JP2008014959A - Method for inspecting coating member for interface defects - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting coating members for interface defects, making clear the interfaces between interface defect parts and sound parts when the interface defect parts of the coating members are to be detected, and nondestructively detecting the shapes and sizes of the interface defect parts. <P>SOLUTION: In the method for inspecting coating members for interface defects and nondestructively inspecting interface defect parts of a coating member, with which substrate surfaces of a metal structure are coated, some location of the coating member is spot-heated to determine a state of thermal diffusion to its periphery from the spot-heated location as center, as a coating surface temperature distribution. Cracks present in the substrate are detected, on the basis of uneven parts of thermal diffusion in the determined coating surface temperature distribution. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an interface defect inspection method for a coating member that inspects an interface defect portion such as a film peeling, a decrease in adhesion, and a crack of a coating member coated on a substrate surface of a metal material.

  Conventionally, various methods have been proposed as an inspection method for diagnosing adhesion, peel strength, etc. of a thick film such as a sprayed film or a thin film such as vapor deposition. For example, there is JIS-R4204 (ceramic coating test method) for evaluation of adhesion. This evaluation method is based on a destructive test, and cannot be applied as it is to nondestructive evaluation of actual plant equipment / parts at the time of periodic inspection.

  For this reason, equipment inspections such as periodic inspections or precision inspections of actual plants, etc., can be applied to the surface of the metal structure during the operation of the coating member, peeling of coating material, lowering of adhesion, interfacial cracks, etc. There is a need to develop non-destructive inspection methods for measuring the shape and dimensions of materials.

  In recent years, many methods have been disclosed for nondestructively inspecting an interface defect portion of a coating member. Among them, an ultrasonic method, a laser holography method, an infrared method, etc. are practically used. .

  As an application example of the ultrasonic method, “Study on peeling of thermal spray coating and estimation of adhesion distribution by ultrasonic method” (菅 etc .: Thermal spraying, Vol. 28, No. 4, p. 26, 1991) and the like can be mentioned. It is done. However, the ultrasonic method requires a lot of time for inspection, and has defects that are difficult to apply to parts of an actual plant having a complicated curved surface shape.

  As an application example of the laser holography method, for example, “non-destructive inspection using shearing” (Ito: Optical Alliance, p. 25, 1991.8) and the like can be mentioned. However, the laser holography method requires a device that vibrates the subject or a device that puts the entire subject in a reduced pressure state, and the smooth progress of work on site is inferior.

  On the other hand, the non-destructive inspection method for coating member defects using an infrared imaging device is relatively inexpensive and compact, and has a high level of smooth work progress on site. As shown in “Thermal Image Analysis and Its Evaluation” (Ito et al .: Journal of the Ceramic Society of Japan, Vol. 97, No. 11, p. 1358, 1989), it is regarded as a promising inspection technique.

  Here, the infrared imaging apparatus used for this inspection will be described with reference to the basic principle diagram shown in FIG. First, when a temperature equal to or higher than normal temperature is generated on the surface of the object 1, the object 1 to be diagnosed always emits an electromagnetic wave corresponding to the surface temperature 2. The wavelength of the radiant energy 3a is in the infrared region of about 0.72 to 1000 μm, and all the objects 1 radiate radiant energy 3b having an absolute temperature of zero degrees (−273 ° C.) or more as infrared rays. Therefore, this radiant energy 3a is detected, converted into an electric signal 5, and displayed as a thermal image 6, and the surface temperature 2 of the object 1 is obtained. This infrared video apparatus basically includes a camera 7, a control unit 8, and a display unit 9. The infrared ray 3 b radiated from the object 1 by the camera 7 is optically condensed via a lens 4, and a detector 10. Lead to. The detector 10 is a semiconductor quantum detector of indium antimony (InSn) or mercury cadmium tellurium (HgCdTe). The detector 10 converts the condensed infrared ray 3b into an electrical signal 5, and sends the electrical signal 5 to the control unit 8 for signal processing, and then displays the image as a thermal image 6 on the display unit 9. It has become.

  Further, even when the surface of the object 1 does not have a temperature equal to or higher than normal temperature, as shown in FIG. 24, heat 11a is forcibly applied from the outside to the object 1 to be diagnosed, and the object is detected from the infrared thermal image generated at that time. 1 abnormality diagnosis is performed. That is, the object 1 is heated by the heat 11a from the heating source 11, and the defect 12 is displayed as a thermal image by using the difference in heat conductivity coefficient and heat capacity of the defect 12 in the object 1 generated at this time. (For example, Koshihara, new equipment diagnosis technology using infrared camera, maintenance, March 1988).

  The method for inspecting the interface defect portion of the coating member by the conventional infrared method shown in FIGS. 23 and 24 in a nondestructive manner is the presence or absence of the interface defect portion when the coating surface or the substrate surface of the coating member is heated by a heat source. By utilizing the fact that the heat conduction state is different, the interface defect part and the healthy part are determined from the temperature distribution on the coating surface.

  This method has a drawback that the boundary is unclear because there is always a temperature gradient at the boundary between the interface defect portion and the healthy portion. In thermal images with unclear boundaries, the shape and dimensions of interface defects cannot be measured accurately, and the inspection reliability is poor.

  Furthermore, since it is difficult to heat the subject uniformly, the temperature distribution in the coating portion is disturbed, and the detection of the interface defect portion is inaccurate.

  The present invention has been made in view of such points, and in detecting the interface defect portion of the coating member, the boundary between the interface defect portion and the healthy portion is clarified, and the shape and dimensions of the interface defect portion are accurately determined. An object of the present invention is to provide a non-destructive estimation method for an interface defect inspection of a coating member.

