WO2018230450A1 - 継目無金属管の製造方法 - Google Patents
継目無金属管の製造方法 Download PDFInfo
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- WO2018230450A1 WO2018230450A1 PCT/JP2018/021960 JP2018021960W WO2018230450A1 WO 2018230450 A1 WO2018230450 A1 WO 2018230450A1 JP 2018021960 W JP2018021960 W JP 2018021960W WO 2018230450 A1 WO2018230450 A1 WO 2018230450A1
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- Prior art keywords
- billet
- groove
- rear end
- hole
- burrs
- Prior art date
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- 239000002184 metal Substances 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title description 19
- 238000005096 rolling process Methods 0.000 claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 claims abstract description 26
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- 208000010201 Exanthema Diseases 0.000 description 32
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- 229910000831 Steel Inorganic materials 0.000 description 11
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- 229910000975 Carbon steel Inorganic materials 0.000 description 8
- 239000010962 carbon steel Substances 0.000 description 8
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- 238000010586 diagram Methods 0.000 description 6
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- 229910045601 alloy Inorganic materials 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C23/00—Extruding metal; Impact extrusion
- B21C23/02—Making uncoated products
- B21C23/04—Making uncoated products by direct extrusion
- B21C23/08—Making wire, bars, tubes
- B21C23/085—Making tubes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B19/00—Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work
- B21B19/02—Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work the axes of the rollers being arranged essentially diagonally to the axis of the work, e.g. "cross" tube-rolling ; Diescher mills, Stiefel disc piercers or Stiefel rotary piercers
- B21B19/04—Rolling basic material of solid, i.e. non-hollow, structure; Piercing, e.g. rotary piercing mills
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B23/00—Tube-rolling not restricted to methods provided for in only one of groups B21B17/00, B21B19/00, B21B21/00, e.g. combined processes planetary tube rolling, auxiliary arrangements, e.g. lubricating, special tube blanks, continuous casting combined with tube rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C25/00—Profiling tools for metal extruding
- B21C25/08—Dies or mandrels with section variable during extruding, e.g. for making tapered work; Controlling variation
Definitions
- the present invention relates to a method for manufacturing a seamless metal pipe. More specifically, the present invention relates to a method for manufacturing a seamless metal pipe using a punch.
- One method for producing seamless metal pipes is to use a perforator.
- the drilling machine includes a plurality of inclined rolls arranged at equal intervals around the pass line, and a plug arranged on the pass line between the plurality of inclined rolls.
- the manufacturing method of the seamless metal pipe using a punching machine is as follows. First, a heated round billet is prepared and placed on the pass line. A round billet is pushed between a plurality of inclined rolls using a pusher arranged in front of the drilling machine. When a round billet is bitten by a plurality of inclined rolls, the round billet is pierced and rolled by an inclined roll and a plug while rotating in a spiral shape to form a hollow shell.
- the plug pierces a round billet.
- a portion (hereinafter referred to as “contact portion”) that is in contact with the plug tip until the plug tip is pulled out of the rear end of the round billet is broken through.
- the pierced contact portion becomes a burr and remains on the inner surface or the rear end of the hollow shell.
- ⁇ Burr may drop and accumulate in the punch after piercing and rolling. In this case, it is necessary to periodically clean the inside of the drilling machine. In addition, if large burrs remain on the inner surface or the rear end of the hollow shell, wrinkles are generated on the inner surface of the hollow shell, the mandrel bar, and the like during the subsequent drawing and rolling.
- Patent Document 1 Methods for suppressing the generation of burrs are disclosed in WO2009 / 122620 (Patent Document 1), JP2001-219205 (Patent Document 2), JP2015-167960 (Patent Document 3) and JP 7-214113 (Patent Document 4).
- Patent Document 1 a hole having a predetermined depth and a plurality of grooves on the inner surface is formed at the center of the rear end of the round billet before piercing and rolling. A part of the shape of the pilot hole appears between the adjacent grooves.
- the round billet in which holes having a plurality of grooves are formed is pierced and rolled.
- the contact portion of the broken rear end surface tends to form a protrusion that can be a starting point of a burr.
- the groove formed in the inner surface of the hole absorbs a contact portion that can be a protrusion. Further, by forming the hole, the excess wall that can increase the size of the protrusion is removed. Thus, Patent Document 1 describes that the generation of burrs can be suppressed.
- Patent Document 2 and Patent Document 3 a hole having no groove of a predetermined depth is formed in the center of the rear end of the round billet before piercing and rolling.
- a round billet having holes formed therein is pierced and rolled.
