CN115343211A - Method for detecting corrosion sensitivity of welding joint - Google Patents
Method for detecting corrosion sensitivity of welding joint Download PDFInfo
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- 238000005260 corrosion Methods 0.000 title claims abstract description 200
- 238000003466 welding Methods 0.000 title claims abstract description 98
- 230000035945 sensitivity Effects 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 32
- XOFYZVNMUHMLCC-ZPOLXVRWSA-N prednisone Chemical compound O=C1C=C[C@]2(C)[C@H]3C(=O)C[C@](C)([C@@](CC4)(O)C(=O)CO)[C@@H]4[C@@H]3CCC2=C1 XOFYZVNMUHMLCC-ZPOLXVRWSA-N 0.000 claims abstract description 34
- 239000000463 material Substances 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims abstract description 29
- 229910052751 metal Inorganic materials 0.000 claims abstract description 29
- 238000012360 testing method Methods 0.000 claims abstract description 26
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- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 11
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- 230000008569 process Effects 0.000 abstract description 7
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- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/02—Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/006—Investigating resistance of materials to the weather, to corrosion, or to light of metals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
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Abstract
The application provides a method for detecting corrosion sensitivity of a welding joint, which comprises the following steps: s10: providing a welded joint section sample, wherein the sample comprises a weld zone, a heat affected zone and a parent metal zone; s20: carrying out erosion treatment on the sample, determining a weld joint area, a heat affected area and a base metal area, detecting the surface potential of the eroded sample and calculating the maximum potential difference delta E of the surface of the sample; s30: carrying out simulated corrosion treatment on the sample, carrying out polarization curve test on a welding seam area, a heat affected zone and a base metal area of the sample after corrosion, and calculating the current density I of the anode metal a (ii) a S40: by analysing Δ E and I a The corrosion sensitivity of the welded joint was evaluated. Can better select welding materials and formulate a welding process according to the corrosion sensitivity of the welding joint, provide guidance for adopting corresponding protective measures to the welding part and ensure the engineering qualityAnd the quantity and the cost are saved.
Description
Technical Field
The application relates to the technical field of electrochemical corrosion, in particular to a method for detecting corrosion sensitivity of a welding joint.
Background
The welded joint is a weak area in the metal corrosion process and is common at the metal connecting part. The reason for the higher corrosion sensitivity of the welded joint is mainly that the difference exists between the chemical components and the microstructure of the welding seam material and the base material, and further the difference also exists in the surface potential in the atmospheric environment or other corrosive media to form a galvanic couple, so that the electrochemical corrosion behavior occurs.
At present, for samples after service at home and abroad, the corrosion condition of a welding joint is judged according to the corrosion rate of a material or the macro-micro corrosion morphology; the tissues similar to the welded joint are obtained by adopting a thermal simulation method for the original material which is not in service, and then relevant corrosion resistance research is carried out.
However, the above-described research methods for weld joints before and after service do not allow the corrosion sensitivity of the weld joint to be evaluated intuitively and conveniently by nature.
Disclosure of Invention
The application provides a method for detecting corrosion sensitivity of a welding joint, which can more conveniently and accurately judge and analyze the corrosion sensitivity of the welding joint.
The application provides a method for detecting corrosion sensitivity of a welding joint, which comprises the following steps:
s10: providing a welded joint section sample, wherein the sample comprises a weld zone, a heat affected zone and a parent metal zone;
s20: carrying out erosion treatment on the sample, determining a weld joint area, a heat affected area and a base metal area, detecting the surface potential of the eroded sample and calculating the maximum potential difference delta E of the surface of the sample;
s30: carrying out simulated corrosion treatment on the sample, carrying out polarization curve test on a welding seam area, a heat affected zone and a base metal area of the sample after corrosion, and calculating the current density I of the anode metal a ；
S40: by analysis of Δ E and I a The corrosion sensitivity of the welded joint was evaluated.
