JPH08120436A - Decision of thermal spraying condition - Google Patents

Abstract

PURPOSE: To simply estimate the temp. distribution of the thermal spraying face at a low cost and to optimize the thermal spraying conditions by thermal- spraying the surface of a thermosetting or thermosoftening plated film provided on the surface of parts and thereafter measuring the hardness of the plated film. CONSTITUTION: On the surface 2a of a base material 2 to be thermal-sprayed in parts 1, a plated film 3 constituted by a thermosetting or thermosoftening material is formed. Next, the surface 3a of the same plated film 3 is thermal- sprayed to form a sprayed coating 4. After that, the hardness of the same plated film 3 is measured. Based on the same hardness measured value, from the correlation between the heat treating temp. and hardness, the temp. distribution in the thermal spraying face is estimated. In accordance with the same temp. distribution, thermal spraying conditions such as thermal spraying distance or the like are optimally decided so as to prevent deterioration in the tight adhesion, excessive oxidation or the like in the sprayed coating.

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 a spraying condition (spraying distance, etc.) when forming a sprayed coating on the surface of a component.

[0002]

2. Description of the Related Art When spraying a part to form a sprayed film on the surface of the part, if only a part of the part is heated to a high temperature due to the heat of spraying, the adhesion of the sprayed film at that part may be insufficient or excessive. Oxidation etc. occurs, and problems related 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 surface of the part looks like in the optimum spray coating design. It is essential.

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

[0004]

However, the method of measuring the temperature of each part on the surface of the component at the time of thermal spraying by the thermocouple to know the temperature distribution on the surface of the component has the following various problems. is there. That is, the temperature can be easily measured by fixing the thermocouple to the back surface of the sprayed surface, but since the temperature can be measured only from the back side of the part, the surface of the part with complicated shape can be measured. In reality, it is not possible to know the temperature distribution of the water. Further, the thermocouple has a problem that it is difficult to measure the temperature of a minute portion of the component.

Further, even if it is not a component having a complicated shape, in order to know the temperature distribution of the component in detail, an extremely large number of thermocouples are required, and the temperature measurement work is troublesome. Even if many thermocouples are used, the temperature can be measured only at the spots on the component, and the temperature distribution in all the surface regions where the thermal spraying is performed cannot be known.

Further, when the temperature is measured while the thermocouple is fixed on the surface of the component during the thermal spraying, the temperature measurement is complicated and the measurement work is difficult because of the wiring of many thermocouples. There is. In particular, when performing thermal spraying while rotating the parts, the wiring of the thermocouple becomes a very disturbing existence.

The present invention has been made in view of the above-mentioned various problems, and its object is to perform thermal spraying even in the case of a component having a complicated shape without using a special temperature measuring device. To provide a thermal spraying condition determination method capable of easily and at low cost measuring the temperature distribution in all surface areas for performing the thermal spraying, and determining the optimal thermal spraying condition based on the measurement result. is there.

[0008]

In order to achieve the above object, in the present invention, a plating film made of a thermosetting or thermosoftening material is formed on the surface of a component to be sprayed, and the plating film is formed on the plating film. After performing thermal spraying on, the hardness of the plating film is measured, and the temperature distribution on the thermal sprayed surface of the component is estimated based on the measured hardness, and the thermal spray distance and the like according to the result of the estimated temperature distribution. The conditions for thermal spraying are determined.

[0009]

[Function] A thermosetting plating film (for example, an alloy plating film such as Ni-P) or a heat-softening plating film (for example, a plating film such as Ni) formed on the surface of a component is exposed to heat during thermal spraying. Since it hardens or softens, the hardness of the plating film after thermal spraying can be measured to understand what temperature distribution the surface of the component to be subjected to thermal spraying will have during thermal spraying. That is, the relationship between the heating temperature of the plating film and the film hardness is measured in advance by experiments, and in light of this measurement result, the temperature distribution of the surface of the component can be inferred from the hardness of the plating film in each part after thermal spraying. You can Then, by re-examining the thermal spraying conditions according to the temperature distribution of the surface of the parts thus estimated, it is possible to determine the optimum thermal spraying conditions that can prevent poor adhesion of the thermal spray coating and excessive oxidation. It becomes possible to optimally perform the thermal spraying work under the conditions. No special device for temperature measurement is required.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

FIG. 1 shows a test piece 1 used in the first embodiment of the present invention. The test piece 1 comprises a base material 2
After the plating film 3 made of thermosetting Ni-P-SiC is formed on the surface 2a of (the same material as the component to be sprayed), the surface 3a of the plating film 3 is sprayed to form the sprayed film 4 thereon. It was formed. The plane shape of the test piece 1 is a rectangle as shown in FIG. 2, and the vertical length L ₁
Is 130 mm and the lateral length L ₂ is 50 mm.

Further, FIG. 3 shows a procedure for carrying out the method according to the present invention, and the carrying out steps are a plating step, a thermal spraying step, and a hardness measuring step. Specifically, in the plating process, alkali etching,
The 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. Note that, for example, one example of the plating bath used when forming the plating film 3 made of 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 Hypophosphite: 1-2 g / l lSiC: 50-100 g / l

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

Thereafter, in the subsequent hardness measuring step, the parts are cut (the part whose hardness is to be measured is cut out), the cut part is embedded in resin, the polishing is performed (mirror finish), and the hardness of the cut surface of the plating film is measured in sequence. Enforce.

