Method and device for introducing internal stress of metal round bar based on stress corrosion performance test

Abstract

The present invention relates to the technical field of mechanical property testing, and provides a method and device for introducing internal stress of a metal round bar based on stress corrosion performance testing, wherein the method for introducing internal stress of a metal round bar based on stress corrosion performance testing is to clamp and relatively fix the first clamping end and the second clamping end at both ends of the parallel section on the round bar sample, and locally heat the parallel section of the round bar sample by setting an induction coil to form a heating zone, and the internal stress is formed after the heating zone is cooled. The method for introducing internal stress of a metal round bar sample based on induction heating technology can quickly and efficiently complete the process of introducing internal stress, and form a stable internal stress state, which significantly improves experimental efficiency, reduces operational difficulty, saves time and resources, and provides new ideas and experimental basis for related research.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical property testing, and in particular to a method and a device for introducing internal stress of a metal round bar based on stress corrosion performance testing. Background Art

[0002] In the field of materials science and engineering, metal round bar tensile tests are widely used to evaluate the mechanical properties of metal materials. Through this test, various performance indicators of metal materials during the tensile process can be obtained, such as elastic modulus, yield strength, tensile strength, elongation after fracture, and cross-sectional shrinkage. These data are crucial for engineers to select appropriate materials when designing products and ensure the safety and reliability of products.

[0003] As a standardized metal material test specimen, a metal round bar specimen usually has a regular cylindrical shape, and its size and shape conform to the provisions of the International Organization for Standardization (ISO) or the standards of a specific country / region. One end of the specimen is usually processed into a specific shape to facilitate clamping on a tensile testing machine. The main purpose of a metal round bar specimen is to simulate the stress conditions of the material in actual application in a tensile test, so as to evaluate the mechanical properties of the material such as strength, plasticity and toughness.

[0004] The formation of internal stress is a common phenomenon during the processing and use of metal materials. Internal stress refers to the stress state inside the material caused by external loads, temperature changes, phase changes and other factors. This internal stress not only affects the mechanical properties of the material, but also causes fatigue, deformation and even fracture of the material during subsequent use. The internal stress formed in the metal structure during the forming process, welding and other processes may cause the performance of the material to deteriorate in actual application, or even cause structural failure. Therefore, it is particularly important to study the internal stress effect on the mechanical properties of metal materials.

[0005] Since traditional tensile tests usually focus on the evaluation of mechanical properties of materials, heat treatment processes such as annealing, normalizing, quenching and tempering, and low-temperature stress relief are generally used to eliminate or reduce the internal stress of the material, or mechanical treatment methods such as vibration power, machining, hammering, and rolling are used to eliminate or reduce the internal stress of the material. For example, the Chinese patent with publication number CN116705997A--Pole piece internal stress removal device and removal method discloses a pole piece internal stress removal device and removal method, the removal device is provided with a heating structure for the pole piece, the heating mechanism includes a box and a heating component, the heating component is made of an electromagnetic induction coil, so as to achieve the heating of the metal material part of the pole piece entering the box, and during the heating process, the metal material in the pole piece is recrystallized, thereby achieving the effect of removing the internal stress of the entire pole piece.

[0006] However, in recent years, with the deepening of understanding of the mechanical properties of materials, researchers have begun to pay attention to the influence of internal stress on material properties. Although the existing technology has made some progress in eliminating internal stress, there are still several major problems in the research and application of introducing internal stress: 1: Lack of systematic methods: There is no systematic and standardized method for introducing internal stress in metal round bars. Existing technologies mostly focus on eliminating internal stress, but lack research on introducing internal stress, which makes it impossible to effectively simulate the internal stress state in actual applications in mechanical property evaluation.

[0007] 2: Difficulty in control: Existing heat treatment and mechanical treatment methods lack precise control means for the introduction and distribution of internal stress. The formation of internal stress is often affected by many factors, such as material composition, processing methods and environmental conditions, resulting in insufficient repeatability and reliability of experimental results.

[0008] 3: Impact on material properties: Although existing methods of eliminating internal stress are effective, they may have a negative impact on the microstructure and macroscopic properties of the material during the processing. For example, the heat treatment process may cause the strength and hardness of the material to decrease, while the mechanical treatment method may introduce surface defects, which in turn affects the subsequent mechanical properties test.

[0009] 4. Limited scope of application: The existing methods for removing internal stress are mostly targeted at specific materials or under specific conditions, and lack universality. This makes it difficult to find a suitable method for introducing internal stress in different types of metal materials or different application scenarios.

[0010] 5: Lack of targeted research: Although some studies have focused on the impact of internal stress on material properties, there are relatively few studies on how to effectively introduce internal stress. This results in engineers being unable to adjust the internal stress state of materials according to specific needs in practical applications, thus affecting product design and safety.

[0011] In response to these problems, it is urgent to develop a systematic and controllable internal stress introduction method to meet the needs of metal round bar tensile testing and related mechanical properties research. This will provide a more reliable experimental basis for the field of materials science and engineering and promote the in-depth development of related research. Summary of the invention

[0012] In view of this, the present invention aims to propose a method and device for introducing internal stress into a metal round bar based on stress corrosion performance testing, so as to solve the technical problems in the prior art that the internal stress effect on the mechanical properties of metal materials cannot be studied when performing metal round bar tensile tests.