- Patent Document 4 In the method disclosed in Patent Document 4, a round billet having a ⁇ (minus) -shaped or + (plus) -shaped streak groove formed on the rear end face is pierced and rolled. Patent Document 4 describes that generation of burrs can be suppressed because there is no surplus in the center region of the end surface or there is little surplus because a minus or plus shaped streak groove is formed on the rear end surface. Yes.
- An object of the present invention is to provide a method for producing a seamless metal pipe capable of suppressing burrs and rashes generated at the rear end of a hollow shell after piercing and rolling even in an alloy steel having low deformability. .
- the method for manufacturing a seamless metal pipe uses a drilling machine including a plurality of inclined rolls and a plug disposed between the plurality of inclined rolls.
- the manufacturing method includes a step of preparing a billet having a diameter B (mm), a step of heating the billet, and a groove width D (mm) satisfying the formula (1) at the center of the rear end of the heated billet, A step of forming a hole including four grooves extending in the axial direction of the billet having a groove height H (mm) satisfying (2) and a groove depth L1 (mm) satisfying Formula (3); And piercing and rolling the billet in which the hole is formed from the tip. 0.12 ⁇ D / B ⁇ 0.25 (1) 0.10 ⁇ H / B ⁇ 0.20 (2) 0.05 ⁇ L1 / B ⁇ 0.10 (3)
- burrs and rashes generated at the rear end of the hollow shell after piercing and rolling can be suppressed even with alloy steel having low deformability.
- FIG. 1 is a cross-sectional view showing the generation of burrs.
- FIG. 2 is a cross-sectional view showing the generation of large burrs.
- FIG. 3 is a cross-sectional view when a billet having a conical hole formed at the rear end is pierced and rolled.
- FIG. 4 is a cross-sectional view when a billet having a cylindrical hole formed at the rear end is pierced and rolled.
- FIG. 5 is a cross-sectional view of a billet having a deep groove at the rear end during piercing and rolling.
- FIG. 6 is a cross-sectional view of a billet having a shallow groove at the rear end during piercing and rolling.
- FIG. 7 is a perspective view of the billet of the present embodiment.
- FIG. 1 is a cross-sectional view showing the generation of burrs.
- FIG. 2 is a cross-sectional view showing the generation of large burrs.
- FIG. 3 is a cross-section
- FIG. 8 is a front view of the billet of the present embodiment.
- FIG. 9 is a cross-sectional view of the billet of the present embodiment.
- FIG. 10 is a front view of a billet in which a hole having a general groove is formed.
- FIG. 11 is a diagram illustrating a process of forming a hole at the center of the rear end of the billet.
- FIG. 12 is a diagram showing a piercing and rolling process.
- FIG. 13 is a diagram showing the relationship between the temperature and the drawing value of steels having different compositions.
- FIG. 1 is a cross-sectional view showing the occurrence of burrs.
- FIG. 1 shows a case where a billet having no hole at the rear end is pierced and rolled.
- a portion (contact portion) 3 that has been in contact with the tip of plug 1 until just before the tip of plug 1 comes off is It is pierced.
- This contact portion 3 is extra for the hollow shell 4. Therefore, the contact portion 3 pierced by the plug 1 remains as a burr 5 on the inner surface or the rear end of the hollow shell 4.
- FIG. 2 is a cross-sectional view showing the occurrence of large burrs.
- FIG. 2 shows a case in which a billet having no hole at the rear end is pierced and rolled.
- the billet 2 is pierced and rolled by the plug 1 having a flat tip.
- the plug 1 having a flat tip has a larger volume of the contact portion 3 than a plug having a sharp tip or a round tip (see FIG. 1). Therefore, the contact portion 3 pierced by the plug 1 remains as a burr 5 having a larger volume than the burr shown in FIG.
- FIG. 3 is a cross-sectional view when a billet having a conical hole formed at the rear end is pierced and rolled.
- the surplus wall that causes the burr is removed by the volume of the hole 7. Therefore, burrs are unlikely to occur.
- a rash 6 may occur on the inner surface of the hollow shell 4.
- FIG. 4 is a cross-sectional view when a billet having a cylindrical hole formed at the rear end is pierced and rolled.
- the surplus portion of the volume of the hole 7 is removed. Therefore, burrs are unlikely to occur.
- the contact portion 3 at the tip of the plug 1 is easily separated from the hollow shell 4. Since the separated contact portion 3 is deposited on the drilling machine, periodic cleaning is required.
- the present inventors examined the detailed shape of the hole having a groove formed at the rear end of the billet in order to suppress both burrs and rashes.
