CN218239756U - Submarine pipeline welded joint local corrosion testing arrangement - Google Patents
Submarine pipeline welded joint local corrosion testing arrangement Download PDFInfo
- Publication number
- CN218239756U CN218239756U CN202221507106.7U CN202221507106U CN218239756U CN 218239756 U CN218239756 U CN 218239756U CN 202221507106 U CN202221507106 U CN 202221507106U CN 218239756 U CN218239756 U CN 218239756U
- Authority
- CN
- China
- Prior art keywords
- ring
- corrosion
- container
- temperature compensation
- welded joint
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
The utility model provides a local corrosion testing device for a submarine pipeline welding joint, which comprises an upper container, a lower container, a corrosion ring, a connecting ring and a temperature compensation ring, wherein the corrosion ring is arranged between the upper container and the lower container; the upper container, the corrosion ring, the connecting ring, the temperature compensation ring and the lower container are sequentially connected to form a solution environment container; and a plurality of signal monitoring electrode probes are uniformly arranged on the corrosion ring and the temperature compensation ring respectively, and the corrosion ring and the temperature compensation ring are separated into a plurality of subareas with the same number. The utility model provides a to weld joint realize the local corrosion degree of depth differentiation discernment of axial and circumference in the space, can monitor weld joint's local corrosion degree of depth under the current flowing environment in real time, analysis welding process is not enough in the annular welding process, guides welding process's optimization and prediction corrosion development trend. Utilize the utility model provides a corrosion resisting property and aassessment local corrosion characteristic that submarine pipeline welded joint can be mastered to the device.
Description
Technical Field
The utility model belongs to the technical field of the local corrosion test, particularly, especially, relate to a submarine pipeline welded joint local corrosion testing arrangement.
Background
The submarine pipeline is a life line for marine oil and gas gathering and transportation, and has the advantages of high efficiency, energy conservation and safety as the most important marine oil and gas transportation mode. With the wide use of marine steel pipelines, the problem of pipeline failure is more prominent, economic and social activities are seriously influenced, and even the safety of human life and property is threatened. In order to realize the long-distance transportation of ocean oil gas, welding becomes the most common and most economical connection mode of long-distance gathering and transportation pipelines. In long haul gathering lines, there is one welded joint every 12 m. The structural changes and defects in the welded joint will seriously affect the overall strength and corrosion resistance of the pipeline, and even threaten the safe operation of the pipeline.
The problem of local corrosion of a welding area of a submarine pipeline is complex, basic corrosion information of the welding area, such as corrosion rates of different areas of the welding area and the like, can be obtained by a traditional electrochemical method or a resistance probe method, but the corrosion depth distribution and the corrosion change rule of the whole welding part cannot be obtained generally. In addition, a resistance probe is arranged near a pipeline welding area to obtain the corrosion depth of the position, but the method cannot fully consider local corrosion of the welding area, and the monitoring result is always conservative.
Therefore, it is very important to design a local corrosion testing device for the welding joint of the submarine pipeline.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a submarine pipeline welded joint local corrosion testing arrangement to the not enough of existence among the prior art.
For this reason, the above-mentioned purpose of the present invention is achieved by the following technical solutions:
the utility model provides a submarine pipeline welded joint local corrosion testing arrangement which characterized in that: the local corrosion testing device for the submarine pipeline welding joint comprises an upper container, a lower container, a corrosion ring, a connecting ring and a temperature compensation ring, wherein the corrosion ring is positioned between the upper container and the lower container;
the upper container, the corrosion ring, the connecting ring, the temperature compensation ring and the lower container are sequentially connected to form a solution environment container;
the corrosion ring and the temperature compensation ring are respectively and uniformly provided with a plurality of signal monitoring electrode probes, and the corrosion ring and the temperature compensation ring are separated into a plurality of subareas with the same number.
The corrosion ring and the temperature compensation ring are respectively formed by processing welded joints after welding. And respectively machining a base metal area corrosion ring, a base metal area temperature compensation ring, a heat affected area corrosion ring, a heat affected area temperature compensation ring, a welding line area corrosion ring and a welding line area temperature compensation ring in a convex shape for a base metal area, a temperature compensation area and a welding line area of the welding joint. The axial separation identification of local corrosion of the welding joint can be realized by respectively processing annular measuring elements in the three welding areas.
