Ultrasonic Flaw Detection for Metallic Pipe Inner Surfaces
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Solution Overview
Problem
Conventional ultrasonic flaw detection methods struggle to detect dent flaws and shallow flaws on the inner surface of metallic pipes due to weak echo signals and difficulty in aligning beam path lengths, leading to reliance on visual inspection.
Innovation Solution
Calculating the path length and change rate of echo signals from the inner surface of metallic pipes using ultrasonic waves, allowing for the detection of flaws on the inner surface by analyzing waveform data and adjusting thresholds for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ultrasonic flaw detection methods (angle beam and normal beam) are used, then the detection of crack-like flaws and inclusions is improved, but the detection of dent flaws and shallow flaws on the inner surface deteriorates due to weak echo signals
Solution Approach 1:
The patent performs preliminary alignment of beam path lengths before flaw detection. By pre-calculating and aligning the beam path lengths based on the geometry of the pipe and probe positions, the method ensures that echo signals from flaws at different locations are comparable in strength, thereby improving the detection of dent flaws and shallow flaws that would otherwise produce weak echoes
Solution Approach 2:
The patent changes the parameter of beam path length alignment dynamically based on probe position and pipe geometry. By adjusting the reference beam path length according to the specific inspection location, the method compensates for variations in echo signal strength, enabling reliable detection of shallow flaws on the inner surface
2Reliability
If the beam path lengths are aligned based on detected bottom echo positions, then the detection of subsurface flaws is improved, but the detection of inner surface flaws deteriorates because the bottom echo position cannot be referenced for inner surface flaws
Solution Approach 1:
The patent performs preliminary calculation of beam path lengths based on known pipe geometry and probe positions before conducting flaw detection. This pre-alignment eliminates the need to reference bottom echo positions, allowing direct detection of inner surface flaws without relying on bottom echo alignment
Solution Approach 2:
Instead of aligning beam paths based on bottom echo positions (conventional approach), the patent inverts the approach by calculating beam path lengths from known geometric parameters and probe positions. This inversion enables direct detection of inner surface flaws by comparing echo signals against geometrically-calculated references
3Reliability
If visual inspection is used for inner surface flaw detection, then the detection of dent flaws and shallow flaws is possible, but the productivity and automation level deteriorate
Solution Approach 1:
The patent replaces manual visual inspection with an automated ultrasonic detection system. By implementing automatic beam path length alignment and echo signal analysis, the system achieves both high detection reliability for inner surface flaws and improved productivity through automation
Solution Approach 2:
The ultrasonic detection system performs self-alignment of beam paths through automatic calculation based on geometric parameters. This self-service capability eliminates the need for manual calibration and enables continuous automated inspection, thereby improving productivity while maintaining detection reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the detection of dent flaws and shallow flaws on the inner surface of metallic pipes, improving the accuracy and reliability of ultrasonic flaw detection beyond conventional methods.
Implementation Method 1
ultrasonic flaw detection methods that use ultrasonic waves have been widely applied
Implementation Method 2
angle beam flaw detection and normal beam flaw detection are usually used
Data Source
Figure 1
Figure 2
Figure 3~4(e)
AI summary
To provide an ultrasonic flaw detection method, an ultrasonic flaw detection apparatus, and a pipe manufacturing method that can detect even dent flaws or shallow flaws in a lapped form arisen on inner surfaces of metallic pipes such as steel pipes, included are a wave memory 11 that acquires and holds waveform data of an echo signal when an ultrasonic probe 2, generating ultrasonic signals toward an inner surface B of a steel pipe 1, and the steel pipe 1 are moved relative to each other; a signal analyzing unit 12 that calculates a path length up to receiving an echo signal from the inner surface B and a change rate of the path length based on the waveform data held; and a flaw detector 13 that detects a flaw BW on the inner surface B based on the path length and the change rate of the path length.