JP6454849B2 - Method for forming metal film on columnar base material - Google Patents

Description

  The present invention relates to a method for forming a metal film for obtaining a metal film by subjecting a sprayed coating fixed on the surface of a metal base material to a melting treatment. In particular, a method for forming a metal film intended for repairing wear, scratches, and surface degradation of a metal material surface on a target base metal surface having a corner at the tip corner. About.

  Conventionally, the thermal spray coating is fixed on the surface of the base metal by thermal spraying of metal powder, and the fixed thermal spray coating is remelted under high pressure to modify the thermal spray coating to have wear resistance, heat resistance, and corrosion resistance. A method for forming a metal film is known. This modification of the sprayed coating involves degassing fine bubbles and gases contained in the sprayed coating by remelting, and the metal oxide in the sprayed coating rises to the surface side to form a dense metal coating and It increases the fixing power on the material surface. When remelting a conventional sprayed coating, heating by a gas flame, induction heating, heating by a furnace, or induction heating by an annular induction coil is performed.

Conventionally, as a spray coating method similar to the above, a coating method in which a metal base sprayed material is sprayed on a peripheral surface of a metal cylinder by a high-speed spray gun to form a dense coating. A method is disclosed in which a thermal spray coating without pores is formed by setting the relative scanning speed of the high-speed gun with respect to the surface to 30 to 80 dm ² / min while suppressing an increase in the temperature of the spray surface in the spray spot. This is achieved by spraying a high-speed spray gun that can form a dense coating in a sprayed state at a higher speed than before, so that the coating does not contain harmful-sized pores. It is said that the density can be improved.

As a method for forming a metal coating layer, conventionally, a primary coating layer of a metal material is formed on the surface of a base material by using a thermal spraying method or the like, and then a small region of the primary coating layer is locally used with an inductor. Inductive heating causes the primary coating layer to melt and moves the inductor along the primary coating layer by moving the inductor relative to the primary coating layer to act on the melting portion. A method is disclosed in which pores and oxides present in the primary coating layer are removed using an electromagnetic stirring force to form a dense secondary coating layer. In this method, the current penetration depth of the induced current at least when the primary coating layer is melted is 1.5 times or more the thickness of the primary coating layer. And by setting the current penetration depth of the induced current when the primary coating layer is melted by induction heating at least 1.5 times the thickness of the primary coating layer, the induced current density of the primary coating layer is In particular, the induced current density of the surface layer can be reduced, thereby reducing the electromagnetic stirring force acting on the molten layer, preventing the occurrence of dents and constriction in the coating layer, and the effect of being able to form a metal coating layer of good quality. It is said that it has.

JP 09-248606 A JP-A-11-209865

However, when remelting a columnar base material having a corner at the tip corner, such as a cylinder or a polygonal column, the conventional thermal spray coating method or metal coating layer forming method is applied around the corner. In some cases, the film thickness after remelting is uneven, or the density of the composition is uneven between the flat portion and the corner portion. This is because melting is performed from the surface and the modification due to melting proceeds from the surface, so that the heat of fusion is partially concentrated near the center of the corner and becomes an excessive application portion of melting energy, On the other hand, it is considered that the flat part other than the corner part is based on the fact that the heat of fusion is relatively insufficient and becomes a part where the melt energy is insufficiently provided.
In particular, in the case of a thick sprayed coating having a sprayed coating thickness of 3 to 5 mm or more, there is a tendency that the coating thickness and the density deviation due to remelting tend to be noticeable. The unevenness may cause a decrease in the properties of the metal film such as wear resistance, heat resistance, and corrosion resistance, or a decrease in the surface smoothness of the metal film. And when using the metal film layer by remelting for the repair reinforcement of a base material, the fall of these properties and the fall of surface smoothness will lead to a fatal defect.

  Therefore, in the present invention, in the method of forming a metal film, when remelting processing is performed on a columnar base material having a corner at the tip corner, such as a cylinder or a polygonal column, partial concentration and deficiency of melting heat is eliminated. It is an object of the present invention to eliminate the unevenness of the film thickness and the composition density after remelting by suppressing the occurrence of an excessively imparted part or an insufficiently imparted part of the melting energy. It is another object of the present invention to prevent a decrease in the properties of the metal film based on the bias or a decrease in the surface smoothness of the metal film.

  In order to solve the above problems, the present invention employs the following means (1) to (6).