- a groove that absorbs the contact portion that causes burrs is important. Therefore, it is conceivable to increase the depth of the groove in order to easily absorb burrs. However, it was found that if the depth of the groove is increased, rashes are likely to occur on the inner surface of the hollow shell after piercing and rolling, as shown in the examples described later.
- the “groove depth” means the length of the groove along the billet axial direction.
- FIG. 5 is a cross-sectional view of a billet having a deep groove at the rear end during piercing and rolling.
- the depth L ⁇ b> 1 of the groove 8 is deeper than the diameter B of the billet 2, the contact portion 3 is pierced before reaching the vicinity of the rear end face 14.
- the plug 1 further advances toward the rear end of the billet 2, the pierced contact portion 3 is rolled by the plug 1. For this reason, a rash is likely to occur on the inner surface of the hollow shell after piercing and rolling.
- FIG. 6 is a cross-sectional view of a billet having a shallow groove at the rear end during piercing and rolling.
- the contact portion 3 is pierced in the vicinity of the rear end face 14 of the billet 2.
- the pierced contact portion 3 is not easily rolled by the plug 1.
- a rash is hardly generated on the inner surface of the hollow shell after piercing and rolling.
- the depth L1 of the groove 8 is too shallow, burrs are generated because the contact portion 3 is difficult to fit in the groove 8 (see FIG. 1).
- the present inventors conducted extensive studies on a method for suppressing both generation of rashes and burrs. As a result, it was found that even when the groove is shallow, the contact portion 3 in which the groove 8 is pierced by the plug 1 can be absorbed by devising the groove shape. More specifically, it has been found that the generation of burrs can be suppressed if the groove width and height are appropriate. It was also found that the generation of rashes can be suppressed if the groove depth is moderately shallow. Furthermore, it has been found from the above findings that the occurrence of burrs and rashes can be suppressed not only with carbon steel but also with alloy steel.
- the manufacturing method of the seamless metal pipe of the present invention has been completed based on the above findings.
- the method for manufacturing a seamless metal pipe according to the present embodiment uses a drilling machine including a plurality of inclined rolls and a plug disposed between the plurality of inclined rolls.
- the manufacturing method includes a step of preparing a billet having a diameter B (mm), a step of heating the billet, and a groove width D (mm) satisfying the formula (1) at the center of the rear end of the heated billet, A step of forming a hole including four grooves extending in the axial direction of the billet having a groove height H (mm) satisfying (2) and a groove depth L1 (mm) satisfying Formula (3); And piercing and rolling the billet in which the hole is formed from the tip. 0.12 ⁇ D / B ⁇ 0.25 (1) 0.10 ⁇ H / B ⁇ 0.20 (2) 0.05 ⁇ L1 / B ⁇ 0.10 (3)
- a billet in which a hole having a groove is formed at the center of the rear end is pierced and rolled.
- the shape of the hole is a cross when viewed in the axial direction.
- channel can absorb the contact part pierced by the plug. Thereby, a burr
- the shape of the groove satisfies the formula (3).
- the groove satisfying the formula (3) has a contact portion pierced near the billet rear end face. That is, the contact portion is broken through at a shallow position of the billet hole. Therefore, the pierced contact portion is difficult to be rolled into the plug, or the time for rolling with the plug is short. Thereby, a rash is hardly generated on the inner surface of the hollow shell. By suppressing the generation of burrs, burrs are less likely to accumulate on the drilling machine. Further, by stretching and rolling the hollow shell tube in which the generation of burrs and rashes is suppressed, wrinkles are unlikely to occur on the inner surface of the seamless metal tube and the tool (eg, mandrel bar) of the rolling mill.
- the tool eg, mandrel bar
- L2 (mm) which is twice the maximum distance from the center of the rear end of the billet to the bottom of the groove on the rear end surface of the billet satisfies the formula (4). 0.30 ⁇ L2 / B ⁇ 0.60 (4)
- L2 / B means the ratio of the maximum hole width to the billet diameter at the billet rear end face. Therefore, if L2 / B is small, it means a small hole, and if L2 / B is large, it means a large hole. If L2 / B is small, the contact portion pierced by the plug is hardly absorbed by the groove. If L2 / B is large, the groove is excessively large, so that the time spent for processing the hole increases. Further, when a hole is formed by press working, the press load increases. Therefore, L2 / B is preferably within a predetermined range (formula (4)), as will be shown in the examples described later.
- the four grooves are provided in a cross shape, and the four grooves extend from the rear end face of the billet.
- four grooves are cross-shaped means that the grooves are arranged at equal intervals around the billet axis and the two grooves adjacent in the circumferential direction are orthogonal to each other when viewed from the billet axial direction.
