JP6041778B2 - Heat transfer tube and manufacturing method thereof - Google Patents

Description

  The present invention relates to a heat transfer tube and a method for manufacturing the same.

  Conventionally, for example, the following are known as heat transfer tubes. That is, as a first example, there is a heat transfer tube including a metal tube and a porous body bonded to the inner surface of the tube (see, for example, Patent Document 1). As a second example, there is a heat transfer tube provided with a metal tube and a spiral coil fixed to the inner surface of the tube by plating (for example, see Patent Document 2).

  According to these heat transfer tubes, the contact area between the fluid flowing inside the heat transfer tube and the heat transfer tube is increased by the porous body or coil provided on the inner surface of the tube.

JP-A 63-189793 JP-A 61-14033

  However, in the heat transfer tube of the first example, since the porous body is bonded to the inner surface of the tube body, the heat transfer performance of the heat transfer tube is reduced by the adhesive interposed between the porous body and the tube body. There is a risk of doing. In addition, since the member provided on the inner surface of the tubular body and in contact with the fluid is a porous body, the heat transfer performance of the heat transfer tube may also be reduced in this respect.

  In addition, when the porous body is fixed to the inner surface of the tube body by adhesion as in the first example, or when the coil is fixed to the inner surface of the tube body by plating as in the second example, In addition, it takes time to fix the porous body and the coil, and the manufacturing cost of the heat transfer tube increases.

  Then, an object of this invention is to provide the heat exchanger tube which can ensure heat transfer property, and can reduce manufacturing cost, and its manufacturing method.

  In order to achieve the above object, a method of manufacturing a heat transfer tube according to claim 1 includes a powder contact step of bringing a metal powder into contact with an inner surface of a metal tube, and the metal powder on an inner surface of the tube. In a state where the body is in contact, a part of the tube body and a part of the metal powder are melted by irradiating a high energy beam from the outside of the tube body toward the tube body and the metal powder. And a welding step of obtaining a heat transfer tube by integrally forming a convex portion protruding inside the tube body by solidifying the melt and generating the melt.

  According to this method for manufacturing a heat transfer tube, the projecting portion protruding inside the tube is integrally formed with the tube. And since this convex part is formed with the melt of a metal powder, it is made from metal. Therefore, the heat transfer property of the heat transfer tube can be ensured. Moreover, since this convex part is formed when a high energy beam is irradiated toward the pipe body and the metal powder from the outside of the pipe body, the convex part is easily formed on the inside of the pipe body. It is possible. Thereby, the manufacturing cost of a heat exchanger tube can be reduced.

  The heat transfer tube manufacturing method according to claim 2 is the heat transfer tube manufacturing method according to claim 1, wherein, in the welding step, the high energy beam is moved relative to the tube body and the metal powder. Then, a part of the tube body and a part of the metal powder are melted along the relative movement direction of the high energy beam.

  According to this method of manufacturing a heat transfer tube, a high energy beam is moved relative to the tube and the metal powder, and a part of the tube and one of the metal powder are moved along the relative movement direction of the high energy beam. Since the portion is melted, a melt can be generated continuously in the relative movement direction of the high energy beam. Thereby, the convex part of a protrusion can be formed in a pipe body by solidifying this melt.

  The method for manufacturing a heat transfer tube according to claim 3 is the method for manufacturing a heat transfer tube according to claim 2, wherein in the welding step, the high energy beam is irradiated so that a part of the tube body and the metal In this method, a molten pool as the melt is formed in a part of the powder, and the high energy beam is relatively moved while forming a keyhole in the molten pool.

  According to this method for manufacturing a heat transfer tube, a high energy beam is relatively moved while forming a keyhole in a molten pool formed in a part of the tube and a part of the metal powder. Therefore, since the high energy beam can reach the deep position of the metal powder through the keyhole, the height of the convex portion protruding to the inside of the tube can be further increased.

  The method for manufacturing a heat transfer tube according to claim 4 is the method for manufacturing a heat transfer tube according to any one of claims 1 to 3, wherein the focus of the high energy beam is the tube body in the welding step. The high energy beam is irradiated from the outside of the tube toward the tube and the metal powder in a state set at any position from the outer surface of the tube to the inside of the metal powder.