(1) The method of forming a metal film on the columnar base material of the present invention is a method of forming a metal film on the columnar base material (1) having a corner (1C) at the periphery of the tip surface (11). And
A thermal spraying step of fixing a thermal spray coating to the entire end of the columnar base material (1) including the tip surface (11) and the corners (1C) by thermal spraying of metal powder;
The thermal spray coating is remelted by a heater (C) that surrounds the side periphery of the columnar base material (1), thereby modifying the thermal spray coating to form a metal coating on the base material surface including the corners. A melting step,
In the remelting step, the columnar base material (1) is slanted in a suspended state (a) in which the tip surface (11) including the corners faces vertically downward, or at a predetermined horizontal inclination angle (θ). It is characterized in that it is held in any state of the inclined state (b / c) facing and is remelted while being rotated around the column axis (1A) of the columnar base material (1).
It is possible to prevent the sprayed coating on the surface of the columnar base material (1) from being removed at the time of remelting by making it a suspended state or an inclined state by the above method and remelting while rotating around the column axis (1A). In particular, the sprayed coating at the corner does not become thin or biased due to its own weight during remelting, and remains the same as the sprayed coating at other portions without being affected by the corner shape of the base material. be able to. That is, as shown in FIG. 2, in a state where the shaft is rotated in a hanging state or an inclined state, the corner (1C) rotates around the vertical axis or the oblique axis while the tip surface (11) is directed vertically downward or obliquely. It will rotate. The sprayed coating layer remelted by the shaft rotation flows so as to flow down by its own weight, so that the inside of the coating is kneaded at a moderate speed, and the entire sprayed coating is modified relatively uniformly.
Here, the inclined state is preferably a downward inclined state (b) in which the tip surface (11) is inclined downward so that the horizontal inclination angle (θ) has a positive value downward. In the downward inclined state (b), the metal film fixed on the corner (1C) always stays on the lower surface or side surface of the corner of the base metal and stays on the corner surface from the corner in the remelting process. As a result, it is melted while maintaining the film thickness of the sprayed coating or increasing the film thickness. Particularly in the downward inclination state (b) in which the inclination angle (θ) with respect to horizontal is 15 degrees or more downward, the angle of gravity that the metal film fixed on the corner portion (1C) receives during remelting sequentially changes. Therefore, the metal film is uniformly rotated by the internal flow.

(2) In the method for forming a metal film on the columnar base material,
In the remelting step, it is preferable that the columnar base material (1) is remelted while being reciprocally displaced one or more times in a predetermined reciprocating direction intersecting with its own column axis (1A).
According to the above method, the re-melted sprayed coating layer receives the inertial force due to the rotation, and alternately receives the linear inertial force to the left side and the right side. Therefore, the metal film is uniformly rotated by the internal flow, and relatively uniform modification is performed on the entire corner.
In the examples described later, more uniform denaturation is possible by re-melting while repeatedly reciprocating in the horizontal direction two or more times with the heater (C). However, it may be remelted while being reciprocated only once.

(3) In the method for forming a metal film on the columnar base material,
In the remelting step, the heating element (C) remelts relative to the columnar base material (1) in a relative displacement direction in which the position of the columnar base material (1) on the column axis (1A) is relatively displaced. It is preferable to do.
By the above method, the heater element (C) is relatively displaced in a direction in which the position of the columnar base material (1) on the column axis (1A) is relatively displaced while covering the periphery of the columnar base material (1). Thus, more uniform heating is possible in the axial direction. In this method, for example, a heating holder (CH) that holds a heating element (C) is fixed to the wall surface of the remelting chamber, and a fixed head (H) that can reciprocate on the frame is provided in the remelting chamber. This is achieved by reciprocating in the remelting chamber while the columnar base material (1) is attached and fixed to the fixed head (H).
In the embodiments described later, the columnar base material (1) itself can be reciprocally slid by the fixed head (H), and the heater (C) is fixed to the fixed head (H) at the tip of the fixed head (H). So that it can reciprocate. That is, in the examples described later, the heating holder (CH) composed of a plurality of rod-shaped frames is surrounded by a holder band (HB) that surrounds the periphery of the mounting base of the columnar base material (1) along the column axis of the columnar base material (1). It is stretched and fixed to the tip side of the fixed head (H). The heating element (C) is slidably held on the rod of the heating holder (CH). In the remelting step, the heating element (H) reciprocates on the heating holder (CH), so that the heating element (H) is repeatedly relatively displaced with respect to the fixed head (H). Further, at this time, since the fixed head (H) is reciprocally displaced, the absolute velocity and absolute acceleration of the heater (H) are larger than the relative displacement velocity, thereby actively promoting the internal flow.
In addition, it is good also as what was fixed to the front-end | tip of the head (H) with the holder band (HB) surrounding the attachment base part separately from the said form. In this case, the heater (C) is not displaced relative to the columnar base material (1) during remelting.

(4) In the method for forming a metal film on any of the columnar base materials,
In the remelting step, the columnar base material (1) is held in an inclined state (b) in which the tip surface (11) including the corner portion is inclined obliquely at a predetermined horizontal inclination angle (θ), and The columnar base material (1) is remelted while being rotated around the column axis (1A), and the horizontal inclination angle (θ) is preferably fixed to more than 0 degree and 45 degrees or less.
The sprayed coating at the corners changes the direction of external force due to gravity while rotating in the inclined state. With the above method, the columnar base material (1) has a horizontal inclination angle θ: greater than 0 ° and less than 45 °. Therefore, the variable range of the external force direction is a relatively large angle range exceeding 90 degrees, and remelting of the sprayed metal by flow is further promoted. Become.

