JP5751854B2 - Thermal spraying method and spraying machine for dissimilar metals - Google Patents

Description

  The present invention relates to a thermal spraying method and a thermal sprayer for spraying different types of metals onto a pipe.

  Already, the present applicant has proposed to form a dissimilar metal film having a sacrificial anode action such as zinc and a zinc alloy on the outer surface of the pipe in order to improve the corrosion resistance of the ductile cast iron pipe or the like. (See Patent Document 1). That is, as disclosed in Patent Document 1, for example, a Zn wire is used as the first wire, and at least one of a Zn—Sn—Mg wire or Ti, Co, Ni, and P is used. Arc spraying is simultaneously performed on the outer surface of the pipe using a zinc alloy wire containing one as the second wire.

  When this thermal spraying method is used, a thermal spray coating of Zn—Sn—Mg alloy can be formed on the iron surface. Since this zinc alloy has a lower potential than iron, it acts as a sacrificial anode, and it is considered that zinc in the zinc alloy melts. The dissolved zinc is believed to form a relatively stable corrosion product on the surface, thereby inhibiting the consumption or dissolution of the remaining zinc. Moreover, zinc and zinc alloys, such as a Zn-Sn-Mg alloy, are used as a wire rather than the porosity of the sprayed coating obtained by using the same kind zinc alloys, such as a Zn-Sn-Mg alloy, as a wire. It is also considered that the anticorrosion performance was improved because of the low porosity of the sprayed coating obtained. For these reasons, it is considered that the corrosion resistance of the outer surface of the pipe can be improved by spraying using zinc and a zinc alloy as a wire.

  As a general thermal spraying method for a metal pipe such as a cast iron pipe, arc spraying is mainly used. As shown in FIGS. 7, 8 (a), (b), a metal pipe such as a cast iron pipe is used. The thermal spraying machine (so-called thermal spraying gun) 50 is moved relative to the thermal spraying object X along the axial direction of the pipe while rotating the thermal spraying object X to be rotated about the pipe axial center O. ing. For example, in the case of spraying different metals of zinc and zinc alloy on a cast iron pipe, zinc wire A is applied to the positive electrode wire sending portion 52 and zinc alloy wire is applied to the negative electrode wire sending portion 53 of the thermal spraying machine 50. B is set to be in contact with each other at the delivery point and sprayed (conversely, a zinc alloy wire B is set in the positive electrode wire sending part 52 and a zinc wire A is set in the minus pole wire sending part 53. Spraying is also possible). 8 (a) and 8 (b), 51 is a gas supply unit for atomization that supplies a gas (gas) such as compressed air for atomization (for atomization), and Y is a thermal spray coating. By using this method, two wire rods A and B made of different metals are melted continuously while being simultaneously fed into one thermal sprayer 50, and these molten metals are sprayed by a gas for atomization sprayed at high speed. It can be sprayed on the object X in the form of fine particles.

  In this case, conventionally, the zinc wire A is set in the positive electrode wire feeding portion 52 of the thermal sprayer 50 and the zinc alloy wire B is set in the negative electrode wire feeding portion 53 and sprayed. The sprayed shape (so-called sprayed pattern) of the sprayed coating Y of the dissimilar metal adhered to the object to be sprayed X is substantially round as schematically shown on the left side of FIG. However, if the sprayed shape is round, the spraying width is small and the amount of spraying varies greatly within that width, so the spraying area per unit time is small, the production efficiency is poor, and the yield is low. is there.

