JP2007107082A - Arc spraying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To atomize a molten metal into finer particles to thereby form a coating film composed of the finer molten metal particles on the surface of a metallic member and to prevent the coating film from becoming uneven. <P>SOLUTION: The arc spraying apparatus is used to atomize and spray spray materials 6 and 6 molten by electricity by supporting two wire-like spray materials 6 and 6 on their respective spray material feeders 5 and 5 provided within a spray cylinder 10 of the arc spraying apparatus to make them ready for electricity application, protruding the front ends of the spray materials 6 and 6 outwardly and opposedly from the opening 3 of the spray cylinder 10, providing a plurality of nozzles 2 and 2 around the opening 3, and spraying air from the nozzles 2 and 2 and the opening 3, wherein the opening 3 at the front end of the spray cylinder 10 has a rectangular cross-section. According to this, the air sprayed from the rectangular cross-section opening 3 and the nozzles formed around it can atomize the molten metal formed by the arc into finer particles, which prevents the coating film from becoming uneven. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an arc spraying apparatus used for anticorrosion outer surface coating.

  For example, when it is necessary to protect the surface of a metal member such as a ductile cast iron pipe disposed underground, a zinc-based primer or the like is applied to the surface of the metal member. As a method for applying this kind of primer, a technique using an arc spraying apparatus is adopted.

For example, as shown in FIG. 10, the arc spraying apparatus is configured such that two wire-like melted materials 6 and 6 are respectively supported by the melt feeding devices 5 and 5 provided in the hollow portion 7 of the sprayed cylinder 1. The tips of the molten materials 6 and 6 are maintained in a state of protruding outward from the circular opening 3 in the front end of the thermal spray cylinder 1.
The two molten materials 6 and 6 are connected to an arc power source at their rear ends via a contact (not shown), and an arc is generated between the two molten materials 6 and 6 by power supply from the power source. By this arc, each of the molten materials 6 and 6 is melted in the vicinity of the tip thereof.

  A plurality of nozzles 2, 2 that open to the front surface 4 are provided around the opening 3 so that high-speed air can be ejected from the nozzles 2, 2.

An arc is generated between the molten materials 6 and 6 by power supply from a power source, the molten materials 6 and 6 are melted, and air is ejected from the opening 3, and high-speed air is ejected from the nozzles 2 and 2. Then, the melted metal is atomized by the air, and the atomized metal adheres to the surface of the metal member to form a rough deposited film (see, for example, Patent Documents 1 to 4).
JP 2000-192221 A Japanese Patent Laid-Open No. 1-198461 (page 6, FIG. 4) Japanese Patent Laid-Open No. 62-183869 (page 8, FIG. 2) JP 2001-181818 (page 7, FIG. 2)

  However, when the arc spraying apparatus having the above configuration is used, the atomized molten metal tends to scatter in a relatively coarse state. For this reason, the film formed on the surface of the metal member has a relatively rough surface, and the coating amount tends to be uneven. The “unevenness in the coating amount” includes, for example, a state in which the number of portions (pores) in which the adhesion amount of the molten metal is smaller than the surroundings is large (see, for example, the leftmost specimen shown in FIG. 13).

  Thus, if the coating particles formed on the surface of the metal member are rough, the appearance of the product will be poor, and if the coating amount is uneven, the anticorrosion effect will not be exhibited evenly over the entire surface. It is not preferable.

  Accordingly, an object of the present invention is to make fine particles of molten metal to be atomized, to make fine particles of a film formed on the surface of the metal member by the molten metal, and to prevent unevenness.

  In order to solve the above-described problems, the present invention is configured such that the opening for projecting the molten material provided at the front end of the arc spraying apparatus has a rectangular cross section.

  In this way, the reason is unknown, but the molten metal generated by the arc becomes finer particles due to the air ejected from the opening and the high-speed air ejected from the nozzle provided around the opening. To become. For this reason, the particle | grains of the film formed on the surface of a metal member can be made finer, and generation | occurrence | production of the nonuniformity to a film can also be suppressed.

  In the present invention, since the opening for projecting the molten material provided at the front end of the arc spraying device has a rectangular cross section, the particles of the coating formed on the surface of the metal member by the arc spraying device are made finer and unevenness is generated. Can also be suppressed.

  As a specific embodiment of the above means, two wire rod-like molten materials are respectively supported by a molten material feeding device provided in a thermal spraying cylinder of an arc thermal spraying apparatus so as to be able to supply power, and the tip of the molten material is the front end of the thermal spraying cylinder, respectively. The metal of the molten material melted by the power feeding is atomized and ejected by projecting outward from the opening of the nozzle, providing a plurality of nozzles around the opening, and ejecting air from each nozzle and the opening. In the arc spraying apparatus, the configuration in which the opening at the front end of the spraying cylinder has a rectangular cross section can be adopted. At this time, if the cross section is rectangular, it may be rectangular or square.

  A first embodiment will be described with reference to FIGS. This Example 1 is an arc spraying device used for corrosion protection of the surface of a ductile cast iron pipe or the like by zinc spraying. FIG. 4 shows the overall configuration of the apparatus G, and FIGS. 1 to 3 show details of the thermal spray cylinder 10 attached to the front end of the arc spray apparatus.