  According to this heat transfer tube manufacturing method, the focal point of the high-energy beam is set at any position from the outer surface of the tube body to the inside of the metal powder. It can be effectively melted to produce a melt.

  The heat transfer tube manufacturing method according to claim 5 is the heat transfer tube manufacturing method according to any one of claims 1 to 4, wherein, in the powder contact step, the metal is disposed inside the tube body. In this method, the metal powder is brought into contact with the inner surface of the tubular body by filling the powder.

  According to this method of manufacturing a heat transfer tube, the metal powder is filled inside the tube body, so that the flow of the metal powder can be suppressed. Thereby, since it can suppress that the shape of the melt of metal powder collapses, a melt can be solidified, maintaining the shape of a melt more stably.

  As described above in detail, according to the present invention, the heat transfer performance of the heat transfer tube can be ensured and the manufacturing cost of the heat transfer tube can be reduced.

It is a figure explaining the flow of the manufacturing method of a heat exchanger tube. It is 1st explanatory drawing explaining the flow which forms a convex part in a tubular body. It is a 2nd explanatory view explaining the flow which forms a convex part in a tubular body. It is an expansion perspective view of the convex part formed in the tubular body, and its peripheral part. It is a figure which shows the 1st specific example of a heat exchanger tube. It is a figure which shows the 2nd specific example of a heat exchanger tube. It is a figure which shows the 3rd specific example of a heat exchanger tube. It is a figure which shows the 4th specific example of a heat exchanger tube. It is a figure which shows the 5th example of a heat exchanger tube. It is a figure which shows the 1st modification of the manufacturing method of a heat exchanger tube. It is a figure which shows the 2nd modification of the manufacturing method of a heat exchanger tube. It is a figure which shows the 3rd modification of the manufacturing method of a heat exchanger tube. It is a figure which shows the 4th modification of the manufacturing method of a heat exchanger tube.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, in the present embodiment, as an example, a method for manufacturing a heat transfer tube 10 having a metal tube 12 and a plurality of convex portions 14 protruding inside the tube 12 will be described. .

  The manufacturing apparatus 20 used for the manufacturing method of the heat transfer tube 10 includes an emission unit 24 that emits a high energy beam, an irradiation unit 26 that irradiates the target with the high energy beam emitted from the emission unit 24, and a tube. A drive unit 28 that rotates and moves the body 12 around an axis and a control unit 30 that controls them are provided.

  The emission unit 24 is configured by a laser oscillator, and the high energy beam emitted from the emission unit 24 is, for example, a laser beam. In the emission unit 24, the energy of the emitted high energy beam can be adjusted. The irradiation unit 26 is configured by an optical system including a lens and the like. In the irradiation unit 26, the focal length of the irradiated high energy beam can be adjusted by moving a lens or the like.

  And with this manufacturing apparatus 20, the heat exchanger tube 10 is manufactured in the following ways. That is, first, as shown in FIG. 1A, the circular tubular body 12 is set in the manufacturing apparatus 20.

  Subsequently, as shown in FIG. 1B, the metal powder 32 is filled inside the tube body 12, and the openings on both sides of the tube body 12 are closed by a pair of lids 34. At this time, a sufficient amount of the metal powder 32 is filled inside the tube body 12 so that the metal powder 32 is brought into contact with the entire inner surface 12A of the tube body 12 (hereinafter referred to as powder contact). Process). In this embodiment, the metal powder 32 which is the same metal as the metal pipe body 12 is used as an example. As this metal, for example, stainless steel, iron, aluminum, copper and the like are appropriately selected.

  Then, as shown in FIG. 1C, the tubular body 12 and the metallic powder are irradiated from the irradiation unit 26 located on the radially outer side of the tubular body 12 with the metallic powder 32 filled inside the tubular body 12. A high energy beam 22 is irradiated toward the body 32.

