Metal material hot salt corrosion-creep test tool and test method

Abstract

The invention discloses a metal material hot salt corrosion-creep test tool and a test method. The test tool comprises a corrosion box, a corrosion cover and a gasket. The test piece penetrates through the corrosion box, the annular convex tip close to the second connecting section is in sealing contact with the annular boss in the first round hole, and corrosion salt covering the scale distance section is filled in the corrosion box. In the whole process of the metal material hot salt corrosion-creep test, the corrosion salt can uniformly coat the periphery of the scale distance section, so that the conditions that the deposited salt is poor in adhesive force, easy to peel off and non-uniform in deposition due to the adoption of a salt pre-deposition mode in the related technology are avoided. According to the test tool, uniform contact of the corrosion salt and the gauge length section of the test piece in the corrosion box is achieved, then uniform hot corrosion of the gauge length section can be achieved when a creep test is carried out, and meanwhile the tool solves the problem that the corrosion salt in the molten state flows out of the gauge length section of the test piece under the high-temperature condition, and then a high-temperature creep testing machine is damaged.

Description

Technical Field

[0001] The present application relates to the field of mechanical property testing of metal materials, and in particular to a hot salt corrosion-creep test fixture and test method for metal materials. Background Art

[0002] When helicopters and ship-based fixed-wing aircraft are operating in marine environments, their engine air intakes draw in large quantities of water vapor containing sodium chloride (NaCl). Under the high-temperature combustion environment of the engine, this water vapor may react chemically with the sulfur-containing combustion gas to form sodium sulfate (Na2SO4). Under the action of high-speed combustion gas flow, a sodium salt mixture composed of NaCl and Na2SO4 gradually deposits on the surface of the hot-end components. As the high-temperature service time increases, the sodium salt mixture becomes a corrosive medium, reacting with the hot-end component materials, causing hot salt corrosion damage to the components and significantly shortening their service life. The coupling of hot salt corrosion and creep loads is the main reason for the rapid decline in the service life of hot-end components. Therefore, it is crucial to study the hot salt corrosion-creep properties of engine hot-end component materials in marine environments.

[0003] Hot salt corrosion-creep coupling refers to the situation where, under high temperature conditions, the hot salt corrosion medium destroys the dense microstructure of the alloy, causing defects such as pits and grain boundary cracks on its surface. As the corrosion time increases, some surface materials peel off, significantly reducing the load-bearing capacity of the alloy. At the same time, under the action of creep load, macro cracks quickly initiate at defects such as pits and surface grain boundary cracks. These cracks rapidly expand under the coupling of subsequent loads and hot salt corrosion, ultimately leading to structural fracture and failure. In order to further study the failure behavior and mechanism of alloys under the coupling of hot salt corrosion and creep loads, it is necessary to carry out hot salt corrosion-creep coupling tests to obtain the hot salt corrosion-creep life distribution law of materials and structures, and to explore the evolution process and characteristics of hot corrosion-creep failure of alloys based on the creep data and micromorphology of the specimens.

[0004] To this end, existing technologies require the following tests: hot salt corrosion tests and hot salt corrosion-creep coupled tests. Based on these tests, data on the high-temperature corrosion kinetics of the material and creep life under the influence of hot salt corrosion are obtained. Furthermore, material characterization and microanalysis techniques are used to determine the dynamic diffusion patterns of elements in the corrosion zone, explore the hot salt corrosion mechanism of the alloy, and the crack initiation and propagation mechanism of the alloy under the coupled action of hot salt corrosion and creep loads.

[0005] Prior art in hot salt corrosion-creep coupled testing of alloys involves depositing a certain amount of corrosive salt on the alloy surface before conducting creep testing at high temperatures. During high-temperature creep loading, the deposited salt causes thermal corrosion on the specimen, thereby achieving coupled loading of hot salt corrosion and creep.

