JP6016742B2 - Method and apparatus for selecting material for sprayed film or overlay weld layer - Google Patents

Description

  The present invention relates to a material selection method and apparatus suitable for selecting main elements of a sprayed film or a built-up weld layer applied to a member placed in an environment of erosion and corrosion.

  Boiler tubes used for land-use boilers, coal gasification combined power generation facilities, or garbage power generation boilers, etc. are used for erosion (mechanical erosion) caused by combustion ash, hydrogen sulfide, sulfate and chloride contained in combustion gas. It is placed in an environment where it is subject to corrosion (electrochemical corrosive action) caused by things. A member used in such an environment needs to have both properties of wear resistance and corrosion resistance, and thinning due to wear or corrosion proceeds even if one of them is missing.

  As a measure for reducing the thickness of a member placed in such an environment, there is a method of covering the surface of the member with a sprayed film or a build-up weld layer. However, even if materials are selected in consideration of wear resistance and corrosion resistance, it is not easy to confirm in advance how much resistance to metal thinning is present in an actual erosion / corrosion environment.

  Patent Document 1 discloses a film quality evaluation method that enables on-site evaluation of whether or not the film quality of a sprayed film actually applied is sound. This evaluation method is based on the correlation between the electrical resistivity, nondestructive hardness, and film thickness of the sprayed film, and a setting process that sets the required area required to satisfy the prescribed function of the sprayed film. A measurement process for measuring the electrical resistivity, nondestructive hardness and film thickness of the sprayed film, and a judgment process for determining that the applied sprayed film is healthy when each measured value is within the required area. It will be.

JP 2011-106922 A

  The film quality evaluation method disclosed in Patent Document 1 is an evaluation method for evaluating the film quality of a sprayed film after being applied, and the sprayed film has wear resistance and corrosion resistance as required specifications before the sprayed film is applied. It doesn't make it predictable. When the applied sprayed film does not satisfy the required wear resistance and corrosion resistance, and it is found that the thinning rate is greater than the expected value, it is necessary to replace the sprayed film and review the maintenance inspection schedule.

  In view of the problems of the prior art, the present invention can reliably exhibit erosion / corrosion resistance characteristics as required when applying a sprayed film or overlay welding on the surface of a member placed in an erosion and corrosion environment. It aims at enabling manufacture of a sprayed film and a build-up weld layer.

  In order to achieve the above object, the method for selecting a material for a sprayed film or a built-up weld layer according to the present invention performs the following steps to form a sprayed film or a built-up weld layer (hereinafter referred to as “sprayed film etc.”). Among the elements contained, the main elements that influence the erosion / corrosion characteristics of the sprayed film, etc., and their contents are selected, and it is possible to produce a sprayed film that can exhibit the erosion / corrosion resistant characteristics as required. .

  First, the main elements that influence the erosion / corrosion resistance properties of the sprayed film, etc. are selected from the elements contained in the sprayed film. Next, from an existing sprayed film that contains the selected main element as a component and is placed in an erosion and corrosion environment, or a sample that is created as a test piece and placed in an erosion and corrosion environment. Then, the content, hardness, film thickness and thinning rate of the main elements are measured, and data of these measured values are collected.

  Next, a three-dimensional map is created from the collected measurement data with the content of the main element, the film thickness and hardness of the sprayed film, etc. as the coordinate axes, and the measurement data is plotted on this three-dimensional map. Further, a required thinning rate of the sprayed film or the like is set, and a required region satisfying the required thinning rate is calculated from a three-dimensional map in which measurement data is plotted. The content of the main element such as the sprayed film is selected from the required area thus calculated. After selecting the contents of the main elements, other necessary elements and their contents are determined, and the component elements such as the sprayed film and their contents are determined.

The hardness of the sprayed film correlates with the denseness of the sprayed film and serves as an index for evaluating wear resistance. Therefore, the higher the hardness, the better the wear resistance (erosion resistance). Similarly, the build-up weld layer has a more excellent wear resistance (erosion resistance) as the hardness of the sound microstructure without weld defects in the weld layer increases.
In a waste-fired circulating fluidized bed boiler, high-calorie waste solidified fuel (RDF) used as fuel contains a large amount of HCl. Therefore, HCl gas and KCl, NaCl, etc. generated from HCl gas during operation are vapor-phase condensed, corrosive gas and molten salt enter the pores, and the sprayed film is transmitted from the inside and becomes the substrate to be sprayed. Corrodes hot tube metal. Since the sprayed film with low density has many pores, it becomes a sprayed film with low corrosion resistance.

