JP2019184326A - Residual strength measurement device and method for multilayer piping by optical three-dimensional measurement - Google Patents

Abstract

To provide a residual strength measurement device and method for multilayer piping capable of visualizing peeling and cracking in the depth direction from a surface of the multilayer piping.SOLUTION: The pipe inner diameter of the multilayer piping which is a cylindrical container is finely changed in the inner diameter thickness when it is weak or incomplete in adhesion or there is a gap between the layers. The cylinder receives bending such as causing swelling (bulging) around a crack or subjected to a circumferential stress by internal pressure. By optical three-dimensional measurement of such changes, cracks, breaks, crack depths such as a peeling on a surface, and a spread length in the axial direction are visualized in detail and quickly measured by precise measurement to allow determination. By rotating the projection light of the light going straight from the P point to the C point, surface cracks, damages, and the maximum depth of the crack such as peeling to allow the measurement to the maximum measurement angle of 30 degrees to 15 degrees or less.SELECTED DRAWING: Figure 3

Description

  The present invention detects defects occurring at the interface and surface between a steel pipe constituting the multilayer pipe and a resin lining coated on the inner surface of the steel pipe in order to evaluate and measure in the manufacturing process of the multilayer pipe and the plant in use. The present invention relates to a residual strength measuring method and a residual strength measuring device for multilayer pipes by optical three-dimensional measurement.

  In multilayer pipes, especially steel pipes, corrosion of the inner surface proceeds due to water flow, and various problems occur. For this reason, the spread of multilayer piping excellent in durability and corrosion resistance is achieved. For example, it has a resin lining structure in which the inner surface of a steel pipe is coated (lining) with hard vinyl chloride or polyethylene. Nowadays, multi-layer piping has become popular due to the importance of environmental resistance.

JP 2009-98031 A JP2013-83545A

  In the production line of multilayer piping, it is obtained by press-fitting a hard vinyl chloride pipe or polyethylene pipe into the inner surface of a steel pipe and further heat-sealing, and these adhesion strengths are quality factors as a pipe material. Therefore, if there is a gap between them, it becomes a serious problem in terms of quality maintenance. In particular, quality control of adhesion strength and thickness after heat fusion is important. The inspections so far have been carried out using various state test methods such as extracting an arbitrary number from the production line and using an electrical pinhole taster.

  However, in the sampling inspection of the multilayer pipe as described above, it is necessary to temporarily stop the production line and measure the film thickness of the resin lining with the electromagnetic film thickness meter over the entire circumference of the multilayer pipe. In addition, the number of work steps is increased, resulting in a disadvantage that the production efficiency of the multilayer piping is lowered.

The optical three-dimensional measurement shown in FIG. 1 is primarily based on the outer surface shape measurement, and projects and projects linear stripe pattern light from the projector 3 onto the 3D object target 1, which is the surface shape of the object. There is known a surface shape defect inspection method in which a parallax image changed by the above is captured by a camera 2 and analyzed. A 3D measurement system 3DSL, which is mainly characterized for measuring corrosion on the outer surface of an object, has been proposed. The angle β between the camera 2 and the object 1 in FIG. 1 and the angle α between the projector and the projector 1 are variable, and the measurement becomes possible by making the cutting light into a thin band shape in order to improve the accuracy of the light. The base line length in FIG. 1 is L, the distance Z to P on the object to be measured is an angle β, and α is 90 °. The distance Z in FIG. 1 can be obtained by the following formula from the distance D between the object to be measured and the projector and the angles α and β, where the base length is L.

  However, since this defect inspection method for corrosion measurement on the outer surface cannot detect the depth of defect cracks on the object, it can only detect the defect shape on the surface, especially the adhesion state, adhesion state and material quality of the tube layer. There was an inconvenience that it was difficult to capture defect information according to properties.

  The present invention has been made in view of the above-described circumstances. The purpose is to observe the inner surface deformation of the line light according to the shape, and to check the adhesion status, intimate state, interface state, defect depth, etc. of the steel pipe and resin lining constituting the multi-layer pipe in detail for these multiple parts. And it can discriminate quickly. An object of the present invention is to provide a residual strength measuring method and a residual strength detecting device for estimating damage evaluation by optical three-dimensional measurement of multilayer piping.

  In order to achieve the above-described object, the apparatus for detecting residual intensity based on optical three-dimensional measurement of multilayer piping according to the present invention projects line-shaped light onto a measurement object, and the line corresponds to the surface shape of the measurement object. A device for measuring the residual strength of multi-layer pipes by optical three-dimensional measurement for observing deformation, and projecting the light onto the measurement object, a camera for capturing the light from the projector, and visualizing physical defect information A three-dimensional surface depth, an inner surface, a surface shape, a crack, and the like, by sequentially moving the light emitted from the projector and capturing it with the camera. It is characterized by visualizing physical defect information.