  More specifically, the focal length of the high energy beam 22 is adjusted by controlling the irradiation unit 26 by the control unit 30 and moving the lens or the like in the irradiation unit 26. As shown in FIG. 2A, the focal point 22A of the high energy beam 22 is set at a position closer to the metal powder 32 than the inner surface 12A of the tube body 12 (inner side of the tube body 12 than the inner surface 12A). . In this state, the high energy beam 22 is irradiated from the outside of the tube body 12 toward the tube body 12 and the metal powder 32.

  When the high energy beam 22 is irradiated in this way, a molten pool 36 as a melt is formed on a part of the tube body 12 and a part of the metal powder 32. When the power density of the high energy beam 22 is high, metal vaporization occurs on the surface of the molten pool 36 and metal vapor 38 is generated. In addition, a repulsive force is generated on the surface of the molten pool 36 by the steam 38, and a dent is generated in the central portion of the molten pool 36. When this recess becomes deep, a keyhole 40 is formed in the molten pool 36. When the keyhole 40 is thus formed in the molten pool 36, the high energy beam 22 reaches the deep position of the metal powder 32 through the keyhole 40.

  Then, as shown in FIG. 2B, the high energy beam 22 is moved relative to the tube body 12 and the metal powder 32 while forming the keyhole 40 in the molten pool 36. The relative movement direction of the high energy beam 22 is the circumferential direction of the tube body 12. In addition, relative movement of the high energy beam 22 with respect to the tube body 12 and the metal powder 32 is such that the drive unit 28 is operated by the control unit 30 shown in FIG. This is done by rotating the

  When the high energy beam 22 is relatively moved in this way, a molten pool 36 is generated along the relative movement direction of the high energy beam 22 as shown in FIG. At this time, the molten pool 36 is formed at the irradiation position P of the relatively moving high energy beam 22, but the high energy beam 22 is relatively moved before the molten pool 36 expands. The molten pool 36 is cooled and solidified on the rear side R from the irradiation position P in FIG.

  As described above, in the present embodiment, the molten pool 36 is formed at the irradiation position P of the relatively moving high energy beam 22, but at the rear side R of the irradiation position P in the relative movement direction of the high energy beam 22. The relative movement speed of the high energy beam 22 is set so that 36 is cooled and solidified.

  Then, as the molten pool 36 is cooled and solidified in this manner, a convex portion 14 that protrudes inside the tube body 12 is formed as shown in FIG. The convex portion 14 is formed by solidifying a molten pool 36 formed by melting a part of the pipe body 12 and a part of the metal powder 32, and is thus integrated with the pipe body 12. It is formed. Moreover, since the high energy beam 22 is relatively moved in the circumferential direction of the tubular body 12 as described above, the convex portion 14 is formed in a protrusion extending in the circumferential direction of the tubular body 12.

  In this embodiment, as shown in FIG. 2C, only a part of the metal powder 32 filled inside the tube body 12 is melted, and the metal powder 32 is not melted. The remaining part remains. When the molten pool 36 is cooled and solidified, the remaining metal powder 32 plays a role of a mold (maintaining the shape of the molten pool 36 and radiating heat). For this reason, in this embodiment, the molten pool 36 is solidified and the convex part 14 is formed in the state in which the shape of the molten pool 36 (a shape in which the optical axis direction of the high energy beam 22 is the depth direction) is maintained. The

  In the present embodiment, as shown in FIG. 1C, after the driving unit 28 is operated by the control unit 30 and the tubular body 12 is moved in the axial direction, the above operation is repeated, thereby Convex portions 14 are respectively formed at a plurality of locations separated in the axial direction of the body 12 (the welding process). Thereafter, the pair of lids 34 is removed from the tube body 12, and the metal powder 32 remaining inside the tube body 12 is discharged from the openings on both sides of the tube body 12 to the outside of the tube body 12 (powder). Removal step).

  In the above manner, as shown in FIG. 1D, the heat transfer tube 10 having the tube body 12 and a plurality of convex portions 14 protruding inside the tube body 12 is obtained.

  2D shows a side cross-sectional view of the convex portion 14 and its peripheral portion in the heat transfer tube 10 manufactured as described above, and FIG. 2E shows the convex portion 14. And the front sectional view of the peripheral part is shown.