(5) Alternatively, in the method for forming a metal film on the columnar base material of the present invention,
In the remelting step, the columnar base material (1) is fixed to the columnar base material (1) by the fixed head (H) provided in the remelting chamber under a high pressure environment, and the tip end surface (11) including the corner portion is in a predetermined range with respect to the horizontal inclination angle. The columnar base material (1) is held by the shaft rotation means (RM) that is held in the inclined state (b) that is directed obliquely at (θ) and that rotates at least the inside of the fixed head (H). Re-melting while rotating around the column axis (1A),
The fixed head (H) holds the heating element (C) together with the columnar base material (1), and is preferably attached by a slide mechanism (SF) so as to be able to reciprocate in the remelting chamber.

(6) Alternatively, in the method for forming a metal film on the columnar base material of the present invention,
The fixed head (H) sandwiches the columnar base material (1) with a chuck (CK) that can be rotated within a predetermined angle range in a state in which the horizontal inclination angle (θ) can be freely changed. Yes,
In the remelting step, the chuck (CK) is axially rotated by the shaft rotating means (RM), so that the columnar base material (1) is rotated while the column shaft has a variable horizontal inclination angle (θ). Is preferred.

  The present invention eliminates the partial concentration or deficiency of the melting heat when performing remelting treatment on a columnar base material having a corner at the tip corner, such as a cylinder or a polygonal column, by means of the above means, By suppressing the generation of excessively imparted portions and excessively imparted portions, a metal film forming method capable of eliminating the unevenness of the film thickness after remelting and the density of the composition was provided. In addition, the present invention provides a method for forming a metal film that can prevent deterioration of the properties of the metal film or deterioration of the surface smoothness of the metal film due to the bias.

FIG. 3 is a perspective state diagram of the thermal spray chamber in the thermal spraying process of the metal film forming method according to the first embodiment. FIG. 3 is a partially enlarged perspective view of a thermal spray portion in a thermal spraying process of the metal film forming method according to the first embodiment. The top view which shows the movement direction control of the movement step in the thermal spraying process of the formation method of the metal film of Example 1. FIG. The side surface state figure in the remelting chamber in the remelting process of the formation method of the metal film of Example 1. FIG. The partial expansion side view which shows the state of the columnar base material (1) of the drooping state (a) and the inclination state (b) in the remelting process of Example 1. FIG. The partial expanded side view which shows the state of the columnar base material (1) tip of an upward inclination state.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for carrying out the present invention will be described below with reference to the drawings shown as embodiments. 1 is a perspective view of a thermal spray chamber in a thermal spraying process of the metal film forming method of Example 1, FIG. 2 is a partially enlarged perspective view of the sprayed portion, and FIG. 3 is a perspective view of the metal film of Example 1. It is a top view which shows the movement direction control of the movement step in the thermal spraying process of a formation method. 4 is a side state diagram in the remelting chamber in the remelting step of the method for forming the metal film on the columnar base material of Example 1 of the present invention, and FIG. 5 is a drooping state in the remelting step of Example 1 ( It is a partial expanded side view which shows the state of the columnar base material (1) tip of a) and a downward inclination state (b). FIG. 6 is a partially enlarged side view showing the state of the tip of the columnar base material (1) in an upwardly inclined state.

In any of the following examples, the method of forming a metal film on the columnar base material of the present invention is performed by applying a metal film to the columnar base material (1) having a corner (1C) at the periphery of the tip surface (11). It is a method of forming. In the embodiment, it is composed of a rod-like cylindrical body having a short cylindrical tip with a reduced diameter due to a step at the tip. And it comprises at least the following basic steps in order.
(Basic process)
A thermal spraying step of fixing a thermal spray coating on the entire end of the columnar base material (1) including the tip surface (11) and the corners (1C) by thermal spraying of metal powder;
-By remelting the thermal spray coating with a heater (C) surrounding the side periphery of the columnar base material (1), the thermal spray coating is modified to form a metal coating on the surface of the base material including the corners. Remelting process.

(Spraying process)
In the thermal spraying process, a metal mixed powder containing a metal matrix of a W-based self-fluxing alloy containing nickel and cobalt is cut out (blown) in a thermal spray chamber sealed in an Ar reduced pressure atmosphere of 100 Torr, and the tip of the cylindrical base material (1) is cut. This is a step of spraying on the target surface. A self-fluxing alloy is a nickel-based / cobalt-based alloy containing a flux component such as boron (B) or silicon (Si). By fusing treatment after thermal spraying, there are few pores and adhesion strength High thermal spray coating can be obtained.