  In order to eliminate this drawback, it has been proposed that the sprayed shape of the sprayed coating Y of the dissimilar metal to be adhered to the sprayed object X is made elliptical as simply shown on the right side of FIG. That is, as shown in FIGS. 10A, 10 </ b> B, and 11, in the thermal spraying machine 60, a wire rod sending unit that feeds two wires A and B made of different metals to the left and right of the gas supply unit 61 for atomization. 62 and 63 are provided, respectively, and a shape control gas supply unit 64 for supplying a gas (gas) such as compressed air is provided above and below the atomization gas supply unit 61 and the wire feed units 62 and 63. A plurality of them are arranged side by side in a direction substantially parallel to the tube axis (so-called lateral direction). And, it is configured so that the molten metal in the form of fine particles is prevented from diffusing up and down by a gas such as compressed air ejected from the shape control gas supply unit 64 to form a horizontally long elliptical flat shape of the thermal spray coating Y. doing. In addition, the wire sending parts 62 and 63 for feeding the two wires A and B made of different metals are, as described above, directions along the direction in which the tube axis O extends, such as the left and right of the gas supply unit 61 for atomization. Are arranged side by side. 10 (a), 10 (b), and FIG. 11, the arrangement configuration of the atomizing gas supply unit, the wire rod feeding unit, the shape control gas supply unit, and the spraying shape of the spray coating Y are the same. An arc spraying device is disclosed in Patent Document 2 and the like. In this arc spraying device, in addition to the configuration shown in FIGS. 10A, 10B, and 11, a virtual cone that is coaxial with the blowout shaft. A gas supply unit for atomization that blows forward along the surface is also provided.

  When different types of metal are sprayed on the sprayed object X made of a cast iron pipe or the like using the thermal sprayer 60 so as to form an oblong shape that is horizontally long with respect to the axial direction of the pipe, the sprayed shape is round. Compared with, the spraying width is large and the variation in the spraying amount in the width direction is small, so the spraying area per unit time can be increased, the production efficiency can be improved, and the yield is also increased. It is thought that it can be improved.

JP 2009-256792 A JP 2001-181818 A

  However, when different types of metals are sprayed using a thermal sprayer 60 as shown in FIGS. 10A, 10B, and 11, the wire feed parts 62 and 63 are connected to the right and left sides of the atomizing gas supply part 61. Since they are arranged side by side in the direction along which the axis O extends, as shown in FIG. 12, the left and right ends of the horizontally long elliptical portion of the thermal spray coating Y are the raw materials for the wire A. A portion C having a large component ratio of one metal (for example, zinc) and a portion D having a large component ratio of the second metal (for example, zinc alloy) that is a raw material of the wire B are formed, and a coating such as a sprayed cast iron pipe is formed. There is a possibility that the component ratio of the sprayed metal on the surface of the sprayed material X may vary with respect to the axial direction of the sprayed material X such as a cast iron pipe. In this case, the corrosion resistance of the outer surface of the sprayed object X such as a cast iron pipe cannot be improved satisfactorily.

  The present invention solves the above problems, and provides a spraying method and a sprayer for dissimilar metals, which can thermally spray dissimilar metals to a sprayed object such as a cast iron pipe in a state without component bias. It is intended.

In order to solve the above-mentioned problem, the present invention provides a dissimilar metal composed of a first metal and a second metal, which are different from each other, while rotating a tube, which is a sprayed object, around its tube axis. A method for spraying dissimilar metals to be sprayed on the surface of a tube, wherein two wire rods made of the dissimilar metals are melted by being brought into contact with the outside of the sprayer from respective wire feed parts individually provided in the sprayer. a wire transmitting operation to feed toward the surface to be thermal sprayed of the thermal spray material, the heterogeneous and gas supply operation for atomization supplies gas for atomization to molten portion of the metal, shape control gas so that spray shape becomes elliptical A gas supply operation for shape control for supplying gas from the supply unit is performed in parallel, and in the wire feeding operation, the wires are arranged in a direction substantially orthogonal to the tube axis at the contact point of these wires. tube when brought into contact, was sprayed with it state The component ratio of the sprayed metal is different at the longitudinal end portion of the sprayed portion substantially orthogonal to the core, and the component ratio of the first metal is obtained by rotating the tube that is the sprayed object around the tube axis. The thermal spraying is performed by superposing a portion having a large component ratio of the second metal on a portion having a large thickness .

Further, the thermal spraying machine of the present invention sprays different kinds of metals composed of a first metal and a second metal, which are different from each other, on a thermal spray target composed of a tube rotated about a tube axis. A thermal spraying machine, two wire feeding parts that feed the wires of different materials in contact with each other so as to be melted; a gas supply unit for atomization that supplies gas that makes the molten metal into fine particles; and A shape-controlling gas supply unit that supplies gas so that the sprayed shape is an ellipse that is long with respect to the direction along the tube axis, and the first metal and the second metal that are different from each other The longitudinal direction of the sprayed portion that is arranged in the direction substantially orthogonal to the tube axis and arranged to be substantially orthogonal to the tube axis when sprayed , wherein the two wire feeding parts for feeding the wire made of the material are arranged The composition ratio of the sprayed metal is different at the end of Certain tubes, by rotating about the tube axis, and characterized by being configured to overlap a portion component ratio of the second metal is greater over portions component ratio of the first metal is greater To do.