- the fact that the four cross-shaped grooves extend from the rear end face of the billet means that the cross-sectional shape of the hole is constant from the rear end face. In this case, the hole can be easily formed.
- the manufacturing method of the present embodiment can be applied to, for example, alloy steel containing 1% to 12% by mass in Cr. Moreover, since carbon steel is less likely to generate burrs than alloy steel, naturally, the production method of this embodiment can also suppress the occurrence of burrs and rashes in carbon steel.
- the hole has an appropriate shape, even a billet made of alloy steel heated to less than 1300 ° C. can be pierced and rolled while suppressing the occurrence of burrs and rashes. Thereby, the fall of the energy basic unit in a heating process can be suppressed.
- the manufacturing method includes a preparation process, a heating process, a forming process, and a piercing and rolling process.
- a billet having a diameter B (mm) is prepared.
- the billet material is, for example, steel.
- the billet is manufactured, for example, by a continuous casting method or an ingot forming method.
- the diameter of the billet is not particularly limited. However, generally, the diameter of the billet produced in the seamless metal pipe is 20 to 400 (mm).
- the billet is heated in a heating furnace.
- the heating temperature is not particularly limited. However, from the viewpoint of suppressing a decrease in energy intensity, the heating temperature is preferably less than 1300 ° C. Further, from the viewpoint of billet deformability, the heating temperature is preferably 1100 ° C. or higher.
- FIG. 7 is a perspective view of the billet of the present embodiment.
- hole 7 is formed at the center of the rear end of billet 2.
- the hole 7 extends from the rear end surface 14 in the axial direction of the billet 2.
- the hole 7 includes four grooves 8 extending from the rear end surface 14 in the axial direction of the billet 2.
- Each of the four grooves 8 is arranged at equal intervals around the axis of the billet 2.
- Each of the four grooves 8 has the same shape. Therefore, hereinafter, one of the four grooves 8 will be described.
- the groove 8 has a groove width D (mm) that satisfies Expression (1), a groove height H (mm) that satisfies Expression (2), and a groove depth L1 (mm) that satisfies Expression (3).
- the groove width D means the distance between the two groove side surfaces 9.
- the groove height H means the distance from the end of the groove side surface 9 to the groove bottom surface 10.
- the groove depth L1 means the distance of the groove 8 in the billet axis direction. 0.12 ⁇ D / B ⁇ 0.25 (1) 0.10 ⁇ H / B ⁇ 0.20 (2) 0.05 ⁇ L1 / B ⁇ 0.10 (3)
- the lower limit of D / B is 0.12.
- the lower limit of D / B is 0.15, and more preferably 0.17.
- the upper limit of D / B is 0.25.
- the upper limit of D / B is 0.23.
- H / B is less than 0.10, since the groove height H is low, the groove hardly absorbs the contact portion pierced by the plug. Therefore, the lower limit of H / B is 0.10. Preferably, the lower limit of H / B is 0.12. If H / B is larger than 0.20, since the groove height H is high, excessive voids are rolled, and folds and cracks are likely to occur. Therefore, the upper limit of H / B is 0.20. Preferably, the upper limit of H / B is 0.16.
- the lower limit of L1 / B is 0.05.
- the lower limit of L1 / B is 0.07.
- the upper limit of L1 / B is 0.10.
- the upper limit of L1 / B is 0.09.
- FIG. 8 is a front view of the billet of the present embodiment.
- the shape of the hole seen from the axial direction of billet 2 is demonstrated. Since the groove 8 satisfies the expressions (1) and (2), the shape of the hole 7 of the billet 2 is a cross.
- the groove side surface 9 of the groove 8 is parallel to the radial direction of the billet 2, and the end closer to the rear end center C of the groove side surface 9 is closer to the rear end center C of the groove side surface 9 of another adjacent groove 8. Connected to the end of That is, a part 100 of the pilot hole shape does not appear between the adjacent grooves 8 (see FIG. 10).
- the groove bottom surface 10 has an R shape. However, the shape of the groove bottom surface 10 is not limited to this. The shape of the groove bottom surface 10 may be flat, for example.
- FIG. 9 is a cross-sectional view of the billet of the present embodiment.
- the groove 8 satisfies the formula (3) and is shallower than the conventional groove.
- the front end surface 24 of the groove 8 has an R shape.
- the shape of the front end surface 24 of the groove 8 is not limited to this.
- the shape of the front end surface 24 of the groove 8 may be flat.
- the groove 8 extends in parallel with the axial direction of the billet 2.
- the extending direction of the groove 8 may not be parallel to the axial direction of the billet 2.