  With the above configuration, a linear stripe pattern light is projected from the projector onto the surface of the steel pipe that constitutes the multi-layer pipe, and this change is captured by the camera from the parallax image of the line light that has changed due to the surface shape of the steel pipe. Observed. The camera shown in FIG. 1 as a light receiving element observes an analysis process by increasing the speed of a computer using a CCD (Charge Coupled Device) camera.

  The observation information is processed in the image signal by the phase calculation based on the data analysis using the pattern light in the calculation processing unit built in the high-speed camera, and the physical defect information is visualized. As shown in FIG. 2, the depth from the surface to the inside, such as cracks, cracks, delamination, spread in the axial direction, length, etc., the depth from point P to point A, point C to point B, β = By measuring the depth of the inner surface of the defect at an angle of up to 15 ° while rotating at 30 °, this change can be measured in more detail and more accurately by optical 3D measurement. The determination can be made quickly and accurately.

  Further, the residual strength measurement detection method for estimating damage evaluation by optical three-dimensional measurement according to the present invention not only receives circumferential stress due to internal pressure but also causes bulging around a crack in a cylindrical container. The strength decreases due to bending. The ratio of the plastic collapse load (Pdc) of a pipe damaged by thinning or the like and the plastic collapse load (Puc) of a healthy pipe is a residual strength factor Rsf (Remaining Strength Factor) indicating that the strength remains. Defined by the American Society of Mechanical Engineers standard ASME FFS-1. The damage evaluation of this multi-layer pipe, which is a cylindrical container, is applied to the residual strength factor by applying physical internal defect information such as peeling, pinholes, cracks, etc., measured and detected by the evaluation software built in the processing unit, and compared with the steel pipe. It is characterized in that physical defect information generated at the interface with the resin lining is visualized.

  As a result, the joint surface, adhesion degree and interface state between the steel pipe and the resin lining constituting the multi-layer pipe are as follows: d: crack depth, t: wall thickness (constant), C: axial crack length, Ri: inner radius , Mt (coefficient: bulling factor), etc., the remaining strength factor shown in FIG. 10 can be accurately estimated using the safety assurance of the cylindrical container etc. as an evaluation index. Without stopping, multi-layer piping can be measured with high accuracy and efficiency without contact and without destruction.

  According to the present invention, scanning the line light on the inner surface or surface of the multilayer pipe and using the three-dimensional shape information, the interface state between the steel pipe and the resin lining is inspected in detail and quickly for each part of each layer pipe material. Can do.

FIG. 3 is a connection diagram illustrating a method for measuring the residual strength of a multi-layer pipe and a measurement detection device by optical three-dimensional measurement according to an embodiment of the present invention. It is sectional drawing when a defect 2mmphi is formed in the multilayer piping used as inspection object. It is sectional drawing of the multilayer piping of 3 layer structure. It is sectional drawing of multilayer piping. It is the processing figure which formed the simulated defect in the multilayer piping used as inspection object. It is a three-dimensional cube shape measurement image of a simulated defect of 2 mmφ. It is an internal defect detection figure in the Y direction of 3 layer structure piping. It is an internal defect detection figure in the X direction of 3 layer structure piping. It is a surface defect detection figure in 3 layer structure piping XY direction. It is a graph which shows the calculation result of 0.5-2 mm (phi) of simulated defects, and residual strength factor Rsf.

  Hereinafter, a residual strength measurement method and a residual strength measurement detection device by optical three-dimensional measurement of multilayer piping according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10.

[Measurement equipment]
The multi-layered pipe residual strength measurement and detection device according to the present embodiment mainly measures the outer surface shape for cracks, cracks, delamination, etc. from the surface of the steel pipe with the resin lining on the inner surface. However, the residual strength factor is included in the evaluation software built in the calculation processing section as an evaluation index for ensuring safety against the damage state of the defects of the steel pipe, etc., even with respect to the interlayer state of the inner surface, contamination, voids, cracks etc. By adopting the improvement of the product quality by the evaluation and the evaluation in the plant in use, it is configured with an arithmetic processing unit that enables visualization.

  As shown in FIG. 1, the residual strength measuring method and the residual strength measuring / detecting device by the optical three-dimensional measurement of the multilayer pipe according to the present embodiment are based on the target 1 that is a 3D object that is the target and the surface shape of the object. It comprises a camera 2 that captures the changed state and a projector 3 that projects a linear stripe reference pattern onto the object 1. The camera 2 includes an arithmetic processing unit that analyzes the image signal and evaluation software that compares and detects the residual intensity factor as the residual intensity detecting device. In this embodiment, a part of the 3DSL series manufactured by S company is used as the three-dimensional measurement system, but the present invention is not limited to this, and other devices may be used.