When adopting above-mentioned technical scheme, the utility model discloses can also adopt or make up and adopt following technical scheme:
as an optimal technical solution of the utility model: and a stirring device is arranged in the solution environment container and used for creating a flowing medium environment.
As an optimal technical solution of the utility model: the stirring device comprises a stirring paddle and a stirring connecting rod connected with the stirring paddle, and the stirring connecting rod is connected with the stirring controller. And converting the rotating speed of the stirrer according to the medium flow in the pipeline to create a flowing medium environment.
As an optimal technical solution of the utility model: the device for testing the local corrosion of the welding joint of the submarine pipeline further comprises a fixed frame, and the fixed frame is used for propping against the upper end of the upper container and propping against the lower end of the lower container.
As a preferred technical solution of the utility model: the fixing frame comprises an upper end cover, a lower end cover, a connecting screw rod and a connecting screw cap, wherein the connecting screw rod and the connecting screw cap are used for connecting the upper end cover and the lower end cover, and the upper end cover, the lower end cover, the connecting screw rod and the connecting screw cap form fastening of the solution environment container.
As an optimal technical solution of the utility model: the connection parts of the upper container, the corrosion ring, the connecting ring, the temperature compensation ring and the lower container are sealed by O-rings.
As an optimal technical solution of the utility model: the upper end and the lower end of the connecting ring are provided with step parts, the lower end face of the corrosion ring and the upper end face of the temperature compensation ring are provided with concave surfaces, and the concave surfaces of the lower end face of the corrosion ring and the upper end face of the temperature compensation ring respectively accommodate the step parts of the connecting ring to form pairwise sealing.
As a preferred technical solution of the utility model: the temperature compensation ring is subjected to insulation anticorrosion treatment by chromium oxide or aluminum oxide plasma spraying so as to prevent the temperature compensation ring from being corroded by corrosive media. The inner surface of the corrosion ring is exposed and is used for contacting a corrosion medium to monitor corrosion, and other surfaces are subjected to chromium oxide or aluminum oxide plasma spraying. The corrosion ring and the temperature compensation ring are connected through a connecting ring, and chromium oxide or aluminum oxide plasma spraying is carried out on all the surfaces of the connecting ring.
As an optimal technical solution of the utility model: the upper container and the lower container are insulated and isolated through a chromium oxide or aluminum oxide insulating anticorrosive coating.
The utility model provides a submarine pipeline welded joint local corrosion testing arrangement provides the local corrosion degree of depth differentiation discernment that realizes axial and circumference to welded joint in the space, can monitor welded joint's local corrosion degree of depth under the current flow environment in real time, and analysis welding process is not enough in annular welding process, guides welding process's optimization and prediction corrosion development trend. Utilize the utility model provides a device can master submarine pipeline welded joint's corrosion resisting property and aassessment local corrosion characteristic, and the technological optimization and the prediction of the life-span of being on active service to submarine pipeline welded joint have the guiding meaning.
Drawings
Fig. 1 is a schematic diagram of a local corrosion testing device for a welded joint of a submarine pipeline provided by the present invention;
FIG. 2 is an internal view of the local corrosion testing device for the welded joint of the submarine pipeline provided by the present invention;
FIG. 3 is a schematic representation of a localized corrosion measurement element process source;
FIG. 4 is a schematic view of a partial corrosion measuring cell;
FIG. 5 is a schematic representation of the connection of the corrosion ring, the connection ring and the temperature compensation ring;
FIG. 6 is a schematic diagram of a localized corrosion measurement circuit;
FIG. 7 is a graph of corrosion depth of a weld joint in a solution environment;
FIG. 8 is a graph of discrete intervals of corrosion rates of a weld joint in a solution environment;
FIG. 9 is a graph of the corrosion rate dispersion coefficient of a weld joint in a certain solution environment;
in the figure: 1-corrosion ring; 2-temperature compensation ring; 3-connecting rings; 4-upper container; 5-lower container; 6-upper end cover; 7-lower end cap; 8-stirring connecting rod; 9-stirring blades; 10-fastening a screw; 11-a fastening nut; 12-a signal monitoring electrode probe; 13-O-ring.