  On the other hand, FIG. 3 shows a case where the relative movement speed of the high energy beam 22 is made slower than in the case of FIG. The manufacturing method shown in FIGS. 3A to 3D is the same as the manufacturing method shown in FIGS. 2A to 2D. FIG. 3D shows a side cross-sectional view of the convex portion 14 and its peripheral portion in the heat transfer tube 10 manufactured by slowing the relative moving speed of the high energy beam 22. ) Shows a front sectional view of the convex portion 14 and its peripheral portion.

  As shown in FIG. 2D, when the relative movement speed of the high energy beam 22 is increased, the spread of heat around the high energy beam 22 is suppressed. The curvature of the curved surface 14 </ b> A formed at both ends of the is small. Further, as shown in FIG. 2 (E), the width of the convex portion 14 is narrowed, and the curvature of the curved surface 14B formed on both sides of the convex portion 14 is also small.

  On the other hand, as shown in FIG. 3D, when the relative movement speed of the high energy beam 22 is decreased, the heat spreads around the high energy beam 22, so that a molten pool 36 is formed. The area is enlarged. Accordingly, the curvature of the curved surface 14A formed at both ends in the length direction of the convex portion 14 is increased. Further, as shown in FIG. 3E, the width of the convex portion 14 is widened, and the curvature of the curved surface 14B formed on both sides of the convex portion 14 is also large.

  Although not particularly illustrated, when the energy of the high energy beam 22 emitted from the emission unit 24 is increased, the heating temperature by the high energy beam 22 is increased and the generation of the molten pool 36 is promoted. The depth of 36, and thus the height of the convex portion 14 is increased. Further, when the focal point 22A of the high energy beam 22 is set at a position (deep position) farther from the inner surface 12A of the tube body 12 on the metal powder 32 side, the high energy beam 22 reaches a deeper position of the metal powder 32. Since it is heated, the depth of the molten pool 36 and, consequently, the height of the convex portion 14 is increased.

  Thus, in the manufacturing method of the heat transfer tube 10 described above, the relative movement speed of the high energy beam 22 and the high energy beam 22 are changed according to the specifications of the heat transfer tube 10 (required height, shape, etc. of the convex portion 14). The energy, the focal length of the high energy beam 22 and the like are set.

  Moreover, the convex part 14 and its peripheral part in the heat exchanger tube 10 manufactured by the above procedure are shown by the perspective view in FIG. As shown in FIG. 4, a plurality of granular protrusions 42 are formed on the surface of the convex portion 14. The plurality of granular protrusions 42 are formed by solidifying the metal powder 32 (see FIGS. 2 and 3) attached to the molten pool 36 when the molten pool 36 is solidified without being completely melted. is there. That is, the granular protrusion 42 is an incomplete melt of the metal powder 32, and therefore retains a powder shape. In addition, it is possible to change the magnitude | size (namely, surface roughness of the convex part 14) of the granular protrusion 42 by changing the particle size of the metal powder 32 used.

  Next, the operation and effect of one embodiment of the present invention will be described.

  As described above in detail, according to the present embodiment, the convex portion 14 protruding inward of the tubular body 12 is formed integrally with the tubular body 12. In addition, the convex portion 14 is made of metal because it is formed by a melt of the metal powder 32. Therefore, the heat transfer property of the heat transfer tube 10 can be ensured. Further, since the convex portion 14 is formed by irradiating the high energy beam 22 from the outside of the tubular body 12 toward the tubular body 12 and the metal powder 32, the convex portion 14 is convex on the inside of the tubular body 12. The portion 14 can be easily formed. Thereby, the manufacturing cost of the heat exchanger tube 10 can be reduced.

  Moreover, after generating the molten pool 36 which makes the optical axis direction of the high energy beam 22 a depth direction, this molten pool 36 is solidified, and the convex part 14 is formed. Therefore, since it is not necessary to laminate the melt of the metal powder 32 in order to form the convex portion 14 on the tube body 12, for example, when producing a laminate such as three-dimensional modeling or powder build-up welding. In comparison, the number of manufacturing steps can be reduced. Thereby, since the time which manufactures the heat exchanger tube 10 can be shortened, the manufacturing cost of the heat exchanger tube 10 can be reduced more.

