embedded in the main body 11 can receive a load in the roll rotation direction applied to the convex portion 20, and can prevent the convex portion 20 from being bent or deformed in the roll rotational direction. it can.

In addition, since the base layer 27 is made of a material that has better bonding properties to the roll body 11 than the material that forms the outer surface layer 28, the bonding strength between the convex portion 20 and the roll body 11 is improved. Can do.
Furthermore, since the outer surface layer 28 is made of a material that is more excellent in wear resistance than the material constituting the base layer 27, the wear resistance of the convex portion 20 can be improved, and the convex portion 20 can be deteriorated early. Can be prevented.

Further, since the base layer 27 is laminated so as to cover the rod-shaped member 26 partially embedded in the roll body 11, a contact area between the base layer 27, the roll body 11 and the rod-shaped member 26 is secured, The underlayer 27 is prevented from peeling from the roll body 11, and the bonding strength of the convex portion 20 can be ensured.
Furthermore, since the Vickers hardness of the underlayer 27 is set to 300 Hv or more and 340 Hv or less, the load applied to the convex portion 20 can be absorbed and relaxed by the underlayer 27.
On the other hand, since the Vickers hardness of the outer surface layer 28 is set to 450 Hv or more and 470 Hv or less, it is possible to surely improve the wear resistance of the convex portion 20 and to prevent early deterioration of the convex portion 20. Become.

In addition, since the diffusion bonding layer 29 formed by mutual diffusion is provided between the base layer 27 and the outer surface layer 28, cracks and the like occur at the interface between the outer surface layer 28 and the base layer 27. The impact resistance of the convex portion 20 can be improved.
Furthermore, a part of the rod-shaped member 26 protruding from the inner surface of the molding groove 12 is integrated with the base layer 27, so that the load applied to the convex portion 20 can be reliably received by the rod-shaped member 26. It becomes possible, and the bending deformation | transformation and breakage of the convex part 20 to the roll rotation direction can be prevented.
Further, since the diameter of the rod-shaped member 26 is 2 mm or more and the embedding depth of the rod-shaped member 26 is 4 mm or more, the load applied to the convex portion 20 can be reliably received by the rod-shaped member 26. .

  Further, in the cross section including the roll axis O of the roll body 11, the center of curvature radius of the forming groove 12 is set as the center point Q, and +45 with respect to the reference line S connecting the center point Q and the center point R of the forming groove 12. Since the convex portion 20 is formed with a relief portion 21 in which the height of the convex portion 20 is reduced and the width of the convex portion 20 is narrowed in a portion at or above and −45 ° or less. It is suppressed that the part located in the radial direction outer side (end part of the shaping | molding groove 12) of the shaping | molding groove | channel 12 collides ahead of the outer surface of the steel pipe 7, and the impact added to the convex part 20 can be reduced.

  According to the manufacturing method of the stepped steel pipe caliber roll 10 according to the present embodiment, the drilling step S01 for drilling the insertion hole 24 in the inner surface of the forming groove 12 of the roll body 11, and the drilled insertion hole 24 in a rod shape. An embedding step S02 for inserting the member 26, a base base layer forming step S03 for forming the base base layer 27a to be the base layer 27 on the inner surface of the molding groove 12, and an outer surface base layer 28a to be the outer surface layer 28 on the base base layer 27a. Since the outer surface base layer forming step S05 is formed, the above-described convex portion 20 can be formed.

  Further, in the base base layer forming step S03, the peening process is performed by an air hammer when performing the overlay welding of the Ni—Fe alloy. Residual stress is reduced in the base layer 27, and it is possible to prevent the base layer 27 from being cracked. More specifically, in this embodiment, the roll body 11 is made of cast iron, and the base layer 27 (base base layer 27a) is made of a Ni—Fe alloy. Therefore, when the Ni—Fe alloy cools and contracts. The underlayer 27 (the underlayer 27a) may be peeled off from the roll body 11. Therefore, in this embodiment, by performing peening with an air hammer while performing welding, the tensile stress is removed while quickly cooling the Ni—Fe alloy, so that the base layer 27 (the base layer 27a) cracks. Is suppressed, and the base layer 27 (base base layer 27a) can be reliably laminated on the roll body 11 made of cast iron.

Further, since the base layer forming step S04 is provided after the base base layer forming step 03, the base base layer 27a can be set to a predetermined height. Therefore, when forming the outer surface base layer 28a on the base layer 27a, the thickness of the outer surface base layer 28a can be adjusted with high accuracy.
Furthermore, since the outer surface base layer forming step 05 is provided with a convex shape shaping step S06 for shaping the shape of the convex portion 20, the shape of the convex portion 20 can be accurately shaped by this convex shape shaping step S06. When manufacturing the stepped steel pipe 8, the groove part 9 can be formed with high dimensional accuracy.