[0006] However, this hot salt corrosion-creep coupled testing method, which couples hot salt corrosion and creep loading by pre-depositing salt, presents several challenges. First, during the pre-deposition of salt, due to operational uncertainty, uniform salt deposition on the gauge section of the alloy specimen is difficult. Second, the weak adhesion of the salt deposited on the gauge section makes it easy for the salt deposited to hit the gauge section during creep testing, leading to partial or complete flaking of the salt deposited, affecting the subsequent hot salt corrosion-creep coupled test results. Furthermore, when the creep test temperature exceeds the melting point of the salt deposited on the gauge section, the salt deposited on the gauge section becomes molten and flows down the gauge section, making it difficult to achieve a good hot corrosion effect. Furthermore, the molten salt that flows down can cause thermal corrosion on the creep fixture, damaging the creep test equipment. To address these issues, a new hot salt corrosion-creep testing method and test fixture for metal materials is needed to better capture hot salt corrosion of metal materials. Summary of the Invention

[0007] The present application provides a hot salt corrosion-creep test fixture and test method for metal materials, which can solve the technical problems in the prior art such as uneven salt deposition, weak adhesion of deposited salt, and easy peeling, and the melting of corrosion salt at high temperature and flowing down the gauge section, thereby damaging the high-temperature creep tester. The technical solution is as follows:

[0008] On the one hand, a hot salt corrosion-creep test fixture for metal materials is provided. The specimen for the hot salt corrosion-creep test of the metal material is in the shape of a round rod, including a first connecting section, a first transition section, a gauge section, a second transition section, and a second connecting section connected in sequence. Both ends of the gauge section have an annular protrusion. The test fixture is characterized in that it includes:

[0009] A barrel-shaped etching box, wherein the bottom of the etching box has a first circular hole, the first circular hole has an annular boss protruding into the first circular hole, and the inner diameter of the annular boss is smaller than the outer diameter of the annular protrusion, and the annular boss and the first circular hole form a stepped hole;

[0010] an etching cover for covering the opening of the etching box, wherein a second circular hole is provided in the center of the etching cover, and the diameter of the second circular hole is larger than the diameter of the first transition section and smaller than the outer diameter of the annular protrusion;

[0011] a washer disposed between the bottom of the corrosion box and a corresponding fixture of a high-temperature creep testing machine for connecting the second connecting section;

[0012] When the specimen is installed in the test fixture, the first connecting section and the second connecting section are respectively connected to corresponding fixtures of the high-temperature creep testing machine, and the annular protrusion close to the second connecting section contacts the annular boss to form a seal.

[0013] Optionally, the corrosion box is in a cylindrical shape, and the corrosion cover includes two semicircular covers that can be assembled into a full circle. A semicircular notch is provided at the center of each semicircular cover, and the two semicircular notches form the second circular hole.

[0014] Optionally, the edge of the semicircular notch of each semicircular cover has a semicircular arc plate extending into the corrosion box, and the outer diameter of each semicircular arc plate is smaller than the inner diameter of the corrosion box.

[0015] Optionally, the edge of the tip of the annular protrusion facing the side of the annular boss has a first rounded corner, and the stepped hole formed by the annular boss and the first circular hole has a second rounded corner matching the first rounded corner, and the first rounded corner and the second rounded corner form a surface seal.

[0016] Optionally, the corrosion box includes a barrel and a base, the outer surface of the lower end of the barrel has a first external thread, the base has a accommodating cavity, the cavity wall of the base has a first internal thread matching the first external thread, and the first circular hole is located at the bottom of the base.

[0017] Optionally, both the first connecting section and the second connecting section have a second external thread, and the second external thread is used to connect to the second internal thread of the fixture of the high-temperature creep testing machine.

[0018] Optionally, there are multiple washers, and the heights of the washers are not all equal.

[0019] The beneficial effects of the technical solutions provided in the embodiments of the present application include at least:

[0020] A hot salt corrosion-creep test fixture for metal materials comprises a corrosion box, a corrosion cover, and a gasket. During the hot salt corrosion-creep test, the specimen is passed through the corrosion box, and the annular protrusion near the second connecting section seals against the annular boss within the first circular hole. Corrosive salt covering the gauge section is then loaded into the corrosion box. The first and second connecting sections of the specimen are respectively connected to two fixtures of a high-temperature creep testing machine. Throughout the hot salt corrosion-creep test, the corrosive salt is evenly coated around the gauge section, thereby avoiding the poor adhesion, easy flaking, and uneven deposition of the deposited salt that are common in related art methods using pre-deposited salt. The hot salt corrosion-creep test fixture of the present application ensures uniform contact between the corrosive salt and the gauge section of the specimen within the corrosion box, thereby ensuring uniform hot corrosion of the gauge section during creep testing. The fixture also addresses the problem of molten corrosive salt flowing from the gauge section of the specimen into the high-temperature creep testing machine under high-temperature conditions, thereby damaging the machine.

