Test device and test method for simulating hydrogen embrittlement

Abstract

The invention relates to the technical field of hydrogen embrittlement tests, and relates to a hydrogen embrittlement simulation test device and a hydrogen embrittlement simulation test method. The sample assembly comprises a support, a tension-pressure sensor, a bolt sample, a nut and a cathode binding post, the bolt sample penetrates through a center hole of the tension-pressure sensor and an installation hole of the support, the nut arranged at the end of the bolt sample is screwed to the preload level through a wrench, the cathode binding post is arranged on the support, and the nut is arranged on the support. The cathode is connected to the cathode of the direct-current power supply; the sample assembly is placed in the electrolytic bath, and a proper amount of sodium hydroxide aqueous solution is poured into the electrolytic bath; the anode plate is placed in the electrolytic cell, the anode plate is connected with the positive electrode of the direct-current power source and serves as an anode, and the test sample is subjected to simulation test research and evaluation under the preload and hydrogen charging environment and under the condition closer to the real hydrogen embrittlement occurrence condition.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen embrittlement testing, and relates to a test device for fracture mode simulation research, and is specifically suitable for being a test device and a test method for simulating hydrogen embrittlement. Background Art

[0002] Hydrogen infiltration into the metal causes damage, which in turn causes metal parts to break under the continuous action of static stress below the material's yield limit. This is called hydrogen embrittlement fracture, or hydrogen embrittlement for short. Hydrogen embrittlement is caused by hydrogen atoms entering the metal, which can cause it to break under the action of residual stress or external stress generated during service. Metal parts may absorb hydrogen atoms during processes such as pickling or electroplating, or even in the working atmosphere, and break under the action of residual stress or static stress generated during service. Therefore, a large number of tests are needed to study and evaluate the hydrogen embrittlement sensitivity of metal parts in terms of materials, processes, and use processes, and to determine their hydrogen embrittlement tendency. The current methods for hydrogen embrittlement testing are mostly to increase the stress level step by step and maintain it for a long time to study its hydrogen embrittlement sensitivity and judge its hydrogen embrittlement tendency, such as GB / T 24185-2009 "Test method for determining the critical value of hydrogen embrittlement in steel by step-by-step force method", GB / T 3098.17-2000 "Preload test for hydrogen embrittlement of fasteners by parallel bearing surface method" and HB 5067.1-2005 "Hydrogen embrittlement test for plating process Part 1: Mechanical method". However, these test methods only simulate the need for a certain static stress level when hydrogen embrittlement occurs, and lack the hydrogen filling environment (hydrogen atom adsorption and action process). This makes the hydrogen embrittlement test somewhat distorted in simulating the process of hydrogen embrittlement. Summary of the invention

[0003] The purpose of the present invention is to provide a test device and test method for simulating hydrogen embrittlement, which can make the sample under preload and hydrogen-filled environment, closer to the actual hydrogen embrittlement occurrence conditions for simulation test research and evaluation, and can monitor and record the load level of hydrogen embrittlement in real time. It provides a better test device for hydrogen embrittlement research, hydrogen embrittlement sensitivity and tendency evaluation of metal materials or their products.

[0004] Technical solution:

[0005] A test device for simulating hydrogen embrittlement, the test device comprising:

[0006] A direct current power supply, a positive electrode and a negative electrode of the direct current power supply;

[0007] The sample assembly includes a bracket, a tension-compression sensor, a bolt sample, a nut and a cathode terminal. The bolt sample passes through the center hole of the tension-compression sensor and the mounting hole of the bracket. The nut arranged at the end of the bolt sample is tightened to the preload level using a wrench. The cathode terminal is arranged on the bracket and connected to the negative electrode of the DC power supply as a cathode.

[0008] An electrolytic cell, wherein the sample assembly is placed in the electrolytic cell, and an appropriate amount of sodium hydroxide aqueous solution is poured into the electrolytic cell;

[0009] An anode plate is placed in the electrolytic cell and connected to the positive electrode of a DC power supply to serve as an anode.

[0010] Furthermore, the test device also includes: a display instrument, which is connected to the tension-compression sensor via a data output line and is used to display the preload force generated after the bolt sample is tightened.

[0011] Furthermore, the cathode terminal is connected to the negative electrode of the DC power supply through a wire to serve as a cathode, and the anode plate is connected to the positive electrode of the DC power supply through a wire to serve as an anode.

[0012] Furthermore, the DC power supply is used to convert AC power into DC power and adjust the current and voltage required for electrolysis.

[0013] Furthermore, the anode plate material is 0Cr18Ni9 austenitic stainless steel plate.

[0014] Furthermore, the formula of the sodium hydroxide aqueous solution is: 500g sodium hydroxide+3L water.