Moreover, the outstanding erosion-corrosion characteristic can be acquired by making film thickness, such as a sprayed film, into an appropriate film thickness according to a use. If the film thickness of the sprayed film or the like is greater than a certain value, the accuracy of hardness measurement can be increased. Further, if the film thickness of the sprayed film or the like is thick, the wear resistance and corrosion resistance of the sprayed film or the like is improved, but if the film thickness is too thick, problems such as cracking and peeling occur.
Therefore, by selecting these parameters as evaluation indexes and selecting a required region satisfying the required thinning rate from the correlation between these parameters, a sprayed film having erosion / corrosion resistance can be manufactured.

  The film quality of the sprayed film and the like depends on the conditions during construction (spraying distance and spraying angle between the spraying gun and the surface to be sprayed, the overlay welding method, etc.). In contrast, in the method of the present invention, an existing sprayed film or the like placed in an erosion or corrosion environment or a test piece is placed in a similar environment for various contents of the main elements. Using the sample of the sprayed film, etc., select the content of the main elements that satisfy the required thinning rate of the sprayed film from the correlation of the hardness, film thickness, and thinning rate of the sprayed film, etc. measured from these samples. Therefore, the sprayed coating produced by the method of the present invention can exhibit the erosion / corrosion resistance characteristics as required.

As an embodiment of the method of the present invention, a plurality of two-dimensional maps are created from the three-dimensional map, with the hardness and film thickness of the sprayed film and the like as coordinate axes for each different content of the main element. It is possible to plot the hardness, film thickness and thinning rate of the sprayed film on this two-dimensional map, and calculate the required specification region that satisfies the required thinning rate of the sprayed film and the like from the two-dimensional map.
This makes it possible to clearly grasp the required specification region that satisfies the required thinning rate, such as a sprayed film, on the two-dimensional map.

Examples of erosion and corrosion environments include environments containing sulfur components. This is because sulfur contained in coal, petroleum, waste, etc. is contained in the exhaust gas as sulfate ash or H ₂ S gas. These materials cause wear and corrosion of the sprayed film.
8 shows an isocorrosion curve of 0.13 mm / year in a high temperature H ₂ S environment (Source: AS Coupler and JW Gorman: Mater. Prot. Perform., 10, No. 1). 31 (1971)). From this figure, it can be seen that an alloy having a higher Cr content exhibits superior corrosion resistance in a sulfidation corrosion environment. Therefore, Cr can be selected as a main element in an environment containing a sulfur component.

As an erosion / corrosion environment, for example, an environment containing a chlorine component is conceivable. The garbage combustion gas contains HCl gas generated by the combustion of vinyl chloride in the plastic content. Moreover, since Cl is also mixed from inorganic substances and sea salt particles in the garbage, chloride is usually present on the heat transfer surface of the boiler tube on which the combustion ash is deposited. These chlorides cause wear and corrosion of the sprayed film.
FIG. 9 shows the high temperature corrosion characteristics of austenitic heat resistant material (400 ° C., 20 hr heating, under chloride ash environment, * is a high Cr high Ni alloy) (Sumitomo Metals, Vol. 46 No. 2 (1994)). From the figure, it can be seen that the higher the Ni alloy, the better the corrosion resistance.

  The inventors of the present invention have found that Ni and Mo are main elements that affect the erosion / corrosion resistance characteristics of a sprayed film and the like in an environment containing a chlorine component such as chloride. Therefore, in an environment containing a chlorine component, the (Ni + Mo) content may be selected from a required specification region that satisfies a required thinning rate such as a sprayed film.

As one embodiment of the method of the present invention, when measuring data is collected, the measured value obtained in the nondestructive hardness test is adopted as the measured value related to the hardness of the sprayed film, and the thickness of the sprayed film to be measured is measured. Can include at least 1,00 to 5,000 μm (5 mm).
Nondestructive hardness refers to the hardness measured without deforming the sprayed film, which is a non-measurement object. In the present invention, since the sprayed film is relatively thin, the Vickers hardness test is positioned as a nondestructive hardness test. When measuring non-destructive hardness, it is affected by the hardness of the base material.Therefore, grasp the hardness of the sprayed film that contains the base material in advance, and check the correlation between the hardness and the thinning speed. Evaluation needs to proceed.