  According to the above spraying method and thermal spraying machine, when dissimilar metals are sprayed, the proportion of the two metals that are the raw materials of the wire material is the same in most parts of the horizontally long elliptical part. At the end in the vertical direction, although there are few portions where the component ratios of the two metals that are raw materials of the wire are different, they are slightly formed. However, since the tube to be sprayed is rotated around the axis of the tube, that is, the sprayed material is rotated so that the surface of the sprayed portion moves along the longitudinal direction of the horizontally long elliptical portion. However, since the thermal spraying is continued, the thermal spraying can be performed in a good state where the component ratio of the thermal spray coating is finally almost the same.

  In the thermal spraying apparatus of the present invention, the gas supply unit for atomization is preferably disposed between the two wire rod feeding units, and the gas supply unit for shape control goes directly to the tube axis. It is preferable that a plurality of wires are placed in the direction along the tube axis or connected in the direction along the tube axis, with the two wire feed parts sandwiched between the two wire feeding parts. . With this configuration, it is possible to spray a good elliptical shape.

  As described above, according to the present invention, in the wire feeding operation, the wires are brought into contact with each other in a state where they are arranged in a direction substantially perpendicular to the tube axis at the contact portion of these wires, or different metals are sprayed. In the thermal spraying machine, by arranging the two wire feeding parts in a direction substantially perpendicular to the tube axis, the dissimilar metal is almost entirely deposited on the entire surface of the sprayed material. Thermal spraying can be performed in the same good state, and the corrosion resistance of the tube can be improved satisfactorily.

(A) And (b) is the side surface sectional view and plane sectional view which show the thermal spraying method and thermal spraying machine of a dissimilar metal based on embodiment of this invention. It is a simplified front view of the thermal sprayer concerning the embodiment. It is a figure which shows the thermal spraying state of the thermal spraying method which concerns on the same embodiment. (A) is an electron micrograph of a thermal sprayed part by a different metal spraying method according to an embodiment of the present invention and its vicinity, and (b) is an electron micrograph of a thermal sprayed part by a conventional different metal spraying method and an electron micrograph of its vicinity. Show. (A) is a figure which shows the thermal spraying part by the spraying method of the dissimilar metal which concerns on embodiment of this invention corresponding to FIG. 4 (a), and the zinc distribution state of the vicinity, (b) is FIG. It is a figure which shows the thermal spraying part by the conventional thermal spraying method of a dissimilar metal, and the zinc distribution state of the vicinity corresponding to b). (A) is a figure which shows the thermal spraying part by the thermal spraying method of the dissimilar metal which concerns on embodiment of this invention corresponding to FIG. 4 (a), and the distribution state of Sn of the vicinity, (b) is FIG. It is a figure which shows the thermal spraying part by the conventional thermal spraying method of a dissimilar metal, and the Sn distribution state of the vicinity corresponding to b). It is a figure which shows simply the thermal spraying method to a pipe | tube. (A) And (b) is side sectional drawing and plane sectional drawing which show the conventional thermal spraying method. It is a figure which shows simply the spraying shape to a to-be-sprayed object. (A) And (b) is a side sectional view and a plane sectional view showing other conventional thermal spraying methods. It is a simplified front view of the thermal sprayer used for the other conventional thermal spraying method. It is a figure which shows the thermal spraying state in the other conventional thermal spraying method.