  In addition, since only a part of the metal powder 32 in contact with the metal tube 12 is melted, when the molten pool 36 is solidified, the remaining metal powder 32 is in contact with the molten pool. It plays the role of mold (maintenance of the molten pool 36 and heat dissipation). Therefore, since the shape of the molten pool 36 (the shape in which the optical axis direction of the high energy beam 22 is the depth direction) can be maintained, the molten pool 36 can be solidified while maintaining the shape of the molten pool 36. . Thereby, the height of the convex part 14 is securable.

  Further, the high energy beam 22 is moved relative to the tube body 12 and the metal powder 32, and a part of the tube body 12 and a part of the metal powder 32 are moved along the relative movement direction of the high energy beam 22. Since it is melted, the molten pool 36 can be generated continuously in the relative movement direction of the high energy beam 22. Thereby, the convex part 14 of a protrusion can be formed in the pipe body 12 by solidifying this molten pool 36. FIG.

  Further, since the focal point 22A of the high energy beam 22 is set at a position closer to the metal powder 32 than the inner surface 12A of the tube body 12 (inside the tube body 12 than the inner surface 12A), it is deeper than the inner surface 12A of the tube body 12. The molten pool 36 can be generated by melting the metal powder 32 to the position. Thereby, the height of the convex part 14 can be made higher.

  Further, the high energy beam 22 is relatively moved while forming the keyhole 40 in the molten pool 36 formed in a part of the tube body 12 and a part of the metal powder 32. Accordingly, since the high energy beam 22 can reach the deep position of the metal powder 32 through the keyhole 40, the height of the protrusion 14 of the ridge can be further increased.

  Moreover, since the metal powder 32 is filled inside the tube body 12, the flow of the metal powder 32 can be suppressed. Thereby, since it can suppress that the shape of the molten pool 36 which is a melt of the metal powder 32 collapses, the molten pool 36 can be solidified, maintaining the shape of the molten pool 36 more stably. .

  Next, a specific example of the heat transfer tube 10 will be described.

  The heat transfer tube 10 according to the specific example shown below is manufactured by applying the above-described method for manufacturing the heat transfer tube 10. The following heat transfer tubes 10 are used in, for example, heat exchangers, boilers, absorption refrigerators, heat pumps, air conditioners, and the like. For ease of understanding, in the specific examples shown below, the same names as those in the above embodiment will be described using the same reference numerals.

[First example]
In the heat transfer tube 10 according to the first specific example shown in FIG. 5, a plurality of convex portions 14 (four convex portions 14 as an example) are formed. Each of the plurality of convex portions 14 is formed in a spiral shape. Further, the plurality of convex portions 14 have the same shape, and are formed at regular intervals in the circumferential direction of the tubular body 12. The pitch of the spiral shape in each convex portion 14 is constant.

[Second example]
One convex portion 14 is formed on the heat transfer tube 10 according to the second specific example shown in FIG. The convex portion 14 is formed in a spiral shape. Further, the helical pitch in the convex portion 14 is changed. That is, the helical pitch in the convex portion 14 is increased from the one side in the axial direction of the tube body 12 toward the other side.

[Third example]
A plurality of convex portions 14 are formed on the heat transfer tube 10 according to the third specific example shown in FIG. Each of the plurality of convex portions 14 is formed in an annular shape along the circumferential direction of the tube body 12. Moreover, the space | interval of the some convex part 14 is wide in the axial direction one side of the tubular body 12, and the space | interval of the some convex part 14 is narrow in the axial direction other side of the tubular body 12. FIG. Further, the number of the plurality of convex portions 14 is small on one side in the axial direction of the tubular body 12, and the number of the plurality of convex portions 14 is large on the other side in the axial direction of the tubular body 12. The axial direction other side of the pipe body 12 is made into the area | region which wants to improve heat conductivity as an example. In this way, in the region where heat transfer is desired to be increased, when the number of the plurality of convex portions 14 is increased and the interval between the plurality of convex portions 14 is reduced, the fluid flowing inside the heat transfer tube 10 and the heat transfer tubes 10 This is preferable because the contact area increases.