  The material selection device for the thermal spray film or overlay welding layer of the present invention used for directly carrying out the method of the present invention is the main element such as a thermal spray film applied on the surface of a member placed in an erosion and corrosion environment. A material selection device for selecting the content, including the main elements that affect the erosion / corrosion resistance characteristics, containing the main elements from the sprayed film, etc. that is applied to the surface of the member and placed in the erosion and corrosion environment. A measuring instrument for measuring the amount, hardness, film thickness and thinning rate, and a three-dimensional map with the content of main elements and the film thickness and hardness of the sprayed film as coordinate axes, respectively, Three-dimensional map creation means for plotting the content of main elements measured by the measuring instrument, hardness of the sprayed film, film thickness and thinning rate; setting means for setting the required thinning rate of the sprayed film; The three It is equipped with calculation means for calculating the required area that satisfies the required thinning rate of sprayed film, etc. from the original map, and content selection means for selecting the content of main elements such as sprayed film from the required area. is there.

With the above configuration, the method of the present invention can be implemented. That is, an existing sprayed film or the like placed in an environment of erosion or corrosion, or a sample such as a sprayed film placed as a test piece and placed in the environment, from the sprayed film or the like by the measuring instrument. Content, hardness, film thickness and thinning rate are measured, and measurement data is collected in advance. Then, a three-dimensional map in which these measurement data are plotted is created by the three-dimensional map creating means.
The calculation means calculates the required area from the three-dimensional map and the required thinning rate of the sprayed film or the like set by the setting means. By selecting the content of the main element from the calculated required area, it is possible to manufacture a sprayed coating or the like that can accurately reproduce the erosion / corrosion characteristics satisfying the set required thinning rate.

As one embodiment of the apparatus of the present invention, a plurality of two-dimensional maps are created from the three-dimensional map, each of the two-dimensional maps taking the film thickness and hardness of the sprayed film and the like on the coordinate axes for each different content of the main element. Two-dimensional map creation means for plotting the hardness, film thickness, and thinning rate of the sprayed film on the map can be further provided. Then, the required area that satisfies the required thinning rate of the sprayed film or the like is calculated from the two-dimensional map by the calculating means.
In this way, by creating a plurality of two-dimensional maps for each main element content, a required specification region that satisfies a required thinning rate such as a sprayed film can be clearly identified on the map.

  In addition, this invention is applicable also when evaluating whether the sprayed film etc. after construction have the property as a required specification.

  According to the present invention, since the content of main elements such as a sprayed film is selected from a three-dimensional map created from a measured value measured from a sprayed film placed in an erosion-corrosion environment, without trial and error. Thus, it is possible to accurately produce a sprayed film having desired erosion / corrosion resistance.

It is a flowchart of the work process which concerns on 1st Embodiment of this invention. It is a block diagram of the material selection apparatus used by the said 1st Embodiment. It is the three-dimensional map which plotted the erosion corrosion test result with the said material selection apparatus. It is a two-dimensional map created from the three-dimensional map. It is a two-dimensional map created from the three-dimensional map. It is a two-dimensional map created from the three-dimensional map. It is a two-dimensional map created from the three-dimensional map. Is a diagram showing an equivalent corrosion curve due to the high temperature H _{2 S} environment. It is a diagram which shows the high temperature corrosion characteristic of an austenitic heat-resistant material.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
Next, a first embodiment of the present invention will be described with reference to FIGS. The present embodiment is an example of a sprayed film or the like applied to a boiler pipe placed in an H ₂ S environment. FIG. 1 shows a work process of this embodiment. In FIG. 1, first, main elements are selected (S10). In the present embodiment, Cr is selected as a main element that affects the erosion / corrosion resistance characteristics of a sprayed coating or the like. Next, the process proceeds to the measurement data collection process (S12).

In the measurement data collection step (S12), measurement samples such as a sprayed film having various Cr contents are prepared. The measurement sample is a sprayed film or the like used for actually measuring the nondestructive hardness, the film thickness, and the thinning rate. The sample for measurement may be an existing sprayed film actually used in an H ₂ S environment, or a newly created spray specimen as a test piece and placed in an H ₂ S environment for a predetermined period. It may be.