[0021] On the other hand, a hot salt corrosion-creep coupled test method for metal materials is provided, which is applied to the above-mentioned test fixture, and the hot salt corrosion-creep coupled test method for metal materials comprises the following steps:

[0022] Step 1: Processing the test profile into a specimen, wherein the specimen comprises a first connecting section, a first transition section, a gauge section, a second transition section, and a second connecting section connected in sequence, wherein both ends of the gauge section have an annular protrusion, wherein the diameter of the gauge section of the specimen is a preset diameter, and the length is a preset length;

[0023] Step 2: Clean the specimen with clean water and anhydrous ethanol in sequence, and blow dry;

[0024] Step 3: Pass the second connecting section of the specimen through the first circular hole and the washer of the corrosion box in sequence, so that the annular protrusion close to the second connecting section contacts the annular boss;

[0025] Step 4: Adjust the position of the gasket in the high-temperature creep tester so that the centerline of the gasket and the centerline of the specimen are on the same vertical line. Connect the second connecting section of the specimen to a fixture of the high-temperature creep tester to ensure that the annular protrusions of the specimen are in sealed contact with each other.

[0026] Step 5: Prepare a mixed salt of 5% NaCl + 95% Na2SO4 and mix it evenly. Pour it into the corrosion box so that the corrosion salt completely covers the gauge length of the specimen.

[0027] Step 6: Buckle the corrosion box cover onto the opening of the corrosion box;

[0028] Step 7: Connect the first connecting section of the specimen to another fixture of the high-temperature creep testing machine;

[0029] Step 8: Perform creep test.

[0030] Furthermore, in step 8, the creep test includes the following sub-steps:

[0031] Sub-step 8.1: Apply a constant preset creep tensile load to the specimen;

[0032] Sub-step 8.2: Set the high temperature creep testing machine to the target temperature;

[0033] Sub-step 8.3: After the temperature in the high-temperature creep testing machine reaches the target temperature, maintain the preset holding time until the temperature of the specimen and the fixture is uniform;

[0034] Sub-step 8.4: Apply a tensile load to the specimen until it reaches the target tensile load. When the tensile load reaches the target tensile load, start creep loading.

[0035] Sub-step 8.5: When the specimen fractures under the coupled action of hot salt corrosion and creep load, stop the creep test and start cooling;

[0036] Sub-step 8.6: After the specimen and fixture cool to room temperature, remove the specimen and fixture, and the test is complete.

[0037] Sub-step 8.7: Ultrasonic clean the specimen and fixture using hot water, where the specimen is used for subsequent characterization analysis.

[0038] Furthermore, the preset creep tensile load range is 150N-200N;

[0039] The target temperature range is 800°C-1000°C;

[0040] The target tensile load range is 5800N-14000N.

[0041] The beneficial effects brought about by the technical solution provided in the embodiment of the present application can be referred to the beneficial effects of the above-mentioned hot salt corrosion-creep test fixture for metal materials, which will not be described in detail here.

[0042] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0044] Figure 1 is the longitudinal cross-sectional view of the specimen;

[0045] Figure 2 1 is a longitudinal cross-sectional view of a metal material hot salt corrosion-creep test fixture and a test piece provided in an embodiment of the present application;

[0046] Figure 3 This is a longitudinal cross-sectional view of an embodiment of a corrosion box in a metal material hot salt corrosion-creep test tool provided in an embodiment of the present application;

[0047] Figure 4 This is an exploded schematic diagram of another embodiment of a corrosion box in a metal material hot salt corrosion-creep test tool provided in an embodiment of the present application;

[0048] Figure 5 It is a schematic diagram of an exploded view of an embodiment of a corrosion cover in a metal material hot salt corrosion-creep test tool provided in an embodiment of the present application.

[0049] Description of Reference Numerals

[0050] 1-test piece; 101-first connecting section; 102-first transition section; 103-gauge length section; 104-second transition section; 105-second connecting section; 106-annular protrusion; 2-corrosion box; 201-first circular hole; 202-annular boss; 203-cylinder; 204-base; 3-corrosion cover; 301-second circular hole; 302-semicircular cover; 303-semicircular arc plate; 4-gasket. DETAILED DESCRIPTION

[0051] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0052] In this disclosure, unless otherwise indicated, directional terms such as "upper" and "lower" generally refer to the relative positions of the corresponding components in the direction of gravity when in use. "Inside" and "outside" refer to the relative positions of the corresponding components themselves. Furthermore, the terms "first" and "second" used in this disclosure are intended to distinguish one element from another and do not convey sequential or significant meanings. In the following description, when referring to the drawings, unless otherwise indicated, identical reference numerals in different drawings indicate identical or similar elements.