  The pattern light is projected from the projector 3 in FIG. 1 onto the inner surface of the steel pipe and the resin lining, and the changed state is observed with a camera. The camera 2 in FIG. 1 as the light receiving element performs analysis processing of the image signal by speeding up the computer in the built-in arithmetic processing unit, and compares the remaining strength factor Rsf in the remaining strength detection device by the built-in evaluation software. Detect and accurately infer as a safety evaluation index. By comparing and detecting these, a normal determination output can be obtained.

  When detecting the residual intensity, the line light from the projector 3 is projected onto the object 1 that is a measurement object. The residual intensity detection apparatus according to the present embodiment is a line light scanning method that observes deformation according to the surface shape of an object with this line light. In this scanning method, as shown in FIG. 2, in the three-layer structure pipe, the line light is rotated from P to C to the inside, thereby reflecting the inner wall surface and 3 It becomes possible to measure defect information from the depth of the layer. The depth of point A is changed from point A to point P in FIG. 2 and from point C to point B, and the bottom of the object 1 is changed by an angle of up to 15 ° while rotating the line light at β = 30 ° at 15 °. Enables measurement of depth inner wall.

  In FIG. 2, the inner surfaces of A to B are measured at an angle of β = 30 ° by rotating the line light between the defect surfaces P and C of the three-layer structure pipe cross section. Furthermore, by measuring the inner surface at an angle of β = 15 °, it is possible to measure the inner surface at a deep depth, and it is possible to measure the information of the defect from the measured surface, thereby enabling more accurate calculation processing. .

[Measurement target]
FIG. 3 is a longitudinal sectional view showing an example of a multilayer pipe. The multi-layer pipe is composed of a lining layer 4 having a resin lining such as hard vinyl chloride on the outer peripheral surface, a steel (carbon steel) layer 5 and an inner surface 6 being a resin lining layer such as hard vinyl chloride. Composed. FIG. 4 shows a galvanized steel pipe structure for water supply as another multi-layer pipe, in which a resin lining 7 such as hard vinyl chloride is applied to the inner peripheral surface of the steel pipe (carbon steel). The outer peripheral surface is rust-proofed by a galvanized layer (W: SGP pipe for water service) 8. A multilayer pipe having such a three-layer structure can also be used as an inspection target for physical states such as a joint surface, adhesion degree, and interface state according to the present invention.

  Next, a sample actually measured by the residual strength measurement detection device will be described with reference to FIG. In the three-layered pipe, the first layer is 1.5 mm thick hard vinyl chloride, the second layer is 2.8 mm thick steel layer, and the third layer is 1.5 mm thick hard vinyl chloride. A 2 mmφ artificial defect was formed from the surface of the multilayer pipe to the inner surface.

  The three-layer structure pipe can measure the defect from the depth of the third layer from the reflected light from the low part of the defect by optical three-dimensional measurement. FIG. 5 (a) is a diagram with the inner surface of the half-divided multilayer piping, and FIG. 5 (b) is a diagram with the outer surface of the half-divided multilayer piping. In either case, a 0.5 mmφ drill hole was formed at a position 3 cm from one end face, a 2 mmφ drill hole was formed at a position 3 cm from the other end face, and a 1 mmφ drill hole was formed at the center. In FIG. 5A, a drill hole is formed so as to reach the second steel layer from the inside, and in FIG. 5B, the second steel layer is reached from the outside. A drill hole is formed. The artificial defect formed in this way becomes an inspection target of physical states such as the joint surface, adhesion degree, and interface state according to the present invention.

[Measurement result]
Next, the measurement result of the 2 mmφ drill hole in FIG. 5A will be described with reference to FIGS. The 3D measurement result shown in FIG. 6 has a plane resolution of 0.4 mm and a depth resolution of 50 μm of the measuring instrument, and can measure the inner surface of the defect at a deeper depth. The surface shape in the X direction shown in FIG. 9 is shown in FIG. 8, and the surface shape in the Y direction shown in FIG. 9 is shown in FIG. Based on the reflected light captured by the camera 2, the arithmetic processing unit performs image processing, and as shown in FIGS. 7 and 8, a defect depth of 2.97 mm is confirmed.

  In FIG. 7, since the light from the projector 3 reaches the defect low part, the camera 2 can capture reflection from the second layer thickness of 2.8 mm at a depth of 2.97 mm. In the polyvinyl chloride layer, artificial defects are greatly spread by the drill, and the points A and B where the level difference is generated in the steel layer can be observed from the reflected light captured by the camera 2 by a calculation process. Here, point A is the boundary between the vinyl chloride layer and the steel material layer.