In particular, in this embodiment, a so-called composite spraying process is performed in which laser-assisted irradiation is performed at the same time as the thermal spraying range of the target surface of the base material at the same time as the thermal spraying of the metal mixed powder (FIG. 1). Since the laser has a high energy density and can control the irradiation intensity, irradiation intensity and timing of the beam, it must form a good high-density sprayed coating and ensure good adhesion to the base material. Can do. Composite spraying means plasma spraying of metal powder (mm) in which tungsten carbide powder (mw) having a predetermined maximum particle size (mwΦ) is mixed with binder powder (mc) at a predetermined mixing ratio (Rwc) (P ) And laser irradiation with a laser beam (L) are superimposed on the same spraying spot (p) in the surface of the cylindrical base material (1), and combined irradiation is performed, thereby spraying on the cylindrical base material (1). This is a step of forming a film. By combining the features of the present invention and the composite thermal spraying, it is possible to form a more uniform high-density metal film while securing the fixing property to the base material.

  Specifically, a laser gun (LG) fixed obliquely downward from one upper side of the spraying chamber, and a spray gun (PG) fixed obliquely downward from the other upper side of the same thermal spraying chamber, And a holding frame (F) with a holding hole (FH) for holding the columnar base material (1) in an upright state. The holding frame (F) is a rectangular parallelepiped that can be moved and controlled in the biaxial direction in plan view along the holding rail in the spraying chamber, and is provided with two holding holes (FH) drilled in the vertical direction from the upper surface. . A cylindrical columnar base material (1) (1 ') is inserted into each holding hole (FH) one by one. In the inserted state, only the short cylindrical portion having a reduced diameter at the tip of the columnar base material (1) protrudes upward from the hole edge of the holding hole (FH), and other portions are unnecessarily affected by laser or thermal spraying. I am doing so.

The laser beam from the laser gun (LG) and the thermal spray powder (P) from the thermal spray gun (PG) are combined and irradiated to a predetermined area range (PA) that is a part of the tip surface (11) of the columnar base material (1). Is done. The holding frame (F) is placed and held so as to be capable of parallel movement control in two axial directions orthogonal to each other in plan view, and a position perpendicular to the reciprocating direction, that is, a reciprocating line (R1, R2, R3, R4 in FIG. 3). Can be moved while reciprocating in parallel in the thermal spraying chamber while shifting by a predetermined interval (see R1, R2, R3, R4 in FIG. 3). Then, the predetermined area range (PA) irradiated in a complex manner on the tip surface (11) of the lieutenant general base material (1) is reciprocating along the tip surface (11) of the lieutenant general base material (1) ( )
Reciprocating in parallel while changing (Fig. 2). As a result, the entire tip surface (11) is sprayed over the shape edge of the tip surface, that is, the corner, and a sprayed coating is formed from the tip surface to the side surface around the corner as shown in FIGS. The

In the thermal spraying process,
Setting elements including each of the powder supply rate (mm1) of the metal powder (mm) in the plasma spraying (P), the laser irradiation rate (L1), and the laser output (L2) in the laser irradiation (L), A setting step for setting each to a predetermined set value and storing it in the control means;
And a moving step during composite spraying, in which the thermal spraying spot (p) is moved on the substrate surface while performing the composite thermal spraying according to the set values of the setting elements set in the setting step.
And the said setting step responded to predetermined | prescribed mixing ratio conditions according to the primary correlation which consists of energy density (ED) [J / mm < ² >], power density (PD) [W / mm < ² >], and primary increase rate A. Each setting value of the setting element is set.

[Condition 1] When the mixing ratio (Rwc1) of tungsten carbide powder (mw) is 50% or more and less than 80%: ED [J / mm ² ] is 3 or more and 7 or less, PD [W / mm2] is 20 or more and 90 or less And PD is set to a PD value corresponding to a primary increase rate A [W / J] of 4 to 15 per unit increase of ED.
[Condition 2] When the mixing ratio (Rwc1) of tungsten carbide powder (mw) is 80% or more and less than 95%: ED [J / mm ² ] is 6 or more and 16 or less, PD [W / mm2] is 55 or more and 115 [ W / mm 2] or less, and PD is set to a PD value corresponding to a primary increase rate A [W / J] of −24 to −6 per unit increase of ED [J / mm ² ]. .
Alternatively, the setting step includes
According to the primary correlation of energy density (ED) [J / mm ² ] and power density (PD) [W / mm ² ], each setting value of the setting element corresponding to the following mixing ratio condition is set. Forming a metal film.
[Condition 3] When the mixing ratio (Rwc1) of tungsten carbide powder (mw) is 50% or more and less than 80%: ED [J / mm ² ] is 3 or more and 12 or less, PD [W / mm ² ] is 60 or more and 120 The PD falls within the following range, and the PD is set according to a primary reduction rate of 7 to 33 per unit increase of ED−A [W / J] (A: primary coefficient of positive value).
[Condition 4] When the mixing ratio (Rwc1) of tungsten carbide powder (mw) is 80% or more and less than 95%: ED [J / mm ² ] is 3 or more and 12 or less, PD [W / mm ² ] is 25 or more and 60 Within the following range, PD is set according to a primary reduction rate of 2.5 to 5 per unit increase of ED—A [W / J] (A: primary coefficient of positive value).