[Fourth example]
In the heat transfer tube 10 according to the fourth specific example shown in FIG. 8, a plurality of convex portions 14 (four convex portions 14 as an example) are formed. Each of the plurality of convex portions 14 extends linearly along the axial direction of the tubular body 12. Further, the plurality of convex portions 14 have the same shape, and are formed at regular intervals in the circumferential direction of the tubular body 12.

[Fifth example]
In the heat transfer tube 10 according to the fifth example shown in FIG. 9, the tube body 12 is formed by bending. The heat transfer tube 10 has a plurality of convex portions 14 (four convex portions 14 as an example). Each of the plurality of convex portions 14 extends along the axial direction of the tubular body 12. In addition, the plurality of convex portions 14 are formed at regular intervals in the circumferential direction of the tubular body 12.

  In each of the above specific examples, the convex portion 14 is formed perpendicular to the peripheral wall portion of the tubular body 12. However, the projection 14 may be formed obliquely with respect to the peripheral wall portion of the tubular body 12 by irradiating the peripheral wall portion of the tubular body 12 with the high energy beam 22 obliquely.

  Moreover, the convex part 14 may be formed so that it may extend in the shape of a curve or a bent line other than the shape given in the above specific example, or may be formed in other shapes.

  The convex portion 14 may be formed to have a substantially constant height, and at least one of the relative movement speed of the high energy beam 22, the energy of the high energy beam 22, and the focal length of the high energy beam 22. The shape of the convex portion 14 (for example, at least one of height and width) may be changed by changing.

  In addition, the tubular body 12 is formed in a circular tube shape, but may be formed in a shape other than the circular tube shape (for example, a cross-sectional square shape or a cross-sectional elliptical shape).

  Next, a modification of one embodiment of the present invention will be described.

[First modification]
In the above embodiment, as shown in FIG. 1, the metal powder 32 is filled inside the tube body 12. However, as shown in FIG. 10, a smaller amount of the metal powder 32 than filled may be accommodated inside the tube body 12. That is, in the modification shown in FIG. 10, the tube body 12 is arranged so that its central axis extends in the horizontal direction. Further, the amount of the metal powder 32 is set so that the surface of the metal powder 32 is located at a position lower than the central axis of the tube body 12 and higher than the convex portion 14 in a side sectional view of the tube body 12. .

  Further, when a smaller amount of the metal powder 32 than is filled in this way is accommodated inside the tube body 12, the high energy beam 22 is irradiated from the lower side in the vertical direction of the tube body 12 and is driven. The tube body 12 may be rotated around the axis by the portion 28.

  If it does in this way, the quantity of the metal powder 32 to be used can be decreased. Further, even if the tube 12 rotates around the axis, the metal powder 32 is located in the lower portion of the tube 12 due to its own weight, so that the tube is irradiated by the high energy beam 22 irradiated from the lower side in the vertical direction of the tube 12. A part of 12 and a part of the metal powder 32 can be melted, whereby the protrusion 14 of the protrusion can be formed.

[Second modification]
Moreover, in the said embodiment, as FIG. 1 shows, in the state which the pipe body 12 has been arrange | positioned so that the center axis | shaft of the pipe body 12 may extend in a horizontal direction, the convex part 14 is on the surrounding wall part of this pipe body 12. As shown in FIG. Was formed. However, as shown in FIG. 11, the convex portion 14 may be formed on the peripheral wall portion of the tubular body 12 in a state where the tubular body 12 is arranged so that the central axis of the tubular body 12 extends in the vertical direction. . Moreover, the convex part 14 may be formed in several places spaced apart in the axial direction of the pipe body 12. FIG.

  Thus, when forming the convex part 14 in the several places spaced apart to the axial direction of the tubular body 12, if it is set as the state which has arrange | positioned the tubular body 12 so that the central axis of the tubular body 12 may extend in a perpendicular direction, a convex part It is preferable because the metal powder 32 can be retained by its own weight in a region where the 14 is to be formed.