The thermal spray cylinder 10 is composed of a main body portion 13 and a cap 12, and the main body portion 13 and the cap 12 have their protrusions 12a and 13a mesh with each other as shown in FIGS. It is fixed via a packing 15 fitted in a packing groove 12b formed on the cap 12 side.
Further, a flange 10a is formed on the outer periphery of the rear end of the main body portion 13, and the front end of the arc spraying device is fitted and fixed in the hollow portion 7 at the rear end of the main body portion 13.

  In the thermal spray cylinder 10, two wire-like molten materials 6 and 6 are arranged. The tips of the molten materials 6 and 6 are fixed in a state of projecting outward from the opening 3 of the cap 12 of the thermal spray cylinder 10. Further, the melt materials 6 and 6 are supported by the melt material feeding devices 5 and 5 provided in the thermal spray cylinder 10 of the arc spray device so as to function as electrodes, and the rear ends thereof are connected to an arc power source (not shown). Yes. This protrusion amount can be adjusted.

  The opening 3 is provided in the bottom surface 11 a of the recess 11 having a circular cross section provided on the front surface 4 of the cap 12. Further, in the recess 11, two nozzles 2, 2 are provided around the opening 3 so that air can be ejected from the nozzles 2, 2 at high speed.

When an arc is generated between the melts 6 and 6 by power feeding from the arc power source and the melt 6 is melted, the melted metal is atomized by the air from the nozzle 2 and the air from the opening 3, The atomized metal is injected as indicated by arrows a and b shown in FIG.
At this time, since the annular groove 14 shown in FIGS. 2 and 3 is provided in the connection portion between the main body 13 side and the cap 12 side of the nozzle 2, more air is ejected from both nozzles 2 and 2. There is an effect that it becomes close to an equal injection amount and injection speed.

  In the second embodiment, as shown in FIGS. 6 to 8, the bottom surface 11a of the concave portion 11 provided in the cap 12 of the first embodiment has a spherical shape. Although the annular groove 14 is not provided as in the first embodiment, other configurations are the same as those in the first embodiment.

Experimental example

  Tables 1 and 2 show the results of experiments in which the shape of the recess 11 formed in the cap 12 and the cross-sectional shape and inner diameter of the opening 3 were changed to confirm the sprayed state of the molten metal.

FIG. 11 is a photograph showing a thermal spraying state of a conventional example in which the circular cross section having a hole diameter of 24 mm shown in Table 1 is adopted as Experimental Example 1. FIG. 12 is a photographic view showing a thermal spraying state when the cross-sectional rectangle (square) having a hole diameter of 8 mm shown in Table 1 is adopted as Experimental Example 2.
When the opening 3 having a rectangular cross section is adopted, the spray pattern becomes elliptical in this way. Therefore, if the spray position is slid along the short axis direction of the ellipse, a more uniform spray surface can be obtained. it can.

FIG. 13 is a comparison of the thermal spraying states of the four experimental examples. From the left, the experimental example 1, the cross-sectional rectangle with a hole diameter of 15 mm, the cross-sectional rectangle with a hole diameter of 10 mm, and the cross-sectional rectangle with a hole diameter of 8 mm. When square holes were used rather than round holes, the particles were finer, and when square holes were used, good results were obtained with a hole diameter of about 10 mm or 8 mm.
In these experimental examples, the opening 3 has a rectangular cross-section and has a square cross-section, and the hole diameter indicates the length of one side.

The perspective view which shows the thermal spraying cylinder of Example 1. FIG. Cut side view of the thermal spray cylinder of Example 1 Exploded perspective view of thermal spray cylinder of Example 1 Overall view of arc spraying equipment Cut side view showing the injection state of molten metal The perspective view which shows the thermal spraying cylinder of Example 2. FIG. Cut side view of thermal spray cylinder of Example 2 The perspective view which shows the main-body part of the thermal spraying cylinder of the Example 2. The perspective view which shows the cap of the spraying cylinder of a prior art example Cutting side view showing a conventional thermal spray cylinder cap Photograph showing the thermal spray state of Experimental Example 1 Photograph showing the thermal spraying state of Experimental Example 2 Photographs comparing the thermal spraying conditions of each experimental example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 Thermal spray cylinder 2 Nozzle 3 Opening 4 Front surface 5 Molten material feeder 6 Melt material 7 Hollow part 10a Flange 11 Recessed part 11a Recessed bottom face 12 Cap 12a, 13a Protruding part 12b Packing groove 13 Main part 14 Annular groove 15 Packing

Claims (1)

The two wire-like molten materials 6 and 6 are respectively supported by the molten material feeders 5 and 5 provided in the thermal spraying cylinder 10 of the arc spraying apparatus so that power can be supplied, and the tips of the molten materials 6 and 6 are respectively supplied to the thermal spraying cylinders. 10 by projecting outwardly from the opening 3 at the front end, providing a plurality of nozzles 2, 2 around the opening 3, and ejecting air from each of the nozzles 2, 2 and the opening 3. In an arc spraying apparatus for atomizing and injecting molten metal 6 and 6,
An arc spraying apparatus characterized in that the opening 3 at the front end of the spraying cylinder 10 has a rectangular cross section.