In the setting step, the powder supply gas flow rate [l / min] in plasma spraying is within 3.0 to 4.0, and the “powder supply rate (mm1)” [rpm] is 0.5 [rpm]. In the case of 1.0 [rpm] or less, the “relative movement speed (pV)” [mm / s] is set to 10 or more and 30 or less.
Alternatively, in the setting step, when the spraying distances [mm] of plasma spraying and laser spraying are both 150 mm and 170 or less, the “laser output (L2)” [kw] is within the range of 0.5 to 40.0. It is to set.

(Device configuration)
As an apparatus configuration for performing composite spraying, for example,
A plasma spraying machine (P) for performing plasma spraying of the metal powder at a constant spraying distance;
A laser irradiator (L) that performs laser spraying by focusing a laser beam on a spraying spot (p) range at a constant spraying distance;
Holding and moving machine (V) for relatively moving the position of the spraying spot on the substrate while maintaining the composite spraying state to the spraying spot by the plasma spraying machine and the laser irradiation machine (L);
At least “powder supply speed (mm1)” which is the rotational speed of a cutting device for metal powder (mm) in plasma spraying, “laser output (L2)” in laser irradiation, and spray spot (p) are cylindrical And a control means for variably controlling the setting elements including each of the “relative movement speeds (pV)” to be relatively moved on the tip surface (11) of the base material (1) to predetermined values. (FIG. 1).

The control means, a first storage area for storing each input value of the mixing ratio (Rwc1) of the tungsten carbide powder (mw) of the metal powder (mm) to be used and the maximum particle size (mwΦ),
A second memory for storing at least “powder supply speed (mm1)” which is the rotational speed of the metal powder (mm) cutting device in the plasma spraying and the area value (PA) of the irradiation spot (p). And a region.
Each input value stored in the first storage area is classified into one of a plurality of input areas composed of combinations of input value ranges set in advance,
Depending on the classified input area,
“Powder supply speed (mm1)” which is the rotational speed of the metal powder (mm) cutting device in the plasma spraying, and “Laser output (L2)” in the laser irradiation, which are stored in the second memory area, “Relative moving speed (pV)” for relatively moving the irradiation spot (p) on the tip surface (11) of the cylindrical base material (1) is set as an area value of the irradiation spot (p) ( The calculation is performed according to the following calculation formula using PA).
Then, each calculated value based on the calculation formula is automatically set to a predetermined set value and displayed.

[Calculation Formula] (L2 / PA) = A · (pV / (L2 · √PA)) + B
However, A in Formula 1 is selected from any of A1, A2, A3, and A4 according to the mixing ratio (Rwc) of the tungsten carbide powder (mw) and the binder powder (mc).
(1) When tungsten carbide powder (mw) having a maximum particle size (mwΦ1) of 1 μm or more is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: −7 <A1 <−35 (central value−18)
(2) When tungsten carbide powder (mw) having a maximum particle size (mwΦ1) of 1 μm or more is contained at a mixing ratio (Rwc2) of 80% or more: −2.5 <A2 <−5 (central value −7)
(3) When tungsten carbide powder (mw) having a maximum particle size (mwΦ2) of less than 1 μm is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: 4 <A3 <6 (center value 8)
(4) When containing tungsten carbide powder (mw) having a maximum particle size (mwΦ2) of less than 1 μm at a mixing ratio (Rwc2) of 80% or more:
E2 (L2, PA) = A1 · E1 (L1, L2, PL); provided that −5.5 <A4 <−24 (central value −10)

In addition, the setting step according to the mixing ratio (Rwc) of the tungsten carbide powder (mw) and the binder powder (mc),
Each setting value of the setting element is set according to the correlation of the following energy density (E1) [J / mm ² ] and power density (E2) [W / mm ² ].

(When the particle size is relatively small)
Especially for the maximum particle size (mwΦ) in the range of 0.1 μm or more and 0.9 μm or less, depending on the mixing ratio of the tungsten carbide powder, the first condition region of the high frequency power density and the low frequency energy density and the low frequency power It has been found that it is preferable to set the following corresponding values divided into the second condition region of density and high energy density.
(Condition 1) When 50% ≦ mixing ratio R ≦ 80%: PD [W / mm ² ] is in the range of 70 to 110, ED is in the range of 3 to 7, and PD is an increase in ED The corresponding value increases at a primary increase rate A [W / J] of 4 to 15.
(Condition 2) When 80% ≦ mixing ratio R ≦ 95%: PD [W / mm ² ] is in the range of 30 to 60 and ED [J / mm ² ] is in the range of 6 to 16 , PD is a corresponding value that decreases at a primary increase rate A [W / J] of −6 to −24 as ED [J / mm ² ] increases.