In the technical scheme of the application, the potential difference delta E and the current density I of the anode metal of the base metal area and the welding seam area in the sample of the cross section of the welding joint are respectively detected a And by analysis of Δ E and I a The value of (a) determines the corrosion sensitivity of the welded joint. Compared with the prior art, the technical scheme provided by the application can detect the welding joint before service, and can more conveniently and accurately judge the corrosion sensitivity of the welding joint, so that the welding material can be better selected and the welding process can be formulated according to the result, and the guidance is provided for taking corresponding protective measures to the welding part, thereby ensuring the engineering quality and saving the cost.
In some embodiments of the present application, the coupons are flat in top and bottom cross-section, with any cross-sectional surface roughness less than or equal to 5000# sic sandpaper roughness.
In some embodiments of the present application, the erosion processing the sample and determining the weld zone, the heat-affected zone, and the parent material zone in step S20 specifically includes:
polishing the sample, selecting a proper etchant and an erosion method for processing the polished sample, and observing and determining a weld joint area, a heat affected area and a base material area of the eroded sample by using a metallographic microscope.
In some embodiments of the present application, the detecting the surface potential of the eroded sample in step S20 specifically includes:
the surface potential of the weld zone, the heat affected zone and the base metal zone of the eroded sample was measured by a Scanning Kelvin Probe (SKP) technique.
In some embodiments of the present application, the performing of the simulated corrosion treatment on the sample in step S30 specifically includes:
and selecting reasonable simulated corrosion conditions according to the working environment of the welding joint, and carrying out simulated corrosion treatment on the sample.
In some embodiments of the present application, the performing the polarization curve test on the weld zone, the heat affected zone, and the parent material zone of the corroded sample in step S30 specifically includes:
and testing the open-circuit potential and drawing a polarization curve for the weld joint area, the heat affected area and the parent metal area of the corroded sample by using an electrochemical test pen of a three-electrode system.
In some embodiments of the present application, the step S30 further includes:
and (4) carrying out rust removal treatment on the sample subjected to the polarization curve test, and then measuring the depth and width of an etch pit of the sample subjected to rust removal.
In some embodiments of the present application, the step S40 specifically includes:
determining the corrosion rating of the welding joint by analyzing the value of delta E and combining the corrosion rating standard of the welding joint;
by analysis of I a Determining the corrosion rate rating of the welding joint by combining the corrosion rate rating standard of the welding joint;
the corrosion rating and the corrosion rate rating of the weld joint are combined to evaluate the corrosion susceptibility of the weld joint.
In some embodiments of the present application, the weld joint corrosion rating criteria is:
if delta E is less than or equal to 50mV, the corrosion rating of the welding joint is low galvanic corrosion sensitivity;
if delta E is more than 50 and less than or equal to 250mV, the corrosion rating of the welding joint is general galvanic corrosion sensitivity;
if delta E is more than 250mV, the corrosion rating of the welding joint is high galvanic corrosion sensitivity;
the rating standard of the corrosion rate of the welding joint is as follows:
if I a ≤0.3μA/cm 2 The corrosion rate of the welded joint is rated as the slower galvanic corrosion rate;
if 0.3 < I a ≤1.0μA/cm 2 The corrosion rate of the welded joint is rated as the general galvanic corrosion rate;
if I a ＞1.0μA/cm 2 The weld joint corrosion rate is rated as the faster galvanic corrosion rate.
In some embodiments of the present application, the working distance of the welded joint to generate galvanic couple effect is determined by analyzing the depth and width of the corrosion pit of the sample after rust removal and the corrosion sensitivity of the welded joint.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
Fig. 1 is a schematic flow chart of the technical solution of the present application.
FIG. 2 is a diagram of the internal structure of an electrochemical test pen according to some embodiments of the present application.
With the above figures, there are shown specific embodiments of the present application, which will be described in more detail below. These drawings and written description are not intended to limit the scope of the inventive concepts in any manner, but rather to illustrate the inventive concepts to those skilled in the art by reference to specific embodiments.