  Furthermore, another object of the present invention is to obtain a coating surface temperature distribution by correcting an error due to uneven heating of the specimen, determine a boundary between the interface defect portion and the healthy portion from the obtained coating surface temperature distribution, Another object of the present invention is to provide an interface defect inspection method for coating members that accurately and non-destructively estimates the shape and dimensions of the coating member.

  In order to achieve the above object, a method for inspecting an interface defect of a coating member according to the present invention provides a non-destructive interface defect portion of a coating member coated on a substrate surface of a metal structure as described in claim 1. In a method for inspecting an interface defect of a coating member to be inspected, a position where the coating member is located is spot-heated, a state in which heat is diffused around the spot-heating position is obtained as a coating surface temperature distribution, and the obtained coating surface This is a method of detecting cracks existing in a substrate from an unbalanced portion of thermal diffusion in a temperature distribution.

  In order to achieve the above object, an interface defect inspection method for a coating member according to the present invention provides a non-destructive interface defect portion of a coating member coated on a substrate surface of a metal structure. In a method for inspecting an interface defect of a coating member to be inspected, a position where the coating member is located is spot-heated, a state in which heat is diffused around the spot-heating position is obtained as a coating surface temperature distribution, and the obtained coating surface In this temperature distribution, a crack existing in the substrate is detected from an unbalanced portion of thermal diffusion, and the depth of the crack is estimated from a difference in coating surface temperature on both sides of the crack.

  In order to achieve the above object, a method for inspecting an interface defect of a coating member according to the present invention provides a non-destructive interface defect portion of a coating member coated on a substrate surface of a metal structure as described in claim 3. In the interface defect inspection method for a coating member to be inspected, the surface temperature distribution of the coating member is obtained, the depth of the interface defect portion is estimated from the obtained surface temperature distribution, and the depth, electromagnetic method and ultrasonic method are selected. This is a method for estimating the thickness of the remaining coating member when the interface defect portion develops and the coating member falls off from the film thickness of the coating member measured either.

  According to the interface defect inspection method for a coating member according to the present invention, it is possible to accurately measure the shape and dimensions of the interface defect portion existing below the coating member based on a thermal image obtained by an infrared imaging device. It is.

  Further, according to the interface defect inspection method for a coating member according to the present invention, it is possible to estimate the depth and width of the interface defect portion existing below the coating member based on a thermal image obtained by an infrared imaging device. Thus, together with the coating thickness measurement result, the thickness of the remaining coating layer after the interface defect portion has progressed and the coating member has fallen off can be predicted.

  Furthermore, according to the interface defect inspection method for a coating member according to the present invention, it is possible to evaluate the depth of the base material crack under the coating, so that damage to the coating member can be accurately predicted, and excessive safety side evaluation is avoided. Thus, the maintenance management cost can be reduced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a coating member interface defect inspection method according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a view showing a coating surface temperature distribution in the vicinity of the tip of an interface defect portion used for explaining a first embodiment of a coating member interface defect inspection method according to the present invention.

  As shown in FIG. 1, the coating surface temperature distribution line 13 is obtained by modeling a coating member having an interface defect portion having a radius of 5 mm at the center portion of a disk sample having a radius of 15 mm as a two-dimensional axisymmetric and uniform on the surface thereof. It is the result calculated | required by unsteady FEM (finite element method) analysis by adding a heat. In this case, an interface defect portion is formed on the coating member as the subject as shown in FIG.

  Further, FIG. 1 shows the result of FEM analysis, but the result of measuring the actual surface temperature distribution of the coating member being heated can also obtain a substantially similar temperature distribution.

  Further, in the horizontal axis of FIG. 1, the interface defect portion is from 0 to 5 mm, the healthy portion is from 5 to 15 mm, and the tip of the interface defect portion exists at a position of 5 mm. Furthermore, the coating surface temperature distribution line 13 in FIG. 1 is obtained by obtaining the coating surface temperature after applying uniform heat to the coating member surface at 20 ° C. for 5 seconds by FEM analysis and displaying it as a distribution. In the interface defect portion, since the heat is not transmitted to the base material, the coating surface temperature becomes high. On the contrary, in the healthy part where the interface defect part does not exist, the heat is transferred to the base material, so that the coating surface temperature is lowered. In the vicinity of the boundary between the interface defect portion and the healthy portion, the coating surface temperature gradually increases from the level of the healthy portion, and exhibits a gentle temperature distribution that reaches the level of the interface defect portion.

  When a coating surface temperature image of a subject having an interface defect portion at the center is drawn based on the coating surface temperature distribution line 13, a distribution is formed in which contour lines 14 are drawn around the interface defect portion as shown in FIG. In the coating surface temperature image shown in FIG. 3, the presence of the interface defect portion can be confirmed, but since the temperature transition region is imaged as a contour line 14 near the tip, the shape and size of the interface defect portion can be accurately obtained. Absent.

  Further, the coating surface temperature distribution line 13 shown in FIG. 1 is an FEM analysis of a specific case where the interface defect portion is located about 200 μm below the coating surface. If the width of the interface defect portion is different, the coating surface temperature The temperature distribution is different.

  In the coating surface temperature distribution line 13 in FIG. 1, there is a rising position point 15 of the coating surface temperature distribution at which the temperature rise due to the interface defect portion starts. As described above, regardless of the shape of the coating surface temperature distribution line 13, the temperature rise due to the interface defect portion always starts from the outside of the tip of the interface defect portion. Therefore, the boundary between the interface defect portion and the healthy portion always shows a value larger than the actual interface defect portion when the dimension of the interface defect portion is measured as the rising position point 15 of the coating surface temperature distribution. That is, an evaluation value on the safe side is obtained.