(When the particle size is relatively large)
In particular, at the maximum particle size (mwΦ) in the range of 1.0 μm to 2.0 μm,
PD [W / mm @ 2] is 55 or more and 90 or less, and the ED [J / mm ^2] is the common condition range in the range of 55 or more and 90 or less, setting the corresponding value of the following in accordance with the mixing ratio of the tungsten carbide powder It turned out to be preferable.
(Condition 3) When 50% ≦ mixing ratio R ≦ 80%: PD [W / mm ² ] is a primary increase rate A [W / J] of 4 to 15 as ED [J / mm ² ] increases. The corresponding value to increase.
(Condition 4) When 80% ≦ mixing ratio R ≦ 95%: PD [W / mm ² ] increases from −6 to −24 in a primary increase rate A [W / J as ED [J / mm ² ] increases. ] Corresponding value to decrease.

The setting step includes
Each setting value of the setting element is set according to a primary correlation of energy density (ED) [J / mm2] and power density (PD) [W / mm2].
[Case 1] When tungsten carbide powder (mw) having a maximum particle size (mwΦ) of 0.1 μm or more and 0.9 μm or less is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: PD increases with an increase in ED It increases at an increase rate A [W / J] of 4-15.
[Case 2] When the maximum particle size (mwΦ) is 1 μm or more and 2 μm or less:
E2 (L2, PA) = A · E1 (L1, L2, PL)
(1) When tungsten carbide powder (mw) having a maximum particle size (mwΦ1) of 1 μm or more is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: −7 <A1 <−35 (central value−18)
(2) When tungsten carbide powder (mw) having a maximum particle size (mwΦ1) of 1 μm or more is included at a mixing ratio (Rwc2) of 80% or more: −2.5 <A2 <−5 (central value −7)
(3) When tungsten carbide powder (mw) having a maximum particle size (mwΦ2) of less than 1 μm is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: 4 <A3 <6 (center value 8)
(4) When containing tungsten carbide powder (mw) having a maximum particle size (mwΦ2) of less than 1 μm at a mixing ratio (Rwc2) of 80% or more:
E2 (L2, PA) = A1 · E1 (L1, L2, PL); provided that −5.5 <A4 <−24 (central value −10)

Here, the inventor has found that a preferable coating structure can be formed by following the correlation of the following power density (PD) [W / mm ² ] and energy density (ED) [J / mm ² ].
(Correlation equation) PD (L2, PA) = A · ED (L1, L2, PL) + B
However, A in Formula 1 is selected from any of A1, A2, A3, and A4 according to the mixing ratio (Rwc) of the tungsten carbide powder (mw) and the binder powder (mc).
(1) When tungsten carbide powder (mw) having a maximum particle size (mwΦ1) of 1 μm or more is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: −7 <A1 <−35 (central value−18)
(2) When tungsten carbide powder (mw) having a maximum particle size (mwΦ1) of 1 μm or more is contained at a mixing ratio (Rwc2) of 80% or more: −2.5 <A2 <−5 (central value −7)
(3) When tungsten carbide powder (mw) having a maximum particle size (mwΦ2) of less than 1 μm is contained in a mixing ratio (Rwc1) of 50% or more and less than 80%: 4 <A3 <6 (center value 8)
(4) When containing tungsten carbide powder (mw) having a maximum particle size (mwΦ2) of less than 1 μm at a mixing ratio (Rwc2) of 80% or more:
E2 (L2, PA) = A1 · E1 (L1, L2, PL); provided that −5.5 <A4 <−24 (central value −10)

(Remelting process)
Thus, in the remelting step after the composite spraying step, the tip end surface (11) including the corner portion and the columnar base material (1) on which the uniform sprayed coating is formed over the entire side surface are converted into the tip end surface (11). A columnar base material (1) which is held in either a hanging state (a) facing downward vertically or an inclined state (b / c) facing a diagonal direction at a predetermined horizontal inclination angle (θ) ) And remelting while rotating around the column axis (1A) (FIGS. 5 and 6). In particular, in the present invention, so-called fusing heat treatment is performed in which high-frequency induction heating is performed in a reduced-pressure atmosphere.

  In particular, the thermal spray coating on the surface of the columnar base material (1) is remelted by re-melting while being rotated around the column axis (1A) in the suspended state (a) or the downward inclined state (b) shown in FIG. It can be prevented from being removed. In particular, the sprayed coating at the corner does not become thin or biased due to its own weight during remelting, and remains the same as the sprayed coating at other portions without being affected by the corner shape of the base material. be able to. That is, as shown in FIG. 5, in the state where the shaft is rotated in the suspended state or the downwardly inclined state, the tip surface (11) is directed vertically downward or obliquely, unlike the state where the shaft is rotated in the upwardly inclined state shown in FIG. The corner (1C) rotates around the vertical axis or the oblique axis. The sprayed coating layer remelted by the shaft rotation flows so as to flow down by its own weight, so that the inside of the coating is kneaded at a moderate speed, and the entire sprayed coating is modified relatively uniformly.