- the groove 8 may gradually become smaller toward the distal end surface 24. Even in this case, the groove 8 satisfies the expressions (1) and (2) in the cross section at an arbitrary position viewed from the axial direction.
- FIG. 11 is a diagram showing a process of forming a hole at the center of the rear end of the billet.
- the clamp die 11 includes a die 12 having a circular hole shape, and a driving device 13 that raises and lowers the die 12.
- a punch attached to the front end of a hydraulic cylinder (not shown) is pushed into the center of the rear end surface 14 of the constrained billet 2.
- the hole 7 is formed.
- the hole 7 may be formed by machining or may be formed by pressing.
- the hole 7 may be formed by melting the center of the rear end of the billet 2 with plasma gas or the like.
- FIG. 12 is a diagram showing a piercing and rolling process.
- billet 2 is pierced and rolled using piercing machine 15.
- the punching machine 15 includes two cone-type inclined rolls (hereinafter simply referred to as “inclined rolls”) 16, the plug 1, and a cored bar 17.
- the two inclined rolls 16 are arranged to face each other across the pass line PL. Each inclined roll 16 has an inclination angle and a crossing angle with respect to the pass line PL.
- the plug 1 is disposed between the two inclined rolls 16 and on the pass line PL.
- the cored bar 17 is arranged along a path line PL on the exit side of the punching machine 15. The front end of the core metal 17 is connected to the rear end of the plug 1.
- the pusher 18 is arranged along the pass line PL in front of the entrance side of the punching machine 15.
- the pusher 18 includes a cylinder body 19, a cylinder shaft 20, a connection member 21, and a billet push rod 22.
- the billet push rod 22 is connected to the cylinder shaft 20 by the connecting member 21 so as to be rotatable in the circumferential direction.
- the connection member 21 includes a bearing for allowing the billet push rod 22 to rotate in the circumferential direction.
- the cylinder body 19 that is a drive device is hydraulic or electric and moves the cylinder shaft 20 forward and backward.
- the pusher 18 brings the front end surface of the billet push rod 22 into contact with the rear end surface of the billet 2 and advances the cylinder shaft 20 and the billet push rod 22 by the cylinder body 19 to push the billet 2 from the rear.
- An entrance guide 23 is disposed on the pass line PL between the pusher 18 and the inclined roll 16.
- the inlet guide 23 prevents the billet 2 from being displaced from the pass line PL while the billet 2 is pushed forward by the pusher 18.
- the billet 2 in which a hole having a groove is formed is disposed on the pass line PL between the inclined roll 16 and the pusher 18. At this time, the rear end surface of the billet 2 faces the pusher 18, and the front end surface of the billet 2 faces the plug 1.
- the pusher 18 pushes the billet 2 along the pass line PL and pushes it between the two inclined rolls 16.
- the billet 2 is bitten by the two inclined rolls 16.
- the billet 2 moves forward while rotating spirally by the inclined roll 16.
- the plug 1 is pushed into the axis of the billet 2. Thereby, the plug 1 and the inclined roll 16 pierce-roll the billet 2.
- a hollow shell can be obtained by piercing and rolling the billet 2.
- the hollow shell is rolled by a mandrel mill, an elongator, a sizing mill or the like to produce a seamless metal pipe.
- L2 (mm) which is twice the maximum distance from the center C of the rear end of the billet 2 to the groove bottom surface 10, on the rear end surface 14 of the billet 2 satisfies the formula (4). preferable.
- the rear end center C of the billet 2 means the axis of the billet 2 on the rear end surface 14 of the billet 2. 0.30 ⁇ L2 / B ⁇ 0.60 (4)
- L2 / B indicates the ratio of the maximum width of the hole 7 to the billet diameter B on the rear end face 14 of the billet 2. If L2 / B is small, the contact portion pierced by the plug is hardly absorbed by the groove. If L2 / B is large, the groove 8 becomes excessively large, and the time spent processing the hole 7 increases. Further, when the hole 7 is formed by press working, the press load increases. Therefore, L2 / B is preferably within a predetermined range, as shown in Examples described later.
- the billet 2 may be, for example, steel (hereinafter also referred to as “alloy steel”) containing Cr: 1 to 12% by mass. Seamless metal pipes used in oil wells are required to have strength and corrosion resistance. Alloy steel is suitable as a material for seamless metal pipes used in oil wells and the like because of its high strength and corrosion resistance. On the other hand, alloy steel has low deformability. If the deformability of the billet is low, large burrs are likely to occur, and the entire burr may not fit in the groove. However, as shown in the examples described later, according to the manufacturing method of this embodiment, not only carbon steel but also a billet made of alloy steel suppresses the generation of burrs and manufactures a seamless metal tube. it can.