  When diagnosing the lifetime of a structure, it is more realistic to calculate it based on the lower limit value and evaluate it on the safe side rather than calculating it based on the average value of the material strength data. It is.

  Therefore, in this embodiment, since the size of the interface defect portion is greatly estimated, it is possible to prevent the coating member as the specimen from being destroyed.

  FIG. 4 is a view showing a coating surface temperature distribution in the vicinity of the interface defect portion tip used for explaining a second embodiment of the interface defect inspection method for a coating member according to the present invention.

  As shown in FIG. 4, the coating surface temperature distribution line 16 is a two-dimensional axisymmetric configuration in which a coating member having an interface defect portion with a radius of 5 mm exists in the center of a disk sample with a radius of 15 mm, as in the first embodiment. This is a result obtained by modeling, applying uniform heat to the surface, and obtaining by unsteady FEM analysis. The coating member as the subject has an interface defect portion as in the first embodiment shown in FIG.

  In addition, in the horizontal axis of FIG. 4, the interface defect portion is from 0 to 5 mm, the healthy portion is from 5 to 15 mm, and the tip of the interface defect portion exists at a position of 5 mm. The analysis conditions are the same as in the case of the first embodiment, except that the depth of the interface defect portion is set to 40 μm, which is shallower than 200 μm analyzed in the first embodiment, and the tip is distorted so as to approach the coating surface. Different from one embodiment. Furthermore, the coating surface temperature distribution line 16 in FIG. 4 exhibits a temperature distribution in which the transition region between the healthy part temperature and the interface defect part temperature is narrower than the coating surface temperature distribution line 13 of the first embodiment. This is due to the rapid transfer of heat from the interface defect portion to the healthy portion in the vicinity of the interface defect portion tip because the tip of the interface defect portion exists at a shallow position.

  Also, the coating surface temperature distribution line 16 in FIG. 4 has a falling position point 17 of the coating surface temperature distribution at the end of the temperature transition region between the healthy part and the interface defect part. The falling position point 17 of the coating surface temperature distribution line 16 always exists inside the tip of the interface defect. This does not depend on the shape of the coating surface temperature distribution line 16. Therefore, a region connecting the falling positions 42 of the coating surface temperature distribution line 16 indicates a region in which an interface defect portion necessarily exists. That is, when the falling position point 17 of the coating surface temperature distribution line 16 is the boundary between the interface defect part and the healthy part, the minimum dimension of the existing interface defect part can be known. If the progress life of the interface defect portion is evaluated based on this minimum dimension, the maximum life evaluation value of the specimen can be obtained.

  According to this embodiment, the minimum dimension of the interface defect portion can be known, and the maximum life evaluation value of the coating member as the specimen can be obtained.

  FIG. 5 is a view showing a coating surface temperature distribution in the vicinity of the front end of an interface defect used for explaining a third embodiment of the interface defect inspection method for a coating member according to the present invention.

  As shown in FIG. 5, the coating surface temperature distribution line 18 indicates that the coating member having an interface defect portion having a radius of 5 mm at the center portion of a disk sample having a radius of 15 mm is two-dimensionally axisymmetric as in the first embodiment. This is a result obtained by modeling, applying uniform heat to the surface, and obtaining by unsteady FEM analysis. In addition, the coating member as a subject has an interface defect portion as in the first embodiment shown in FIG.

  Further, in the horizontal axis of FIG. 5, the interface defect portion is from 0 to 5 mm, the healthy portion is from 5 to 15 mm, and the tip of the interface defect portion exists at a position of 5 mm. As in the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 4, the coating surface temperature distribution line 18 has a temperature transition region in the vicinity of the tip of the interface defect portion. Therefore, the tip of the interface defect portion always exists between the rising position point 19 of the coating surface temperature distribution line 18 and the falling position point 20 of the coating surface temperature distribution line 18. Here, the tip of the interface defect portion substantially coincides with the rising position point 19 of the coating surface temperature distribution line 18 and the intermediate point 21 of the falling position point 20 of the coating surface temperature distribution line 18.

  That is, when the coating surface temperature distribution line 18 shown in FIG. 5 is obtained, an intermediate point 21 between the rising position point 19 of the coating surface temperature distribution line 18 and the falling position point 20 of the coating surface temperature distribution line 18 is an interface. If the tip of the defect portion is used, the dimension measurement accuracy of the interface defect portion can be improved.

  Thus, in this embodiment, since the intermediate point 21 between the rising position point 19 and the falling position point 20 of the coating surface temperature distribution line 18 is used as the tip of the interface defect portion, the dimension of the interface defect portion is accurately measured. Is possible.

  FIG. 6 is a view showing a coating surface temperature distribution in the vicinity of the tip of the interface defect used for explaining the fourth embodiment of the coating member interface defect inspection method according to the present invention. Similar to the first embodiment, this coating surface temperature distribution line 22 models a coating member having an interface defect portion having a radius of 5 mm at the center portion of a disk siple having a radius of 15 mm as a two-dimensional axis symmetry, and is formed on the surface thereof. It is the result calculated | required by unsteady FEM analysis, applying uniform heat. The coating member as the subject has an interface defect portion as in the first embodiment shown in FIG.

  Further, in the horizontal axis of FIG. 6, the interface defect portion is from 0 to 5 mm, the healthy portion is from 5 to 15 mm, and the tip of the interface defect portion is present at a position of 5 mm. As shown in FIG. 6, the coating surface temperature distribution line 22 has a temperature transition region in the vicinity of the interface defect portion. This is because heat is transferred from the coating member at the interface defect portion to the coating member at the healthy portion.