Detailed Description
The present invention is further described in detail below with reference to the drawings so that those skilled in the art can implement the invention with reference to the description.
It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials, if not otherwise specified, are commercially available; in the description of the present invention, the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings only for convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
As shown in fig. 1-2, fig. 1 is a schematic diagram of a local corrosion testing device for a welded joint of a submarine pipeline provided by the present invention; FIG. 2 is an internal view of the local corrosion testing device for the welded joint of the submarine pipeline provided by the present invention; the testing device in the figure comprises a corrosion ring 1, a temperature compensation ring 2, a connecting ring 3, an upper container 4, a lower container 5, an upper end cover 6, a lower end cover 7, a stirring connecting rod 8, a stirring blade 9, a fastening screw rod 10 and a fastening nut 11.
As shown in FIG. 3, the corrosion ring 1 and temperature compensation ring 2 are machined from an eight inch subsea pipe weld joint, in this example the pipe parent metal is X65 line steel and the weld material is E7010 electrode. Each group of corrosion rings 1 and temperature compensation rings 2 are cut from a base metal ring, or a temperature compensation ring, or a welding line ring under the same welding process. In order to achieve a fixed connection of the corrosion ring and the temperature compensation ring, the ring assembly is machined in the cross section shown in fig. 4, and the connection is made in the form shown in fig. 5, wherein the radial movement of the measuring element is limited by the "convex" form, wherein the shoulder acts as a structural strength support for the measuring element and the wall of the platform is sealed with the connection ring 3 by the O-ring 13.
The connecting ring 3, the upper container 4 and the lower container 5 do not participate in corrosion reaction, and the materials are selected to meet the connection strength, in this embodiment, X65 pipeline steel is selected. Wherein, the temperature compensation ring is subjected to insulation and corrosion prevention treatment by alumina plasma spraying to prevent the temperature compensation ring from being corroded by corrosive media. The inner surface of the corrosion ring is exposed and is used for contacting a corrosion medium to monitor corrosion, and the other surfaces are subjected to aluminum oxide plasma spraying. And the adjacent upper container, the corrosion ring, the connecting ring, the temperature compensation ring and the lower container are sealed at the end face by adopting an O-shaped ring made of nitrile rubber. And all measuring elements and connecting elements are fastened by adopting a high-strength fastening screw rod and a fastening nut through an upper end cover and a lower end cover which are made of polytetrafluoroethylene materials.
After the welding joint local corrosion testing device is assembled, corrosive solution is added into the welding joint local corrosion testing device, and the solution is selected according to transport media in an actual pipeline so as to simulate the corrosion process of the welding joint of the submarine pipeline. In order to create a flowing environment, the stirring blades are immersed into the solution through the stainless steel stirring connecting rod, and the rotating speed is controlled through an external stirrer, so that different wall surface flow rates are realized.
Specifically, the local corrosion test device for the welding joint of the submarine pipeline performs a local corrosion test in the following way:
the local corrosion test of the welding joint is based on a six-partition micro-resistance measurement principle, as shown in fig. 6, a corrosion ring and a temperature compensation ring in the same welding area are equally divided into 6 partitions, and 12 signal monitoring electrode probes 12 are uniformly distributed on the outer side of the ring. Three external exciting currents are sequentially led into the corrosion ring and the temperature compensation ring which are connected in series through the constant current source, and the voltage data of each subarea is measured through the high-precision voltmeter, so that the non-uniform corrosion monitoring of six circumferential subareas in each welding area is realized. Wherein, the corrosion depth of each subarea of the welding area can be calculated according to the following formula:
in the formula, k i0 Representing the initial resistance ratio, k, between the same sections of the corrosion ring and the temperature compensation ring i Representing the resistance ratio between the same sections of the corrosion ring and the temperature compensation ring after corrosion occurs, and a, b, c and h are the cross-sectional geometric dimensions of the corrosion ring or the temperature compensation ring.