  Next, a three-dimensional map is created with the Cr content, nondestructive hardness (Vickers hardness HV) and film thickness as coordinate axes. Then, the measurement data collected in the measurement data collection step (S12) is plotted on this three-dimensional map (S14). Then, from this three-dimensional map, a plurality of two-dimensional maps are created for each different content of Cr, which is the main element, with the non-destructive hardness and the film thickness of the sprayed film as the coordinate axes (S16). Next, after setting the required thinning speed (S18), a required area that satisfies the required thinning speed set from a plurality of two-dimensional maps is calculated (S20).

  Finally, the content of Cr, which is a main element such as a sprayed film, is selected from the calculated required region (S22). Thereafter, other necessary elements and their contents are determined, and components such as a sprayed film and their contents are determined.

Next, the structure of the material selection apparatus 10 used in this embodiment will be described with reference to FIG.
The material selection device 10 includes a data acquisition unit 19 including a Cr content measuring instrument 12, a nondestructive hardness meter 14, a film thickness meter 16, and a thickness reduction meter 18. Cr content, nondestructive hardness (Vickers hardness HV), film thickness and thinning rate of the prepared measurement sample are measured by Cr content measuring instrument 12, nondestructive hardness meter 14, film thickness meter 16 and thinning degree. A total 18 is used for measurement. As Cr content measuring instrument 12, it measures using a simple fluorescent X-ray apparatus etc., for example. The nondestructive hardness meter 14 is measured nondestructively using a Vickers hardness meter. As the film thickness meter 16, for example, a film thickness meter such as an electromagnetic film thickness meter or an ultrasonic film thickness meter is used to measure the film thickness of the sprayed film. As the thickness reduction meter 18, for example, a measuring instrument similar to the ultrasonic thickness meter or the film thickness meter 16 is used.

These measured values are temporarily stored in the storage unit 22 built in the control device 20. Then, the four types of measurement values stored in the storage unit 22 are sent to the three-dimensional map creation unit 20 to create a three-dimensional map. The three-dimensional map creation unit 24 divides the thinning degree measured by the thinning degree meter 18 by the period in which each measurement sample is placed in the H ₂ S environment to calculate the thinning speed, and FIG. 3D map is created.

  In FIG. 3, the x-axis of the three-dimensional map is the Cr content (w%), the y-axis is the nondestructive hardness (Vickers hardness HV), and the z-axis is the film thickness (μm). On this three-dimensional map, the measured value obtained from the measurement sample is plotted, and the calculated thinning rate (mm / year) is plotted. Next, from this three-dimensional map, for each different Cr content, a plurality of two-dimensional maps are created with the sprayed film thickness as the x-axis and the nondestructive hardness as the y-axis.

  4 to 7 are four two-dimensional maps created in this way. 4 is a two-dimensional map when the Cr content is 10 w% (point A), FIG. 5 is a two-dimensional map when the Cr content is 22 w% (point B), and FIG. 6 is the Cr content. FIG. 7 is a two-dimensional map when the amount is 30 w% (point C), and FIG. 7 is a two-dimensional map when the Cr content is 40 w% (point D). In these drawings, the shaded area indicates the region of the thinning rate that satisfies the required thinning rate (0.2 mm / year or less). Further, in FIG. 5, point E is in a region where the thinning rate is 0.2 mm / year or less, and satisfies the required specifications of this embodiment. On the other hand, point F has a thickness reduction rate of 0.3 mm / year or more and does not satisfy the required specifications of this embodiment.

In the present embodiment, the measured values are plotted in the film thickness region (z axis) of the measurement sample in the range of 100 to 5,000 μm (5 mm) and its peripheral film thickness. When measuring non-destructive hardness, it is affected by the hardness of the base metal, and therefore, the hardness of the sprayed coating or overlay weld layer containing the base material must be ascertained beforehand, and the correlation between the hardness and the thickness reduction rate. Advance the evaluation of relationships.
When measuring the non-destructive hardness, the thickness of the measurement sample is increased to a certain level or more, that is, by including 1,000 to 3,000 μm and its peripheral region, the hardness of the base material is increased. Non-destructive hardness (Vickers hardness) can be measured with high accuracy without being affected by the thickness.