  The coating surface temperature position 23 of the interface defect portion is higher than the coating surface temperature position 24 of the healthy portion. This is because when the coating surface is heated, heat transfer to the base material is hindered at the interface defect portion, whereas heat is transferred to the base material at the healthy portion. Therefore, the coating surface temperature at the tip of the interface defect portion is lower than the coating surface temperature position 23 of the interface defect portion and higher than the coating surface temperature position 24 of the healthy portion. Here, the coating surface temperature at the tip of the interface defect portion substantially coincides with the intermediate temperature position 25 between the coating surface temperature position 23 of the interface defect portion and the coating surface temperature position 24 of the healthy portion.

  That is, as shown in FIG. 6, if the position representing the intermediate temperature position 25 between the coating surface temperature position 23 of the interface defect portion and the coating surface temperature position 24 of the healthy portion is the tip of the interface defect portion, the temperature of the coating surface The shape and dimensions of the interface defect portion can be simply and accurately evaluated only by measurement.

  Thus, in this embodiment, since the intermediate temperature position 25 between the coating surface temperature position 23 of the interface defect portion and the coating surface temperature position 24 of the healthy portion is set as the tip of the interface defect portion, the dimension of the interface defect portion is accurately determined. Can be measured.

  FIG. 7 is a view showing a coating surface temperature distribution in the vicinity of the front end of the interface defect used for explaining the fifth embodiment of the interface defect inspection method for a coating member according to the present invention. Similar to the first embodiment, the coating surface temperature distribution line 26 models a coating member having an interface defect portion having a radius of 5 mm at the center portion of a disk sample having a radius of 15 mm as a two-dimensional axis symmetry, and is formed on the surface thereof. It is the result calculated | required by unsteady FEM analysis, applying uniform heat. The coating member as the subject has an interface defect portion as in the first embodiment shown in FIG.

  Further, in the horizontal axis of FIG. 7, the interface defect portion is from 0 to 5 mm, the healthy portion is from 5 to 15 mm, and the tip of the interface defect portion exists at a position of 5 mm. As shown in FIG. 7, the coating surface temperature distribution line 26 has a temperature transition region in the vicinity of the tip of the interface defect portion. This is because heat is transferred from the coating at the interface defect portion to the coating at the healthy portion. This amount of heat transfer can be obtained by integrating the transition region of the coating surface temperature distribution line 26, and this integrated value is divided into two at the tip of the interface defect portion. That is, the position where the areas of the temperature transition integration region 27 on the interface defect portion side shown in FIG. 7 and the temperature transition integration region 28 on the healthy portion side are equal is the tip of the interface defect portion.

  That is, as shown in FIG. 7, if the temperature transition integration region 27 on the interface defect portion side and the temperature transition integration region 28 on the healthy portion side are obtained by calculation and the position where both are equal is the tip of the interface defect portion, The shape and size of the interface defect portion can be estimated.

  Thus, in the present embodiment, the temperature transition integration region 27 on the interface defect portion side and the temperature transition integration region 28 on the healthy portion side are obtained by calculation, and the position where both are divided into two is set as the tip of the interface defect portion. Therefore, it is possible to estimate the dimension of the interface defect portion with high accuracy.

  FIG. 8 shows the interface defect portion length of the coating member according to the inspection method shown in the first to fifth embodiments used to explain the sixth embodiment of the interface defect inspection method of the coating member according to the present invention. It is the graph which compared with the interface defect part length of the coating member which cut out actual equipment, cut | disconnected the material, and investigated.

  From this FIG. 8, it was found that the interface defect length of the coating member by the inspection method shown in the fifth embodiment and the interface defect length of the coating member investigated by examining the actual machine were the closest. In addition, the coating member as a test piece used in the first to fifth embodiments is formed in advance so as to damage the same as the actual equipment to form an interface defect portion.

  As described above, when inspecting the interface defect portion of the coating member, if a non-destructive inspection method that matches well with the measurement result obtained by cutting the actual machine is selected in advance, a highly accurate investigation result can be obtained.

  FIG. 9 is used to explain the seventh embodiment of the coating member interface defect inspection method according to the present invention, and is a diagram showing the coating surface temperature distribution when the position of the heating source is changed.

  As shown in FIG. 9, the coating surface temperature distribution line 29 is a model in which a coating member in which an interface defect portion having a radius of 5 mm exists in the center portion of a disk sample having a radius of 15 mm is represented as a two-dimensional plane, as in the first embodiment. The results are obtained by unsteady FEM analysis with uniform heat applied to the surface. The coating member as the subject has an interface defect portion as in the first embodiment shown in FIG.

  In FIG. 9, a coating surface temperature distribution line 29 indicated by a dotted line is a temperature distribution when heated from directly above the central portion of the coating member as the subject. Further, the coating surface temperature distribution line 30 shows a coating when the distance from the center part of the coating member as the subject is 15 mm (position of +15 mm in FIG. 7), that is, when heated from above the right end of the coating member. Surface temperature distribution. The coating surface temperature distribution line 30 is such that the temperature peak exhibits a surface temperature curve on the heating side as compared to when the coating member is heated from directly above the central portion of the coating member. In the range of the analysis shown in FIG. 9, a clear temperature difference is recognized between the healthy part and the interface defect part in both cases of the coating surface temperature distribution lines 29 and 30, but the position of the heating source is farther than that. In this case, since the temperature difference may be eliminated, in this embodiment, the distance between the heating source and the subject is measured in advance and corrected by the amount of heat received by the subject to obtain a clear coating surface temperature distribution. It is important to ask for it.

