Method for testing annular orientation of pipe

A technology of orientation degree and pipe material, which is applied in the analysis of solid directions by using sound wave/ultrasonic wave/infrasonic wave, can solve the problems such as the difficulty in characterizing the degree of orientation in the circumferential direction of biaxially oriented pipe materials, achieve scientific and accurate test results, improve production efficiency, and solve test difficulties Effect

Active Publication Date: 2013-07-24
BEIJING UNIV OF CHEM TECH
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AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to solve the difficulties in the characterization of the degree of hoop orientation in the production process of biaxially oriented pipes

Method used

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  • Method for testing annular orientation of pipe
  • Method for testing annular orientation of pipe
  • Method for testing annular orientation of pipe

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Experimental program
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Effect test

Embodiment Construction

[0024] The test method for hoop orientation degree of pipe mainly includes the following implementation steps:

[0025] 1) The angle between the initial position of the probe should be moderate, about 10°, which will not affect the results. Set the rotation angle, measure the outer diameter and wall thickness of the pipe.

[0026] 2) Test the hoop ultrasonic velocity of the oriented pipe.

[0027] 3) Test the hoop ultrasonic velocity of a completely unoriented pipe material of the same material as the tested pipe material.

[0028] 4) Calculate the hoop orientation degree of the pipe according to the ultrasonic orientation degree formula (1).

[0029] The actual operation process and results are as follows:

[0030] 1. Select an oriented PVC pipe with an outer diameter of 90mm and a wall thickness of 4mm. The outer diameter of the PVC pipe before expansion is 50mm and the wall thickness is 8mm. The rotation angle of the probe is 5°.

[0031] 2. Test the ultrasonic velocity...

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Abstract

The invention discloses a method for testing annular orientation of a pipe. A nondestructive detection means is applied in the field of production of plastic pipes. In the processing process, macromolecular chains in a plastic pipe are orientated under the action of an external force. In the orientated pipe, the ultrasonic speed in the orientation direction is changed. The method for testing the annular orientation of the pipe is characterized by comprising the following steps of: measuring the speed of ultrasonic propagated along the annular direction of the pipe by using a Rayleigh wave probe, and calculating the annular orientation of the pipe through the measured annular ultrasonic speed and the ultrasonic speed when the same material is not orientated at all. By adopting the method, the ultrasonic speed can be measured along the annular direction, so that the annular orientation of the pipe can be characterized simply and conveniently, and the defects of harsh making of the conventional orientation testing sample, indefinite orientation direction, high testing cost and the like are overcome. The method is suitable for characterizing the average orientation level of the plastic pipes, thereby providing a scientific proof for characterization of performance of the plastic pipes, and being favorable for simply and effectively realizing online detection.

Description

technical field [0001] The invention discloses a method for testing the degree of orientation in the hoop direction of pipes, which belongs to the field of detection of degree of orientation of plastic pipes. Background technique [0002] Polymer materials make the regular arrangement of polymer chains in the product through orientation processing, thereby improving the overall performance of the product. The processing of biaxially oriented PVC pipe is based on this principle, and the PVC-U pipe is stretched axially and expanded circumferentially through the corresponding expansion device. The performance and quality of processed PVC pipes are closely related to the degree of orientation of the pipes. For thin-walled pipes under internal pressure, the hoop stress is twice the axial stress. The quality of the hoop mechanical properties of the pipe directly affects the life of the pipe. Therefore, the test of the degree of orientation in the hoop direction is more importan...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/07
Inventor 吴大鸣上官洲鑫许红刘颖林伟国
Owner BEIJING UNIV OF CHEM TECH
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