Hereinafter, a thermal spraying method for dissimilar metals according to an embodiment of the present invention and a thermal spraying machine used in the thermal spraying method will be described with reference to the drawings.
As shown in FIGS. 1 (a), (b), FIG. 2, etc., in the thermal spraying method for dissimilar metals according to the embodiment of the present invention, arc spraying is used, which is a metal tube such as a cast iron tube. A spraying machine (so-called spray gun) 1 is rotated with respect to the sprayed object X in the direction of the tube axis (arrow in FIG. 7) while rotating the sprayed object X around the tube axis O with a rotating roller (not shown). Construction is performed by relatively moving in the e direction) (in this embodiment, the thermal sprayer 1 is moved). The thermal spraying machine 1 is arranged so that the spraying direction is substantially perpendicular to the sprayed surface of the sprayed object X, that is, toward the tube axis O. In FIGS. 1 (a) and 1 (b), the thermal spraying is performed. The case where the machine 1 is facing substantially horizontally apart on the left side of the sprayed object X is illustrated. Moreover, in this embodiment, the thermal spraying of zinc as a first metal and a zinc alloy as a second metal different from the first metal is performed on a ductile cast iron pipe as the sprayed object X. In this case, the zinc wire A as the first wire is supplied to the positive wire delivery portion 3 of the thermal sprayer 1, and the zinc as the second wire is supplied to the negative wire delivery portion 4 in this case. The alloy wire B is set and sprayed so as to be in contact with each other in front of the delivery point (reversely, the zinc alloy wire B is applied to the positive electrode wire delivery portion 3 and zinc is applied to the negative electrode wire delivery portion 4. The wire A may be set and sprayed).

  Also in the thermal sprayer 1 according to the embodiment of the present invention, in addition to the above-described two wire feed parts 3 and 4 that feed the wires A and B of different materials in contact with each other so as to melt, the molten metal A gas supply unit 2 for supplying fine particles for supplying a gas made of compressed air or the like for making the particles fine, and supplying a gas made of compressed air or the like so that the sprayed shape becomes a long ellipse with respect to the direction along the tube axis. The shape control gas supply unit 5 is provided. However, in the thermal spraying machine 1 according to the embodiment of the present invention, the two wire material feeding sections 3 and 4 for feeding the wire materials A and B made of different materials are connected to each other as shown in FIGS. In this embodiment, they are arranged side by side in a direction substantially perpendicular to the center O, in the vertical direction in this embodiment. Further, a gas supply unit 2 for atomization that supplies a gas composed of compressed air or the like that turns molten metal into a fine particle form is provided between the two wire feed units 3 and 4, in this embodiment, the thermal sprayer 1. It is arranged at the center.

  In addition, the shape control gas supply unit 5 of the thermal sprayer 1 is arranged at a position that is a predetermined distance away from the wire feed units 3 and 4 in the circumferential direction of the tube, that is, at a location that is separated upward and downward in this embodiment. A plurality of elements are arranged side by side in a direction (so-called lateral direction) substantially parallel to the axial direction (direction extending along the tube axis O). Then, the gas such as compressed air ejected from the shape control gas supply unit 5 is prevented from diffusing the molten metal in the form of fine particles in the vertical direction (circumferential direction of the tube) so as to have a horizontally long elliptic flat shape. It is configured.

  In this configuration, two wires A and B made of different metals are brought into contact with each other at a location in front of the thermal sprayer 1 in a state where a high voltage is applied from each of the wire feeders 3 and 4 individually provided in the thermal sprayer 1. Wire feeding operation for feeding toward the sprayed surface of the sprayed material X so as to melt, and for atomization supplying compressed air as atomization gas from the atomizing gas supply unit 2 to the melting point of dissimilar metal The gas supply operation and the shape control gas supply operation for supplying compressed air from the shape control gas supply unit 5 are performed in parallel so that the sprayed shape becomes an ellipse. In particular, in the wire feeding operation, the two wires A and B made of different metals are brought into contact with each other in a state where they are aligned in a direction substantially orthogonal to the tube axis O at the contact point between these wires A and B. . In this way, the first metal such as zinc (Zn) and the second metal such as zinc alloy (for example, Zn—Sn—Mg alloy) are formed on the surface of the thermal spray X made of a metal tube such as a cast iron tube. And sprayed coating Y is formed.