  FIG. 10 is a diagram showing the relationship between the distance between the heat source and the subject and the amount of heat flux. In general, the heat flux is inversely proportional to the square of the distance from the point light source and also depends on the incident angle to the subject. Therefore, in the diagram shown in FIG. 10, assuming that the heat input directly below the heating source is 100, the heat input decreases as the distance from the center of the subject increases, and is 240 mm from the center of the subject. It drops to almost 5%. 9 is corrected by multiplying the coating surface temperature distribution line 30 of FIG. 9 by the inverse of the curve obtained from FIG. 10 and analyzing the coating surface temperature distribution with the corrected heat flux amount, A corrected coating surface temperature distribution line 31 was obtained. Since the coating surface correction temperature distribution line 31 after the heat flux correction completely coincides with the coating surface temperature distribution line 39 when heated from the center of the coating member, the distance between the heating source and the coating member is obtained in advance. If the obtained coating surface temperature distribution is corrected, a coating surface temperature distribution in which the temperature peak is not shifted to the heating side can be obtained.

  As described above, in the present embodiment, even when the heating source cannot be installed in the center of the coating member, the interface defect portion is detected nondestructively from the coating surface correction temperature distribution line 31 obtained by correcting the heat flux amount. Therefore, it is possible to estimate the size of the interface defect portion with high accuracy.

  FIG. 11 is used to explain the seventh embodiment of the interface defect inspection method for a coating member according to the present invention and is a diagram showing the influence of the width of the interface defect portion on the coating surface temperature distribution curve. Here, the width of the interface defect portion refers to the thickness of the interface defect portion existing in the film thickness direction when the coating member is cut at the interface defect portion as shown in FIG.

  As shown in FIG. 11, the coating surface temperature distribution line 32 models a coating member in which an interface defect portion having a radius of 5 mm and a width of 0.04 mm exists in the center of a disk sample having a radius of 15 mm as a two-dimensional axis symmetry, It is a result obtained by applying uniform heat to the surface and performing unsteady FEM analysis. Similarly to the above, the coating surface temperature distribution line 33 displays an analysis result in the case where an interface defect portion having a radius of 5 mm and a width of 0.01 mm exists in the central portion of the disk sample having a radius of 15 mm.

  As shown in FIG. 11, when the width of the interface defect portion increases, the amount of heat transfer at the interface defect portion decreases, and thus the coating surface temperature of the interface defect portion tends to increase. FIG. 12 is a graph in which the temperature difference between the healthy part and the interface defect part is calculated from the coating surface temperature distribution line shown in FIG. 11 and plotted on the vertical axis, and the horizontal axis is plotted as the width of the interface defect part. The increase in the width of the interface defect portion means that the air layer existing in the interface defect portion becomes thick. Therefore, since the amount of heat transferred through the air layer is reduced, the temperature of the interface defect portion is increased, and the temperature difference between the healthy portion and the interface defect portion is increased.

  In other words, since there is a clear correlation between the coating surface temperature difference between the healthy part and the interface defect part and the width of the interface defect part, measure the coating surface temperature difference between the healthy part and the interface defect part. For example, the width of the interface defect portion can be known, and the cross-sectional shape of the interface defect portion can be estimated nondestructively.

  Thus, in this embodiment, since the coating surface temperature difference of a healthy part and an interface defect part is measured and the width | variety of an interface defect part is calculated, it becomes possible to prescribe | regulate the cross-sectional shape of an interface defect part.

  FIG. 13 is used to explain the ninth embodiment of the interface defect inspection method for a coating member according to the present invention and is a diagram showing the influence of the interface defect depth on the coating surface temperature distribution line. Here, the interface defect part depth refers to the distance from the coating member surface to the interface defect part as illustrated in FIG.

  As shown in FIG. 13, the coating surface temperature distribution line 34 is a two-dimensional axis indicating a coating member in which an interface defect portion having a radius of 5 mm and an interface defect portion depth of 0.075 mm exists at the center of a disk sample having a radius of 15 mm. This is a result obtained by modeling as symmetric, applying uniform heat to the surface, and obtaining by non-stationary FEM analysis. In addition, the coating surface temperature distribution line 35 displays the analysis result when a radius of 5 mm and an interface defect exist at the center of the disk sample having a radius of 15 mm, as described above.

  From these two types of coating surface temperature distribution lines 34 and 35 shown in FIG. 13, the shape of the coating surface temperature distribution changes depending on the depth of the interface defect portion. The temperature gradient tends to be gentler on the interface defect side than the defect / sound part boundary. Therefore, by evaluating the shape of the coating surface temperature distribution lines 34 and 35, it is possible to estimate the depth of the interface defect portion. Furthermore, since it is possible to know the remaining coating thickness when the interface defect part has progressed and the coating has fallen off, the danger of the interface defect part can be known in advance.

  According to the present embodiment, by comparing the coating surface temperature distribution measured from the coating member as the object with the coating surface temperature distribution near the tip of the interface defect portion, which varies depending on the defect depth, the depth of the interface defect portion is determined. Can be estimated.

  FIG. 14 is used for explaining a tenth embodiment of the interface defect inspection method for a coating member according to the present invention. The change in emissivity before and after coating of a coating member as an object to which oxide scale is attached is shown. FIG.

  As shown in FIG. 14, the emissivity line 36 before application of the paint represents the emissivity when oxide scale adheres to a part of the coating member as the subject. Compared with the position where there is no oxide scale, the emissivity is lowered at the position where the oxide scale is attached.

  The coating surface temperature that can be measured by the infrared method measures the amount of infrared radiation that depends on the emissivity of the surface, and therefore the temperature measurement value varies depending on the change in the surface emissivity. Therefore, there is a possibility that a difference in the measured temperature appears depending on the presence or absence of oxide scale adhesion, and the interface defect part to be inspected cannot be detected, and the healthy part may be mistaken for the interface defect part.