  In other words, when forming the convex portions 14 at a plurality of locations spaced apart in the axial direction of the tubular body 12, the tubular body 12 is arranged such that the central axis of the tubular body 12 extends in the horizontal direction (see FIG. 1). When one convex portion 14 is formed, the metal powder 32 is biased toward the one convex portion 14, and a cavity is formed in the metal powder 32 at a place where the other convex portion 14 is formed. There is a fear.

  However, when forming the convex portions 14 at a plurality of positions spaced apart in the axial direction of the tubular body 12, assuming that the tubular body 12 is arranged so that the central axis of the tubular body 12 extends in the vertical direction, the convex portion 14 is The metal powder 32 can be retained by its own weight in the region to be formed. Thereby, since it can suppress that a metal powder 32 forms a cavity in the area | region which wants to form the convex part 14, the convex part 14 can be formed stably.

[Third modification]
Further, in the above embodiment, as shown in FIG. 1, the metal powder 32 is in contact with the inner surface 12 </ b> A of the tube body 12 by filling the inside of the tube body 12 with the metal powder 32. However, for example, as shown in FIG. 12A, the metal powder 32 is contained in a paste 58 such as an adhesive, and the paste 58 containing the metal powder 32 is formed on the tube body 12. The metal powder 32 may be brought into contact with the inner surface 12A of the tubular body 12 by being attached to the inner surface 12A.

  Then, as shown in FIGS. 12B and 12C, the high energy beam 22 is irradiated toward the tube body 12 and the metal powder 32 in the same manner as described above, whereby one of the tube bodies 12 is irradiated. The part 14 and a part of the metal powder 32 are melted to form a molten pool, and the convex portion 14 may be formed on the tube body 12 by solidifying the molten pool.

  Thus, when the paste agent 58 containing the metal powder 32 is used, the amount of the metal powder 32 to be used can be reduced.

  Any method may be used as long as the metal powder 32 can be brought into contact with the inner surface 12A of the tube body 12. For example, the metal powder 32 may be brought into contact with the inner surface 12 </ b> A of the tube body 12 by the metal powder 32 being piled up on the inner surface 12 </ b> A of the tube body 12. Further, for example, the metal powder 32 may be brought into contact with the inner surface 12A of the tubular body 12 by using a holding material such as a tape or a film.

[Fourth modification]
Moreover, in the said embodiment, the heat exchanger tube 10 was comprised by the pipe body 12 and the convex part 14. As shown in FIG. However, as shown in FIG. 13, the heat transfer tube 10 may be configured by a tube body 12 (outer tube), an inner tube 62 as a holding member, and a convex portion 14. The inner tube 62 is inserted inside the tube body 12. The tube body 12 and the inner tube 62 constitute a double tube 64 as a double structure, and a space is provided between the tube body 12 and the inner tube 62.

  FIGS. 13A to 13D show a flow of manufacturing the heat transfer tube 10 by forming a plurality of convex portions 14 on the double tube 64. The procedure of the manufacturing method shown in FIGS. 13A to 13D is the same as the procedure of the manufacturing method shown in FIGS. 1A to 1D.

  Further, in the modified example shown in FIG. 13, the tube body 12 is formed from the outside of the double tube 64 with the metal powder 32 filled inside the tube body 12 (between the tube body 12 and the inner tube 62). The high energy beam 22 is irradiated toward the inner tube 62 and the metal powder 32. At this time, the high energy beam 22 is irradiated from the outside of the double tube 64 to the tube 12, the inner tube 62 and the metal powder 32 (so that the high energy beam 22 reaches the inner tube 62). The energy of the beam 22 and the focal length of the high energy beam 22 are set. And the convex part 14 which connects the tubular body 12 and the inner tube | pipe 62 is formed by irradiating the high energy beam 22 to the tubular body 12, the inner tube | pipe 62, and the metal powder 32 in this way.

  As described above, the method for manufacturing the heat transfer tube 10 includes the double tube 64 having the tube body 12 and the inner tube 62, and the convex portion 14 that protrudes inside the tube body 12 and connects the tube body 12 and the inner tube 62. It may be applied to the manufacture of the heat transfer tube 10 having the following.

