JP3147277B2 - Spraying condition determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for optimally determining the spraying conditions (such as the spraying distance) when forming a sprayed coating on the surface of a component.

[0002]

2. Description of the Related Art When a thermal spray coating is formed on a surface of a component by performing thermal spraying on the component, if only a part of the component is heated to a high temperature by heat during thermal spraying, poor adhesion of the thermal spray coating or excessive Oxidation and the like occur, and problems relating to film quality occur. Therefore, when performing thermal spraying on a part, it is important to know how much heat acts on each part of the part and what the temperature distribution on the part surface will be, in order to design an optimal thermal spray coating. Indispensable.

As a general means for measuring the temperature of the surface of a component, a thermocouple or the like is usually used.
When measuring the temperature distribution on the component surface using this thermocouple, it is conceivable to attach a thermocouple to the back side of the surface to be sprayed and measure the temperature.

[0004]

However, in the method of measuring the temperature of each part on the surface of the component at the time of thermal spraying with a thermocouple to know the temperature distribution on the surface of the component, the following various problems occur. is there. In other words, the temperature can be easily measured by fixing the thermocouple to the back of the sprayed surface, but the temperature can be measured only from the back side of the part. In fact, it is not possible to know the state of the temperature distribution accurately. Further, the thermocouple has a disadvantage that it is difficult to measure the temperature of a minute part of the component.

[0005] Even if the component is not of a complicated shape, in order to know the temperature distribution of the component in detail, a very large number of thermocouples are required, and the temperature measurement operation is troublesome. In addition, even if many thermocouples are used, only the temperature measurement of the parts scattered in the component can be performed, and the temperature distribution in all the surface regions where the thermal spraying is performed cannot be known.

Further, performing temperature measurement while performing thermal spraying with the thermocouple fixed to the component surface during thermal spraying is complicated in terms of wiring of a large number of thermocouples, and the measurement operation is difficult. There is. In particular, when performing thermal spraying while rotating components, the wiring of the thermocouple becomes a very hindrance.

SUMMARY OF THE INVENTION The present invention has been made in view of such various problems, and has as its object the purpose of spraying even a component having a complicated shape without using a special temperature measuring device. To provide a thermal spray condition determining method that can easily and inexpensively measure the temperature distribution in all the surface regions where the thermal spraying is performed, and determine the optimal thermal spraying condition based on the measurement result. is there.

[0008]

In order to achieve the above-mentioned object, the present invention forms a plating film made of a thermosetting or heat-softening material on the surface of a component to be sprayed and forms a coating film on the plating film. After spraying, the hardness of the plating film is measured, and based on the measured hardness, the temperature distribution on the sprayed surface of the component is estimated, and the spraying distance or the like is determined according to the result of the estimated temperature distribution. Are determined.

[0009]

[Function] A thermosetting plating film (for example, Ni-P alloy plating film) or a thermo-softening plating film (for example, Ni plating film) formed on the surface of a part is exposed to heat during thermal spraying. By measuring the hardness of the plated film after thermal spraying, it is possible to understand what temperature distribution the component surface to be subjected to thermal spraying has during thermal spraying. That is, the relationship between the heating temperature of the plating film and the film hardness is measured in advance by an experiment, and the temperature distribution on the component surface is estimated from the hardness of the plating film in each part after thermal spraying in light of the measurement results. Can be. Then, by re-examining the spraying conditions according to the temperature distribution of the component surface estimated in this way, the optimum spraying conditions that can prevent poor adhesion of the sprayed coating and excessive oxidation are determined. Under such conditions, the spraying operation can be performed optimally. Note that no special device for temperature measurement is required.

[0010]

1 to 3 show an embodiment of the present invention.
This will be described with reference to FIG.

FIG. 1 shows a test piece 1 used in a first embodiment of the present invention.
After a plating film 3 made of thermosetting Ni-P-SiC is formed on the surface 2a (the same material as the part to be sprayed), the surface 3a of the plating film 3 is sprayed to form a sprayed coating 4. It is formed. The planar shape of the test piece 1 is a rectangle as shown in FIG. 2, the vertical length L ₁
But 130 mm, the horizontal length L ₂ is 50 mm.