[0053] In the first aspect, according to an embodiment of the present application, a metal material hot salt corrosion-creep test fixture is provided, wherein reference is made to Figure 1 The specimen 1 for the hot salt corrosion-creep test of the metal material is in the shape of a round rod, and includes a first connecting section 101, a first transition section 102, a gauge section 103, a second transition section 104 and a second connecting section 105 connected in sequence, and both ends of the gauge section 103 have an annular protrusion 106 respectively.

[0054] refer to Figure 2 The test tooling includes: a corrosion box 2, a corrosion cover 3 and a gasket 4.

[0055] refer to Figure 3 The bottom of the etching box 2 has a first circular hole 201 , and the first circular hole 201 has an annular boss 202 protruding into the first circular hole 201 , and the inner diameter of the annular boss 202 is smaller than the outer diameter of the annular protrusion 106 .

[0056] refer to Figure 1 and Figure 5 The corrosion box 2 is used to cover the opening of the corrosion box 2. A second circular hole 301 is provided in the center of the corrosion cover 3. The diameter of the second circular hole 301 is larger than the diameter of the first transition section 102 and smaller than the outer diameter of the annular protrusion 106.

[0057] The gasket 4 is provided between the bottom of the corrosion box 2 and a corresponding fixture of a high temperature creep testing machine for connecting the second connecting section 105 .

[0058] When the specimen 1 is installed in the test fixture, the first connecting section 101 and the second connecting section 105 are respectively connected to the corresponding fixtures of the high-temperature creep testing machine, and the annular protrusion 106 close to the second connecting section 105 contacts the annular boss 202 to form a seal.

[0059] In the above embodiment, when conducting a hot salt corrosion-creep test on a metal material, the specimen 1 passes through the corrosion box 2, and the annular protrusion 106 near the second connecting section 105 is in sealed contact with the annular boss 202 in the first circular hole 201. Corrosion salt covering the gauge section 103 is loaded into the corrosion box 2, and the first connecting section 101 and the second connecting section 105 of the specimen 1 are respectively connected to the two fixtures of the high-temperature creep testing machine. During the entire process of the hot salt corrosion-creep test on the metal material, the corrosion salt can be evenly coated around the gauge section 103, thereby avoiding the problems of poor adhesion, easy peeling, and uneven deposition of the deposited salt in the method of pre-depositing salt in the related art. The hot salt corrosion-creep test fixture for metal materials of the present application realizes uniform contact between the corrosion salt and the gauge section 103 of the specimen in the corrosion box 2, and thus can achieve uniform hot corrosion of the gauge section 103 when conducting the creep test. At the same time, the fixture solves the problem that molten corrosive salt flows from the gauge section 103 of the specimen 1 to the high-temperature creep testing machine under high-temperature conditions, thereby damaging the high-temperature creep testing machine.

[0060] According to the embodiments of this application, reference Figure 2 、 Figure 4 and Figure 5 The corrosion box 2 may be in the shape of a cylinder. Accordingly, the corrosion cover 3 may include two semicircular covers 302 that can be assembled into a full circle. A semicircular notch is provided at the center of each semicircular cover 302. The two semicircular notches form the second circular hole 301. The semicircular notch is used to avoid the first transition section 102 of the specimen 1.

[0061] According to the embodiments of this application, reference Figure 2 In order to make the two semicircular covers 302 better fit on the mouth of the corrosion box 2, the edge of the semicircular notch of each semicircular cover 302 has a semicircular arc plate 303 extending into the corrosion box 2, and the outer diameter of each semicircular arc plate 303 is smaller than the inner diameter of the corrosion box 2.

