Device for testing hydrogen-induced delayed fracture of high-strength steel

Abstract

The utility model relates to a device for testing hydrogen-induced delayed fracture of high-strength steel, which comprises an upper pressing cake, a lower pressing cake, an upper pressing block, a lower pressing block and a screw rod, a plurality of clamping grooves are uniformly distributed on the upper pressing block along the circumferential direction, the upper pressing block and the lower pressing block have the same structure, and the upper pressing cake and the lower pressing cake are connected on the screw rod in a penetrating manner; the upper pressing block and the lower pressing block are also connected to the threaded rod in a penetrating mode and are symmetrically arranged between the upper pressing cake and the lower pressing cake, a plurality of hydrogen-induced delayed fracture samples are arranged on corresponding clamping grooves of the upper pressing block and the lower pressing block respectively, the upper pressing cake and the upper pressing block can be locked and fixed to the threaded rod through nuts, and the lower pressing cake and the lower pressing block can be locked and fixed to the threaded rod through nuts. The hydrogen-induced delayed fracture experiment requirement of the high-strength steel with the pressure ranging from 1000 MPa to 2 GPa can be met, and reliable analysis data can be obtained when the hydrogen-induced delayed fracture experiment is carried out on the high-strength steel. Positioning and fixing holes are not required to be punched during sample preparation, a plurality of samples can be prepared by one clamp, and a bending test of a plurality of metal test pieces is allowed to be performed in one test.

Description

Technical Field

[0001] The utility model relates to the technical field of metal material evaluation, in particular to a device for testing hydrogen-induced delayed fracture of high-strength steel. Background Art

[0002] The higher the strength of steel, the greater the sensitivity to hydrogen embrittlement. Hydrogen embrittlement tests are generally used to evaluate the hydrogen-induced delayed fracture capability of high-strength steel.

[0003] There is no unified standard evaluation test method for delayed cracking of high-strength steel, but all test methods mainly include two steps: stress application step and accelerated hydrogen charging step. The utility model aims to design a fixture structure for clamping samples in order to achieve the above two test steps.

[0004] Patent document No. 107907416A discloses a brittleness detection device for spring washers, which includes a power device, a base, and a compression device arranged on the base; the spring washer is placed in the compression device for detection, and the power device drives the compression device to compress the spring washer, thereby detecting the brittleness of the spring washer; the invention can detect the brittleness of elastic washers with delayed fracture according to different detection standards, can be applied to the brittleness detection of spring washers of different shapes, can detect multiple elastic washers at the same time, has a simple structure, and has the characteristics of high test accuracy, low manufacturing cost, and high test efficiency, and has a good market prospect. However, the device cannot be applied to the test of hydrogen-induced delayed fracture capacity of lath-shaped high-strength steel. Utility Model Content

[0005] The purpose of the utility model is to provide a device for testing hydrogen-induced delayed fracture of high-strength steel, which can meet the requirements of hydrogen-induced delayed fracture test of high-strength steel with tensile strength of 1000MPa to 2GPa, and can obtain reliable analysis data when conducting hydrogen-induced delayed fracture test on high-strength steel. There is no need to drill positioning and fixing holes when preparing samples, and one fixture can complete multiple samples, allowing bending tests of multiple metal test pieces to be performed in one test.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A device for testing hydrogen-induced delayed fracture of high-strength steel comprises an upper pressing cake, a lower pressing cake, an upper pressing block, a lower pressing block and a screw rod, wherein the upper pressing block is evenly arranged with a plurality of slots along the circumferential direction, the upper pressing block and the lower pressing block have the same structure, the upper pressing cake and the lower pressing block are connected to the screw rod, the upper pressing block and the lower pressing block are also connected to the screw rod and are symmetrically arranged between the upper pressing cake and the lower pressing block, a plurality of hydrogen-induced delayed fracture specimens are respectively placed on the corresponding slots of the upper pressing block and the lower pressing block, the upper pressing cake and the upper pressing block can be locked and fixed by a nut and a screw rod, and the lower pressing cake and the lower pressing block can be locked and fixed by a nut and a screw rod.

[0008] The upper pressing block comprises a base and a sample support. The base is a regular polygon. The bottom surface of the sample support is provided with a card slot. Several sample supports are evenly arranged on several sides of the base and are integrally formed with the base.

[0009] The base is square and there are four sample supports.

[0010] The hydrogen-induced delayed fracture specimen is a rectangular specimen, and grooves are arranged at both ends of the rectangular specimen.

[0011] The length and width dimensions of the hydrogen-induced delayed fracture specimen are (30-35)×(180-200) mm.

[0012] During the downward bending test, the lower pressing cake and the lower pressing block are locked and fixed by nuts and screws. During the hydrogen-induced delayed fracture test after bending, the upper pressing cake and the upper pressing block are also locked and fixed by nuts and screws.

[0013] The upper pressed cake and the lower pressed cake are both circular.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1) The utility model solves the problem that the current hydrogen-induced delayed fracture test can only bend one sample at a time, requires drilling, has cumbersome procedures, is difficult to clamp and center, and has many experimental steps. Moreover, when one sample is bent, the stress is concentrated in the middle part, which is inconsistent with the actual stress of the parts. The utility model can perform prestressed loading bending tests on multiple samples at a time, and the stress is not concentrated only in the middle part, but the whole sample is stressed.

[0016] 2) The utility model can simplify the experimental process, greatly improve the experimental efficiency, and meet the increasing demand for high-strength steel hydrogen-induced delay experiments. It can be soaked in acid and does not react with hydrochloric acid.

[0017] 3) The utility model can meet the requirements of hydrogen-induced delayed cracking test of high-strength materials with tensile strength below 2Gpa. During the experiment, the sample is uniformly stressed and the experimental results are accurate and stable. This set of fixtures is simple to install the sample, and no drilling and positioning is required. It is directly fixed by screws, which reduces the preparation requirements of the sample. Multiple samples can be bent at one time, greatly improving the experimental efficiency. This fixture can not only be installed on imported hydraulic servo chucks, but also can be directly installed on mechanical domestic universal testing machines. It is easy to install and disassemble, not easy to damage, and compact and light. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model.

[0019] Figure 2 It is a schematic diagram of the upper pressing block in the utility model.

[0020] Figure 3 It is a schematic diagram of a sample in the present utility model.

[0021] In the figure: 1-screw, 2-nut, 3-upper press cake, 4-upper press block, 5-hydrogen induced delayed fracture specimen, 6-lower press block, 7-lower press cake, 8-slot, 9-base, 10-specimen support, 11-groove. DETAILED DESCRIPTION

[0022] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings:

[0023] like Figure 1-Figure 3 As shown, a device for testing hydrogen-induced delayed fracture of high-strength steel comprises an upper pressing cake 3, a lower pressing cake 7, an upper pressing block 4, a lower pressing block 6 and a screw rod 1. The upper pressing block 4 is evenly arranged with a plurality of slots 8 along the circumferential direction. The upper pressing block 4 has the same structure as the lower pressing block 6. The upper pressing cake 3 and the lower pressing block 7 are connected to the screw rod 1. The upper pressing block 4 and the lower pressing block 6 are also connected to the screw rod 1 and are symmetrically arranged between the upper pressing cake 3 and the lower pressing block 7. A plurality of hydrogen-induced delayed fracture specimens 5 are respectively placed on the slots 8 corresponding to the upper pressing block 4 and the lower pressing block 6. The upper pressing cake 3 and the upper pressing block 4 can be locked and fixed to the screw rod 1 by a nut 2, and the lower pressing cake 7 and the lower pressing block 6 can be locked and fixed to the screw rod 1 by a nut 2.

[0024] See Figure 2 The upper pressing block 4 includes a base 9 and a sample support 10. The base 9 is a regular polygon. The bottom surface of the sample support 10 is provided with a card slot 8. Several sample supports 10 are evenly arranged on several sides of the base 9 and are integrally formed with the base 9.

[0025] The base 9 is square, and there are four sample supports 10.

[0026] The hydrogen-induced delayed fracture specimen 5 is a rectangular specimen, and grooves 11 are provided at both ends of the rectangular specimen.

[0027] The length and width dimensions of the hydrogen-induced delayed fracture specimen 5 are (30-35)×(180-200) mm.

[0028] During the downward bending test, the lower pressing cake 7 and the lower pressing block 6 are locked and fixed to the screw rod 1 through the nut 2. During the hydrogen-induced delayed fracture test after bending, the upper pressing cake 3 and the upper pressing block 4 are also locked and fixed to the screw rod 1 through the nut 2.

[0029] The upper pressed cake 3 and the lower pressed cake 7 are both circular.