FIG. 3 shows a procedure for carrying out the method according to the present invention, which comprises a plating step, a thermal spraying step, and a hardness measuring step. Specifically, in the plating process, alkaline etching,
A plating film 3 is formed on the base material 2 by sequentially performing water washing, mixed acid treatment, water washing, Zn substitution, water washing, nitric acid treatment, water washing, Zn substitution, water washing, and plating treatment. An example of a plating bath used for forming the plating film 3 made of, for example, Ni-P-SiC has the following components. Plating bath reagent concentration Nickel sulfamate: 400 to 500 mg / l Nickel chloride: 10 to 20 g / l Boric acid: 40 to 50 g / l Saccharin soda: 5 to 10 g / l Hypophosphorous acid: 1-2 g / l Si C: 50-100 g / l

Next, in a subsequent thermal spraying step, a thermal spraying is performed after performing a degreasing treatment to form a thermal spray coating 4 on the plating film 3.

Thereafter, in a subsequent hardness measurement step, cutting of parts (cutting out a portion for measuring hardness), embedding of the cut portion in resin, polishing (mirror finish), and measurement of hardness of the cut surface of the plating film are sequentially performed. Enforce.

Apart from this, the correlation between the heat treatment temperature and the hardness (micro Vickers hardness Hv) of the plating film 3 is measured in advance by experiments. The experimental result is
As shown in Table 1 below, the measurement results are shown in a graph as shown by the broken line α in FIG. In the case of a thermosetting heat-curable plating film, the heat treatment is usually performed only for a predetermined time (for example, at 400 ° C. for one hour). In the case of film curing by thermal spraying, thermal spraying is performed. Experiments have shown that it cures in a short time. Therefore, the spraying time has almost no effect on the above-mentioned correlation characteristics.

[0016]

[Table 1]

In forming the thermal spray coating 4 on the plating film 3, first, as shown by an arrow P in FIG. 2, along the ladder-like thermal spray path from one end of the test piece 1 to the other end. Thermal spraying was performed, and the film was turned back at the lowermost stage on the other end side and sprayed along a spraying path toward one end side.

After the completion of the thermal spraying, the hardness (micro-Vickers hardness Hv) of the three scattered portions indicated by reference numerals A, B and C in FIG. 2 was measured. The measurement results are as shown in Table 2 below.

[0019]

[Table 2]

First, the hardness is measured by spraying while keeping the spraying distance constant, and the measurement result is compared with the relationship between the heat treatment temperature and the hardness shown in Table 1 and FIG. It was inferred that the hardness was 810 or more at the portion C where the temperature rose, and the temperature was increased to 200 ° C. or more. That is, in this case, at the time of thermal spraying, the other end portion of the test piece 1 (end portion of the thermal spraying path)
Was heated to a temperature higher than its one end (the beginning of the thermal spraying path) and was heated to a temperature of 200 ° C. or higher (see the middle column of Table 2).

Therefore, based on this result, the above-mentioned location C
On the other end side of the portion, when the spraying was performed with the spraying distance relatively increased, the hardness at the portion C became 810 or less, so that the spraying could be performed at 200 ° C. or less (Table 2). In the right column). Thus, the final thermal spraying conditions in the actual thermal spraying process can be appropriately changed, and the problem that only a part of the test piece 1 is heated to a higher temperature than other parts during thermal spraying can be avoided. .

Here, how to change the thermal spraying requirements will be described as follows. First, when performing temperature control at the time of thermal spraying, since a particular problem is that the temperature of the component is too high, parameters related to the temperature increase are changed. The thermal spraying conditions include a thermal spraying distance, a supply current, a powder supply gas pressure, an auxiliary gas pressure, and the like. The effects of these conditions on the characteristics of the thermal spray coating are experimentally obtained as a correlation equation. Therefore, among those conditions which are considered to be related to the temperature rise, one of the conditions is set so as not to lower the characteristics.
By changing one or more conditions as appropriate,
Control the temperature.

A specific example of temperature control will be described below. First, it is assumed that it has been found that a temperature rise in a certain part is remarkable in a thermal spraying process on a part.
In this case, the spraying distance which is considered to be relatively easy to control and effective is changed among the above-described spraying conditions. However, it is a prerequisite that the adhesion strength of the sprayed coating does not decrease with a change in the condition of the spraying distance.

Here, it is assumed that a correlation equation between the adhesion strength and the spraying condition is represented by the following equation. Adhesion strength = ax + by + cz + d, where x: supply current y: spraying distance z: powder supply gas pressure (1) When b> 0 or b = 0 If the spraying distance is increased, the adhesion strength increases, so there is no problem. (2) In the case of b <0 Since the adhesion strength decreases as the spraying distance increases, it is necessary to stop increasing the spraying distance or to minimize the increase in the spraying distance. In such a case,
This is dealt with by changing other spraying conditions. (3) When b <0 and the value of b is sufficiently small There is no problem because the adhesion strength does not change so much.