  As shown in FIG. 14, the emissivity line 37 after application of the paint represents the emissivity after the paint is applied to the entire coating member to which the oxide scale is attached. This paint is a transparent lacquer mainly composed of silicon resin, and has an effect of making the emissivity constant for coating members having various emissivities. In addition to this paint, a heat-resistant paint mainly composed of acrylic resin, nitrocellulose, etc. is also effective. After applying the paint to the coating member, the difference in emissivity due to the presence or absence of the oxide scale can be suppressed, so that the measured coating surface temperature distribution purely reflects the presence or absence of an interface defect. Therefore, if the coating surface temperature distribution measured after applying the paint is handled by the method shown in the first to eighth embodiments, the interface defect portion can be accurately evaluated. These paints can be easily removed by washing with a solvent or the like, and do not hinder the actual operation after the nondestructive inspection.

  According to this embodiment, the coating surface temperature distribution that does not affect the emissivity change due to the oxide scale can be obtained by applying the paint to the surface of the coating member as the subject, and the shape and dimensions of the interface defect portion can be obtained. It is possible to evaluate with high accuracy.

  FIG. 15 is a flowchart used for explaining the eleventh embodiment of the coating member interface defect inspection method according to the present invention. First, the coating surface temperature distribution A is measured in a state where the coating member as the subject is not heated, and is stored as data in advance. In this coating surface temperature distribution A, the difference in emissivity on the measurement surface due to the adhesion of oxide scale or the like is imaged as a change in temperature distribution.

  Next, the coating temperature distribution B at the same position is measured while heating the coating member. In this coating surface temperature distribution B, in addition to the influence of oxide scale adhesion, a change in temperature distribution due to the presence of an interface defect is imaged.

  Subsequently, the difference between the obtained coating surface temperature distribution B and the coating surface temperature distribution A is calculated, and the coating surface temperature distribution C is calculated. These coating surface temperature distributions A and B were measured before and during heating by fixing the infrared temperature measuring device and the coating member previously stored as data, so it is easy to calculate between images. The difference can be taken. The coating surface temperature distribution C thus obtained is data obtained by imaging only the influence of the presence or absence of an interface defect portion without any influence of the oxide scale.

  Finally, using this coating surface temperature distribution C, if the interface defect portion is evaluated by the method shown in the first to ninth embodiments, the shape and size of the interface defect portion can be estimated.

  According to the present embodiment, by subtracting the temperature distribution before heating from the coating member temperature distribution as the subject under heating, it is possible to obtain a coating surface temperature distribution that is not affected by the change in emissivity due to the oxide scale. It is possible to accurately estimate the shape and dimensions of the defective part.

  FIG. 16: is a schematic diagram which shows the relationship between the infrared wavelength and emissivity used in order to demonstrate 12th Embodiment of the sea surface defect inspection method of the coating member based on this invention.

  FIG. 16 shows the emissivity distribution line 38 and the soot emissivity distribution line 39 of the coating layer, respectively. Infrared temperature measuring devices measure the infrared intensity in a certain wavelength range and convert it into temperature values. However, commercially available infrared temperature measuring devices have a large infrared wavelength range, and various temperature distribution measurement results can be obtained. Infrared rays with a wavelength of are mixed, affecting the measurement results.

  As shown in FIG. 16, the emissivity distribution line 38 of the coating layer and the soot emissivity distribution line 39 attached to the surface of the coating member have different shapes. Therefore, when the infrared intensity in a wide range is measured, a temperature distribution affected by both the infrared intensity by the coating layer and the infrared intensity by soot can be obtained.

  On the other hand, the wavelength range of infrared rays for intensity measurement can be narrowed by a filter. That is, in FIG. 16, by measuring the infrared intensity in a region where only the emissivity of the coating layer is high (for example, the infrared intensity measurement range 40), it is possible to obtain a temperature distribution with less influence of soot adhering to the coating layer surface. It is. Therefore, if a filter that transmits only the infrared intensity measurement range 40 is attached to the infrared temperature measurement device and the interface defect portion is evaluated based on the obtained temperature distribution, the shape and size of the interface defect portion are estimated. it can.

  Thus, according to the present embodiment, by measuring the infrared intensity in the wavelength range where only the emissivity of the coating layer is high, it is possible to obtain a coating surface temperature distribution that is not affected by emissivity changes due to soot, It is possible to accurately evaluate the shape and dimensions of the interface defect portion.

  FIG. 17 is a view showing a coating surface temperature image and its horizontal and vertical temperature gradient images used to explain the thirteenth embodiment of the coating member interface defect inspection method according to the present invention. In FIG. 17, (A) shows the coating surface temperature image P having an interface defect at the center, (B) shows the contour line EQHL of the lateral temperature gradient, and (C) shows the contour line of the longitudinal temperature gradient. Each EQVL is shown.

  As already shown in the first to third embodiments, the method for obtaining the gradient, rising position, falling position, intermediate temperature position, etc. based on the coating surface temperature distribution curve in the vicinity of the interface defect is the interface. It is effective for evaluating the shape and dimensions of the defective part. However, in an actual infrared temperature measuring device, the temperature of the coating member symmetry plane as a subject is displayed as a two-dimensional image. When the coating surface temperature distribution in only one direction is extracted from the two-dimensional image and the contour lines EQHL and EQVL are obtained, the tip of the interface defect portion parallel to the direction cannot be clearly found. That is, in the contour line EQHL of the lateral temperature gradient of the coating surface image P shown in FIG. 17, the tip of the interface defect in the vertical direction can be clearly imaged, but the tip of the interface defect in the lateral direction is unclear. Become. Conversely, the contour line EQVL of the longitudinal temperature gradient of the coating surface image P cannot image the tip of the interface defect portion in the longitudinal direction.