  FIG. 8 is an image in the X direction of the reflected light from the defect low part. Since the X axis shown in FIG. 9 is shifted from the center of the surface shape and passes through the periphery of the artificial defect, in FIG. 8, some lines are shown as being interrupted. The surface vibration of the image indicates external light disturbance (disturbance) caused by surface roughness due to light to be irradiated. It is possible to visualize physical defect information such as inner surface depth, interlayer state, wall surface, surface shape, and the like, and to inspect physical states such as a joint surface, adhesion degree, and interface state by reflected light from the lower part of the defect. In FIG. 8 as well, a point A ′ that is a step between the vinyl chloride layer and the steel material layer is observed.

  FIG. 9 shows the measurement result of the surface shape. The defect shape 2 mmφ in FIG. 5B is measured at the point C. The three-layer structure pipe can obtain defect information from the depth of the third layer from the reflected light from the defect lower part by optical three-dimensional measurement.

Multi-layer piping is not only subjected to circumferential stress due to internal pressure, but also subjected to bending that causes swelling around the crack. For multi-layer piping, which is a cylindrical container, we made an artificial scratch and evaluated the damage. If the cylindrical container suffers from thinning damage due to peeling or pinholes, the strength remains in the ratio of the plastic collapse load (Pdc) of the multilayer pipe etc. to the plastic collapse load (Puc) of the sound multilayer pipe. It can be estimated by a residual strength factor Rsf (Remaining Strength Factor) representing This residual strength factor Rsf is Rt (residual thickness ratio) = 1-dmm / tmm, d: crack depth, t: wall thickness (constant), C: axial crack length, Ri: inner radius, It can obtain | require by the type | formula. Here, Mt is a coefficient.
According to the above formula, as shown in FIG. 10, the residual strength Rsf increases rapidly when the defect outer diameter φ decreases to 1 mmφ or less, and the residual strength increases.

  As described above, this embodiment can be used as a non-destructive inspection technique for estimating the degree of defect damage that occurs during laying operation as a plant maintenance technique for a multi-layer pipe having a three-layer structure by optical three-dimensional measurement. The residual strength factor Rsf is used for the defect damage of the cylindrical container or the like with safety as an evaluation index. According to the trial calculation of the 2 mmφ drill diameter, Rsf = 0.982, and it was confirmed from the measurement result that 98.2% strength remained. This is a 1.8% drop in strength. If a judgment index for damage evaluation can be provided from the viewpoint of fracture mechanics to the soundness of a plant or the like, it can be used as a judgment technique for effective nondestructive inspection.

  The present invention has an effect that the interface state between the steel pipe and the resin lining can be determined and evaluated in detail and quickly for these plural parts, and the steel pipe constituting the multilayer pipe and the resin coated on the inner surface of the steel pipe This is a method and apparatus for measuring residual strength by optical three-dimensional measurement of multilayer piping for detecting defects generated at the interface with the lining.

In the present invention, in addition to the conventional function of capturing the outer surface shape of a target object in a non-contact manner by optical three-dimensional measurement, the inner surface shape of a plurality of parts of a multilayer pipe is measured in detail and quickly, and defect inspection is simultaneously performed. Enable. The importance of the evaluation detection technique accompanying the deformation of an object is required to shorten the measurement time in combination with the measurement technique. The effect is useful for a residual strength measurement method and apparatus by optical three-dimensional measurement of multilayer piping.

DESCRIPTION OF SYMBOLS 1 3D object 2 Camera 3 Projector 4 Hard vinyl chloride layer 5 Steel (carbon steel) layer 6 Hard vinyl chloride layer 7 Resin lining layer 8 Zinc plating

Claims (2)

A line-shaped light is projected onto a measurement object, and this line is a residual strength measuring device for multi-layer piping by optical three-dimensional measurement in which deformation is observed according to the surface shape of the measurement object,
A projector that projects the light onto the measurement object;
A camera that captures light from the projector;
An arithmetic processing unit that visualizes physical defect information,
Three-dimensional shape information can be obtained by moving the light emitted from the projector in order and capturing with the camera,
An apparatus for measuring the residual strength of multi-layer pipes that visualizes physical defect information such as surface depth, inner surface, and surface shape in three dimensions. Scanning the line-shaped light on the surface of the steel pipe with the resin lining on the inner surface;
The light travels on the surface and inner surface of the defect existing in the steel pipe and the resin lining, thereby capturing the reflected light of the light, the physical thickness (t), the surface crack depth (d), and the remaining thickness. Measuring the defect information of the ratio (Rt), and a method for measuring the residual strength of the multilayer pipe by optical three-dimensional measurement.