The application effect and the evaluation process of the welding joint local corrosion testing device are described through the concrete implementation process. According to the six-subarea micro-resistance measurement principle, a local corrosion behavior test of the welded joint in a flowing sodium chloride solution with 3.5 percent of mass fraction is designed, wherein the pH value of the solution is 4, and the wall surface flow velocity is 0.3m/s. The measurement result of the local corrosion depth of the circumferential six-subarea of the parent metal area after 8-day test is shown in fig. 7, the corrosion depth of three subareas (subarea two, subarea three and subarea four) positioned at the lower half part of the pipeline is greater than that of the three subareas at the upper half part of the pipeline, and the corrosion depth of the subarea three is the largest. For the corrosion ring of the base metal area, the corrosion depth of the third area is the maximum; the corrosion degree of the second partition and the fourth partition is similar; the corrosion degree of the first subarea and the fifth subarea is similar, and the corrosion depth is the minimum in all the immersed subareas. The final etching depths of the first to sixth subareas on the base material area etching ring are respectively 18.4 μm,24.8 μm,28.5 μm,22.9 μm,18.8 μm and 21.9 μm by the end of the test.
Based on the corrosion depth result of each subarea, respectively calculating the average value of the corrosion rates of the six subareas in the homogeneous area, wherein the calculation formula is as follows:
in the formula, v i Is the corrosion rate of a certain subarea in unit time, deltax is the corrosion depth change value of a certain subarea in unit time, deltat is the unit time length,
is the average of the corrosion rates, v, of six zones in a homogeneous region i Corrosion rate, σ, for any zone v Standard deviation of six zonal corrosion rates;
thus, the discrete intervals of corrosion rates for six partitions within a homogeneous region can be calculated by the following equation:
in the formula, v upper Upper limit of discrete interval of corrosion rate, v lower Is the lower limit of the discrete interval of the corrosion rate; the calculation formula of the coefficient of dispersion (CV) is as follows:
FIG. 8 is a graph showing a discrete interval of corrosion rates in the base material region of a weld joint, and the larger the discrete interval, the more uneven the corrosion in the circumferential direction in the base material region is. When the pH value of the medium is 4, the discrete interval of the parent metal area is increased along with the experiment, which shows that the difference of circumferential corrosion is increased, if the discrete interval is too large, the wall thickness loss of the area is possibly caused to be serious, the local stress is enhanced, and the damage of the pipeline structure is accelerated. If the observation of the galvanic corrosion among the regions of the welding joint is further combined, the inhomogeneous monitoring of the galvanic corrosion among the axially heterogeneous regions and the local corrosion in the circumferentially homogeneous region of the welding joint can be evaluated, and the region or the subarea where the local corrosion is concentrated in the welding joint is judged.
FIG. 9 is a graph of corrosion rate dispersion coefficients for a base material region of a weld joint. As can be seen from fig. 8, although the discrete region of the base material region increases with time, the coefficient of variation is substantially stabilized at 0.15 to 0.20, indicating that the nonuniformity of the internal corrosion is not strong and the probability of occurrence of local stress concentration is small although the wall thickness of the base material region decreases, and the overall structural strength of the pipe needs to be focused.
Claims (7)
1. The utility model provides a submarine pipeline welded joint local corrosion testing arrangement which characterized in that: the local corrosion testing device for the welding joint of the submarine pipeline comprises an upper container, a lower container, a corrosion ring, a connecting ring and a temperature compensation ring, wherein the corrosion ring is positioned between the upper container and the lower container;
the upper container, the corrosion ring, the connecting ring, the temperature compensation ring and the lower container are sequentially connected to form a solution environment container;
the corrosion ring and the temperature compensation ring are respectively and uniformly provided with a plurality of signal monitoring electrode probes, and the corrosion ring and the temperature compensation ring are separated into a plurality of subareas with the same number.
2. The subsea pipeline welded joint localized corrosion test device of claim 1, wherein: and a stirring device is arranged in the solution environment container and used for creating a flowing medium environment.
3. The subsea pipeline welded joint localized corrosion test device of claim 2, wherein: the stirring device comprises a stirring paddle and a stirring connecting rod connected with the stirring paddle, and the stirring connecting rod is connected with the stirring controller.
4. The subsea pipeline welded joint localized corrosion test device of claim 1, wherein: the device for testing the local corrosion of the welding joint of the submarine pipeline further comprises a fixed frame, and the fixed frame is used for propping against the upper end of the upper container and propping against the lower end of the lower container.