The three-dimensional map created by the three-dimensional map creation unit 24 and the two-dimensional map created by the two-dimensional map creation unit 26 are stored in the storage unit 22, respectively. In addition, a two-dimensional map is input to the request region calculation unit 28 and a request thinning rate set by the request thinning rate setting unit 28 is input. The required area calculation unit 30 calculates a required area that satisfies the required thinning speed from the two-dimensional map and the required thinning speed. The Cr content selection unit 32 selects a Cr content satisfying the required area from the required areas calculated by the required area calculation unit 30.
After the Cr content, which is the main element, is selected in this way, the content of other contained elements is selected, and the components constituting the sprayed film and the like are determined.

According to this embodiment, the Cr content, the non-destructive hardness, and the film thickness are measured using a sample for measuring a sprayed film placed in an H ₂ S environment with respect to the content of Cr as a main element such as a sprayed film. By plotting the measured thinning speed on a three-dimensional map with the coordinate axis as the coordinate axis, the required thinning speed can be grasped. Therefore, a sprayed film having desired erosion / corrosion resistance can be accurately manufactured.
Furthermore, by creating a plurality of two-dimensional maps for each different Cr content from the three-dimensional map, the required thinning rate of the sprayed film etc. can be clearly shown on the map, so the selection of the Cr content Can be done accurately.

  When measuring non-destructive hardness, it is affected by the hardness of the base metal.Therefore, measure the hardness of the sprayed coating or overlay weld layer containing the base material in advance, By grasping the evaluation of the correlation, it is possible to accurately evaluate the thinning rate.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. This embodiment is an example of selecting a material such as a thermal spray film to be applied to a boiler tube placed in an environment where chloride such as HCl gas exists, such as a garbage power generation boiler. In this example, Ni and Mo are selected as main elements. Subsequent processes are the same as those in the first embodiment shown in FIG. 1 using the material selection apparatus 10 in FIG.

  That is, in the measurement data collection step, measurement samples such as a sprayed film having various (Ni + Mo) contents are prepared (S12). This sample for measurement is a sprayed film that is used to actually measure nondestructive hardness, film thickness, and thinning speed, and is an existing sprayed film that is actually used in a chloride environment. Alternatively, it may be a sprayed coating newly prepared as a test piece and placed in a chloride environment for a predetermined period.

Next, a three-dimensional map is created with the (Ni + Mo) content, nondestructive hardness (Vickers hardness HV), and film thickness as coordinate axes. Then, the measurement data collected in the measurement data collection step (S12) is plotted on this three-dimensional map (S14).
Further, from this three-dimensional map, a plurality of two-dimensional maps are created for each different (Ni + Mo) content, with the non-destructive hardness such as a sprayed film and the film thickness taken as coordinate axes (S16).
Next, after setting the required thinning speed (S18), a required area that satisfies the required thinning speed set from a plurality of two-dimensional maps is calculated (S20).

Finally, the content of Cr, which is a main element such as a sprayed film, is selected from the calculated required region (S22). Thereafter, other necessary elements and their contents are determined, and components such as a sprayed film and their contents are determined.
Also in this embodiment, it is possible to accurately manufacture a sprayed film having desired erosion / corrosion resistance characteristics in a chloride environment. Furthermore, by creating a plurality of two-dimensional maps for each different (Ni + Mo) content from the three-dimensional map, the required thinning rate of the sprayed film, etc. can be clearly represented on the map, so (Ni + Mo) content The quantity can be selected accurately.

  According to the present invention, for example, when a sprayed film is applied to the surface of a member placed in an erosion and corrosion environment such as a boiler tube, the thermal spraying can surely exhibit the erosion and corrosion resistance characteristics as required. Membranes and the like can be manufactured.