[0013] To achieve the above object, the technical solution of the present invention is achieved as follows: The first purpose of the present invention is to propose a method for introducing internal stress of a metal round rod based on stress corrosion performance testing, wherein a first clamping end and a second clamping end at both ends of a parallel section on the round rod sample are clamped and relatively fixed, and an induction coil is set in the parallel section of the round rod sample to locally heat it to form a heating zone, and internal stress is formed after the heating zone is cooled.

[0014] Furthermore, a protective cover is arranged outside the portion where the induction coil is arranged on the round rod sample, for introducing protective gas when the induction coil heats the heating zone on the round rod sample.

[0015] The method for introducing internal stress into a metal round rod specimen based on induction heating technology can achieve precise control and flexible adjustment of internal stress, meet the requirements of different experiments on internal stress states, improve the pertinence and accuracy of the experiment, and the local heating method reduces the impact on the entire material, avoiding the problem of overall material performance degradation that may be caused by traditional heat treatment methods.

[0016] Another object of the present invention is to provide a device for introducing internal stress into a metal round bar based on stress corrosion performance testing, which is used to perform the method for introducing internal stress into a metal round bar based on stress corrosion performance testing as described above, comprising: A base device, including a base plate, for fixing the round bar specimen and a supporting device; A heating device, comprising an induction coil, wherein the induction coil is sleeved on a parallel section of the round rod sample and connected to the supporting device by a first connecting device; A fastening device, including a thimble screw, for pressing and fixing the round bar sample; The opposite ends of the round rod sample can be fastened by the base device and the fastening device respectively. The induction coil is connected with current to inductively heat the round rod sample inside it to form a heating zone, and internal stress is formed on the round rod sample after cooling.

[0017] Furthermore, a protective cover is sleeved on the outer side of the parallel section on the round rod sample, and at least one set of air inlet pipes and air outlet pipes are arranged on the protective cover for introducing or discharging protective gas into the protective cover.

[0018] Furthermore, the protective cover includes a first cover shell and a second cover shell, the first cover shell and the second cover shell are hinged and fixed by a first hinge, a sealing strip is arranged on the opening and closing surfaces of the first cover shell and the second cover shell, and an avoidance groove is arranged on the sealing strip for sealing connection with the round rod sample.

[0019] Furthermore, a first mounting hole is provided on the protective cover for sealing connection of the induction coil or the first connecting device when the induction coil or the first connecting device passes through the protective cover.

[0020] Furthermore, the first cover shell and the second cover shell can be locked by fastening clips and fastening slots.

[0021] Furthermore, the supporting device includes a supporting rod, the lower end of which is detachably fixed to the base device, and the first connecting device includes a first connecting rod and a first connecting seat, the first connecting rod is used to connect to the induction coil, and the first connecting seat is clamped and fastened to the supporting rod.

[0022] Furthermore, the protective cover is detachably connected to the support rod via a second connecting device, the second connecting device includes a second connecting rod and a second connecting seat, the second connecting rod is detachably connected to or integrally formed with one of the cover shells of the protective cover, and the second connecting seat is fastened to the support rod by clamping.

[0023] Furthermore, the fastening device also includes a lifting knob and a third connecting device. The lifting knob is sleeved on the ejector screw rod. The ejector screw rod is continuously moved upward or downward by rotating the lifting knob. The lifting knob is detachably connected to the support rod through the third connecting device.

[0024] Compared with the prior art, the metal round bar internal stress introduction device based on stress corrosion performance test described in the present invention has the following advantages: (1) The device for introducing internal stress into a metal round rod based on stress corrosion performance testing of the present invention can accurately introduce internal stress into a metal round rod sample by means of inductive heating and cooling. The device is suitable for metal round rod samples of different diameters and lengths, meets diverse experimental requirements, and has good adaptability and scalability.

[0025] (2) The device for introducing internal stress into a metal round rod based on stress corrosion performance testing described in the present invention can quickly and efficiently complete the process of introducing internal stress and form a stable internal stress state, which significantly improves experimental efficiency, reduces operational difficulty, saves time and resources, and provides new ideas and experimental basis for related research. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of setting a heating zone on a sample according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the top view of the structure of the device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to an embodiment of the present invention; Figure 3It is a schematic diagram of the main structure of the device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to an embodiment of the present invention; Figure 4 It is a side structural schematic diagram of a stress introduction device for a metal round bar based on stress corrosion performance testing according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the top view of the protective cover according to an embodiment of the present invention; Figure 6 It is a front view structural schematic diagram of the protective cover according to an embodiment of the present invention; Figure 7 It is a left-side structural schematic diagram of the protective cover according to an embodiment of the present invention; Figure 8 It is a schematic diagram of the side structure of the protective cover according to an embodiment of the present invention; Description of reference numerals: 100-base device; 200-heating device; 300-fastening device; 400-support device; 1-round rod sample; 101-parallel section; 102-first clamping end; 103-second clamping end; 104-heating zone; 2-induction coil; 3-protective cover; 301-first cover shell; 302-second cover shell; 303-first hinge shaft; 304-sealing strip; 305-avoidance groove; 306-fastening card; 307-fastening card slot; 308-first mounting plate; 309-first mounting hole; 4-entry Air pipe; 5-air outlet pipe; 6-first connecting device; 601-first connecting rod; 602-first connecting seat; 7-second connecting device; 701-second connecting rod; 702-second connecting seat; 8-support rod; 9-thimble screw; 901-first limiting boss; 10-lifting knob; 11-fastening sleeve; 1101-first limiting groove; 12-third connecting device; 1201-third connecting rod; 1202-third connecting seat; 13-base plate; 14-first connecting sleeve; 15-second connecting sleeve. DETAILED DESCRIPTION