[0062] According to the embodiments of this application, reference Figure 1 and Figure 2As shown, the edge of the tip of the annular protrusion 106 facing the annular boss 202 has a first fillet 107. The stepped hole formed by the annular boss 202 and the first circular hole 201 has a second fillet 205 that matches the first fillet 107. The first fillet 107 and the second fillet 205 form a surface seal. When the second connecting section 105 is connected to the clamp at the bottom of the high-temperature creep tester and a certain preload is applied, the sizes of the first fillet 107 and the second fillet 205 match. On the one hand, this allows the specimen 1 to be automatically centered at the bottom of the corrosion box 2. On the other hand, the first fillet 107 and the second fillet 205 increase the contact area between the two contact surfaces, thereby improving the sealing performance of the specimen 1 and the corrosion box 2, and preventing molten corrosion salts under high temperature conditions from flowing from the gauge section 103 of the specimen 1 to the high-temperature creep tester, thereby damaging the high-temperature creep tester.

[0063] According to an embodiment of the present application, in order to facilitate manufacturing, the corrosion box 2 may include a barrel 203 and a base 204, the outer surface of the lower end of the barrel 203 has a first external thread, the base 204 has a accommodating cavity, the cavity wall of the base 204 has a first internal thread matching the first external thread, and the first circular hole 201 is located at the bottom of the base 204.

[0064] According to the embodiments of this application, reference Figure 1 The first connecting section 101 and the second connecting section 105 each have a second external thread, which is used to connect to the second internal thread of the fixture of the high-temperature creep tester. In other embodiments, the connection between the fixture of the high-temperature creep tester and the specimen 1 can also be a flange connection, a mechanical lock connection, or other connection methods, which are not limited in this application.

[0065] According to an embodiment of the present application, there are multiple washers 4, and the heights of the washers 4 are not all equal. This ensures that when the second connecting section 105 of the specimen 1 is connected to the fixture of the high-temperature creep tester, there is sufficient threaded connection between the second connecting section 105 of the specimen 1 and the angle of the high-temperature creep tester, thereby ensuring a reliable seal between the annular protrusion 106 of the specimen 1 and the annular boss 202 of the corrosion chamber 2. The height of the washers 4 can be selected based on actual conditions.

[0066] In a second aspect, an embodiment of the present application further provides a hot salt corrosion-creep coupled test method for a metal material. The above-mentioned test fixture comprises the following steps:

[0067] Step 1: Processing the test profile into a specimen, wherein the specimen comprises a first connecting section, a first transition section, a gauge section, a second transition section, and a second connecting section connected in sequence, wherein both ends of the gauge section have an annular protrusion, wherein the diameter of the gauge section of the specimen is a preset diameter, and the length is a preset length;

[0068] Step 2: Clean the specimen with clean water and anhydrous ethanol in sequence, and blow dry;

[0069] Step 3: Pass the second connecting section of the specimen through the first circular hole and the washer of the corrosion box in sequence, so that the annular protrusion close to the second connecting section contacts the annular boss;

[0070] Step 4: Adjust the position of the gasket in the high-temperature creep tester so that the centerline of the gasket and the centerline of the specimen are on the same vertical line. Connect the second connecting section of the specimen to a fixture of the high-temperature creep tester to ensure that the annular protrusions of the specimen are in sealed contact with each other.

[0071] Step 5: Prepare a mixed salt of 5% NaCl + 95% Na2SO4 and mix it evenly. Pour it into the corrosion box so that the corrosion salt completely covers the gauge length of the specimen.

[0072] Step 6: Buckle the corrosion box cover onto the opening of the corrosion box;

[0073] Step 7: Connect the first connecting section of the specimen to another fixture of the high-temperature creep testing machine;

[0074] Step 8: Perform creep test.

[0075] Furthermore, in step 8, the creep test may include the following sub-steps:

[0076] Sub-step 8.1: Apply a constant preset creep tensile load to the specimen;

[0077] Sub-step 8.2: Set the high temperature creep testing machine to the target temperature;

[0078] Sub-step 8.3: After the temperature in the high-temperature creep testing machine reaches the target temperature, maintain the preset holding time until the temperature of the specimen and the fixture is uniform;

[0079] Sub-step 8.4: Apply a tensile load to the specimen until it reaches the target tensile load. When the tensile load reaches the target tensile load, start creep loading.

[0080] Sub-step 8.5: When the specimen fractures under the coupled action of hot salt corrosion and creep load, stop the creep test and start cooling;

[0081] Sub-step 8.6: After the specimen and fixture cool to room temperature, remove the specimen and fixture, and the test is complete.

[0082] Sub-step 8.7: Ultrasonic clean the specimen and fixture using hot water, where the specimen is used for subsequent characterization analysis.