DESCRIPTION OF SYMBOLS 10 Material selection apparatus 12 Cr content measuring device 14 Nondestructive hardness meter 16 Film thickness meter 18 Thinning degree meter 19 Data acquisition part 20 Control apparatus 22 Memory | storage part 24 3D map creation part 26 2D map creation part 28 Demand reduction Meat speed setting section 30 Required area calculation section 32 Cr content selection section

Claims (7)

A method for selecting a material for a sprayed film or an overlay weld layer, which selects a content of a main element of a sprayed film or an overlay weld layer applied to the surface of a member placed in an erosion and corrosion environment,
A main element selecting step for selecting a main element that affects the erosion / corrosion characteristics of the sprayed film or the overlay welding layer among the elements contained in the spray coating or the overlay welding layer;
The content, hardness, film thickness, and thickness reduction rate of the main element from the sprayed film or the overlay welding layer that is applied to the surface of the member and contains the selected main element and is placed in an erosion and corrosion environment. And a data collection process for collecting these measurement data in advance,
A three-dimensional map creation step of plotting the measurement data on a three-dimensional map with the content of the main element, the sprayed film or the thickness and hardness of the overlay weld layer as coordinate axes,
A required thinning rate setting step for setting a required thinning rate of the sprayed film or the overlay welding layer,
From the three-dimensional map, a calculation step for calculating a required region that satisfies a required thinning rate of the sprayed film or the overlay welding layer;
A material selection method for selecting a content of a main element of the sprayed film or the overlay welding layer from the required region. From the three-dimensional map, a plurality of two-dimensional maps are created, each of which has a coordinate axis that is the hardness and thickness of the sprayed film or the overlay weld layer for each different content of the main element, and the two-dimensional map includes the two-dimensional map. Further comprising a two-dimensional map creation step for plotting the hardness, film thickness and thinning rate of the sprayed film or the overlay weld layer,
The said calculation process calculates the request | requirement area | region which satisfy | fills the request | requirement thinning speed of the said thermal spray film or the said overlay welding layer from the said two-dimensional map, The thermal spray film or overlay of Claim 1 characterized by the above-mentioned. Material selection method for the weld layer.   The thermal sprayed film or the overlay welding layer is used in an erosion and corrosion environment containing a sulfur component, and the main element of the thermal spray film or the overlay welding layer is Cr. The method for selecting a material for the thermal sprayed film or the overlay welding layer as described. The sprayed film or the overlay welding layer is used in an erosion and corrosion environment containing a chlorine component, and the main elements of the spray coating or the overlay welding layer are Ni and Mo,
The material selection method according to claim 1 or 2, wherein the content selection step selects (Ni + Mo) content.   In the data collection step, the measured value related to the hardness of the sprayed film or the overlay welding layer is a measurement value obtained by a nondestructive hardness test, and the sprayed film or the overlay welding layer film to be measured The method for selecting a material for a sprayed film or a build-up weld layer according to claim 1, wherein the thickness includes at least 100 to 5,000 μm. A material selection device for a sprayed film or a built-up weld layer that selects the content of the main elements of the sprayed film or the built-up weld layer applied to the surface of a member placed in an erosion and corrosion environment,
Containing main elements that affect erosion / corrosion resistance, the content, hardness, and film thickness of the main elements from a sprayed coating or overlay weld layer that is applied to the surface of the member and placed in an erosion and corrosion environment And a measuring instrument for measuring the rate of thinning,
A three-dimensional map is created with the content of the main element, the thickness of the sprayed coating or the thickness and hardness of the build-up weld layer as the coordinate axes, and the main element measured by the measuring instrument on the three-dimensional map. A three-dimensional map creating means for plotting the content, the hardness of the sprayed film or the build-up weld layer, the film thickness, and the thinning rate;
A required thinning rate setting means for setting a required thinning rate of the sprayed film or the build-up weld layer;
From the three-dimensional map, a calculation means for calculating a required area that satisfies the required thinning rate of the sprayed coating;
A material selection device for sprayed film or overlay welding layer, comprising: content selection means for selecting a content of main elements of the sprayed film or overlay welding layer from the required region. From the three-dimensional map, for each content of the main element, a plurality of two-dimensional maps are created by taking the film thickness and hardness of the sprayed coating or the overlay welding layer as coordinate axes, respectively, and the plurality of two-dimensional maps Further comprising two-dimensional map creation means for plotting the hardness, film thickness and thickness reduction rate of the sprayed film or the overlay weld layer on the map,
The sprayed film or overlay according to claim 6, wherein the calculation means calculates a required region satisfying a required thickness reduction rate of the sprayed film or the overlay welding layer from the two-dimensional map. Welding layer material selection device.

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