  Here, the inclined state includes an upward inclined state (c: FIG. 6) in which the tip surface (11) is inclined upward so that the horizontal inclination angle (θ) has a positive value upward, and a horizontal inclination angle ( There is a downwardly inclined state (b: FIG. 5B) in which the tip surface (11) is inclined downward so that θ) has a positive value downward. Of these, the downward inclined state (b: FIG. 5B) is more preferable than the upward inclined state (c: FIG. 6). This is because, in the downward inclined state (b), the metal film fixed on the corner (1C) is always fixed on the lower surface or side surface of the base metal corner in the remelting process, from the corner to the corner surface. This is because it dries while staying, and as a result, the film thickness of the sprayed coating is maintained or melted in a state where the film thickness becomes large, and the metal film thickness after remelting is stably secured. can do. Particularly in the downward inclination state (b) in which the inclination angle (θ) with respect to horizontal is 15 degrees or more downward, the angle of gravity that the metal film fixed on the corner portion (1C) receives during remelting sequentially changes. Therefore, the metal film is uniformly rotated by the internal flow.

In the remelting step, the columnar base material (1) is preferably remelted while being reciprocally displaced one or more times in a predetermined reciprocating direction intersecting with its own column axis (1A). As a result, the re-melted sprayed coating layer is alternately subjected to the inertial force that goes straight to the left and right while receiving the inertial force due to the rotation. Therefore, the metal film is uniformly rotated by the internal flow, and relatively uniform modification is performed on the entire corner.
In the embodiment shown in FIG. 4, both the columnar base material (1) and the heating element (C) are only reciprocated in the horizontal direction by the slide mechanism (SF) mechanically controlled by the slide motor (SM), or More uniform denaturation is possible by re-melting while reciprocating at a predetermined reciprocating length (SL) for two or more reciprocations. The slide mechanism (SF) includes a plurality of slide angles (SA) fitted on slide rails fixedly installed on the floor surface in the remelting chamber, and the slide movement of the slide angles (SA) is performed by a slide motor ( SM). As the slide base (SB) supported by the slide angle (SA) slides, the slide base (SB), the arm (A) integrally extended with the slide base (SB), and the arm ( A) The fixed head (H) fixed to the upper part is reciprocated in parallel as an integral structure.

In the remelting step, the heating element (C) is remelted while being relatively displaced in the relative displacement direction in which the position of the columnar base material (1) on the column axis (1A) is relatively displaced with respect to the columnar base material (1). It is preferable to do. By this method, the heater element (C) is relatively displaced in the direction in which the position of the columnar base material (1) on the column axis (1A) is relatively displaced while covering the periphery of the columnar base material (1). Thus, more uniform heating is possible in the axial direction. In this method, for example, a heating holder (CH) that holds a heating element (C) is fixed to the wall surface of the remelting chamber, and a fixed head (H) that can reciprocate on the frame is provided in the remelting chamber. This is achieved by reciprocating in the remelting chamber while the columnar base material (1) is attached and fixed to the fixed head (H).

In the embodiment, the columnar base material (1) itself can reciprocate by the fixed head (H), and the heater (C) reciprocates relative to the fixed head (H) at the tip of the fixed head (H). Held possible. That is, in the examples described later, the heating holder (CH) composed of a plurality of rod-shaped frames is surrounded by a holder band (HB) that surrounds the periphery of the mounting base of the columnar base material (1) along the column axis of the columnar base material (1). It is stretched and fixed to the tip side of the fixed head (H). The heating element (C) is slidably held on the rod of the heating holder (CH). In the remelting step, the heating element (H) reciprocates on the heating holder (CH), so that the heating element (H) is repeatedly relatively displaced with respect to the fixed head (H). Further, at this time, since the fixed head (H) is reciprocally displaced, the absolute velocity and absolute acceleration of the heater (H) are larger than the relative displacement velocity, thereby actively promoting the internal flow.

In addition, it is good also as what was fixed to the front-end | tip of the head (H) with the holder band (HB) surrounding the attachment base part separately from the said form. In this case, the heater (C) is not displaced relative to the columnar base material (1) during remelting.

  In the remelting step, the columnar base material (1) is held in an inclined state (b) in which the front end surface (11) including the corners is directed obliquely at a predetermined horizontal inclination angle (θ), and The columnar base material (1) is remelted while being rotated around the column axis (1A), and the horizontal inclination angle (θ) is preferably fixed to more than 0 degree and 45 degrees or less. The sprayed coating at the corners changes the direction of the external force due to gravity as the shaft rotates while in the inclined state. With this method, the columnar base material (1) has a horizontal inclination angle θ: greater than 0 ° and less than 45 °. Therefore, the variable range of the external force direction is a relatively large angle range exceeding 90 degrees, and remelting of the sprayed metal by flow is further promoted. Become.

