A method for detecting corrosion degree of pipe fittings

A pipe fitting and pipe measuring technology, applied in the field of ultrasonic thickness measurement, can solve the problems of inaccurate thickness, inaccurate ultrasonic sound velocity, no corrosion degree of pipe fittings, etc., and achieve the effect of accurate corrosion degree

Active Publication Date: 2018-10-23
CHINA NAT OFFSHORE OIL CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the existing methods, the ultrasonic sound velocity is assumed to be a specific value at different high temperatures. However, the ultrasonic sound velocity in the same material is not always constant, and it changes with the change of temperature. Therefore, the existing The aforementioned method assumes that the ultrasonic sound velocity at different high temperatures is not accurate. Correspondingly, the thickness measured by the ultrasonic thickness gauge is not accurate, and thus the corrosion degree of the equipment cannot be accurately detected.
Moreover, there is currently no more accurate method for detecting the corrosion degree of pipe fittings that can be used for reference.

Method used

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  • A method for detecting corrosion degree of pipe fittings
  • A method for detecting corrosion degree of pipe fittings
  • A method for detecting corrosion degree of pipe fittings

Examples

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Comparison scheme
Effect test

Embodiment 1

[0029] This example is used to illustrate the method for detecting the degree of corrosion of 20# carbon steel pipe fittings.

[0030] (1) Measure the thickness D of 20# carbon steel pipe fittings at 25°C with a vernier caliper to be 13.15mm;

[0031] (2) Take the 20# carbon steel pipe fitting in step (1) as the standard sample, and take the thickness D (i.e. 13.15mm) measured in step (1) as the benchmark, at 25°C, set the ultrasonic sound velocity v to 5000m / s, Using an ultrasonic thickness gauge to measure the thickness of 20# carbon steel pipe fittings at 25°C, the obtained thickness value d is 11.05mm. The time t' used for propagation in 20# carbon steel pipe fittings is 0.00221s, the ratio of the thickness D (ie 13.15mm) measured in step (1) to the time t' (ie 0.00221s) is the ultrasonic wave at 25°C in 20# carbon The superficial sound velocity of ultrasonic waves in steel pipe fittings is 5950m / s.

[0032] (3) Heat 20# carbon steel pipe fittings to 50°C, 100°C, 200°C, ...

Embodiment 2

[0035] This example is used to illustrate the method for detecting the corrosion degree of 321 stainless steel pipe fittings.

[0036] (1) Measure the thickness D of 321 stainless steel pipe fittings at 25°C with a vernier caliper to be 24.32mm;

[0037] (2) Take the 321 stainless steel pipe fitting in step (1) as the standard sample, and take the thickness D (ie 24.32mm) measured in step (1) as the reference, set the ultrasonic sound velocity v to 5000m / s at 25°C, and use ultrasonic The thickness gauge measures the thickness of 321 stainless steel pipe fittings at 25°C, and the obtained thickness value d is 21.10mm. The time t' used for propagation is 0.00422s, and the ratio of the thickness D (ie 24.32mm) measured in step (1) to the time t' (ie 0.00422s) is the superficial sound velocity of ultrasonic waves in 321 stainless steel pipe fittings at 25°C , is 5763m / s.

[0038] (3) Heat the 321 stainless steel pipe fittings to 100°C, 200°C, 300°C, 400°C and 450°C respectively,...

Embodiment 3

[0041] This example is used to illustrate the method for detecting the corrosion degree of 304 stainless steel pipe fittings.

[0042] (1) Measure the thickness D of 304 stainless steel pipe fittings at 25°C with a vernier caliper to be 9.55mm;

[0043] (2) Take the 304 stainless steel pipe fitting in step (1) as the standard sample, and take the thickness D (9.55mm) measured in step (1) as the reference, set the ultrasonic sound velocity v to 5000m / s at 25°C, and use ultrasonic The thickness gauge measures the thickness of 304 stainless steel pipe fittings at 25°C, and the obtained thickness value d is 8.30mm. The time t' used for propagation is 0.00166s, and the ratio of the thickness D (ie 9.55mm) measured in step (1) to the time t' (ie 0.00166s) is the superficial sound velocity of ultrasonic waves in 304 stainless steel pipe fittings at 25°C , is 5753m / s.

[0044] (3) Heat the 304 stainless steel pipe fittings to 50°C, 100°C, 200°C, 250°C, 300°C, 400°C and 450°C respectiv...

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Abstract

The invention discloses a method for detecting corrosion degree of pipe parts. The method includes: 1) measuring the thickness of a to-be-detected pipe part at 25 DEG C; 2) with the to-be-detected pipe part in the step (1) as a standard sample and the thickness measured in the in the step (1) as a basis, obtaining ultrasonic apparent sound velocity at different temperatures within 25-450 DEG C through an ultrasonic thickness meter to acquire a function curve between the ultrasonic apparent sound velocity and temperature; and (3) with a pipe part, which is made from the same material of the to-be-detected pipe part in the step (1), in practical production as a standard sample, measuring the thicknesses at a specific temperature at the time T and the time (T+t) according to the ultrasonic apparent sound velocity at the specific temperature in the function curve in the step (2), and comparing the two thickness values at the two times to obtain the corrosion degree of the pipe part within the time t. The method can accurately measure the thicknesses of the pipe part in different stages, and furthermore accurately detects the corrosion degree of the pipe part. The method allows effectively guidance of corrosion detection in a refinery factory.

Description

technical field [0001] The invention relates to the technical field of ultrasonic thickness measurement, in particular to a method for detecting the corrosion degree of pipe fittings. Background technique [0002] Ultrasonic thickness measurement technology has developed into one of the key technologies for corrosion monitoring in refineries because it can accurately measure the thickness of equipment and pipelines from one side without damaging equipment and components, and detect the corrosion of pipe fittings. [0003] Most of the pipelines and equipment in the refinery operate under high temperature conditions. To perform accurate ultrasonic thickness measurement on them, it is necessary to know the accurate ultrasonic sound velocity at the corresponding high temperature. In the existing methods, the ultrasonic sound velocity is assumed to be a specific value at different high temperatures. However, the ultrasonic sound velocity is not always constant in the same materia...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N17/00G01B17/02
Inventor 郑明光夏长平杨威王旭孙亮安辉张绍良欧阳健闻明科侯艳宏李燕妹
Owner CHINA NAT OFFSHORE OIL CORP
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