  At the time of thermal spraying, the thermal spray object X made of a cast iron pipe is rotated while the tube axis O is rotated, and at the same time, the thermal sprayer 1 is moved relative to the thermal spray object X in the direction of the tube axis. The moving distance in the tube axis direction when the sprayed object X is rotated once around the tube axis O is set to be smaller than the width of the spray coating Y. In addition, the sprayed material X made of cast iron pipe is rotated in a state where the rotational speed of the sprayed material X is sufficiently larger than the moving speed in the axial direction of the tube, and the sprayed coating Y has a gap on the entire peripheral surface (outer surface) of the sprayed material X. To be formed without any problems.

  According to this thermal spraying method, when different types of metals are sprayed, the positions of the wire rods A and B at the time of melting differ slightly in a direction substantially orthogonal to the tube axis O at the moment of thermal spraying. Therefore, as shown in FIG. 3, most of the locations in the direction (vertical direction in FIG. 3) that is substantially orthogonal to the tube axis O of the elliptical portion in the sprayed portion, more specifically, in the location near the center in the vertical direction, Although the dissimilar metals are mixed well and the component ratio of the two metals is the same, the end portions in the vertical direction (in this embodiment, the upper edge portion and the lower edge portion) are the raw materials for the wires A and B 2 Parts with different proportions of the two metals are formed. That is, when different types of metals are sprayed, at the instant of spraying, a portion C having a large component ratio of the first metal, which is the raw material of the wire A such as zinc, is formed at the upper edge portion of the sprayed coating Y. At the lower edge of the coating Y, a portion D having a high component ratio of the second metal, which is a raw material of the wire B such as a zinc alloy, is formed.

  However, since the tube that is the sprayed object X is rotated around the tube axis O, that is, the surface of the sprayed part X moves so that the surface of the sprayed portion moves along the longitudinal direction of the horizontally long elliptical portion. Will be sprayed while rotating. Therefore, when the tube being the sprayed object X is sprayed while being rotated around the tube axis O, the portion D having the large second metal component ratio on the portion C having the large first metal component ratio D. Finally, the component ratio of the thermal spray coating Y does not deviate depending on the location, and the thermal spraying can be performed in a good state that is almost the same. Thereby, the corrosion resistance of a pipe | tube can be improved favorably.

  Further, even with the above-described spraying method, different types of metal can be sprayed on the object to be sprayed X made of cast iron pipe or the like so as to have an elliptical shape that is horizontally long with respect to the axial direction of the tube. Compared to the shape, the spray width is large and the variation of the spray amount in the width direction is small, so that the spray area per unit time can be increased and the production efficiency can be improved. At the same time, the yield can be improved.

  As described above, as the thermal sprayer 1, it is preferable that the gas supply unit 2 for atomization is disposed between the two wire feed units 3 and 4. However, the present invention is not limited to this. In addition, it is preferable that a plurality of shape control gas supply units 5 are arranged in a direction along the tube axis O, or arranged in a state connected in a direction along the tube axis O. With this configuration, Although it can be sprayed to a good oval shape, it is not limited to this.

Here, in order to confirm the thermal spraying state by the thermal sprayer 1 and the thermal spraying method of the present embodiment, the following tests were performed.
That is, a cast iron pipe having a diameter of 100 mm is used as the sprayed object X, a Zn (zinc) wire having a diameter of 3.17 mm as the first metal wire A, and a Zn having a diameter of 3.17 mm as the second metal wire B. Electric arc spraying was performed using −40% Sn—0.3% Mg (zinc alloy) wire (Sn: 40% by mass, Mg: 0.3% by mass, Zn: balance). The thermal spraying amount is 325 g / m ² and the thickness of the thermal spray coating Y is about 50 μm. The sprayed coating Y was formed on the outer peripheral surface (outer surface) of the sprayed material X made of a cast iron pipe. Here, FIGS. 4A and 4B show electron micrographs of the thermal spray X including the sprayed coating Y portion, and FIG. 4A shows the thermal sprayer 1 according to the embodiment of the present invention. FIG. 4B is based on the thermal spraying method, and FIG. 4B is based on the conventional thermal sprayer 60 and the thermal spraying method shown in FIGS. FIGS. 5 (a) and 5 (b) are diagrams showing the presence of Zn (zinc) elements in the portions corresponding to FIGS. 4 (a) and 4 (b), and FIGS. 6 (a) and 6 (b). These are the figures which analyzed the presence location of Sn (tin) element of the part corresponding to Drawing 4 (a) and (b). In addition, when imaging the to-be-sprayed object X and the sprayed coating Y with an electron micrograph, in order to image a cross section in a favorable state, it grind | polishes after cut | disconnecting the to-be-sprayed object X and the sprayed coating Y, but FIG. F in a) and (b) is a resin for embedding a sample during cutting and polishing.