The embedding step S02 includes a screwing step S21 for screwing the bolt 22 into the insertion hole 24 and a head removing step S22 for removing the head 23 of the bolt 22 protruding from the inner surface of the forming groove 12. The convex portion 20 can be formed using a general-purpose bolt 22, and the caliber roll 10 for a stepped steel pipe can be easily manufactured. Further, since the screw portion of the bolt 22 is screwed into the roll main body 11, the screw portion is engaged with the inner peripheral surface of the insertion hole 24, and the bolt 22 (rod-like member 26) can be prevented from coming off. . Furthermore, by adjusting the screwing amount, it is possible to easily adjust the embedding depth h _B of the bolt 22 (rod-like member 26) and the protrusion height h _P of the bolt 22 (rod-like member 26).

Then, in the embedding step S02, since setting the embedment depth h _B of the rod-shaped member 26 than 4 mm, it is possible to reliably receive the rod-like member 26 the load applied to the convex portion 20.
On the other hand, by setting the protrusion height _{h P} of the rod-shaped member 26 in the range of 0.5mm or 14.5mm or less, it is possible to firmly bond the rod-like member 26 and the base layer 27.

Further, in the base base layer forming step S03, since the thickness of the base base layer 27a is 0.5 mm or more and 14.5 mm or less, a part of the base base layer 27a is diffused in the outer surface base layer forming step S05 so that the diffusion bonding layer 29 is formed. Even if formed, the thickness of the underlayer 27 can be secured. Therefore, it is possible to reliably absorb the load applied to the convex portion 20 by the base layer 27.
In the outer surface base layer forming step S05, the thickness of the outer surface base layer 28a at the protruding end is set to 0.5 mm or more and 3 mm or less. Therefore, even if the protruding portion 20 is processed in the protruding portion shaping step S06, the protruding end of the protruding portion 20 is formed. The outer surface layer 28 can be disposed in a portion in the range of 1 mm or more and 3 mm or less, and the outer surface layer 28 can reliably improve the wear resistance of the convex portion 20.

As mentioned above, although the manufacturing method of the caliber roll for stepped steel pipes and the caliber roll for stepped steel pipes which is an embodiment of the present invention was explained, the present invention is not limited to this and deviates from the technical idea of the invention. It is possible to change appropriately within the range not to be.
For example, although it demonstrated as what manufactures the stepped steel pipe shown in FIG. 1, it is not limited to what was illustrated, You may manufacture the stepped steel pipe which has a step part of a different shape. For example, as shown in FIG. 11, a stepped steel pipe 108 having a groove 109 extending in a direction oblique to the axis of the steel pipe may be manufactured on the outer surface of the steel pipe. When manufacturing such a stepped steel pipe 108, the caliber roll 110 for stepped steel pipes which has the convex part 120 as shown in FIG. 12 will be used.

Moreover, although demonstrated as what arrange | positions seven rod-shaped members with respect to a convex part, it is not limited to this, The magnitude | size (outer diameter of a stepped steel pipe), the magnitude | size of a convex part, etc. In consideration of the above, it is preferable to appropriately design the arrangement position of the rod-shaped member.
Furthermore, although it demonstrated as a structure which defines the shaping | molding hole which lets a steel pipe pass by arrange | positioning the shaping | molding groove | channel of two caliber rolls for stepped steel pipes facing, it is not limited to this but is 3 or more steps | paragraphs. You may define the above-mentioned shaping | molding hole using the caliber roll for steel pipes. In this case, since the size of the forming groove formed in each caliber roll for a stepped steel pipe is reduced, the difference in peripheral speed between the end of the forming groove and the center portion of the forming groove is reduced. Thus, there is no need to form an escape portion.