  However, if the temperature gradient calculation direction is set to two or more directions from the same coating surface temperature image, the tip of the interface defect portion in all directions can be clearly imaged. That is, if both the horizontal and vertical temperature gradient contours EQHL and EQVL are obtained from the coating surface temperature image P having the interface defect portion at the center, the entire interface defect portion can be identified.

  As described above, according to the present embodiment, by obtaining a temperature gradient in two directions from the coating surface temperature image of the coating member and imaging it, the entire interface defect portion can be clearly identified, and the interface defect portion It is possible to accurately evaluate the shape and dimensions of the.

  FIG. 18 is a conceptual diagram for detecting a crack in a substrate by spot heating used for explaining a fourteenth embodiment of a coating member interface defect inspection method according to the present invention.

  When the heating range is narrowed and a certain position of the coating member is heated, the heat is transmitted circularly around the coating surface around the heating position. Furthermore, heat is transmitted also to the base material side, and spreads around the spot heating position even in the base material.

  The temperature of the coating surface is related not only to the heat conducted through the coating layer but also to the temperature of the substrate immediately below. That is, when there is a crack in the substrate, the outside of the crack is less likely to transfer heat through the substrate, so the substrate temperature is lowered. Therefore, since the coating surface temperature also decreases, it is possible to determine the presence or absence of cracks generated in the substrate by measuring the coating surface temperature.

  As described above, according to the present embodiment, by measuring the coating surface temperature of the spot-heated coating member and imaging the temperature distribution, it is possible to evaluate the presence or absence of cracks generated in the base material under the coating. Is possible.

  FIG. 19 is a diagram showing the relationship between the crack depth of the base material used to explain the fifteenth embodiment of the interface defect inspection method for a coating member according to the present invention and the coating surface temperature difference on both sides of the crack. . Here, the coating surface temperature difference on both sides of the substrate is the difference between the coating surface temperature on the left side and the right side of the crack shown in FIG. The deeper the cracks present in the substrate, the smaller the amount of heat transferred around the cracks, so that the coating surface temperature difference tends to increase.

  This embodiment pays attention to such points, and measures the coating surface temperature image, determines the temperature difference on both sides of the crack, and estimates the depth of the crack generated in the base material from the calculated temperature difference. It is.

  Therefore, according to the present embodiment, the coating surface temperature of the spot-heated coating member is measured and the difference in coating surface temperature on both sides of the crack is obtained, so that the depth of the crack generated in the substrate can be easily estimated. Is possible.

  FIG. 20 is a measurement principle diagram of the coating thickness by the surface ultrasonic method used for explaining the sixteenth embodiment of the coating member interface defect inspection method according to the present invention. When an ultrasonic wave is incident by a transmitting probe from a critical angle direction determined by a substance, the surface ultrasonic wave propagating on the surface of the subject is excited and leaks in the critical angle direction, and is received by the receiving probe. Since the surface ultrasonic wave propagates from the surface to a depth of about one wavelength, it is possible to selectively obtain information up to a specific depth by selecting a frequency. Here, since the elastic properties of the coating layer and the substrate are different, the speed of sound measured by the receiving probe depends on how much the coating layer and the base material are included in the depth of propagation of surface ultrasonic waves. Is different.

  FIG. 21 is a diagram showing the relationship between the thickness of the coating layer and the surface ultrasonic wave velocity. When the entire surface ultrasonic wave propagation depth is occupied by the coating layer, the sound velocity of the coating layer alone is measured. When there is no coating layer, the sound speed peculiar to the substrate is measured. Furthermore, when both the coating layer and the substrate are included in the depth at which the surface ultrasonic wave propagates, the speed of sound changes depending on the thickness of the coating layer. Therefore, it is possible to measure the thickness of the coating layer by measuring the speed of sound of surface ultrasonic waves having a frequency corresponding to the thickness of the coating layer.

  FIG. 22 is a measurement principle diagram for measuring the thickness of the coating layer by the eddy current method. The eddy current method is a method of measuring an eddy current amount determined from the magnetic permeability and conductivity of the subject 42 by bringing the eddy current probe 41 into contact with or close to the subject 42. Since the permeability and conductivity of the coating layer as the subject 42 and the base material are different, the eddy current amount of the coating layer alone as the subject 42 and the eddy current amount of the base material alone are measured in advance. The calibration curve of the output voltage according to the thickness of the coating layer as 42 is created, the amount of eddy current generated in the coating layer as the object 42 is measured, and the thickness of the coating layer is measured.

  This embodiment pays attention to the fact that the thickness of the coating layer can also be measured by the surface ultrasonic method or the eddy current method. The thickness of the coating layer obtained by the surface ultrasonic method or the eddy current method and the eighth embodiment By combining with the depth of the interface defect portion determined in the form, the thickness of the coating layer remaining after the interface defect portion progresses and the coating layer falls off is estimated.

  Therefore, according to the present embodiment, since both the thickness of the coating layer and the depth of the interface defect portion are measured, it is possible to estimate the remaining coating thickness when the interface defect portion rapidly progresses, and whether or not the repair is performed. Can be quickly determined.