Detailed Description
The examples or embodiments are described in a progressive arrangement throughout this specification, each with emphasis on illustrating differences from the other examples.
In the description of the present specification, references to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
The steel serves as a framework of a modern engineering building, welding is inevitable, and a welding joint is a weak link in a metal corrosion process and severely limits the service life of the building, so that the corrosion sensitivity of the welding joint needs to be evaluated. In the prior art, the corrosion condition of the welding joint is judged according to the corrosion rate of the material or the macro-micro corrosion morphology of the sample after service, or the tissues similar to the welding joint are obtained by adopting a thermal simulation method for the original material which is not in service for relevant research, although the former can judge the corrosion condition of the welding joint more accurately, the detection of the sample after service is obviously of little significance, and the waste of the material is caused; although the latter can save the test cost, the sample prepared by the thermal simulation method obviously cannot accurately represent the welding joint, and has larger deviation.
The inventor wants to provide a method for intuitively and conveniently evaluating the corrosion sensitivity of a welded joint by nature, and the inventor notices that the reason for causing the higher corrosion sensitivity of the welded joint is that the difference of chemical components and microstructures exists between a welding seam material and a base material, and further, in an atmospheric environment or other corrosive mediums, the difference of surface potentials also exists, a couple is formed, and electrochemical corrosion behavior occurs. The inventors therefore thought to evaluate the corrosion sensitivity of a welded joint by measuring its electrochemical parameters.
The application provides a method for detecting corrosion sensitivity of a welding joint, which comprises the following steps as shown in figure 1:
s10: providing a welded joint section sample, wherein the sample comprises a welding seam area, a heat affected area and a base material area;
s20: carrying out erosion treatment on the sample, determining a weld joint area, a heat affected area and a base metal area, detecting the surface potential of the eroded sample and calculating the maximum potential difference delta E of the surface of the sample;
s30: carrying out simulated corrosion treatment on the sample, and carrying out polarization curve test on a welding seam area, a heat affected area and a parent metal area of the sample after corrosionAnd calculating the current density I of the anode metal a ；
S40: by analysis of Δ E and I a The corrosion sensitivity of the welded joint was evaluated.
In the technical scheme of the application, the potential difference delta E and the current density I of the anode metal of the base metal area and the welding seam area in the sample of the cross section of the welding joint are respectively detected a And by analysis of Δ E and I a The value of (a) determines the corrosion sensitivity of the welded joint. Compared with the prior art, the technical scheme provided by the application can detect the welding joint before service, and can more conveniently and accurately judge the corrosion sensitivity of the welding joint, so that the welding material can be better selected and the welding process can be formulated according to the result, and the guidance is provided for taking corresponding protective measures to the welding part, thereby ensuring the engineering quality and saving the cost.
In the technical scheme of the application, the welded joint section sample provided in the step S10 includes a weld joint area, a heat affected area and a base metal area, and this is because a metal material is subjected to phase change in the processes of high-temperature fusion welding and post-weld temperature reduction, which causes a difference between a metal component and a metallographic microstructure on a section of the welded joint in different areas, thereby causing a difference in electrochemical potential between the different areas, forming a corrosion galvanic cell, and preferentially corroding an anode area with a lower point position. Therefore, in order to more accurately detect the corrosion sensitivity of the welded joint, it is necessary to detect the electrochemical parameters of different regions of the welded joint, and the provided test sample must include a weld zone, a heat affected zone, and a base material zone.
In some embodiments of the present application, the coupons are flat in top and bottom cross-section, with any cross-sectional surface roughness less than or equal to 5000# sic sandpaper roughness.
In some embodiments, the smooth upper and lower sections of the sample are favorable for facilitating the detection of the sample, the precision and the accuracy of a detection result can be improved, and only one side of the sample is tested, so that only any section roughness of SiC sand paper with the roughness being less than or equal to 5000#, and the sample preparation time is reduced.