[0027] In order to make the technical means, objectives and effects of the present invention easy to understand, the embodiments of the present invention are described in detail below with reference to specific drawings.

[0028] It should be noted that all the terms used in the present invention for directional and positional indications, such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside", "top", "lower", "lateral", "longitudinal", "center", etc., are only used to explain the relative positional relationship and connection status between the components in a certain state (as shown in the accompanying drawings), and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features.

[0029] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0031] In the tensile test of metal round bars, the existing technology mainly focuses on the elimination of internal stress, while the research on the introduction of internal stress is relatively weak, resulting in the inability to effectively simulate the internal stress state in practical applications. There is currently a lack of systematic and standardized methods for introducing internal stress, and the existing heat treatment and mechanical treatment methods have difficulties in controlling the formation and distribution of internal stress, which affects the repeatability and reliability of the experimental results.

[0032] In response to this demand, the present application proposes a method for introducing internal stress in a metal round rod based on stress corrosion performance testing, wherein the parallel section 101 of the round rod specimen 1 is locally heated by setting an induction coil 2 to form a heating zone 104, and the first clamping end 102 and the second clamping end 103 at both ends of the parallel section 101 of the round rod specimen 1 are clamped and relatively fixed, and internal stress is formed after the heating zone 104 is cooled.

[0033] The present application is based on the method for introducing internal stress of a metal round bar for stress corrosion performance testing. By using induction heating technology, an induction coil 2 is set on the parallel section 101 of the round bar sample to locally heat the area. Specifically, the two ends of the parallel section 101 of the round bar sample 1 are clamped and fixed to form stable clamping ends, which are the first clamping end 102 and the second clamping end 103, respectively. In this way, during the heating process, the electromagnetic field generated by the induction coil 2 causes the metal material in the heating area 104 to heat up rapidly. When the area reaches a predetermined temperature, it is then cooled. During the cooling process, due to the change in temperature gradient, the metal material produces different thermal expansion and contraction in the heating area, thereby forming internal stress. By accurately controlling parameters such as heating time, current intensity, coil winding length, heating temperature and cooling rate, flexible regulation of the size and distribution of internal stress can be achieved. The introduction of such internal stress can effectively simulate the stress state that the material may encounter in actual applications, and provide more realistic experimental conditions for subsequent mechanical properties testing.

[0034] The method for introducing internal stress of a metal round bar specimen based on induction heating technology in this application can achieve precise control and flexible adjustment of internal stress, meet the requirements of different experiments on internal stress states, improve the pertinence and accuracy of the experiment, and the local heating method reduces the impact on the entire material, avoiding the problem of overall material performance degradation that may be caused by traditional heat treatment methods. The method for introducing internal stress of a metal round bar based on stress corrosion performance testing described in this application can quickly and efficiently complete the process of introducing internal stress, and form a stable internal stress state, significantly improving experimental efficiency, saving time and resources, and providing new ideas and experimental basis for related research.

[0035] As a preferred example of the present application, a protective cover 3 is provided outside the portion where the induction coil 2 is provided on the round rod sample 1, for introducing a protective gas when the induction coil 2 heats the heating zone 104 on the round rod sample 1. Preferably, the protective gas is argon. When the induction coil starts to work, the protective gas (preferably argon) is continuously introduced into the protective cover 3, effectively isolating the heating zone 104 from the outside air. As an inert gas, argon has stable chemical properties and can prevent the metal material during the heating process from chemically reacting with oxygen, nitrogen, etc. in the air, thereby avoiding the influence of adverse factors such as oxidation and nitridation on the material properties, protecting the original properties of the material, and ensuring the smooth progress of the internal stress introduction process.

[0036] The present application also discloses a device for introducing internal stress into a metal round bar based on stress corrosion performance testing, comprising: The base device 100 includes a base plate 13 for fixing the round rod sample 1 and the supporting device 400; The heating device 200 comprises an induction coil 2, wherein the induction coil 2 is sleeved on the parallel section 101 on the round rod sample 1 and connected to the supporting device 400 by a first connecting device 6; The fastening device 300 includes a thimble screw 9, which is used to press and fix the round rod sample 1; The opposite ends of the round rod sample 1 can be fastened by the base device 100 and the fastening device 300 respectively. The induction coil 2 is connected with current to inductively heat the round rod sample 1 inside thereof to form a heating zone 104, and internal stress is formed on the round rod sample 1 after cooling.

