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TOFD detection verification method of large-scale spiral case welding seam

A verification method, a spiral technique, applied in the direction of measuring devices, analysis of solids using sonic/ultrasonic/infrasonic waves, instruments, etc.

Inactive Publication Date: 2012-07-04
SHANGHAI BAOSTEEL IND TECHNOLOGICAL SERVICE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the application of TOFD technology in large-scale spiral shell weld engineering is still rare.

Method used

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  • TOFD detection verification method of large-scale spiral case welding seam
  • TOFD detection verification method of large-scale spiral case welding seam
  • TOFD detection verification method of large-scale spiral case welding seam

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Embodiment Construction

[0017] The present invention can be applied in the TOFD inspection process of the spiral shell weld seam of the important pressure part on the large-scale power station generator set and the RT, UT comparison test process, and is extended to the verification comparison test of the TOFD method replacing RT in large spherical tanks and thick-walled pressure vessels In work, the TOFD method has fast detection speed, low overall cost, and no radiation hazards to the human body and the surrounding environment. It can save costs for the owner to a large extent, and has a great application prospect. The large-scale spiral shell weld TOFD detection process and the RT, UT comparative test method include the following four steps:

[0018] Make samples, determine acceptance criteria for volute defects and TOFD detection process parameters

[0019] The welding seam structure of the volute is relatively complex, and TOFD technology is applied for the first time, so a large number of compar...

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Abstract

The invention relates to a detection method of a spiral case welding seam. The TOFD detection verification method of a large-scale spiral case welding seam comprises the following steps: step one, preparing a sample, determining spiral case defect acceptance standards and TOFD detection technological parameters; step two, performing a spiral case welding seam contrast test in which TOFD, UT and RT are performed respectively, that is, firstly performing TOFD, then performing UT and RT respectively after detection, and finally dissecting unqualified defects determined respectively so as to verify respective detection accuracy; step three, performing a welding test plate contrast test, that is, preparing welding defects of cracks, incomplete fusion, lack of penetration, dense pores, slag inclusion, and the like on a test plate, and performing a contrast test with reference to step two; step four, performing contrast test analysis, and verifying TOFD reliability according to the defect detection rates of the three methods. The invention forms a TOFD, RT, and UT contrast test method of large-scale spiral case welding seams, and can be successfully applied to the detection of power station unit spiral case on-site installation welding seams.

Description

technical field [0001] The invention relates to a method for detecting a weld seam of a spiral shell, in particular to a method for non-destructive detection of a weld seam of a large spiral shell. Background technique [0002] TOFD (Time-of-flight diffraction) detection method, also known as ultrasonic diffraction time-of-flight method, is an ultrasonic detection technology not based on the amplitude of the sound wave. The detection method that the same or similar probes are placed on both sides of the weld. The basic principle is based on the Huygens principle. After the incident wave reaches the defect tip, the defect tip is a series of new diffracted wave sources, so the receiving probe can receive defect diffracted waves from all directions. TOFD waveform display adopts radio frequency display, so that the phase of defect wave and lateral wave can be found out. The measurement of the depth of the defect and its own height is based on the time difference method, that i...

Claims

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Application Information

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IPC IPC(8): G01N29/07G01B17/06
Inventor 洪作友毛华群
Owner SHANGHAI BAOSTEEL IND TECHNOLOGICAL SERVICE
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