In the technical scheme of the application, in the step S20, the surface stains of the sample are removed by eroding the sample, so that the detection is more accurate, the weld joint area, the heat affected zone and the base material area of the sample are determined to determine the test range of the subsequent sample, the surface potential of the eroded sample is measured, and the maximum potential difference Δ E of the sample surface is calculated, wherein the larger Δ E is, the more susceptible the welded joint is to galvanic corrosion, and the higher corrosion sensitivity is, so that Δ E can be used for evaluating the corrosion sensitivity of the welded joint.
In some embodiments of the present application, the erosion processing the sample and determining the weld zone, the heat-affected zone, and the parent material zone in step S20 specifically includes:
polishing the sample, selecting a proper etchant and an erosion method for processing the polished sample, and observing and determining a weld joint area, a heat affected area and a base material area of the eroded sample by using a metallographic microscope.
In some of the above embodiments, in order to detect the electrochemical parameters of different areas of the welded joint subsequently, the positions of the weld zone, the heat affected zone and the base material zone on the sample need to be confirmed, so that the sample needs to be polished and then treated by selecting a proper etchant and etching method, and the sample after etching is observed and confirmed by using a metallographic microscope, wherein the etchant and etching method are different due to the different materials of the sample, and the proper etchant and etching method can be selected according to the material of the sample by referring to standard "GB/T26956-2011 etchant for macroscopic and microscopic inspection of metal material weld joint destructive test".
In some embodiments of the present application, the detecting the surface potential of the eroded sample in step S20 specifically includes:
and measuring the surface potential of the weld joint area, the heat affected area and the base metal area of the corroded sample by a scanning Kelvin probe technology.
In some embodiments, the SKP technology is used to measure the surface potentials of the weld zone, the heat affected zone and the base material zone of the eroded sample, and because the SKP technology can detect the potential distribution of the metal surface without damage under a non-contact condition, give the micro-zone change information of the sample, is very sensitive to the micro-change of the interface state, can detect the corrosion state at the initial stage of corrosion occurrence, has very high sensitivity and resolution, and can accurately measure the potentials of the weld zone, the heat affected zone and the base material zone of the sample.
In the technical scheme of the application, step S30 is to carry out simulated corrosion treatment on the sample, carry out polarization curve test on a welding seam area, a heat affected zone and a base metal area of the sample after corrosion and calculate the current density I of the anode metal a (ii) a And (3) corroding the sample for a period of time, and detecting the intensity of the galvanic couple effect at the moment after the surface of the sample is in a stable state to judge the corrosion rate of the welding joint. Wherein, in the polarization curve test, the side with relatively low potential in the sample is anode metal, and the current density I of the anode metal a The larger the value of (A) is, the larger the corrosion rate of the welded joint is, and this is an index for evaluating the corrosion sensitivity of the welded joint.
In some embodiments of the present application, the performing of the simulated corrosion treatment on the sample in step S30 specifically includes:
and selecting reasonable simulated corrosion conditions according to the working environment of the welding joint, and carrying out simulated corrosion treatment on the sample.
In some embodiments, reasonable simulated corrosion conditions are selected according to the working environment of the welding joint, the sample is subjected to simulated corrosion treatment, and the corrosion condition of the welding joint can be detected more intuitively through the simulated corrosion conditions. Different simulated corrosion conditions can be selected according to different working environments of materials, so that the application range and accuracy of the testing method are expanded; meanwhile, if the long-term environment needs to be restored in a short time, corresponding simulated accelerated corrosion conditions can be selected, and the detection efficiency can be improved.
In some embodiments of the present application, the performing the polarization curve test on the weld zone, the heat affected zone, and the parent material zone of the corroded sample in step S30 specifically includes:
and testing the open-circuit potential and drawing a polarization curve for the weld joint area, the heat affected area and the parent metal area of the corroded sample by using an electrochemical test pen of a three-electrode system.