Separately 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 an experiment. The experimental result is
As shown in Table 1 below, the measurement result is shown in a graph as shown by the broken line α in FIG. In the case of a thermosetting heat-curable plating film, heat treatment is usually performed for a fixed time (for example, 1 hour at 400 ° C.), but in the case of film curing by thermal spraying, thermal spraying is performed. It has been confirmed by experiments that it cures in a short time. Therefore, the spraying time has almost no influence on the above-mentioned correlation characteristics.

[0016]

[Table 1]

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

After the thermal spraying was completed, the hardness (micro Vickers hardness Hv) at the three spots indicated by the symbols 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 was measured by performing thermal spraying with the thermal spraying distance kept constant, and the measurement results were compared with the relationship between the heat treatment temperature and the hardness shown in Table 1 and FIG. At the rising portion C, the hardness was 810 or higher, and therefore, it was inferred that the temperature was raised to 200 ° C. or higher. That is, in this case, the other end portion of the test piece 1 during spraying (the end portion of the spray path)
Was heated to a temperature higher than that of its one end portion (starting portion of the thermal spray 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 point C
On the other end side of the portion, when the thermal spraying distance was relatively increased and the thermal spraying was performed, the hardness at the location C became 810 or less, so that it became possible to perform the thermal spraying at 200 ° C. or less (Table 2). See the right column). Therefore, the final thermal spraying conditions in the actual thermal spraying process can be appropriately changed, and it is possible to avoid the problem that only a part of the test piece 1 is heated to a higher temperature than other parts during the thermal spraying. .

The method of changing the thermal spraying requirements will be described below. First, when temperature control during thermal spraying is performed, the problem is that the temperature of the component rises too much, so the parameters related to the temperature rise are changed. The spraying conditions include the spraying distance, the supply current, the powder supply gas pressure, the auxiliary gas pressure, and the like, and the effect of these conditions on the characteristics of the sprayed coating has been experimentally obtained as a correlation equation. Therefore, among these conditions, among those that are thought to be related to temperature rise, do not 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 was found that the temperature rise in a certain part was remarkable in the thermal spraying process on the part.
In this case, among the above-mentioned thermal spraying conditions, the thermal spraying distance, which is considered to be relatively easy to control and has a large effect, is changed. However, it is a precondition that the adhesion strength of the thermal spray coating does not decrease with the change in the conditions regarding the thermal spray distance.

Here, it is assumed that the correlation equation between the adhesion strength and the spraying condition is represented by the following equation. Adhesion strength = ax + by + cz + d However, x: supply current y: spraying distance z: powder supply gas pressure (1) When b> 0 or b = 0 Adhesion strength increases as the spraying distance increases, so there is no problem. (2) When b <0 Since the adhesion strength decreases as the spray distance increases, it is necessary to either stop increasing the spray distance or minimize the increase in the spray distance. In such cases,
This is dealt with by changing other thermal 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.

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

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

[0027]

[Table 3]

Even when the thermal softening plating film 5 is used as the undercoat of the thermal spray coating 4 as described above, if the relationship between the heating temperature and the coating hardness is measured in advance, the plating film 5 after thermal spraying 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. Accordingly, similar to the above-described first embodiment, it is possible to appropriately change the thermal spraying conditions such as the thermal spraying distance based on the estimated temperature distribution to determine the optimum thermal 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 idea of the present invention. For example, in the above-mentioned embodiment, 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 coating 4 is sprayed. Although the temperature distribution at the time is measured, 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 optimum thermal spraying conditions based on the temperature distribution during thermal spraying can be appropriately changed as necessary.

[0031]

As described above, according to the present invention, a plating film made of a thermosetting or thermosoftening material is formed on the surface of a component to be sprayed, and after the plating film is sprayed, The hardness of the plating film is measured, and the temperature distribution on the sprayed surface of the component is estimated based on the measured hardness, and the spraying conditions such as the spraying distance are determined according to the result of the estimated temperature distribution. Therefore, it is possible to set the optimum thermal spraying conditions in which only a part is abnormally heated and problems such as poor adhesion and excessive oxidation do not occur. That is, the mutual relationship between the heating temperature and the hardness of a thermosetting or thermosoftening plating film (a plating film made of a material whose hardness changes depending on the heating temperature) is measured in advance, and this mutual relationship and the actual The temperature distribution of the surface to be sprayed (component surface) can be accurately grasped by comparing the hardness of the plating film measured after thermal spraying on the
Depending on the result, the spraying conditions such as the spraying distance can be appropriately changed so as to be optimum.

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 (all areas) where thermal spraying is performed, and even in the case of a part having a complicated shape, a minute portion of each part You can accurately understand the temperature distribution,
By re-examining the thermal spraying conditions based on the results of measuring the temperature distribution, it becomes possible to carry out an optimum design capable of preventing poor adhesion and excessive oxidation of the thermal spray coating.

Moreover, since no special measuring device for temperature measurement such as a thermocouple is required, the cost is low.
There is also an advantage that the measurement work is simple.

[Brief description of 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 flow chart showing the procedure for carrying out the method according to the present invention.

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

FIG. 5 is a cross-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 Ni-P-SiC plating film 3a Surface 4 Thermal spray coating 5 Ni plating film

Claims (1)

[Claims] 1. A plating film made of a thermosetting or heat-softening material is formed on the surface of a component to be sprayed, and after spraying the plating film, the hardness of the plating film is measured, The thermal spraying condition is characterized in that the temperature distribution on the sprayed surface of the part is estimated based on the measured hardness, and the spraying conditions such as the spraying distance are determined according to the result of the estimated temperature distribution. How to decide.