In the embodiment, a holding shaft orthogonal to the arm (A) is incorporated in the upper part of the arm (A), and a substantially cylindrical fixed head is provided on one end side of the holding shaft via a rotary fastening arm hinge (AH). (H) is fixed (FIG. 4). The other end of the holding shaft is mechanically connected to a rotary motor having a drive shaft, which is a shaft rotating means (RM). The chuck (CK) in the fixed head (H) is rotated by the rotational drive of the drive shaft passing through the holding shaft. The fixed head rotates around the horizontal arm hinge axis perpendicular to the holding axis by adjusting the tightening of the arm hinge (AH), and can hold a predetermined rotation angle (versus horizontal inclination angle (θ)). ing.

  A plurality of chucks (CK) are distributed and incorporated in the cylindrical circumferential direction of the fixed head (H) so as to protrude from the inside of the fixed head (H) to the side tip, and the proximity distance between the chucks (CK) is adjusted. By fixing, the columnar base material (1) is sandwiched in a state in which the tip end surface (11) protrudes to the side. The chuck (CK) and the drive shaft of the shaft rotating means (RM) are connected to each other through a union socket, and the fixed head (H) is angled with respect to the horizontal (θ) exceeding 0 degrees by the arm hinge (AH). ), The driving force of the rotating shaft of the shaft rotating means (RM) is transmitted as the rotating force of the chuck (CK).

With the above configuration, in the remelting step, the columnar base material (1) is paired with the tip surface (11) including the corner portion in a predetermined range by the fixed head (H) provided in the remelting chamber under a high pressure environment. The columnar base material (1) is held by the shaft rotating means (RM) that holds the tilted state (b) facing the oblique direction at the horizontal tilt angle (θ) and rotates the shaft at least inside the fixed head (H). It is remelted while being rotated around the column axis (1A) while being held.
The fixed head (H) holds the heating element (C) together with the columnar base material (1), and is attached so as to be able to reciprocate in the remelting chamber by a slide mechanism (SF).

(Other Embodiments) As a configuration different from the above-described embodiments, the fixed head (H) is configured such that the columnar base material (1) is tilted with respect to the horizontal by a chuck (CK) that can be rotated within a predetermined angle range. (Θ) is sandwiched in a freely variable state,
In the remelting step, the chuck (CK) is rotated by the shaft rotating means (RM) so that the columnar base material (1) is rotated while the angle of inclination (θ) with respect to the column axis is variable. It can also be. Because the rotation angle of the shaft rotation allows the angle of inclination (θ) of the lieutenant general (1) to be freely variable together with the heating element (C), it drives the direction of external force due to gravity that the sprayed coating receives during the remelting process. It can be freely changed without using force.

  The present invention is not limited to the above-described embodiments, but the method elements of each embodiment, the configuration of each implement, or the partial omission / extraction of some elements, other known configurations or combinations of other known elements The present invention can be modified as appropriate without departing from the spirit of the present invention, such as substitution replacement of some elements.

Tip surface (11)
Corner (1C)
Columnar base material (1)
Heater (C)
Column axis (1A)
Hanging state (a)
Inclined state (b)
Fixed head (H)
Horizontal tilt angle (θ)
Shaft rotation means (RM)
Slide mechanism (SF)
Chuck (CK)

Claims (3)

A method of forming a metal film on a columnar base material having corners on the periphery of the tip surface,
A thermal spraying step of fixing a thermal spray coating by thermal spraying of metal powder on the entire end of the columnar base material including the tip surface and the corners;
A remelting step of modifying the thermal spray coating by remelting the thermal spray coating with a heater surrounding a side periphery of the columnar base material to form a metal coating on the surface of the base material including the corners. And
In the remelting step, the columnar base material is held in an inclined state in which the tip surface including the corner portion is inclined obliquely at a predetermined horizontal inclination angle, and is rotated around the column axis of the columnar base material. The method for forming a metal film on a columnar base material is characterized in that it is remelted while the horizontal inclination angle is fixed to more than 0 degree and 45 degrees or less . In the remelting step, the columnar base material is inclined by a fixed head provided in a remelting chamber under a high-pressure environment so that the tip surface including the corner portion is inclined obliquely at a predetermined horizontal inclination angle. It is held and re-melted while rotating around the column axis while holding the columnar base material by the shaft rotating means for rotating the shaft at least inside the fixed head,
The method of forming a metal film on a columnar base material according to claim 1, wherein the fixed head holds a heater together with the columnar base material, and is attached so as to be able to reciprocate in the remelting chamber by a slide mechanism . The fixed head sandwiches the columnar base material with a chuck that can be rotated within a predetermined angle range in a state in which the angle of inclination with respect to the horizontal can be freely changed,
3. The columnar mother according to claim 1, wherein, in the remelting step, the columnar base material is rotated while the axis of the chuck is rotated by the shaft rotating unit while the angle of inclination of the column axis with respect to the horizontal axis is variable. A method for forming a metal film on a material.

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