5. The subsea pipeline welded joint localized corrosion test device of claim 4, wherein: the fixing frame comprises an upper end cover, a lower end cover, a connecting screw rod and a connecting screw cap, wherein the connecting screw rod and the connecting screw cap are used for connecting the upper end cover and the lower end cover, and the upper end cover, the lower end cover, the connecting screw rod and the connecting screw cap form fastening of the solution environment container.
6. The subsea pipeline welded joint localized corrosion test device of claim 1, wherein: the connection positions of the upper container, the corrosion ring, the connecting ring, the temperature compensation ring and the lower container are sealed by O-rings.
7. The subsea pipeline welded joint localized corrosion test device of claim 1, wherein: the upper end and the lower end of the connecting ring are provided with step parts, the lower end face of the corrosion ring and the upper end face of the temperature compensation ring are provided with concave surfaces, and the concave surfaces of the lower end face of the corrosion ring and the upper end face of the temperature compensation ring respectively accommodate the step parts of the connecting ring to form pairwise sealing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221507106.7U CN218239756U (en) | 2022-06-15 | 2022-06-15 | Submarine pipeline welded joint local corrosion testing arrangement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221507106.7U CN218239756U (en) | 2022-06-15 | 2022-06-15 | Submarine pipeline welded joint local corrosion testing arrangement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218239756U true CN218239756U (en) | 2023-01-06 |
Family
ID=84671687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221507106.7U Active CN218239756U (en) | 2022-06-15 | 2022-06-15 | Submarine pipeline welded joint local corrosion testing arrangement |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218239756U (en) |
-
2022
- 2022-06-15 CN CN202221507106.7U patent/CN218239756U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Vanaei et al. | A review on pipeline corrosion, in-line inspection (ILI), and corrosion growth rate models | |
| CN101261213B (en) | Electrochemical test probe for erosion critical characteristic on-line monitoring | |
| Marcassoli et al. | Modeling of potential distribution of subsea pipeline under cathodic protection by finite element method | |
| US20150060273A1 (en) | Corrosion Resistance Evaluators | |
| CN218239756U (en) | Submarine pipeline welded joint local corrosion testing arrangement | |
| Chen et al. | Research on corrosion protection of buried steel pipeline | |
| CN115096798A (en) | Local corrosion testing device for submarine pipeline welding joint and local corrosion degree determining method | |
| JP2014051713A (en) | Electrolytic protection monitoring method and apparatus of metal structure | |
| Sanni et al. | Introduction: Corrosion basics and corrosion testing | |
| Stepovaja et al. | Methods for precautionary management for environmental safety at energy facilities | |
| CN209069805U (en) | A kind of corrosion on-line measurement device of boiler tube Process of Chemical Cleaning | |
| Bourenane et al. | Monitoring and inspection to combat corrosion of pipeline lines in an oil field | |
| Budden | Analysis of the Type IV creep failures of three welded ferritic pressure vessels | |
| CN105953018A (en) | Rubber-lining equipment corrosion online monitoring and control system | |
| CN105784803A (en) | Clamp used for measuring stainless steel pipe outer surface critical point corrosion temperature | |
| Kou et al. | Galvanic corrosion based on wire beam electrode technique: progress and prospects | |
| CN109238955A (en) | A kind of corrosion on-line measurement device and method of boiler tube Process of Chemical Cleaning | |
| CN115096805B (en) | High-flux detection method for corrosion depth of stray current of welding line ring of buried gas pipe | |
| Rachmawati et al. | Comparison of corrosion rate on mild steel welded joints using acid and alkaline solutions | |
| Lu | Discussions of general methods for measurement and monitoring of corrosion in the oil & gas industry | |
| Bergman et al. | Evaluation of the Real-Time Active Pipeline Integrity Dectection System for Corrosion Quantification | |
| Kadhafi | Subsea Pipeline Corrosion: A Review of Detection Methods, Mechanisms and Prevention Strategies | |
| Elechi et al. | Predictive Model for Corrosion Control in Crude Oil and Gas Production Facilities | |
| CN115389403A (en) | Detection device and detection method for corrosion rate of pipeline | |
| KR20230123270A (en) | The detecting apparatus to determine defects of inside-coated pipes |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |