CN116046537A - Stress corrosion micro-area in-situ test device and method - Google Patents

Abstract

The invention discloses a stress corrosion micro-area in-situ test device and method. The test device includes a stress ring test system, a micro-area scanning electrochemical system and a monitoring system; the micro-area scanning electrochemical system includes a driving arm, a probe Needle, auxiliary electrode, reference electrode, the probe is arranged in the cavity body of the stress ring test system and connected to the L-shaped sleeve, the driving arm is connected to the probe through the L-shaped sleeve, It is used to control the movement of the probe relative to the sample to be tested; the auxiliary electrode and the reference electrode pass through the upper cover so that one end is located in the cavity body; the monitoring system is used to monitor the loading of the stress ring The magnitude of the force and the fracture of the sample to be tested. The present invention can carry out micro-area scanning electrochemical in-situ test synchronously during stress corrosion stretching, so as to accurately study the micro-area stress corrosion of simulated materials in the process of loading in a corrosive environment, and to reveal the stress corrosion mechanism of metal materials in service environments provide technical support.

Description

An in-situ test device and method for stress corrosion micro-area

technical field

The invention relates to the technical field of material testing, in particular to a stress corrosion micro-area in-situ testing device and method.

Background technique

In actual production operations, metal materials will undergo stress corrosion cracking in the gas phase, liquid phase, and gas-liquid multi-phase corrosion environment containing corrosive gases. In severe cases, it may even cause casualties, which is extremely harmful. In order to understand the stress corrosion cracking performance of metal materials in experimental research, uniaxial tensile experiments are often used for stress corrosion testing. This method is relatively simple and easy to operate. However, this method cannot deeply study the corrosion mechanism of metal materials in the process of stress corrosion cracking, and cannot provide technical support for revealing the stress corrosion mechanism of metal materials in service environments.

Although some stress corrosion experimental devices are disclosed in the prior art, these experimental devices cannot observe the stress corrosion of the micro-area of the metal material, cannot perform in-situ real-time testing of the micro-area stress corrosion of the tensile sample, and cannot clearly understand the stress corrosion of the tensile sample. The microscopic changes of stress corrosion occur during the stretching process, and correspondingly, it is impossible to understand the stress corrosion mechanism of metal materials in service environment more clearly and deeply.

Contents of the invention

In view of the above problems, the present invention aims to provide a stress corrosion micro-area in-situ testing device and method.

Technical scheme of the present invention is as follows:

On the one hand, a stress corrosion micro-area in-situ test device is provided, including a stress ring test system, a micro-area scanning electrochemical system, and a monitoring system;

The stress ring test system includes a stress ring and a corrosive medium cavity, and the corrosive medium cavity includes a cavity body and an upper cover and a lower cover that are detachably connected to the upper and lower ends of the cavity body; the corrosive medium The cavity is provided with an air inlet and an air outlet that can be switched; the center of the upper cover and the lower cover are symmetrically provided with sample mounting holes, and when the sample to be tested is tested, the sample to be tested passes through the The sample installation holes are respectively connected to the inner top and inner bottom of the stress ring; the upper cover is provided with a through hole for installing an L-shaped sleeve, and the L-shaped sleeve is provided in the through hole, and the The shorter end of the L-shaped sleeve is located inside the cavity body;

The micro-area scanning electrochemical system includes a driving arm, a probe, an auxiliary electrode, and a reference electrode. The probe is arranged in the cavity body and connected to the L-shaped sleeve. The driving arm passes through the The L-shaped sleeve is connected with the probe, and is used to control the movement of the probe relative to the sample to be tested; the auxiliary electrode and the reference electrode respectively pass through the upper cover so that one end is located Inside the cavity body;

The monitoring system is used to monitor the loading force of the stress ring and the fracture condition of the sample to be tested.

Preferably, the upper and lower ends of the sample to be tested are respectively connected to the inner top and inner bottom of the stress ring through an upper sample holder and a lower sample holder.

As a preference, the inner top and inner bottom of the stress ring are provided with threaded columns protruding toward the center of the stress ring, and the upper and lower sample holders are respectively connected to the upper and lower sides of the stress ring. Threaded posts at both ends are threaded.

As a preference, one end of the upper sample holder and the lower sample holder connected to the sample to be tested is provided with a groove matching the sample to be tested, and the sample to be tested is inserted into the After the above groove, fix it with the bolt.

Preferably, the lower cover is provided with an accommodating chamber, and a heating device is provided in the accommodating chamber; the monitoring system further includes a temperature monitoring device, and the detection end of the temperature monitoring device extends through the upper cover into the inside the body of the cavity.

Preferably, the heating device is a heating rod; the temperature monitoring device is a thermometer.

Preferably, the monitoring system uses a position finder to monitor the loading force of the stress ring, and uses a fracture sensor to monitor the fracture of the sample to be tested.

Preferably, the air inlet is arranged at the lower part of the cavity body, and the air outlet is arranged on the upper cover.

Preferably, the upper cover and the lower cover are made of stainless steel, the cavity body is made of corrosion-resistant glass, and the L-shaped sleeve is made of polytetrafluoroethylene.

On the other hand, it also provides an in-situ test method for stress corrosion micro-area, which is tested by using the stress corrosion micro-area in-situ test device described in any one of the above.

The beneficial effects of the present invention are:

The present invention can introduce various corrosive media (gas phase, liquid phase or gas/liquid multi-phase) into the corrosive medium cavity, so as to simulate the practical application of metal materials under the coupling effect of different corrosive environments and different loading loads Working environment: when the present invention performs tensile testing on tensile samples under simulated corrosion working conditions, real-time and in-situ micro-area scanning tests can be performed on the fracture of the sample gauge section, and the whole test records the samples. The micro-area current evolution process when stress corrosion occurs provides a more reliable scientific basis for exploring the cause of stress corrosion cracking in materials and revealing the stress corrosion mechanism.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the structural representation of stress corrosion micro-area in-situ testing device of the present invention;

Fig. 2 is a schematic structural view of a corrosion medium chamber of the stress corrosion micro-area in-situ testing device of the present invention.

In the figure: 1-support long rod, 2-movable connecting rod, 3-emphasis nut, 4-stress ring, 5-base, 6-position measuring instrument, 7-fracture sensor, 8-upper sample fixture, 9-sample to be tested, 10-corrosion medium chamber, 10-1-upper cover, 10-2-cavity body, 10-3-lower cover, 11-lower sample holder, 12-reference electrode, 13-Temperature monitoring device, 14-Auxiliary electrode, 15-Drive arm, 16-Probe, 17-Accommodating cavity, 18-Through hole, 19-Connecting probe wire, 20-L-shaped sleeve, 21-Inlet , 22-gas outlet.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the case of no conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. The disclosure of the present invention uses "comprises" or "comprises" and other similar words to mean that the elements or objects appearing before the words include the elements or objects listed after the words and their equivalents, without excluding other elements or objects.

On the one hand, as shown in Figure 1-2, the present invention provides a stress corrosion micro-area in-situ test device, including a stress ring test system, a micro-area scanning electrochemical system and a monitoring system;

The stress ring testing system includes a stress ring 4 and a corrosive medium chamber 10. The corrosive medium chamber 10 includes a chamber body 10-2 and upper and lower ends respectively detachably connected to the upper and lower ends of the chamber body 10-2. Cover 10-1 and lower cover 10-3; the corrosive medium chamber 10 is provided with an air inlet 21 and an air outlet 22 that can be switched. Optionally, the air inlet 21 is arranged in the chamber In the lower part of the main body 10-2, the air outlet 22 is arranged on the upper cover 10-1; the upper cover 10-1 and the lower cover 10-3 are centrally symmetrically provided with a sample mounting hole, and the sample to be tested 9 When testing, the sample to be tested 9 is connected to the inner top and inner bottom of the stress ring 4 through the sample installation hole; the upper cover 10-1 is provided with an L-shaped sleeve 20 The through hole 18 of the through hole 18 is provided with the L-shaped sleeve 20, and the shorter end of the L-shaped sleeve 20 is located inside the cavity body 10-2; optionally, the The through hole 18 is set in a tapered shape, and the end with the larger inner diameter is on the top.

The micro-area scanning electrochemical system includes a driving arm 15, a probe 16, an auxiliary electrode 14, a reference electrode 12, and a scanning electrochemical microscope control unit connected by wires, and the probe 16 is arranged on the cavity body 10-2 and connected with the L-shaped sleeve 20, the driving arm 15 is connected with the probe 16 through the L-shaped sleeve 20, and is used to control the probe 16 relative to the tested The sample 9 is moved; the auxiliary electrode 14 and the reference electrode 12 respectively pass through the upper cover 10-1 so that one end is located in the cavity body 10-2;

The monitoring system is used to monitor the loading force of the stress ring 4 and the fracture condition of the test sample 9 .

It should be noted that, in the above-mentioned embodiment, the probe 16 is connected to the driving arm by connecting the probe wire 19, and the auxiliary electrode 14 and the reference electrode 12 are also connected to the micro-area scanning electrode through a wire. The microscope control unit of the chemical system is connected, and the micro-area electrochemical test is carried out through the computer control system, so as to obtain the micro-area current information when the stress electrochemical corrosion occurs on the surface of the sample during the loading and stretching process. The principle of micro-area electrochemical testing performed by the micro-area scanning electrochemical system is an existing technology, and details will not be repeated here.

In a specific embodiment, the monitoring system uses 6 to monitor the loading force of the stress ring 4 , and uses a fracture sensor 7 to monitor the fracture of the sample to be tested 9 . The position measuring instrument 6 can indirectly display the magnitude of the loading force, and its test results are more accurate and can ensure the stability of the loading parameters. The fracture sensor 7 can display the fracture time of the sample 9 to be tested, which can greatly reduce the number of test personnel. Working hours, no need to pay attention to the tensile state of the sample all the time. The above two monitoring devices are all prior art, and the specific structure will not be repeated here.

In a specific embodiment, as shown in FIG. 1 , the stress ring test system includes, in addition to the stress ring 4 and the corrosive medium chamber 10 , a booster nut that applies force to the stress ring 4 3. The base 5 supporting the stress ring 4, the support rod 1 arranged on the base 5 and located on the side wall of the stress ring 4, the support rod 1 is provided with a movable connecting rod 2, the The position detector 6 and the fracture sensor 7 in the monitoring system are arranged on the movable connecting rod 2 , and optionally, the movable connecting rod 2 moves up and down on the supporting long rod 1 by loosening screws.

In a specific embodiment, the base 5 and the long support rod 1 are welded as a whole, and gaskets are installed at the bottom four corners of the base 5 to buffer and adjust the horizontal plane. The support rod 1 is located directly behind the base 5, and is vertically fixed on the base 5, and is on the same plane as the central symmetry line of the stress ring 4, and the distance between them is much larger than the radius of the corrosive medium cavity, and the height Higher than the top height of the stress ring.

In a specific embodiment, in order to ensure that the sample 9 to be tested is subjected to a tensile test on the central axis of the stress ring 4, the corrosive medium chamber 10 needs to be guaranteed to be parallel to the platform of the base 5. In order to ensure that the lower cover 10-3 The seal is liquid-tight, and the center position is inlaid with a sealing rubber that matches the shape of the test sample 9. The test sample 9 is symmetrical up and down in the corrosive medium cavity, and the center of the upper cover 10-1 is also inlaid with a 9. A sealing rubber that fits in shape, and the purpose is to ensure that the sample 9 to be tested is subjected to a tensile test on the central axis.

It should be noted that the stress ring test system is a prior art, except for the stress ring test system used in this embodiment, other stress ring test systems in the prior art can also be applied to the present invention, for example, CN203811126U, a kind of stress ring test system The stress ring test system disclosed in prior art such as ring deformation detection device, CN216695824U.

In a specific embodiment, the upper and lower ends of the test sample 9 are respectively connected to the inner top and inner bottom of the stress ring 4 through the upper sample fixing part 8 and the lower sample fixing part 11 . Optionally, the inner top and the inner bottom of the stress ring 4 are provided with threaded columns protruding toward the center of the stress ring 4, and the upper sample holder 8 and the lower sample holder 11 are respectively connected to The threaded columns at the upper and lower ends of the stress ring 4 are connected by threads. Optionally, one end of the upper sample holder 8 and the lower sample holder 11 connected to the sample to be tested 9 is provided with a groove matching the sample to be tested 9, and the sample to be tested 9 After the test sample 9 is inserted into the groove, it is fixed by a bolt.

In order to be able to test the corrosion mechanism of materials by corrosive media at different temperatures, in a specific embodiment, the lower cover 10-3 is provided with a housing chamber 17, and a heating device is provided in the housing chamber 17; the monitoring system A temperature monitoring device 13 is also included, and the detection end of the temperature monitoring device 13 protrudes into the cavity body 10-2 through the upper cover 10-1. Optionally, the heating device is a heating rod; the temperature monitoring device is a thermometer. It should be noted that the above embodiments are only for enabling the corrosive medium chamber to have a heating function, and other relevant heating structure arrangements in the prior art are also applicable to the present invention.

In a specific embodiment, the upper cover 10-1 and the lower cover 10-3 are made of stainless steel, and the cavity body 10-2 is made of corrosion-resistant glass or transparent and durable polypropylene, The L-shaped sleeve 20 is made of polytetrafluoroethylene. In this embodiment, the chamber body 10-2 is made of corrosion-resistant glass or transparent and durable polypropylene, which can make the corrosion process visible, and is convenient for observers to directly observe the sample at any time.

On the other hand, it also provides an in-situ test method for stress corrosion micro-area, which is tested by using the stress corrosion micro-area in-situ test device described in any one of the above. In a specific embodiment, when using the stress corrosion micro-area in-situ testing device of the present invention for testing, its working principle is as follows:

First disassemble the corrosive medium chamber 10, fix the sample 9 to be tested on the lower cover 10-3 through sealing rubber inlay, connect the sample 9 to be tested with the lower sample fixing part 11, and use the upper cover 10-1 The L-shaped sleeve 20 is installed in the through hole on the top, the probe 16 is installed, and the distance between the tip of the probe 16 and the test sample 9 is adjusted to prevent the surface of the tensile sample from being damaged when the upper cover 10-1 is installed. Probe, adjust the final position of the probe 16 under the software interface conditions of the micro-area scanning electrochemical system, so that the tip of the electronic probe 16 is at the best position on the surface of the sample 9 to be tested. The test sample 9 is fixed, and the corrosive medium cavity 10 is installed as a whole by screws and nuts and placed in the center of the stress ring, and the upper sample fixing part 8 and the sample to be tested 9 are connected at the same time, and the upper sample fixing part 8 Tighten and fix the corrosive medium cavity 10 on the central axis of the stress ring with the lower sample fixture 11, adjust the position of the position detector 6, and at this time, the displacement count is 0, loosen the booster nut 3 to make the stress ring 4 Restore the deformation, apply a constant load force to the test sample 9, and convert the reading of the position detector 6 into the loading force by referring to relevant standards, set the test force by adjusting the booster nut 3, and adjust the position of the fracture sensor 7 , use the stress ring test system to switch, after installing the whole device, add corrosive liquid, if heating is required, insert the heating rod into the containing chamber 17, if the gas environment needs to be tested, close the gas outlet 22, open the gas inlet 21, and then By inserting a reference electrode 12, a thermometer 13 and an auxiliary electrode 14 into the corrosive medium cavity 10, the stress corrosion test is started using the stress ring test system, and the relevant temperature parameters are adjusted at the same time. During the whole test process, micro The microscope control unit of the area-scanning electrochemical system adjusts the test position of the probe 16 to conduct micro-area scanning electrochemical tests, measure the trend of the micro-area current change and morphology of the stress corrosion of the sample under the action of multiple environments, and observe the stress corrosion of the sample in real time simultaneously. Microscopic changes, further revealing the mechanism of stress corrosion.