[Other variations]
Moreover, in the said embodiment, although the metal powder 32 which is the same metal as the metal pipe body 12 was used, even if the metal powder 32 which is a metal different from the metal pipe body 12 is used. good. In addition, when the metal powder 32 which is a different metal from the metal pipe body 12 is used, the convex part 14 is formed with the alloy of a dissimilar metal. For example, a combination of a metal having good corrosion resistance and a metal having good heat conductivity is preferably used as the dissimilar metal because the corrosion resistance and heat conductivity in the convex portion 14 can be secured.

  In the above embodiment, the emitting unit 24 is configured by a laser oscillator, and the high energy beam 22 is a laser beam as an example. However, the emitting unit 24 may be configured to emit a high energy beam other than a laser, such as an electron beam or a plasma beam. And the convex part 14 may be formed using high energy beams other than this laser.

  In the above embodiment, the focal point 22A of the high energy beam 22 is set at a position closer to the metal powder 32 than the inner surface 12A of the tube body 12 (inside the tube body 12 from the inner surface 12A). However, for example, if a part of the tube body 12 and a part of the metal powder 32 can be melted, the focal point 22A of the high energy beam 22 extends from the outer surface of the tube body 12 to the inside of the metal powder 32. It may be set at any of the positions. That is, the focal point 22A of the high-energy beam 22 may be set on the outer surface of the tube body 12, or may be set at any position from the inner side to the inner surface of the tube body 12, as described above. As described above, it may be set at a position closer to the metal powder 32 than the inner surface of the tube body 12 (inside the metal powder 32). Further, when the focal point 22A of the high energy beam 22 is set at any position from the outer surface of the tube body 12 to the inside of the metal powder 32 in this way, a part of the tube body 12 and the metal powder 32 are removed. The molten pool 36 may be formed in part, and the keyhole 40 may be formed in the molten pool 36.

  Further, in the above embodiment, the high energy beam 22 is moved relative to the tubular body 12 and the metal powder 32 by rotating the tube body 12 around the axis by the drive unit 28. The high energy beam 22 may be moved relative to the tube body 12 and the metal powder 32 by moving the irradiation unit 26.

  In addition, the example which can be combined among the said some specific example and modification may be combined suitably, and may be implemented.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 ... Heat-transfer tube, 12 ... Tube, 12A ... Inner surface, 14 ... Convex part, 20 ... Manufacturing apparatus, 22 ... High energy beam, 22A ... Focus, 24 ... Emitting part, 26 ... Irradiation part, 28 ... Drive part, 30 ... Control part, 32 ... Metal powder, 34 ... Lid, 36 ... Melting pool (an example of a melt), 38 ... Steam, 40 ... Keyhole, 42 ... Granular protrusion, 58 ... Paste agent, 62 ... Inner tube (holding) Example of member), 64 ... Double tube (Example of double structure)

Claims (5)

A powder contact process in which metal powder is brought into contact with the inner surface of a metal tube;
In a state where the metal powder is in contact with the inner surface of the tube body, by irradiating a high energy beam from the outside of the tube body toward the tube body and the metal powder, a part of the tube body and the Welding to obtain a heat transfer tube by melting a part of the metal powder to produce a melt and solidifying the melt to form a convex portion projecting inside the tube integrally with the tube. Process,
The manufacturing method of the heat exchanger tube provided with. In the welding step, the high energy beam is relatively moved with respect to the tube and the metal powder, and a part of the tube and one of the metal powder are moved along a relative movement direction of the high energy beam. Melt the part,
The manufacturing method of the heat exchanger tube of Claim 1. In the welding process, by irradiating the high energy beam, a molten pool as the melt is formed in a part of the tubular body and a part of the metal powder, and a keyhole is formed in the molten pool. While relatively moving the high energy beam,
The manufacturing method of the heat exchanger tube of Claim 2. In the welding step, the tube and the metal powder from the outside of the tube body in a state where the focal point of the high energy beam is set to any position from the outer surface of the tube body to the inside of the metal powder. Irradiating the high-energy beam toward
The manufacturing method of the heat exchanger tube as described in any one of Claims 1-3. In the powder contact step, the metal powder is brought into contact with the inner surface of the tube by filling the tube with the metal powder.
The manufacturing method of the heat exchanger tube as described in any one of Claims 1-4.

Images