Next, a second embodiment of the present invention will be described as follows. That is, in this example, as shown in FIG. 5, a plating film 5 made of thermo-softening Ni is formed on the base material 2 instead of the plating film 3 made of thermosetting Ni-P-SiC. A test piece 6 having a sprayed film 4 formed on the plating film 5 was used.

In this case, the hardness after thermal spraying was measured in the same manner as in the first embodiment, and the measurement results shown in Table 3 below were obtained. The result of plotting this measurement result on a graph is as shown by a broken line β in FIG.

[0027]

[Table 3]

As described above, even when the heat-softening plating film 5 is used as the base plating of the thermal spray coating 4, if the relationship between the heating temperature and the coating hardness is measured in advance, the plating film 5 after thermal spraying can be obtained. By measuring the hardness distribution, the temperature distribution on the surface 1a (part surface) of the base material 1 during thermal spraying can be estimated and grasped. Thus, similar to the first embodiment described above, it is possible to appropriately change the spraying conditions such as the spraying distance based on the estimated temperature distribution and determine the optimum spraying conditions.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made based on the technical concept of the present invention. For example, in the above-described embodiment, thermal spraying is performed using the test piece 1 or 6 in which the plating film 3 made of Ni-P-SiC or the plating film 5 made of Ni is interposed between the base material 1 and the sprayed film 4. The temperature distribution at the time is measured, but the present invention is not limited to this, and a plating film made of various thermosetting or thermosoftening materials other than Ni-P-SiC or Ni may be used as the underlayer. It is possible.

The method of selecting the thermal spraying path P and the method of determining the optimal thermal spraying conditions based on the temperature distribution during thermal spraying can be appropriately changed as needed.

[0031]

As described above, according to the present invention, after forming a plating film made of a thermosetting or heat-softening material on the surface of a component to be sprayed and performing spraying on the plating film, Measure the hardness of the plating film, estimate the temperature distribution on the sprayed surface of the component based on the measured hardness, and determine the spraying conditions such as the spraying distance according to the result of the estimated temperature distribution. Therefore, it is possible to set an optimal thermal spraying condition in which only a part is abnormally heated and a problem such as poor adhesion or excessive oxidation does not occur. That is, the relationship between the heating temperature and the hardness of a thermosetting or thermosoftening plating film (plating film made of a material whose hardness changes depending on the heating temperature) is measured in advance, and the relationship between the heating temperature and the actual hardness is measured. The temperature distribution on the sprayed surface (part surface) can be accurately grasped by comparing the hardness of the plating film measured after thermal spraying on the surface.
Depending on the result, the spraying conditions such as the spraying distance can be appropriately changed so as to be optimal.

Further, according to the method of the present invention, it is possible to directly measure the temperature distribution at the time of thermal spraying at all locations (entire regions) where thermal spraying is performed, and it is also possible to measure a minute part of each part even with a component having a complicated shape. Temperature distribution can be accurately grasped,
By re-examining the thermal spraying conditions based on the result of the measurement of the temperature distribution, an optimal design that can prevent poor adhesion of the thermal sprayed coating and excessive oxidation can be achieved.

Further, since a special measuring device such as a thermocouple for temperature measurement is not required, the cost can be reduced.
Another advantage is that the measurement operation is simple.

[Brief description of the drawings]

FIG. 1 is a sectional view of a test piece used in a first embodiment of the present invention.

FIG. 2 is a plan view of the test piece described above.

FIG. 3 is a flowchart showing a procedure for implementing a method according to the present invention.

FIG. 4 is a graph showing a relationship between a heat treatment temperature of a plating film and a micro Vickers hardness.

FIG. 5 is a sectional view of a test piece used in a second embodiment of the present invention.

[Explanation of symbols]

 1, 6 Test piece 2 Base material 2a Surface (part surface) 3 Plating film composed of Ni-P-SiC 3a Surface 4 Thermal spray coating 5 Plating film composed of Ni

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-145761 (JP, A) JP-A-55-149710 (JP, A) JP-A-55-58360 (JP, A) 65705 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 4/00-4/18 C23C 28/00-28/04

Claims (1)

(57) [Claims] 1. After forming a plating film made of a thermosetting or thermo-softening material on the surface of a component to be sprayed and spraying the plating film, the hardness of the plating film is measured. A spraying condition characterized by estimating a temperature distribution on a sprayed surface of the part based on the measured hardness and determining a spraying condition such as a spraying distance according to a result of the estimated temperature distribution. Decision method.