[0030] During the experiment, the hydrogen-induced delay test sample 5 is installed on the slots 8 of the upper pressing block 4 and the lower pressing block 6. Figure 1 After the assembly shown, the lower pressing cake 7 and the lower pressing block 6 are locked and fixed to the screw 1 by the nut 2 under the lower pressing cake 7 and the nut 2 on the lower pressing block 6, and the tail of the screw 1 is installed on the lower clamp of the universal testing machine and tightened. Through the universal testing machine, the screw is pressed down and bent according to different strain amounts. After bending, the nut 2 on the upper pressing cake 3 on the screw 1 and the nut 2 under the upper pressing block 4 are locked. After being removed from the universal testing machine and placed for 24 hours, it is immersed in a 0.1mol / L hydrochloric acid solution, and the container is a PET barrel. Hydrogen-induced delayed cracking test can be carried out.

[0031] The screw rod 1, the nut 2, the upper pressing cake 3 and the lower pressing cake 7 are all made of 316 stainless steel.

[0032] The upper pressing block 4 and the lower pressing block 6 are made of nylon material by 3D printing.

[0033] Embodiment 1:

[0034] In this embodiment, the bases 9 of the upper pressing block 4 and the lower pressing block 6 are square, and there are four sample supports 10 .

[0035] 1. Take 2Gpa hot-pressed steel, cut it into 4 30×180mm strips, and use wire cutting to process it. Figure 3 For the hydrogen-induced delayed fracture specimen 5 shown in the figure, the edges of the specimens shall be deburred and chamfered at 45° after the specimen processing is completed.

[0036] 2. Install the hydrogen-induced delayed fracture specimen 5 into the slots 8 of the upper pressing block 4 and the lower pressing block 6, and press Figure 1 After the assembly as shown, the lower pressing cake 7 and the lower pressing block 6 are locked and fixed to the screw rod 1 by the nut 2 under the lower pressing cake 7 and the nut 2 on the lower pressing block 6 .

[0037] 3. Install the tail of the screw 1 of the assembled sample fixture onto the lower fixture of the universal testing machine and clamp it.

[0038] 4. Start the tensile testing machine program and perform the bending test at a speed of 1mm / min according to the operating standard.

[0039] 5. After the experiment, tighten the nut 2 on the upper pressing cake 3 and the nut 2 under the upper pressing block 4. Remove the entire fixture and the sample, place them at room temperature for 24 hours, and then immerse them in a 0.1 mol / L hydrochloric acid solution in a PET container.

[0040] 6. Count the time from when the sample is placed in the hydrogen-containing medium, monitor in real time whether the sample cracks, and record the cracking time.

Claims

1. A device for testing hydrogen-induced delayed fracture of high-strength steel, characterized in that: It includes an upper pressing cake, a lower pressing cake, an upper pressing block, a lower pressing block and a screw rod. The upper pressing block is evenly arranged with a plurality of slots along the circumferential direction. The upper pressing block and the lower pressing block have the same structure. The upper pressing cake and the lower pressing block are connected to the screw rod. The upper pressing block and the lower pressing block are also connected to the screw rod and are symmetrically arranged between the upper pressing cake and the lower pressing block. A plurality of hydrogen-induced delayed fracture specimens are respectively placed on the corresponding slots of the upper pressing block and the lower pressing block. The upper pressing cake and the upper pressing block can be locked and fixed by nuts and screw rods, and the lower pressing cake and the lower pressing block can be locked and fixed by nuts and screw rods.

2. The device for testing hydrogen-induced delayed fracture of high-strength steel according to claim 1, characterized in that: The upper pressing block comprises a base and a sample support. The base is a regular polygon. The bottom surface of the sample support is provided with a card slot. Several sample supports are evenly arranged on several sides of the base and are integrally formed with the base.

3. The device for testing hydrogen-induced delayed fracture of high-strength steel according to claim 2, characterized in that: The base is square and there are four sample supports.

4. The device for testing hydrogen-induced delayed fracture of high-strength steel according to claim 1, characterized in that: The hydrogen-induced delayed fracture specimen is a rectangular specimen, and grooves are arranged at both ends of the rectangular specimen.

5. A high-strength steel hydrogen-induced delayed fracture testing device according to claim 1 or 4, characterized in that: The length and width dimensions of the hydrogen-induced delayed fracture specimen are (30-35)×(180-200) mm.

6. The device for testing hydrogen-induced delayed fracture of high-strength steel according to claim 1, characterized in that: During the downward bending test, the lower pressing cake and the lower pressing block are locked and fixed by nuts and screws. During the hydrogen-induced delayed fracture test after bending, the upper pressing cake and the upper pressing block are also locked and fixed by nuts and screws.

7. The device for testing hydrogen-induced delayed fracture of high-strength steel according to claim 1, characterized in that: The upper pressed cake and the lower pressed cake are both circular.

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