- FIG. 13 is a diagram showing the relationship between the temperature and the drawing value of steels having different compositions. More specifically, FIG. 13 shows the results of various steels heated to various temperatures and subjected to tensile tests on the various steels.
- the vertical axis indicates the aperture value (%)
- the horizontal axis indicates the temperature (° C.) of the steel.
- circles indicate the results for carbon steel (S45C)
- square marks indicate the results for alloy steel (2Cr steel).
- the “aperture value” is calculated by the following equation.
- the drawing value shown in FIG. 13 is less than 95%, it is known that burrs are likely to occur after piercing and rolling due to the low deformability of the billet.
- carbon steel has a drawing value of 95% or more in the temperature range of 1000 ° C. or higher, whereas alloy steel has an extremely small drawing value when the temperature is lower than 1200 ° C. I understand that. That is, it is clear that alloy steel has a lower deformability than carbon steel.
- the temperature at which the drawing value becomes 95% or more is about 1200 ° C. Therefore, when the billet made of alloy steel is pierced and rolled, the temperature of the billet is desirably 1200 ° C. or higher.
- a billet including a hole having a groove is used.
- the hole has an appropriate shape, the occurrence of burrs is suppressed regardless of the billet heating temperature, that is, even billets made of alloy steel with a heating temperature of less than 1300 ° C. Can be pierced and rolled. Thereby, in manufacture of a seamless metal pipe, the fall of an energy basic unit can be suppressed.
- the present inventors changed the shape of the hole formed in the central part of the billet rear end, and manufactured a hollow shell by piercing and rolling. More specifically, the billet was heated to form various holes having grooves shown in Table 2 at the center of the rear end of the billet. Each billet hole had four grooves. The four grooves of each billet were arranged at equal intervals in the billet circumferential direction. The heating temperature of the billet was 1245 ° C. The heated billet was pierced and rolled with a piercing machine to produce a hollow shell. The hollow shell had a diameter of 82 mm and a wall thickness of 11 mm. About the manufactured hollow shell, the present inventors evaluated generation
- Table 1 shows the billet composition used in this example.
- Table 2 shows the shape of the hole formed in the center of the rear end of the billet and the evaluation result of the presence or absence of burrs and rashes.
- the letter “NG” indicates that burrs or rashes have occurred
- the letter “A” indicates that a slight allowable burr or rash has occurred
- the letter “G” This shows that no burrs or rashes occurred.
- test numbers 1 and 5 large burrs occurred at the rear end of the hollow shell.
- test numbers 2 and 3 a rash occurred on the inner surface of the hollow shell.
- test numbers 6 to 8 burrs were generated at the rear end of the hollow shell, and rashes were generated on the inner surface.
