Ultrasonic flaw detection method, ultrasonic flaw detection apparatus, and pipe manufacturing method

Patent metadata

Field	Value
Publication number	US-9341599-B2
Application number	US-201214374989-A
Country	US
Kind code	B2
Filing date	May 9, 2012
Priority date	Jan 31, 2012
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

An ultrasonic flaw detection method to detect flaws on an inner surface of a metallic pipe using ultrasonic waves includes a waveform hold step that acquires and holds waveform data of an echo signal when an ultrasonic probe that generates ultrasonic signals toward the inner surface and the metallic pipe are moved relative to each other, a signal analyzing step that calculates a path length up to receiving an echo signal from the inner surface and a change rate of the path length based on the waveform data held, and a flaw detecting step that detects flaws on the inner surface based on the path length and the change rate of the path length.

First claim

The invention claimed is:

1. An ultrasonic flaw detection method to detect flaws on an inner surface of a metallic pipe using ultrasonic waves comprising:
a waveform holding step that acquires and holds waveform data of an echo signal when an ultrasonic probe that generates ultrasonic signals toward the inner surface and the metallic pipe are moved relative to each other;
a signal analyzing step that calculates a path length up to receiving an echo signal from the inner surface and a change rate of the path length based on the waveform data held; and
a flaw detecting step that detects flaws on the inner surface based on the path length and the change rate of the path length,

wherein
the signal analyzing step further calculates a height of the echo signal from the inner surface based on the waveform data held, and
the flaw detecting step determines that a flaw is present in a portion satisfying a condition in which the path length is equal to or smaller than a given path length threshold, or a portion satisfying a condition in which the change rate of the path length is equal to or greater than a given path-length change rate threshold and the height within a search range preset with respect to a position of the change rate of the path length being equal to or greater than a given path-length change rate threshold as a reference position is equal to or smaller than a given height threshold, and the flaw detecting step determines that no flaw is present in a portion not satisfying the condition.

2. The method according to claim 1 , wherein the signal analyzing step analyzes a noise level of noise components in a portion in which no echo signal is present based on the waveform data held, determines a threshold to detect an echo signal based on the analysis result, and detects the echo signal based on the determined threshold to calculate the path length.

3. An ultrasonic flaw detection apparatus that detects flaws on an inner surface of a metallic pipe using ultrasonic waves comprising:
a waveform holding unit that acquires and holds waveform data of an echo signal when an ultrasonic probe that generates ultrasonic signals toward the inner surface and the metallic pipe are moved relative to each other;
a signal analyzing unit that calculates a path length up to receiving an echo signal from the inner surface and a change rate of the path length based on the waveform data held; and
a flaw detecting unit that detects a flaw on the inner surface based on the path length and the change rate of the path length,

wherein
the signal analyzing unit further calculates a height of the echo signal from the inner surface based on the waveform data held, and
the flaw detecting unit determines that a flaw is present in a portion satisfying a condition in which the path length is equal to or smaller than a given path length threshold, or a portion satisfying a condition in which the change rate of the path length is equal to or greater than a given path-length change rate threshold and the height within a search range preset with respect to a position of the change rate of the path length being equal to or greater than a given path-length change rate threshold as a reference position is equal to or smaller than a given height threshold, and the flaw detecting step determines that no flaw is present in a portion not satisfying the condition.

4. The apparatus according to claim 3 , wherein the signal analyzing unit analyzes a noise level of noise components in a portion in which no echo signal is present based on the waveform data held, determines a threshold to detect an echo signal based on the analysis result, and detects the echo signal based on the determined threshold to calculate the path length.

5. A pipe manufacturing method in which at least a heating process, a piercing process, a rolling process, a reheating process, a shaping process, and an inspection process are performed on a metallic material to manufacture a pipe, the inspection process comprising:
a waveform holding step that acquires and holds waveform data of an echo signal when an ultrasonic probe that generates ultrasonic signals toward an inner surface of the pipe and the pipe are moved relative to each other;
a signal analyzing step that calculates a path length up to receiving an echo signal from the inner surface and a change rate of the path length based on the waveform data held; and
a flaw detecting step that detects flaws on the inner surface based on the path length and the change rate of the path length,

wherein
the signal analyzing step further calculates a height of the echo signal from the inner surface based on the waveform data held, and
the flaw detecting step determines that a flaw is present in a portion satisfying a condition in which the path length is equal to or smaller than a given path length threshold, or a portion satisfying a condition in which the change rate of the path length is equal to or greater than a given path-length change rate threshold and the height within a search range preset with respect to a position of the change rate of the path length being equal to or greater than a given path-length change rate threshold as a reference position is equal to or smaller than a given height threshold, and the flaw detecting step determines that no flaw is present in a portion not satisfying the condition.

6. The method according to claim 5 , wherein the signal analyzing step analyzes a noise level of noise components in a portion in which no echo signal is present based on the waveform data held, determines a threshold to detect an echo signal based on the analysis result, and detects the echo signal based on the determined threshold to calculate the path length.

Assignees

• Iizuka Yukinori
• Ozeki Takafumi
• Matsui Yutaka
• Jfe Steel Corp

Inventors

• Iizuka Yukinori
• Ozeki Takafumi
• Matsui Yutaka

Classifications

• G01N29/11

  by measuring attenuation of acoustic waves · CPC title

• G01N2291/2634

  cylindrical from outside · CPC title

• G01N2291/0289

  Internal structure, e.g. defects, grain size, texture · CPC title

• G01N29/265

  by moving the sensor relative to a stationary material · CPC title

• G01N29/44

  Processing the detected response signal {, e.g. electronic circuits specially adapted therefor (digital signal processing per se G06F17/00)} · CPC title