  As shown in FIG. 6 (b), when thermal spraying is performed with the conventional thermal sprayer 60 and the thermal spraying method shown in FIGS. 10 (a), 10 (b) and FIG. 11, there are places where Sn (tin) in the thermal spray coating Y is not recognized. Were present. On the other hand, in the thermal sprayer 1 and the thermal spraying method according to the embodiment of the present invention, Sn (tin) is well distributed in the thermal spray coating Y, no component bias is observed, and the components of the thermal spray coating Y are not observed. It was confirmed that the thermal spraying was performed in a good state where the ratio was almost the same.

  In the above-described embodiment, the case where the thermal sprayer 1 is disposed horizontally on the left side or the right side of the object X is not limited to this, and the thermal sprayer 1 is not limited to this. It suffices if the spraying direction is arranged so as to be substantially orthogonal to the sprayed surface of the sprayed object X, that is, so as to face the tube axis O, and is arranged above or below the sprayed object X or in an oblique direction. It may be provided. Moreover, although the case where the sprayed object X is a metal pipe such as a cast iron pipe has been described in the above embodiment, the present invention can also be applied to a pipe other than a metal such as a resin pipe.

DESCRIPTION OF SYMBOLS 1 Thermal sprayer 2 Gas supply part for atomization 3 Positive wire delivery part 4 Negative wire delivery part 5 Shape control gas supply part A 1st wire B 2nd wire O Tube axis X Sprayed object Y Thermal spray coating

Claims (4)

In a different metal spraying method, a pipe which is a sprayed object is rotated around the axis of the pipe, and a different metal composed of a first metal and a second metal different from each other is sprayed on the surface of the pipe. There,
Two wires made of the different metals, the wire rods delivery portion provided separately for spray gun, and the wire delivery operation to feed toward the surface to be thermal sprayed of the thermal spray material to melt in contact with thermal sprayer externally , a gas supply operation for atomization supplies gas for atomization to the melting point of said foreign metal, is spray shape and the gas supply operation for shape control supplies gas from the shape control gas supply unit such that the ellipse Done in parallel,
In the wire rod feeding operation, the wire rods are brought into contact with each other in a state of being arranged in a direction substantially orthogonal to the tube axis at the contact portion of these wire rods ,
The component ratio of the sprayed metal is different at the longitudinal end of the sprayed portion that is substantially orthogonal to the tube axis when sprayed.
By rotating the tube that is the object to be sprayed around the axis of the tube, the portion having a large component ratio of the first metal is sprayed on the portion having a large component ratio of the second metal. The thermal spraying method for dissimilar metals. A thermal spraying machine that sprays different kinds of metals composed of a first metal and a second metal, which are different from each other, on a sprayed object composed of a tube rotated about a tube axis,
Two wire feed parts for feeding wires made of different materials in contact with each other so as to melt, a gas supply part for atomization for supplying a gas for making molten metal into fine particles, and a thermal spray shape of the tube axis A gas supply unit for shape control that supplies a gas so as to be a long oval shape in a direction along the heart,
The two wire rod feeding sections for feeding the wire rods made of the first metal and the second metal different from each other are arranged in a direction substantially orthogonal to the tube axis and sprayed. The component ratio of the sprayed metal is different at the longitudinal end of the sprayed part that is substantially perpendicular to the tube axis.
By rotating the tube that is the sprayed object around the tube axis, a portion having a large component ratio of the second metal is configured to overlap a portion having a large component ratio of the first metal . Thermal spraying machine characterized by that.   The thermal spraying machine according to claim 2, wherein the gas supply unit for atomization is disposed between two wire rod feeding units.   A plurality of shape control gas supply units are arranged in the direction along the tube axis with the two wire feed parts sandwiched in the direction perpendicular to the tube axis, or the direction along the tube axis The thermal spraying machine according to claim 2 or 3, wherein the thermal spraying machine is arranged in a state of being connected to.