- test numbers 10 and 13 a small burr allowed at the rear end of the hollow shell was generated.
- the present inventors concluded from the present example as follows. From Test Nos. 1 to 8, as the groove depth L1 / B formed at the center of the rear end of the billet is shallower, the occurrence of rash is suppressed. Further, from the test number 10, when the groove width D / B is small, the contact portion pierced by the plug is not easily absorbed by the groove, and burrs are easily generated.
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- Mechanical Engineering (AREA)
- Extrusion Of Metal (AREA)
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
Abstract
Description
0.12 ≦ D/B ≦ 0.25 (1)
0.10 ≦ H/B ≦ 0.20 (2)
0.05 ≦ L1/B < 0.10 (3)
穿孔圧延後の中空素管の後端に発生するバリ及びかぶれ疵について説明する。
図3は、後端部に円錐形状の穴が形成されたビレットを穿孔圧延する場合の断面図である。図3を参照して、後端部に円錐形状の穴7が形成されたビレット2では、バリの原因となる余肉が穴7の容積分だけ除去されている。そのため、バリは発生しにくい。しかしながら、後端部に円錐形状の穴7が形成されたビレット2を穿孔圧延すると、中空素管4の内面にかぶれ疵6が生じることがある。
図4は、後端部に円柱形状の穴が形成されたビレットを穿孔圧延する場合の断面図である。図4を参照して、後端部に円柱形状の穴7が形成されたビレット2では、穴7の容積分の余肉が除去されている。そのため、バリは発生しにくい。しかしながら、たとえば、先端が平坦なプラグ1によってビレット2を穿孔圧延した場合、プラグ1の先端の接触部分3が中空素管4から切り離されやすい。切り離された接触部分3は、穿孔機に堆積するため、定期的な清掃が必要となる。
0.12 ≦ D/B ≦ 0.25 (1)
0.10 ≦ H/B ≦ 0.20 (2)
0.05 ≦ L1/B < 0.10 (3)
0.30 ≦ L2/B ≦ 0.60 (4)
以下、本実施形態の継目無金属管の製造方法について説明する。製造方法は、準備工程と、加熱工程と、形成工程と、穿孔圧延工程と、を備える。
準備工程では、直径B(mm)を有するビレットを準備する。ビレットの材質はたとえば、鋼である。ビレットはたとえば、連続鋳造法や造塊法によって製造される。ビレットの直径は、特に限定されない。しかしながら、一般に、継目無金属管に製造されるビレットの直径は、20~400(mm)である。
加熱工程では、ビレットを加熱炉で加熱する。加熱温度は特に限定されない。しかしながら、エネルギー原単位の低下を抑制する観点から、加熱温度は1300℃未満であるのが好ましい。また、ビレットの変形能の観点から、加熱温度は1100℃以上であるのが好ましい。
図7は、本実施形態のビレットの斜視図である。図7を参照して、形成工程では、ビレット2の後端中央部に穴7を形成する。穴7は、後端面14からビレット2の軸方向に延びる。また、穴7は、後端面14からビレット2の軸方向に延びる4つの溝8を含む。4つの溝8はそれぞれ、ビレット2の軸心の周りに等間隔に配置されている。4つの溝8それぞれの形状は、同一である。したがって、以下では、4つの溝8のうちの1つの溝について説明する。
溝8は、式(1)を満たす溝幅D(mm)、式(2)を満たす溝高さH(mm)及び式(3)を満たす溝深さL1(mm)を有する。ここで、溝幅Dは、2つの溝側面9の間の距離を意味する。溝高さHは、溝側面9の端から溝底面10までの距離を意味する。溝深さL1は、溝8のビレット軸方向の距離を意味する。
0.12 ≦ D/B ≦ 0.25 (1)
0.10 ≦ H/B ≦ 0.20 (2)
0.05 ≦ L1/B < 0.10 (3)
図12は、穿孔圧延工程を示す図である。図12を参照して、ビレット2に穴を形成した後、ビレット2を穿孔機15を用いて穿孔圧延する。穿孔機15は、2つのコーン型傾斜ロール(以下、単に「傾斜ロール」という)16と、プラグ1と、芯金17とを含む。
0.30 ≦ L2/B ≦ 0.60 (4)
(絞り値[%])=((破断した部分の引張試験前の断面積)-(引張試験において破断した部分の断面積))/(破断した部分の引張試験前の断面積)×100
試験番号2及び3では、中空素管の内面にかぶれ疵が発生した。
試験番号6~8では、中空素管の後端にバリが発生し、内面にかぶれ疵が発生した。
試験番号10及び13では、中空素管の後端に許容される小さなバリが発生した。
試験番号9、11、12、14及び15では、中空素管にバリ、かぶれ疵はほとんど発生しなかった。
2:ビレット
3:接触部分
4:中空素管
5:バリ
6:かぶれ疵
7:穴
8:溝
9:溝側面
10:溝底面
11:クランプダイス
12:ダイス
13:駆動装置
14:後端面
15:穿孔機
16:傾斜ロール
17:芯金
18:プッシャ
19:シリンダ本体
20:シリンダ軸
21:接続部材
22:ビレット押し棒
23:入口ガイド
24:先端面
Claims (3)
- 複数の傾斜ロールと前記複数の傾斜ロールの間に配設されたプラグとを備えた穿孔機を用いた継目無金属管の製造方法であって、
直径B(mm)を有するビレットを準備する工程と、
前記ビレットを加熱する工程と、
加熱された前記ビレットの後端中央部に、式(1)を満たす溝幅D(mm)、式(2)を満たす溝高さH(mm)及び式(3)を満たす溝深さL1(mm)を有し、前記ビレットの軸方向に延びる4つの溝を含む穴を形成する工程と、
前記穿孔機により、前記穴が形成されたビレットを先端から穿孔圧延する工程とを備える、継目無金属管の製造方法。
0.12 ≦ D/B ≦ 0.25 (1)
0.10 ≦ H/B ≦ 0.20 (2)
0.05 ≦ L1/B < 0.10 (3) - 請求項1に記載の継目無金属管の製造方法であって、
前記ビレットの後端面上において、前記ビレットの後端中央から溝底面までの最大距離の2倍であるL2(mm)は、式(4)を満たす、継目無金属管の製造方法。
0.30 ≦ L2/B ≦ 0.60 (4) - 請求項1又は請求項2に記載の継目無金属管の製造方法であって、
前記ビレットの軸方向から見て、前記4つの溝は十字形状に設けられ、
前記4つの溝は、前記ビレットの後端面から延びる、継目無金属管の製造方法。
Priority Applications (6)