In some embodiments, the electrochemical test pen of the three-electrode system is used to draw polarization curves for the open-circuit potentials of the weld joint area, the heat affected area and the parent metal area of the corroded sample, the internal structure diagram of the electrochemical test pen is shown in fig. 2, the electrochemical test pen of the three-electrode system is provided with electrodes and electrolyte, is convenient to carry and use, can be in contact connection with objects to be tested in any shape and size, can quickly measure the local corrosion characteristics of the sample, is particularly suitable for testing the open-circuit potentials of the weld joint area, the heat affected area and the parent metal area of the sample in the technical scheme, and can obviously improve the detection efficiency.
In some embodiments of the present application, the step S30 further includes:
and (4) carrying out rust removal treatment on the sample subjected to the polarization curve test, and then measuring the depth and width of an etch pit of the sample subjected to rust removal.
In some embodiments, a proper solution and a proper method can be selected according to GB/T16545-1996 removing corrosion products on corrosion samples of metals and alloys to carry out rust removal treatment on the surfaces of the samples, and the corrosion conditions of the surfaces of the samples can be more visually observed by measuring the depth and the width of an etch pit of the samples, so that a basis is provided for determining the action distance of the galvanic effect.
Alternatively, the depth and width of the etch pits at different distances on both sides of the weld can be observed and measured by a 3D confocal laser microscope.
In some embodiments, the 3D confocal laser microscope has the characteristics of high definition, high resolution and high sensitivity, and can accurately measure the depth and width of the etching pits of the sample.
In some embodiments of the present application, the step S40 specifically includes:
determining the corrosion rating of the welding joint by analyzing the value of delta E and combining the corrosion rating standard of the welding joint;
by analysis of I a Determining the corrosion rate rating of the welding joint by combining the corrosion rate rating standard of the welding joint;
the corrosion rating and the corrosion rate rating of the weld joint are combined to evaluate the corrosion susceptibility of the weld joint.
In some of the above embodiments, the greater the value of Δ E, the corresponding weld jointThe more easily corrosion occurs, so that a corresponding corrosion rating standard of the welding joint can be set, and the corrosion rating of the welding joint is determined according to the value of delta E; i is a The greater the value of (A), the higher the rate at which the corresponding weld joint corrodes, so the corresponding weld joint corrosion rating standard is set, according to I a Determining a weld joint corrosion rate rating; the corrosion sensitivity of the welding joint is evaluated by integrating the corrosion rating and the corrosion rate rating of the welding joint, the sensitivity of the welding joint is judged from two aspects, the result is more accurate, the reliability is higher, reasonable welding materials are convenient to select, a welding process is convenient to formulate, guidance is provided for taking corresponding protective measures for the welding part, the engineering quality is guaranteed, and the cost is saved.
In some embodiments of the present application, the weld joint corrosion rating criteria is:
if delta E is less than or equal to 50mV, the corrosion rating of the welded joint is low galvanic corrosion sensitivity;
if delta E is more than 50 and less than or equal to 250mV, the corrosion rating of the welding joint is general galvanic corrosion sensitivity;
if delta E is more than 250mV, the corrosion rating of the welding joint is high galvanic corrosion sensitivity;
the rating standard of the corrosion rate of the welding joint is as follows:
if I a ≤0.3μA/cm 2 The corrosion rate of the welded joint is rated as the slower galvanic corrosion rate;
if 0.3 < I a ≤1.0μA/cm 2 The corrosion rate of the welded joint is rated as the general galvanic corrosion rate;
if I a ＞1.0μA/cm 2 The weld joint corrosion rate is rated as the faster galvanic corrosion rate.