[0083] Furthermore, the preset creep tensile load range is 150N-200N; the target temperature range is 800°C-1000°C; and the target tensile load range is 5800N-14000N.

[0084] The following describes in detail the process of performing a hot salt corrosion-creep test on a metal specimen using the hot salt corrosion-creep test fixture of the present invention in conjunction with specific embodiments.

[0085] Example 1

[0086] The test metal material is single crystal high temperature alloy DD6.

[0087] Step 1: Processing a single crystal high-temperature alloy DD6 test profile into a specimen, the specimen comprising a first connecting section, a first transition section, a gauge section, a second transition section, and a second connecting section connected in sequence, wherein the gauge section has an annular protrusion at each end, wherein the gauge section of the specimen has a diameter of 5 mm and a length of 25 mm;

[0088] Step 2: Clean the specimen with clean water and anhydrous ethanol in sequence, and blow dry;

[0089] Step 3: Pass the second connecting section of the specimen through the first circular hole and the washer of the corrosion box in sequence, so that the annular protrusion close to the second connecting section contacts the annular boss;

[0090] Step 4: Adjust the position of the gasket in the high-temperature creep tester so that the centerline of the gasket and the centerline of the specimen are on the same vertical line. Connect the second connecting section of the specimen to a fixture of the high-temperature creep tester to ensure that the annular protrusions of the specimen are in sealed contact with each other.

[0091] Step 5: Prepare a mixed salt of 5% NaCl + 95% Na2SO4 and mix it evenly. Pour it into the corrosion box so that the corrosion salt completely covers the gauge length of the specimen.

[0092] Step 6: Buckle the corrosion box cover onto the opening of the corrosion box;

[0093] Step 7: Connect the first connecting section of the specimen to another fixture of the high-temperature creep testing machine;

[0094] Step 8: Perform creep test.

[0095] In step 8, the creep test may include the following sub-steps:

[0096] Sub-step 8.1: Apply a constant creep tensile load of 200 N to the specimen;

[0097] Sub-step 8.2: Set the high temperature creep testing machine to a target temperature of 950°C;

[0098] Sub-step 8.3: After the temperature in the high-temperature creep testing machine reaches the target temperature, maintain the preset holding time until the temperature of the specimen and the fixture is uniform;

[0099] Sub-step 8.4: Apply a tensile load to the specimen until it reaches a target tensile load of 5887.5 N. When the tensile load reaches the target tensile load of 5887.5 N, initiate creep load holding.

[0100] Sub-step 8.5: When the specimen fractures under the coupled action of hot salt corrosion and creep load, stop the creep test and start cooling;

[0101] Sub-step 8.6: After the specimen and fixture cool to room temperature, remove the specimen and fixture, and the test is complete.

[0102] Sub-step 8.7: Ultrasonic clean the specimen and fixture using hot water, where the specimen is used for subsequent characterization analysis.

[0103] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0105] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A hot salt corrosion-creep test fixture for metal materials, wherein the test piece (1) for the hot salt corrosion-creep test for metal materials is in the shape of a round rod, comprising a first connecting section (101), a first transition section (102), a gauge section (103), a second transition section (104) and a second connecting section (105) connected in sequence, wherein both ends of the gauge section (103) respectively have an annular protrusion (106), and the test piece is characterized in that: The test tooling includes: A barrel-shaped etching box (2), wherein the bottom of the etching box (2) has a first circular hole (201), the first circular hole (201) has an annular boss (202) protruding toward the inside of the first circular hole (201), the inner diameter of the annular boss (202) is smaller than the outer diameter of the annular protrusion (106), and the annular boss (202) and the first circular hole (201) form a stepped hole; a corrosion cover (3) for covering the opening of the corrosion box (2), wherein a second circular hole (301) is provided at the center of the corrosion cover (3), and the diameter of the second circular hole (301) is larger than the diameter of the first transition section (102) and smaller than the outer diameter of the annular protrusion (106); a gasket (4) disposed between the bottom of the corrosion box (2) and a corresponding fixture of a high-temperature creep testing machine for connecting the second connecting section (105); When the test piece (1) is installed in the test fixture, the first connecting section (101) and the second connecting section (105) are respectively connected to corresponding fixtures of the high-temperature creep testing machine, and the annular protrusion (106) close to the second connecting section (105) contacts the annular boss (202) to form a seal.