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EP18817834.7A EP3639938B1 (en) | 2017-06-12 | 2018-06-08 | Method for producing seamless metal pipe |
BR112019026170-2A BR112019026170A2 (pt) | 2017-06-12 | 2018-06-08 | método para produzir tubo de metal sem costura |
US16/619,631 US11305320B2 (en) | 2017-06-12 | 2018-06-08 | Method for producing seamless metal pipe |
JP2019525373A JP6819782B2 (ja) | 2017-06-12 | 2018-06-08 | 継目無金属管の製造方法 |
MX2019014866A MX2019014866A (es) | 2017-06-12 | 2018-06-08 | Metodo para producir tubo de metal sin costura. |
CN201880038325.5A CN110740820B (zh) | 2017-06-12 | 2018-06-08 | 无缝金属管的制造方法 |
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EP (1) | EP3639938B1 (ja) |
JP (1) | JP6819782B2 (ja) |
CN (1) | CN110740820B (ja) |
BR (1) | BR112019026170A2 (ja) |
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JPS59174203A (ja) * | 1983-03-22 | 1984-10-02 | Sumitomo Metal Ind Ltd | 継目無金属管の製造方法 |
JPS60124404A (ja) * | 1983-12-07 | 1985-07-03 | Kawasaki Steel Corp | 中空素管の穿孔圧延方法 |
JPH07214113A (ja) | 1994-01-31 | 1995-08-15 | Sanyo Special Steel Co Ltd | ピアサー穿孔時のバリ発生防止方法 |
JP2001219205A (ja) | 2000-02-10 | 2001-08-14 | Sumitomo Metal Ind Ltd | 継目無管の製造方法 |
JP2004082174A (ja) * | 2002-08-28 | 2004-03-18 | Jfe Steel Kk | 継目無鋼管の製造方法 |
WO2009122620A1 (ja) | 2008-03-31 | 2009-10-08 | 住友金属工業株式会社 | 継目無金属管の製造方法及びそれに用いられるポンチ |
JP2015167960A (ja) | 2014-03-06 | 2015-09-28 | Jfeスチール株式会社 | 継目無鋼管の穿孔方法及びそれに用いるポンチ |
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2018
- 2018-06-08 BR BR112019026170-2A patent/BR112019026170A2/pt unknown
- 2018-06-08 CN CN201880038325.5A patent/CN110740820B/zh active Active
- 2018-06-08 EP EP18817834.7A patent/EP3639938B1/en active Active
- 2018-06-08 WO PCT/JP2018/021960 patent/WO2018230450A1/ja unknown
- 2018-06-08 US US16/619,631 patent/US11305320B2/en active Active
- 2018-06-08 MX MX2019014866A patent/MX2019014866A/es unknown
- 2018-06-08 JP JP2019525373A patent/JP6819782B2/ja active Active
Patent Citations (7)
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JPS59174203A (ja) * | 1983-03-22 | 1984-10-02 | Sumitomo Metal Ind Ltd | 継目無金属管の製造方法 |
JPS60124404A (ja) * | 1983-12-07 | 1985-07-03 | Kawasaki Steel Corp | 中空素管の穿孔圧延方法 |
JPH07214113A (ja) | 1994-01-31 | 1995-08-15 | Sanyo Special Steel Co Ltd | ピアサー穿孔時のバリ発生防止方法 |
JP2001219205A (ja) | 2000-02-10 | 2001-08-14 | Sumitomo Metal Ind Ltd | 継目無管の製造方法 |
JP2004082174A (ja) * | 2002-08-28 | 2004-03-18 | Jfe Steel Kk | 継目無鋼管の製造方法 |
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JP2015167960A (ja) | 2014-03-06 | 2015-09-28 | Jfeスチール株式会社 | 継目無鋼管の穿孔方法及びそれに用いるポンチ |
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Title |
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See also references of EP3639938A4 |
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EP3639938A4 (en) | 2021-03-10 |
MX2019014866A (es) | 2020-02-13 |
JP6819782B2 (ja) | 2021-01-27 |
CN110740820A (zh) | 2020-01-31 |
BR112019026170A2 (pt) | 2020-06-30 |
CN110740820B (zh) | 2020-12-08 |
JPWO2018230450A1 (ja) | 2020-03-19 |
EP3639938B1 (en) | 2022-02-16 |
EP3639938A1 (en) | 2020-04-22 |
US11305320B2 (en) | 2022-04-19 |
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