The figure which shows coating surface temperature distribution of the interface defect part vicinity used in order to demonstrate 1st Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The schematic diagram which shows the cross section of the coating member applied to this invention. The coating surface temperature image figure which represented that the interface defect part exists in the coating member applied to this invention with the contour line. The figure which shows the coating surface temperature distribution of the interface defect part vicinity used in order to demonstrate 2nd Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The figure which shows the coating surface temperature distribution of the interface defect part vicinity used in order to demonstrate 3rd Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The figure which shows the coating surface temperature distribution of the interface defect part vicinity used in order to demonstrate 4th Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The figure which shows the coating surface temperature distribution of the interface defect part vicinity used in order to demonstrate 5th Embodiment of the interface defect inspection method of the coating member which concerns on this invention. This is used to explain the sixth embodiment of the interface defect inspection method for a coating member according to the present invention, and the length of the interface defect portion of the coating member according to the detection method shown in the first to fifth embodiments. The graph which compared the length of the interface defect part of the coating member which cut out the actual equipment, cut | disconnected the material, and investigated. The figure which was used in order to demonstrate 7th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and shows the coating surface temperature distribution when the position of a heating source is changed. The figure which was used in order to demonstrate 7th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and shows the relationship between the distance of a heating source and a coating member, and a heat flux amount. The figure used for describing 8th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and is a figure which shows the influence of the width | variety of the interface defect part which acts on a coating surface temperature distribution line. The graph which was used in order to demonstrate 8th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and shows the relationship between the temperature difference of a healthy part and an interface defect part, and the width | variety of an interface defect part. The figure used for describing 9th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and is a figure which shows the influence of the interface defect part depth which acts on a coating surface temperature distribution line. The figure used for demonstrating 10th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and is a figure which shows the change of the emissivity before and behind coating application in the coating member to which the oxide scale adhered. The flowchart used in order to demonstrate 11th Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The schematic diagram which shows the relationship between an infrared wavelength and emissivity used in order to demonstrate 12th Embodiment of the interface defect inspection method of the coating member which concerns on this invention. It is a figure which shows the coating surface temperature image used in order to demonstrate 13th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and the horizontal and vertical direction temperature gradient image, (A) is a center part. The coating surface temperature image having the interface defect portion, (B) shows the contour line of the lateral temperature gradient, and (C) shows the contour line of the longitudinal temperature gradient. The conceptual diagram which detects the crack of a base material by the spot heating used in order to demonstrate 14th Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The diagram which shows the relationship between the crack depth of the base material used in order to demonstrate 15th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and the coating surface temperature difference of a crack both sides. The coating principle measurement principle figure by the surface ultrasonic method used in order to demonstrate 16th Embodiment of the interface defect inspection method of the coating member which concerns on this invention. The diagram used for explaining the sixteenth embodiment of the coating member interface defect inspection method according to the present invention and showing the relationship between the thickness of the coating layer and the surface ultrasonic velocity. The measurement principle figure which is used in order to demonstrate 16th Embodiment of the interface defect inspection method of the coating member which concerns on this invention, and measures the thickness of the coating layer by an eddy current method. The basic principle figure which shows the conventional infrared imaging device. The conceptual diagram which forcibly heats the object in the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Object 2 Surface temperature 3a, 3b Radiant energy 4 Lens 5 Electrical signal 6 Thermal image 7 Camera 8 Control part 9 Display part 10 Detector 11 Heat source 11a Heat 12 Defect part 13 Coating surface temperature distribution line 14 Contour line 15 Coating surface temperature distribution Rising position point 16 coating surface temperature distribution line 17 Falling position point 18 of coating surface temperature distribution Coating surface temperature distribution line 19 Rising position point 20 of coating surface temperature distribution Falling position point 21 of coating surface temperature distribution Intermediate point 22 Coating Surface temperature distribution line 23 Coating surface temperature position 24 of interface defect portion Coating surface temperature position 25 of healthy portion Intermediate temperature position 26 Coating surface temperature distribution line 27 Temperature transition integration region 28 on interface defect portion side Temperature transition integration region on sound portion side 29,30 Coating surface temperature distribution line 32, 33, 34, 35 Coating surface temperature distribution line 36 Total emissivity line before coating 37 Total emissivity line after coating 38 Emissivity distribution line of coating layer 39 Soot Emissivity Distribution Line 40 Infrared Intensity Measurement Range 41 Eddy Current Probe 42 Subject

Claims (3)

In a coating member interface defect inspection method for nondestructively inspecting an interface defect portion of a coating member coated on a substrate surface of a metal structure, a position where the coating member is located is spot-heated, and the spot heating position is the center. The surface of the coating member is characterized by detecting a state in which heat is diffused around as a coating surface temperature distribution, and detecting cracks existing in the substrate from an unbalanced portion of the thermal diffusion in the obtained coating surface temperature distribution. Defect inspection method. In a coating member interface defect inspection method for nondestructively inspecting an interface defect portion of a coating member coated on a substrate surface of a metal structure, a position where the coating member is located is spot-heated, and the spot heating position is the center. The coating surface temperature distribution is obtained as the coating surface temperature distribution, and cracks existing in the substrate are detected from the unbalanced portion of the thermal diffusion in the obtained coating surface temperature distribution, and the coating surface temperature on both sides of the crack is detected. A method for inspecting an interface defect of a coating member, wherein the crack depth is estimated from the difference. In the interfacial defect inspection method for a coating member that non-destructively inspects an interface defect portion of a coating member coated on a substrate surface of a metal structure, the surface temperature distribution of the coating member is obtained, and the interface is determined from the obtained surface temperature distribution. The depth of the defect is estimated, and the interface member develops from the depth and the film thickness of the coating member measured by either the electromagnetic method or the ultrasonic method, and the coating member falls off. A method for inspecting an interface defect of a coating member, wherein the thickness of the remaining coating member is predicted when the coating member is made.

Images