In some embodiments, when Δ E is less than or equal to 50mV, the galvanic effect generated between different areas of the welded joint is very weak and can be ignored, galvanic corrosion of the welded joint is not easy to occur, and the corrosion rating of the welded joint is low galvanic corrosion sensitivity; when delta E is more than 50 and less than or equal to 250mV, the galvanic couple effect generated between different areas of the welding joint cannot be ignored, and the galvanic couple effect is gradually enhanced along with the increase of the delta E value, and the corrosion rating of the welding joint is general galvanic couple corrosion sensitivity; when the delta E is more than 250mV, the galvanic couple effect generated between different areas of the welding joint is strong, galvanic couple corrosion is easy to occur, and the corrosion rating of the welding joint is high galvanic couple corrosion sensitivity, namely the rating standard for evaluating the corrosion of the welding joint according to the delta E.
On the other hand, when I a ≤0.3μA/cm 2 When the anode metal in the welding joint is corroded, the corrosion rate is very low, namely the corrosion rate is very low and can be ignored, and at the moment, the corrosion rate of the welding joint is rated as a slower galvanic corrosion rate; when 0.3 < I a ≤1.0μA/cm 2 The rate of corrosion of the anode metal in the welded joint is not negligible and follows I a The numerical value is increased, the corrosion speed is higher, and the corrosion rate of the welding joint is rated as the general galvanic corrosion rate; when I is a ＞1.0μA/cm 2 When the anode metal in the welded joint is corroded at a high rate, namely the anode metal is corroded quickly, the corrosion rate of the welded joint is rated as a faster galvanic corrosion rate, namely according to I a A rating scale for corrosion rate of the weld joint was evaluated.
In some embodiments of the present application, integrating the weld joint corrosion rating and the corrosion rate rating to evaluate the corrosion susceptibility of the weld joint specifically includes:
the weld joint corrosion rating and corrosion rate rating are compared to the standards shown in table 1 to rate the corrosion susceptibility of the weld joint.
TABLE 1
In some of the above embodiments, since the nature of the easy corrosion of the welded joint is that a potential difference exists between different regions, which in turn constitutes a galvanic couple in the corrosion system, and the corrosion of the welded joint is accelerated, the corrosion sensitivity of the welded joint can be evaluated by the corrosion rating and the corrosion rate rating of the welded joint, and the corrosion sensitivity of the welded joint can be classified into three grades of corrosion resistance, general corrosion resistance and non-corrosion resistance.
The corrosion sensitivity rating of the welding joint is a corrosion grade, which shows that the galvanic effect is weak, the acceleration effect of the galvanic effect on corrosion can be ignored, the welding joint can be contacted when in use, and measures such as coating protection and the like are not needed; the corrosion sensitivity rating of the welding joint is general corrosion resistance rating, which indicates that the galvanic couple effect is strong, the influence of the galvanic couple effect on the accelerated corrosion of the test sample can not be ignored, when the test sample is in contact use, the test sample does not need to be treated in a short time, and a protective measure is required to be taken on the test sample, particularly the welding joint in a long time, so that the galvanic couple effect is weakened; the rating of the corrosion susceptibility of the welded joint to corrosion is not a corrosion resistance rating indicating a very strong galvanic effect, and long term use of such welded joints in critical components is not recommended, and the entire metal piece must be protected when applied to the remaining components.
In some embodiments of the application, the action distance of the welding joint for generating galvanic effect is determined by analyzing the depth and width of the corrosion pit of the sample after rust removal and the corrosion sensitivity of the welding joint.
In some embodiments, by analyzing the depth and width of the corrosion pit of the sample after rust removal and the corrosion sensitivity of the welding joint, the action distance of the welding joint generating galvanic couple effect to accelerate corrosion and the weak area of the welding seam can be determined by combining the corrosion sensitivity of the welding joint, whether protective measures need to be taken or not is determined according to the corrosion sensitivity, the range of the protective measures is determined according to the depth and width of the corrosion pit, and reasonable protective measures are comprehensively determined to be taken on the welding joint.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. A method for detecting corrosion sensitivity of a welded joint is characterized by comprising the following steps:
s10: providing a welded joint section sample, wherein the sample comprises a weld zone, a heat affected zone and a parent metal zone;
s20: carrying out erosion treatment on the sample, determining a weld joint area, a heat affected zone and a base metal area, detecting the surface potential of the eroded sample and calculating the maximum potential difference delta E of the sample surface;
s30: carrying out simulated corrosion treatment on the sample, carrying out polarization curve test on a welding seam area, a heat affected area and a base metal area of the sample after corrosion, and calculating the current density I of the anode metal a ；
S40: by analysis of Δ E and I a The corrosion sensitivity of the welded joint was evaluated.