In summary, on the basis of the existing stress ring test system, the present invention sets up the micro-area scanning electrochemical system to test the micro-area current evolution process when stress corrosion occurs in the sample, so as to explore the stress corrosion cracking of materials. Causes and reveals the mechanism of stress corrosion. Compared with the prior art, it has significant progress.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solution of the present invention.

Claims (10)

1. A stress corrosion micro-area in-situ test device, characterized in that it includes a stress ring test system, a micro-area scanning electrochemical system and a monitoring system; The stress ring test system includes a stress ring and a corrosive medium cavity, and the corrosive medium cavity includes a cavity body and an upper cover and a lower cover that are detachably connected to the upper and lower ends of the cavity body; the corrosive medium The cavity is provided with an air inlet and an air outlet that can be switched; the center of the upper cover and the lower cover are symmetrically provided with sample mounting holes, and when the sample to be tested is tested, the sample to be tested passes through the The sample installation holes are respectively connected to the inner top and inner bottom of the stress ring; the upper cover is provided with a through hole for installing an L-shaped sleeve, and the L-shaped sleeve is provided in the through hole, and the The shorter end of the L-shaped sleeve is located inside the cavity body; The micro-area scanning electrochemical system includes a driving arm, a probe, an auxiliary electrode, and a reference electrode. The probe is arranged in the cavity body and connected to the L-shaped sleeve. The driving arm passes through the The L-shaped sleeve is connected with the probe, and is used to control the movement of the probe relative to the sample to be tested; the auxiliary electrode and the reference electrode respectively pass through the upper cover so that one end is located Inside the cavity body; The monitoring system is used to monitor the loading force of the stress ring and the fracture condition of the sample to be tested. 2. The stress corrosion micro-area in-situ test device according to claim 1, wherein the upper and lower ends of the sample to be tested pass through the upper and lower sample holders and the stress ring respectively. The inner top is connected to the inner bottom. 3. The stress corrosion micro-area in-situ test device according to claim 2, characterized in that, the inner top and inner bottom of the stress ring are provided with a threaded column protruding toward the center of the stress ring, and the upper The sample fixing part and the lower sample fixing part are respectively connected with threaded posts at the upper and lower ends of the stress ring. 4. stress corrosion micro-area in-situ testing device according to claim 3, is characterized in that, the end that is connected with described sample to be tested is provided with described upper sample holder and described lower sample holder. The groove matching the sample to be tested, and the sample to be tested is fixed by a bolt after being inserted into the groove. 5. The stress corrosion micro-area in-situ test device according to claim 1, wherein the lower cover is provided with a housing chamber, and a heating device is provided in the housing chamber; the monitoring system also includes a temperature monitoring device , the detection end of the temperature monitoring device extends into the cavity body through the upper cover. 6 . The stress corrosion micro-area in-situ test device according to claim 5 , wherein the heating device is a heating rod; and the temperature monitoring device is a thermometer. 7. The stress corrosion micro-area in-situ testing device according to claim 1, wherein the monitoring system uses a position finder to monitor the loading force of the stress ring, and uses a fracture sensor to monitor the under-test Fracture of the sample. 8. The stress corrosion micro-area in-situ test device according to claim 1, wherein the air inlet is arranged at the lower part of the cavity body, and the air outlet is arranged on the upper cover. 9. The stress corrosion micro-area in-situ test device according to any one of claims 1-8, wherein the upper cover and the lower cover are made of stainless steel, and the cavity body is made of corrosion-resistant Made of glass, the L-sleeve is made of PTFE. 10. A stress corrosion micro-area in-situ testing method, characterized in that the stress corrosion micro-area in-situ testing device according to any one of claims 1-9 is used for testing.

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