[0037] The internal stress introduction device for a metal round rod based on stress corrosion performance testing disclosed in the present application realizes the precise introduction of internal stress through the coordinated work of a series of components. First, the base device 100 firmly fixes the bottom end of the round rod sample 1 to ensure that it remains stable during the entire heating and cooling process to avoid displacement or deformation caused by thermal expansion; the induction coil 2 in the heating device 200 is sleeved on the parallel section 101 of the round rod sample 1. When the current is turned on, the induction coil 2 will generate an electromagnetic field to inductively heat the round rod sample 1 inside it to form a local heating zone 104; at the same time, the fastening device 300 applies a fastening force to the end of the round rod sample 1 away from the base plate 13 to further the round rod sample 1. After the heating is completed, the local heating zone 104 is air-cooled or rapidly cooled, and the thermal expansion and contraction effect of the material caused by the temperature gradient causes uneven deformation inside the round rod sample, thereby introducing internal stress. During the whole process, the close cooperation between the base device 100 and the fastening device 300 ensures the stability and consistency of the round rod sample 1, making the introduction process of internal stress more accurate and controllable.

[0038] The device for introducing internal stress into a metal round bar based on stress corrosion performance testing disclosed in the present application can accurately introduce internal stress into a metal round bar sample by means of inductive heating and cooling. The synergistic effect of the base device 100, the heating device 200, the fastening device 300 and the supporting device 400 ensures stable heating and cooling of the round bar sample 1, and improves the consistency and reliability of the introduction of internal stress. At the same time, the device can be applied to metal round bar samples of different diameters and lengths, meeting the diverse experimental requirements and having good adaptability and scalability. In addition, the non-contact inductive heating method effectively avoids the problems of uneven heat conduction and low heating efficiency that may exist in traditional heating methods, further improves the quality and effect of the introduction of internal stress, and provides strong support for the scientific research and engineering application of metal materials.

[0039] As a preferred example of the present application, a protective cover 3 is sleeved on the outer side of the parallel section 101 of the round rod sample 1, and at least one set of air inlet pipes 4 and air outlet pipes 5 are provided on the protective cover 3 to pass or flow out the protective gas into the protective cover 3. In the preferred example of the present application, by sleeved on the outer side of the parallel section 101 of the round rod sample 1, and at least one set of air inlet pipes 4 and air outlet pipes 5 are provided on the protective cover 3, the function of passing or flowing out the protective gas into the protective cover 3 is realized; when the induction coil 2 performs inductive heating on the round rod sample 1, the protective gas is continuously passed into the protective cover 3 through the air inlet pipe 4, forming a layer of protective atmosphere, effectively isolating the oxygen, nitrogen and other gases in the air that may interfere with the heating process, and at the same time, the air outlet pipe 5 is used to discharge the waste gas or excess protective gas in the protective cover 3, ensuring that the gas atmosphere in the protective cover 3 is always kept clean and stable; in this way, the round rod sample 1 can avoid the occurrence of adverse reactions such as oxidation and nitridation during the heating process, ensuring the heating quality and the accuracy of the introduction of internal stress.

[0040] This setting effectively solves the problems of oxidation and nitridation that may occur in the metal round bar sample 1 during the heating process, improves the heating quality and the accuracy of the introduction of internal stress, and also enhances the adaptability and flexibility of the device. The type and flow rate of the protective gas can be adjusted according to actual needs to meet the requirements of different metal materials and heating processes. In addition, the setting of the protective cover 3 also plays an additional role in protecting the induction coil 2 and the round bar sample 1, extending the service life of the equipment and reducing maintenance costs.

[0041] As a preferred example of the present application, the protective cover 3 includes a first cover shell 301 and a second cover shell 302, the first cover shell 301 and the second cover shell 302 are hinged and fixed by a first hinge shaft 303, a sealing strip 304 is arranged on the opening and closing surfaces of the first cover shell 301 and the second cover shell 302, and a avoidance groove 305 for sealing connection with the round bar sample 1 is arranged on the sealing strip 304. The protective cover 3 of the present application adopts an openable and closable split structure, consisting of a first cover shell 301 and a second cover shell 302, which are hinged and fixed by a first hinge shaft 303. The cross-section of the first cover shell 301 and the second cover shell 302 is preferably a semicircular structure, and can also be a long groove type, a square groove type, a polygon, an arc shape, etc. When the round bar sample 1 needs to be heated, the operator only needs to rotate the two parts of the cover shell around the hinge shaft to open it, place the round bar sample 1 inside the protective cover 3 and pass it through the induction coil 2, and then close the cover shell. During the closing process, the sealing strip 304 provided on the opening and closing surfaces of the first cover shell 301 and the second cover shell 302 fits tightly to form an effective sealing barrier to prevent external air from entering the protective cover 3, thereby ensuring that the heating process is not disturbed. In order to further improve the sealing effect, the sealing strip 304 is designed with an avoidance groove 305 that matches the round bar sample 1, which can ensure that the protective cover 3 does not interfere with the round bar sample 1 when closed and sealed, thereby maintaining the sealing of the protective cover 3.

[0042] This design significantly improves the convenience of operation and the quality of the heating process through its split design and sealing structure, so that the protective cover can efficiently and conveniently provide protection for the round rod specimen, while ensuring the stability and effectiveness of the heating process. It is easy to assemble, reduces maintenance time and cost, and provides a more efficient, convenient and reliable solution for the introduction of internal stress in metal materials.

[0043] As a preferred example of the present application, a first mounting hole 309 is provided on the protective cover 3, for sealing connection of the induction coil 2 or the first connecting device 6 when passing through the protective cover 3. In the example of the present application, the first mounting hole 309 is provided on the second cover shell 302, and the first mounting hole 309 includes two independent through holes, which are respectively used for the access and access of the induction coil 2. By providing the first mounting hole 309 on the protective cover 3, so that the induction coil 2 or the first connecting device 6 can pass through the protective cover 3 smoothly and sealed, the first mounting hole 309 is cleverly designed with two independent through holes, and such a design allows the access and access of the induction coil 2 to become easier. In the example of the present application, the induction coil 2 and the protective cover 3 can be relatively fixed, or it can be a structure that is only connected and fixed to the first connecting device 6 through the first mounting hole 309. When the induction coil 2 needs to be connected to the protective cover 3, the operator only needs to pass the two ends of the coil through the two through holes respectively, ensuring smooth and efficient connection. During the connection process, in order to ensure the sealing performance, a sealing member, such as a sealing ring or a sealing glue, can be provided between the through hole and the connection member, which can effectively prevent external air or impurities from entering the interior of the protective cover 3, thereby ensuring the airtightness of the internal environment of the protective cover 3. With this design, the protective cover 3 can realize the convenient access of the induction coil 2 or the first connecting device 6 without affecting its sealing performance, thereby ensuring the stability and effectiveness of the heating process.

[0044] As a preferred example of the present application, the first housing 301 and the second housing 302 can be locked by a fastening card 306 and a fastening card slot 307. In the example of the present application, the fastening card 306 is arranged on the first housing 301, and the fastening card slot 307 is arranged on the second housing 302. When the first housing 301 is rotated to the position relative to the second housing 302, the fastening card 306 can be locked and assembled with the fastening card slot 307. In the example of the present application, the first housing 301 and the second housing 302 are locked and fixed by a detachable connection mechanism, preferably adopting a locking mechanism in which the fastening card 306 and the fastening card slot 307 cooperate with each other. Specifically, the fastening card 306 is cleverly arranged on the first housing 301, and the fastening card slot 307 matched therewith is arranged on the second housing 302. When the user needs to close the first cover 301 and the second cover 302, the user only needs to rotate the first cover 301 to a preset position relative to the second cover 302. At this time, the fastening card 306 will be accurately inserted into the fastening card slot 307, so that the two are tightly locked. Through this simple operation, the user can quickly complete the assembly, and in the closed state, the stability and reliability of the protective cover 3 are enhanced, ensuring its effective use in various working environments. This design not only improves the convenience of operation, but also reduces the potential risks caused by improper assembly.

[0045] This design significantly improves the assembly efficiency of the protective cover 3. The user only needs to simply rotate the first cover shell 301 to achieve locking, avoiding complicated operations or the need to use additional tools, which makes the use of the equipment more user-friendly; secondly, the tight fit between the fastening card 306 and the fastening slot 307 ensures the sealing and stability of the protective cover 3 in the closed state, effectively preventing the intrusion of external impurities or air, providing a safer and more reliable environment for introducing stress during the heating process, and further improving the accuracy and stability of the experiment.

[0046] As a preferred example of the present application, the air inlet pipe 4 is arranged at the upper end of the second housing 302, and the air outlet pipe 5 is arranged at the lower end of the first housing 301. The design optimizes the layout of the air inlet pipe 4, the air outlet pipe 5, the fastening card 306, and the fastening card slot 307. The air inlet pipe 4 and the air outlet pipe 5 are designed to be distributed up and down, so that the gas flow is smoother, the heating efficiency is significantly improved, and the resistance of the gas during the flow is reduced. At the same time, during the induction heating process, the flow direction of the gas is designed to be from top to bottom, which effectively transfers heat to the heating material, avoids the local overheating phenomenon caused by the heat during the gas flow process, reduces the probability of the oxidation reaction, and ensures the quality and performance of the heating material. In addition, the design of the up-down layout can also improve the safety of the system. The gas enters from the top and is discharged from the bottom after heating, which reduces the risk of direct contact of the high-temperature gas to the operator and ensures the safety during the operation.

[0047] As a preferred example of the present application, the fastening card 306 and the fastening card slot 307 are respectively arranged near the middle of the first cover shell 301 and the second cover shell 302. Designing the fastening card 306 and the fastening card slot 307 in the middle position not only simplifies the assembly process and reduces the difficulty of operation for users, but also enhances the structural strength of the protective cover 3, making it more durable during use and able to withstand higher working pressure; in addition, this design also ensures the sealing of the protective cover 3 in the closed state, effectively preventing the intrusion of external impurities or air, providing a safer and more reliable environment for the heating process, and avoiding poor heating effects caused by external factors. By optimizing the design positions of the air inlet pipe 4, the air outlet pipe 5, the fastening card 306, and the fastening card slot 307, the layout of the entire protective cover 3 is more reasonable, which not only improves the aesthetics, but also facilitates user maintenance and operation, further improving the user experience.

[0048] As a preferred example of the present application, the support device 400 includes a support rod 8, the lower end of which is detachably fixed on the base device 100, and the first connecting device 6 includes a first connecting rod 601 and a first connecting seat 602, the first connecting rod 601 is used to connect with the induction coil 2, and the first connecting seat 602 is clamped and fastened on the support rod 8. In the example of the present application, its lower end is designed to be detachable so as to be firmly fixed on the base device 100. This design is not only convenient for installation and disassembly, but also ensures the stability of the support; at the same time, the first connecting seat 602 in the first connecting device 6 is fastened to the support rod 8 by clamping, so that the first connecting device 6 can be flexibly adjusted according to actual needs, thereby realizing the stable installation and precise positioning of the induction coil 2. The combination of the stable support of the support rod 8 and the flexible connection of the first connecting device 6 enables the entire device to maintain good performance during operation, ensuring that the induction coil 2 can play the best effect during the heating process, thereby improving the efficiency and effect of heating.

[0049] This design greatly improves the convenience and flexibility of installing the support rod 8 and the first connecting device 6, so that the entire device can adapt to different working environments and scenarios. The user can quickly complete the operation when the position needs to be replaced or adjusted. The position of the induction coil 2 can be fine-tuned according to actual needs, which improves the accuracy and efficiency of heating and ensures the optimization of the internal stress effect introduced by heating.

[0050] As a preferred example of the present application, the protective cover 3 is detachably connected to the support rod 8 through a second connecting device 7. In the example of the present application, the second connecting device 7 includes a second connecting rod 701 and a second connecting seat 702, and the second connecting rod 701 is detachably connected or integrally formed with one of the housings of the protective cover 3. For example, a first mounting plate 308 is provided on the second housing 302 for connecting and fixing the second connecting rod 701, and the second connecting seat 702 is fastened to the support rod 8 by clamping. Preferably, the second connecting device 7 is provided with two groups, which are respectively located at the upper and lower sides of the first connecting device 6. The setting is achieved by optimizing the connection structure of the protective cover 3. Specifically, the protective cover 3 is detachably connected to the support rod 8 through the second connection device 7. The second connection device 7 is composed of a second connection rod 701 and a second connection seat 702, wherein the second connection rod 701 is connected to the housing of the protective cover 3 (such as the second housing 302). The connection method can be detachable or integrally formed, and the second connection seat 702 is fastened to the support rod 8 by clamping. This design enables the protective cover 3 to be firmly mounted on the support rod 8 and can be easily disassembled when needed. In order to further improve the stability of the protective cover 3, two groups of the second connection device 7 are provided, which are respectively located on the upper and lower sides of the first connection device 6, and the second connection device 7 is designed in parallel with the first connection device 6. Such a layout not only enhances the supporting effect of the protective cover 3, but also ensures that it can withstand the influence of external forces during operation, avoiding falling off or loosening due to vibration or other factors, thereby ensuring the safety and effectiveness of the entire system.

[0051] This design makes the installation and removal of the protective cover 3 more convenient, reduces downtime, and improves work efficiency. The firm clamping of the second connecting seat 702 on the support rod 8 significantly improves the stability of the protective cover 3, effectively preventing it from falling off or loosening due to external force or vibration, and ensuring the safety of the equipment during operation. At the same time, the user can adjust the position and number of the second connecting device 7 according to actual needs to adapt to the requirements of different working environments and scenarios, thereby enhancing the adaptability and practicality of the equipment.

[0052] As a preferred example of the present application, the fastening device 300 also includes a lifting knob 10 and a third connecting device 12. The lifting knob 10 is sleeved on the ejector screw 9. The ejector screw 9 is continuously moved upward or downward by rotating the lifting knob 10. The lifting knob 10 is detachably connected to the support rod 8 through the third connecting device 12. In the example of the present application, the third connecting device 12 includes a third connecting rod 1201 and a third connecting seat 1202. The third connecting rod 1201 is arranged parallel to the second connecting rod 701, and the third connecting seat 1202 is also fastened to the support rod 8 by clamping. By introducing the lifting knob 10 and the third connecting device 12, the fastening device 300 of the present application not only realizes the fine adjustment of the height position of the ejector screw 9, but also significantly improves the convenience and flexibility of operation. The user can easily rotate the lifting knob 10 to adjust the lifting of the ejector screw 9 according to actual work needs, so as to accurately position it and meet the use requirements under different working conditions; at the same time, the detachable design of the third connecting device 12 makes the assembly and disassembly of the entire fastening device 300 simpler and faster, which is conducive to the maintenance, replacement or upgrade of the equipment. In addition, the parallel setting of the third connecting rod 1201 and the second connecting rod 701, as well as the firm clamping of the third connecting seat 1202, jointly ensure the stability and reliability of the fastening device 300 during the working process, effectively improve its service life and performance, and bring greater convenience and value to the user's actual application. As a preferred example of the present application, a fastening sleeve 11 is provided at the lower end of the ejector screw 9, the fastening sleeve 11 is sleeved on one end of the round bar sample 1 away from the base plate 13, and the lower end of the ejector screw 9 extends into the fastening sleeve 11 to press the round bar sample 1. As a specific example of the present application, a first limiting groove 1101 is provided inside the fastening sleeve 11, and a first limiting boss 901 is provided at the lower end of the ejector screw 9, and the first limiting boss 901 cooperates with the first limiting groove 1101 to limit in the axial direction. Preferably, the lower end of the round bar sample 1 is a first clamping end 102, which is threadedly connected to the first connecting sleeve 14 on the base plate 13, and the upper end of the round bar sample 1 is a second clamping end 103, which is threadedly connected to the fastening sleeve 11, and the lower end of the support rod 8 is threadedly connected to the second connecting sleeve 15 on the base plate 13, and the support rod 8 is arranged in parallel with the round bar sample 1. The present application realizes the stable clamping and precise positioning of the round bar sample 1 by arranging the fastening sleeve 11 at the lower end of the ejector screw 9. Specifically, the fastening sleeve 11 is designed to be sleeved on the end of the round bar sample 1 away from the base plate 13, and the lower end of the ejector screw 9 extends into the fastening sleeve 11 and directly presses on the round bar sample 1. Such a design enables the lifting and lowering movement of the ejector screw 9 to effectively apply pressure or adjust the position of the round bar sample 1, ensuring that it always remains in the correct position during the test. In order to further enhance the stability of the connection, a first limiting groove 1101 is provided inside the fastening sleeve 11, which cooperates with the first limiting boss 901 at the lower end of the ejector screw 9, and realizes an effective limiting effect in the axial direction, preventing the relative sliding between the ejector screw 9 and the fastening sleeve 11, and ensuring the stability and consistency of the clamping force. In addition, the lower end of the round rod sample 1 is threadedly connected to the first connecting sleeve 14 on the base plate 13 through the first clamping end 102, and the upper end is threadedly connected to the fastening sleeve 11 through the second clamping end 103, thereby forming a tight clamping structure, the lower end of the support rod 8 is threadedly connected to the second connecting sleeve 15 on the base plate 13, and the support rod 8 is arranged in parallel with the round rod sample 1. Such a structural design further enhances the stability of the overall device, and also makes the force more uniform during the test process, further improves the accuracy and reliability of the test results, and provides a more accurate and efficient solution for application scenarios such as material mechanical properties testing, ensuring that the equipment can maintain good performance in various test environments.

[0053] Through the above design, the present application not only realizes reliable clamping of the round rod sample 1, but also greatly improves the accuracy and stability of the test. The limiting cooperation between the fastening sleeve 11 and the ejector screw 9 ensures the accuracy and consistency of force transmission, reduces the error caused by unstable clamping, and makes the test results more reliable.

[0054] The present application also discloses an operating method of a metal round bar internal stress introduction device based on stress corrosion performance testing, comprising: S1: Fix the induction coil 2 and the protective cover 3 on the support rod 8 through the first connecting device 6 and the second connecting device 7; S2: Open the locking device of the protective cover 3, rotate and open the first cover shell 301, pass the lower end of the round rod sample 1 through the induction coil 2 and screw-lock it with the first connecting sleeve 14 on the base plate 13; S3: Adjust the height of the connection position of the induction coil 2 and the protective cover 3 on the support rod 8. After the adjustment is in place, rotate and close the first cover shell 301, assemble the avoidance groove 305 on the first cover shell 301 and the second cover shell 302 in sealing contact with the round rod sample 1, and then buckle the fastening clamp 306 and the fastening clamping groove 307 to seal and lock the protective cover 3; S4: The ejector screw 9 with the tightening sleeve 11 is threadedly connected to the lifting knob 10, and the lifting knob 10 is assembled to the support rod 8 through the third connecting device 12. By rotating the lifting knob 10, the tightening sleeve 11 is adjusted to be sleeved on the upper end of the round rod sample 1 and tightened therewith, and then the lifting knob 10 and the tightening sleeve 11 are adjusted so that the lower end of the ejector screw 9 can be pressed against the upper end of the round rod sample 1; S5: Connect the air inlet pipe 4 and the air outlet pipe 5 on the protective cover 3 to the protective gas output device, and introduce the protective gas into the protective cover 3 for a preset time T1; S6: Turn on the current input of the induction coil 2, adjust the preset input current value I1 and the preset input time T2, or judge the on and off of the induction coil 2 based on the temperature detected by the temperature sensor in the protective cover 3, and heat the round rod sample 1 inside the induction coil 2 by induction heating; S7: After the heating is completed, the protective gas input is continued for a preset time T3, and then all the protective gas is recovered to the protective gas output device, the protective cover 3 is opened, and the heated round rod sample 1 is air-cooled; S8: After air cooling for a preset time T4, adjust the tightening sleeve 11 and the lifting knob 10, separate the tightening sleeve 11, the ejector screw 9 and the upper end of the round rod sample 1, and take out the round rod sample 1 with introduced stress.

[0055] Preferably, in step S5, the value range of T1 is 35s~180s; the value range of T3 is 30s~180s; the value range of T4 is 10min~24h. In the example of the present application, a temperature sensor is arranged in the protective cover 3 to detect the heating temperature of the heating zone 104 on the round rod sample 1 in the protective cover 3. When the temperature detected by the temperature sensor reaches the preset temperature T 温 After that, it is determined that the induction coil 2 stops heating. In the example of the present application, T温 The value range of is 200°C to 1500°C, preferably 500°C, 650°C, 700°C, 750°C, 780°C, 820°C, 850°C, 900°C, 920°C, 970°C, 1000°C, 1020°C, 1050°C, 1080°C, 1120°C, 1150°C, etc. In the example of the present application, the winding length of the induction coil 2 can also be adaptively adjusted.

[0056] Through the above-mentioned operation method, the metal round bar internal stress introduction device based on stress corrosion performance test can realize the precise control of the current, time and protective gas in the heating process, so as to effectively introduce the internal stress of the metal round bar. The design of the protective cover effectively isolates the influence of the external environment on the heating process, improves the uniformity and stability of the heating, and further enhances the effect and accuracy of the internal stress introduction. The operation steps are clear and simple. The user only needs to adjust the position and state of the induction coil, protective cover, ejector screw and other components to realize the internal stress introduction of metal round bars of different specifications, showing good versatility and adaptability.

[0057] As a preferred example of the present application, the support rod 8, the ejector screw 9, the fastening sleeve 11, and the base plate 13 are all made of steel materials. The protective cover 3 is made of stainless steel sheet or high-temperature resistant plastic material. It is composed of two semi-cylindrical cover shells, which are connected together by hinges. After the round rod sample 1 is placed in it, it can be buckled together to form a relatively closed heating space.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for introducing internal stress into a metal round bar based on stress corrosion performance testing, characterized in that: The first clamping end (102) and the second clamping end (103) at both ends of the parallel section (101) of the round bar sample (1) are clamped and relatively fixed, and the parallel section (101) of the round bar sample (1) is locally heated by arranging an induction coil (2) to form a heating zone (104), and the heating zone (104) forms internal stress after cooling.

2. The method for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 1, characterized in that: A protective cover (3) is arranged outside the portion where the induction coil (2) is arranged on the round rod sample (1) for introducing protective gas when the induction coil (2) heats the heating area (104) on the round rod sample (1).

3. A device for introducing internal stress into a metal round bar based on stress corrosion performance testing, characterized in that: The method for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 1 or 2 comprises: A base device (100) comprising a base plate (13) for fixing the round rod sample (1) and the supporting device (400); A heating device (200) comprises an induction coil (2), wherein the induction coil (2) is sleeved on a parallel section (101) on a round rod sample (1) and connected to a support device (400) by a first connecting device (6); A fastening device (300) comprising a thimble screw (9) for pressing and fixing the round rod sample (1); The opposite ends of the round rod sample (1) can be fastened by a base device (100) and a fastening device (300) respectively. The induction coil (2) is connected to a current to inductively heat the round rod sample (1) inside the induction coil to form a heating zone (104). After cooling, internal stress is formed on the round rod sample (1).

4. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 3 is characterized in that: A protective cover (3) is sleeved on the outer side of the parallel section (101) on the round rod sample (1), and at least one set of air inlet pipes (4) and air outlet pipes (5) are arranged on the protective cover (3) for introducing or discharging protective gas into or out of the protective cover (3).

5. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 4, characterized in that: The protective cover (3) comprises a first cover shell (301) and a second cover shell (302); the first cover shell (301) and the second cover shell (302) are hingedly fixed via a first hinge shaft (303); a sealing strip (304) is provided on the opening and closing surfaces of the first cover shell (301) and the second cover shell (302); and an avoidance groove (305) for sealingly connecting with the round rod sample (1) is provided on the sealing strip (304).

6. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 5, characterized in that: A first mounting hole (309) is provided on the protective cover (3) for sealingly connecting the induction coil (2) or the first connecting device (6) when the induction coil (2) or the first connecting device (6) passes through the protective cover (3).

7. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 5, characterized in that: The first cover shell (301) and the second cover shell (302) can be locked by means of a fastening clamp (306) and a fastening clamp slot (307).

8. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 5, 6 or 7, characterized in that: The support device (400) comprises a support rod (8), the lower end of the support rod (8) being detachably fixed to the base device (100), the first connecting device (6) comprising a first connecting rod (601) and a first connecting seat (602), the first connecting rod (601) being used to connect to the induction coil (2), and the first connecting seat (602) being clamped and fastened to the support rod (8).

9. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 8, characterized in that: The protective cover (3) is detachably connected to the support rod (8) via a second connecting device (7); the second connecting device (7) comprises a second connecting rod (701) and a second connecting seat (702); the second connecting rod (701) is detachably connected to or integrally formed with one of the cover shells of the protective cover (3); and the second connecting seat (702) is fastened to the support rod (8) by clamping.

10. The device for introducing internal stress into a metal round bar based on stress corrosion performance testing according to claim 9, characterized in that: The fastening device (300) further comprises a lifting knob (10) and a third connecting device (12); the lifting knob (10) is sleeved on the ejector screw rod (9); the ejector screw rod (9) is continuously moved upward or downward by rotating the lifting knob (10); and the lifting knob (10) is detachably connected to the support rod (8) via the third connecting device (12).

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