2. The detection method according to claim 1, wherein the upper and lower sections of the test sample are flat, and the surface roughness of any section is less than or equal to 5000# SiC abrasive paper roughness.
3. The inspection method according to claim 1, wherein the step S20 of performing erosion processing on the sample and determining the weld zone, the heat-affected zone, and the base material zone specifically includes:
polishing the sample, selecting a proper etchant and an etching method for processing the polished sample, and observing and determining a weld joint area, a heat affected zone and a base material area of the etched sample by using a metallographic microscope.
4. The method according to claim 1, wherein the step S20 of detecting the surface potential of the eroded sample specifically includes:
and measuring the surface potential of the weld joint area, the heat affected area and the base metal area of the corroded sample by a scanning Kelvin probe technology.
5. The detection method according to claim 1, wherein the step S30 of performing the simulated corrosion treatment on the sample specifically includes:
and selecting reasonable simulated corrosion conditions according to the working environment of the welding joint, and carrying out simulated corrosion treatment on the sample.
6. The method according to claim 1, wherein the step S30 of performing polarization curve testing on the weld zone, the heat affected zone and the parent material zone of the corroded sample specifically comprises:
and testing the open-circuit potential and drawing a polarization curve for the weld joint area, the heat affected area and the parent metal area of the corroded sample by using an electrochemical test pen of a three-electrode system.
7. The detection method according to claim 1, wherein the step S30 further comprises:
and (4) carrying out rust removal treatment on the sample subjected to the polarization curve test, and then measuring the depth and width of an etch pit of the sample subjected to rust removal.
8. The detection method according to claim 1, wherein the step S40 specifically includes:
determining the corrosion rating of the welding joint by analyzing the value of delta E and combining the corrosion rating standard of the welding joint;
by analysis of I a Determining the corrosion rate rating of the welding joint by combining the corrosion rate rating standard of the welding joint;
the corrosion rating and the corrosion rate rating of the weld joint are combined to evaluate the corrosion susceptibility of the weld joint.
9. The inspection method of claim 8, wherein the weld joint corrosion rating criteria is:
if delta E is less than or equal to 50mV, the corrosion rating of the welded joint is low galvanic corrosion sensitivity;
if delta E is more than 50 and less than or equal to 250mV, the corrosion rating of the welding joint is general galvanic corrosion sensitivity;
if delta E is more than 250mV, the corrosion rating of the welding joint is high galvanic corrosion sensitivity;
the rating standard of the corrosion rate of the welding joint is as follows:
if I a ≤0.3μA/cm 2 The corrosion rate of the welded joint is rated as the slower galvanic corrosion rate;
if 0.3 < I a ≤1.0μA/cm 2 The corrosion rate of the welded joint is rated as the general galvanic corrosion rate;
if I a ＞1.0μA/cm 2 The weld joint corrosion rate is rated as the faster galvanic corrosion rate.
10. The detection method as claimed in claim 7, wherein the action distance of the welded joint generating galvanic effect is determined by analyzing the depth and width of the corrosion pit of the sample after rust removal and the corrosion sensitivity of the welded joint.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115931567A (en) * | 2023-01-03 | 2023-04-07 | 华东理工大学 | Stress corrosion sensitivity evaluation method and system for welding component |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115931567A (en) * | 2023-01-03 | 2023-04-07 | 华东理工大学 | Stress corrosion sensitivity evaluation method and system for welding component |
| CN115931567B (en) * | 2023-01-03 | 2023-10-27 | 华东理工大学 | Stress corrosion sensitivity assessment method and system for welded component |
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