2. The metal material hot salt corrosion-creep test fixture according to claim 1, characterized in that: The corrosion box (2) is in the shape of a cylinder, and the corrosion cover (3) comprises two semicircular covers (302) that can be assembled into a full circle. A semicircular notch is provided at the center of each semicircular cover (302), and the two semicircular notches form the second circular hole (301).

3. The metal material hot salt corrosion-creep test fixture according to claim 2, characterized in that: The edge of the semicircular notch of each semicircular cover (302) has a semicircular arc plate (303) extending into the corrosion box (2), and the outer diameter of each semicircular arc plate (303) is smaller than the inner diameter of the corrosion box (2).

4. The metal material hot salt corrosion-creep test fixture according to claim 3, characterized in that: The edge of the tip of the annular protrusion (106) facing the side of the annular boss (202) has a first rounded corner (107), and the stepped hole formed by the annular boss (202) and the first circular hole (201) has a second rounded corner (205) matching the first rounded corner (107), and the first rounded corner (107) and the second rounded corner (205) form a surface seal.

5. The metal material hot salt corrosion-creep test fixture according to claim 1, characterized in that: The corrosion box (2) comprises a barrel (203) and a base (204), wherein the outer surface of the lower end of the barrel (203) has a first external thread, the base (204) has a receiving cavity, the cavity wall of the base (204) has a first internal thread matching the first external thread, and the first circular hole (201) is located at the bottom of the base (204).

6. The metal material hot salt corrosion-creep test fixture according to claim 1, characterized in that: The first connecting section (101) and the second connecting section (105) both have a second external thread, and the second external thread is used to connect with a second internal thread of a fixture of a high-temperature creep testing machine.

7. The metal material hot salt corrosion-creep test fixture according to claim 1, characterized in that: There are multiple washers (4), and the heights of the washers (4) are not all equal.

8. A hot salt corrosion-creep coupled test method for metal materials, using the test fixture according to claim 1, characterized in that: The hot salt corrosion-creep coupling test method for metal materials comprises the following steps: Step 1: Processing the test profile into a specimen, wherein the specimen comprises a first connecting section, a first transition section, a gauge section, a second transition section, and a second connecting section connected in sequence, wherein both ends of the gauge section have an annular protrusion, wherein the diameter of the gauge section of the specimen is a preset diameter, and the length is a preset length; Step 2: Clean the specimen with clean water and anhydrous ethanol in sequence, and blow dry; Step 3: Pass the second connecting section of the specimen through the first circular hole and the washer of the corrosion box in sequence, so that the annular protrusion close to the second connecting section contacts the annular boss; Step 4: Adjust the position of the gasket in the high-temperature creep tester so that the centerline of the gasket and the centerline of the specimen are on the same vertical line. Connect the second connecting section of the specimen to a fixture of the high-temperature creep tester to ensure that the annular protrusions of the specimen are in sealed contact with each other. Step 5: Prepare a mixed salt of 5% NaCl + 95% Na2SO4 and mix it evenly. Pour it into the corrosion box so that the corrosion salt completely covers the gauge section of the specimen. Step 6: Buckle the corrosion box cover onto the opening of the corrosion box; Step 7: Connect the first connecting section of the specimen to another fixture of the high-temperature creep testing machine; Step 8: Perform creep test.

9. The hot salt corrosion-creep coupled test method for metal materials according to claim 8, characterized in that: In step 8, the creep test includes the following sub-steps: Sub-step 8.1: Apply a constant preset creep tensile load to the specimen; Sub-step 8.2: Set the high temperature creep testing machine to the target temperature; Sub-step 8.3: After the temperature in the high-temperature creep testing machine reaches the target temperature, maintain the preset holding time until the temperature of the specimen and the fixture is uniform; Sub-step 8.4: Apply a tensile load to the specimen until it reaches the target tensile load. When the tensile load reaches the target tensile load, start creep loading. Sub-step 8.5: When the specimen fractures under the coupled action of hot salt corrosion and creep load, stop the creep test and start cooling; Sub-step 8.6: After the specimen and fixture cool to room temperature, remove the specimen and fixture, and the test is complete. Sub-step 8.7: Ultrasonic clean the specimen and fixture using hot water, where the specimen is used for subsequent characterization analysis.

10. The hot salt corrosion-creep coupled test method for metal materials according to claim 9, characterized in that: The preset creep tensile load range is 150N-200N; The target temperature range is 800°C-1000°C; The target tensile load range is 5800N-14000N.

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