DESCRIPTION OF SYMBOLS 10 Caliber roll for stepped steel pipe 11 Roll main body 12 Forming groove 20 Protruding part 21 Escape part 22 Bolt 23 Head 24 Insertion hole 26 Rod-shaped member 27 Underlayer 27a Underground layer 28 Outer surface layer 28a Outer surface layer 29 Diffusion bonding layer

Claims (14)

A caliber roll for a stepped steel pipe used when manufacturing a stepped steel pipe having stepped portions formed at a constant pitch on the outer surface of the steel pipe,
A roll body that rotates around a roll axis is formed, and a forming groove that is brought into contact with the outer surface of the steel pipe is formed on the outer peripheral surface of the roll body. In the forming groove, an inner surface of the forming groove is formed. Protruding protrusions are provided,
The convex portion is embedded in the inside of the roll body and partly protrudes from the inner surface of the forming groove, and of the rod-shaped member, the protruding portion protrudes from the inner surface of the forming groove. A caliber roll for a stepped steel pipe, characterized by having a built-up part formed so as to cover the part. The build-up portion includes an underlayer disposed on the inner surface of the forming groove of the roll body, and an outer surface layer disposed on a protruding end side of the convex portion, so as to cover the rod-shaped member, These base layer and outer surface layer are disposed,
The base layer is made of a material having better bonding properties with the roll body than the outer surface layer,
The caliber roll for a stepped steel pipe according to claim 1, wherein the outer surface layer is made of a material having higher wear resistance than the base layer. The underlayer is laminated so as to cover a portion of the rod-shaped member that protrudes from the inner surface of the forming groove, and the outer surface layer is laminated and disposed above the underlayer,
3. The step according to claim 2, wherein the underlayer has a Vickers hardness of 300 Hv to 340 Hv, and the outer surface layer has a Vickers hardness of 450 Hv to 470 Hv. Caliber roll for steel pipes.   The diffusion bonding layer formed by mutual diffusion of an element constituting the underlayer and an element constituting the outer surface layer is provided between the underlayer and the outer surface layer. The caliber roll for stepped steel pipes according to Item 2 or Claim 3.   The stage according to any one of claims 1 to 4, wherein a part of a portion of the rod-shaped member that protrudes from the inner surface of the forming groove is integrated with the build-up portion. Caliber roll for steel pipe.   The caliber roll for a stepped steel pipe according to any one of claims 1 to 5, wherein a diameter of the rod-shaped member is 2 mm or more and an embedding depth of the rod-shaped member is 4 mm or more. .   In the cross section including the roll axis of the roll body, the center of curvature radius of the forming groove is a center point, and a reference line connecting the center point and the center point of the forming groove is + 45 ° or more, and − The stepped steel pipe caliber according to any one of claims 1 to 6, wherein a relief portion in which a height of the convex portion is lowered is formed in a portion of 45 ° or less. roll. It is a manufacturing method of the caliber roll for stepped steel pipes which manufactures the caliber roll for stepped steel pipes described in any one of Claims 1-7,
A drilling step of drilling an insertion hole in the inner surface of the molding groove of the roll body, an embedding step of inserting a part of the rod-like member into the drilled insertion hole, and forming a built-up portion on the inner surface of the molding groove And a built-up part forming step,
A method for producing a caliber roll for a stepped steel pipe, wherein the convex portion is formed on an inner surface of the forming groove.   The step according to claim 8, wherein in the embedding step, the rod-shaped member is formed by screwing a bolt into the insertion hole and removing a head portion of the bolt protruding from the inner surface of the forming groove. Manufacturing method of caliber roll for steel pipe.   The said embedding process WHEREIN: The embedding depth of the said rod-shaped member shall be 4 mm or more, and the protrusion height of the said rod-shaped member shall be 0.5 mm or more and 14.5 mm or less, The Claim 8 or Claim 9 characterized by the above-mentioned. Manufacturing method of caliber roll for stepped steel pipe.   The build-up part forming step includes a base base layer forming step of forming a base base layer serving as a base layer on the inner surface of the molding groove, and an outer surface base layer forming step of forming an outer surface base layer serving as an outer surface layer on the base base layer, The method for manufacturing a caliber roll for a stepped steel pipe according to any one of claims 8 to 10, wherein the convex portion is formed on an inner surface of the forming groove.   The base base layer forming step is configured such that the base base layer is formed by overlay welding a metal on the inner surface of the forming groove, and when the metal is overlay welded, peening is performed on the welded metal. The method for producing a caliber roll for a stepped steel pipe according to claim 11, wherein the processing is performed.   The method for producing a caliber roll for a stepped steel pipe according to claim 11 or 12, further comprising a convex shaping step for shaping the shape of the convex after the outer surface base layer forming step.   In the foundation base layer forming step, the maximum thickness of the foundation base layer is 0.5 mm to 14.5 mm, and in the outer surface base layer forming step, the thickness of the outer surface base layer at the tip is 0.5 mm to 3 mm. The method for producing a caliber roll for a stepped steel pipe according to any one of claims 11 to 13, wherein:

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