[0015] The test method using the test device simulating hydrogen embrittlement comprises the following steps:

[0016] Step 1: First, the metal material or its workpiece to be subjected to the hydrogen embrittlement simulation test is machined into a bolt specimen;

[0017] Step 2: Pass the bolt specimen through the center hole of the tension-compression sensor and the mounting hole of the bracket, and tighten the nut with a wrench to achieve the preload level required for the test;

[0018] Step 3: At this time, the preload required for the test measured by the tension-compression sensor is displayed in real time on the display instrument through the data output line;

[0019] Step 4: Place the sample assembly consisting of the bracket, tension-compression sensor, bolt sample, nut, data output line, display instrument and cathode terminal in the electrolytic cell, and connect the negative electrode of the DC power supply to the cathode terminal through a wire, which serves as the cathode;

[0020] Step 5: Connect the positive pole of the DC power supply and the anode plate through a wire to serve as the anode;

[0021] Step 6: Pour an appropriate amount of sodium hydroxide aqueous solution into the electrolytic cell as an electrolyte solution;

[0022] Step 7: Turn on the DC power supply, adjust the current and voltage appropriately, and the sodium hydroxide aqueous solution in the electrolytic cell releases oxygen at the anode end and hydrogen at the cathode end under the action of electrolysis. The simulated bolt specimen is kept under the combined action of hydrogen and stress for a period of time;

[0023] Step 8: After the simulated hydrogen embrittlement test is completed, turn off the DC power supply, remove the nut, take out the bolt sample, and use non-destructive testing, stereo microscope or scanning electron microscope to check whether the bolt sample has hydrogen embrittlement cracks.

[0024] Further, in step 7, the simulated bolt sample is maintained under the combined action of hydrogen and stress for 24 hours or 72 hours.

[0025] Beneficial effects: The present invention provides a test device and test method for simulating hydrogen embrittlement, which can make the sample in a preload and hydrogen-filled environment, closer to the actual hydrogen embrittlement occurrence conditions for simulation test research and evaluation, and can monitor and record the load level of hydrogen embrittlement in real time. It provides a better test device for hydrogen embrittlement research, hydrogen embrittlement sensitivity and tendency evaluation of metal materials or their products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the test device for simulating hydrogen embrittlement;

[0027] Among them: 1-DC power supply, 2-wire, 3-electrolytic cell, 4-anode plate, 5-sample assembly.

[0028] Figure 2 It is a schematic diagram of the sample component structure.

[0029] Wherein: 6- bracket, 7- tension-compression sensor, 8- bolt sample, 9- nut, 10- data output line, 11- display instrument, 12- cathode terminal;

[0030] Figure 3 This is the view of the TC4 titanium alloy sample under a microscope after the hydrogen embrittlement test;

[0031] Figure 4 This is the view of the 15-5PH sample under a microscope after the hydrogen embrittlement test. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides a test device for simulating hydrogen embrittlement, which can make the sample in a preloaded and hydrogen-filled environment, closer to the actual hydrogen embrittlement occurrence conditions for simulation test research and evaluation, and can monitor and record the load level of hydrogen embrittlement in real time. It provides a better test device for hydrogen embrittlement research, hydrogen embrittlement sensitivity and tendency evaluation of metal materials or their products.

[0034] One embodiment of the present invention is to provide a test device for simulating hydrogen embrittlement ( Figure 1-2 ), including a DC power supply 1, a conductor 2, an electrolytic cell 3, an anode plate 4, a sample assembly 5, a bracket 6, a tension-compression sensor 7, a bolt sample 8, a nut 9, a data output line 10, a display instrument 11 and a cathode terminal 12. Figure 2 The bolt sample 8 is passed through the center hole of the tension-compression sensor 7 and the mounting hole of the bracket 6, and the nut 9 is tightened with a wrench to the preload level. At this time, the tension-compression sensor 7 will display the preload force of the bolt sample 8 in real time through the connected data output line 10 and the display instrument 11. After the sample assembly 5 consisting of the bracket 6, the tension-compression sensor 7, the bolt sample 8, the nut 9, the data output line 10, the display instrument 11 and the cathode terminal 12 is installed, it is placed in the electrolytic cell 3, and the wire 2 is connected to the cathode terminal 12 as the cathode. The wire 2 is connected to the anode plate 4 as the anode. The wires 2 connecting the anode and the cathode are connected to the positive and negative electrodes of the DC power supply 1, and an appropriate amount of sodium hydroxide aqueous solution (500g NaOH+3L H2O) is poured into the electrolytic cell 3 as an electrolyte solution. Turn on the DC power supply 1, adjust the current and voltage appropriately, and the sodium hydroxide aqueous solution in the electrolytic cell 3 releases oxygen at the anode end and hydrogen at the cathode end under the action of electrolysis. Bolt specimen 8 can complete the hydrogen embrittlement simulation test under the action of both static stress and hydrogen atom adsorption and penetration.

[0035] The second embodiment of the present invention provides a test method for a test device simulating hydrogen embrittlement. The specific operation process is as follows:

[0036] Step 1: First, the metal material or its product to be subjected to the hydrogen embrittlement simulation test is machined into a bolt specimen 8.

[0037] Step 2: Pass the bolt specimen 8 through the center hole of the tension-compression sensor 7 and the mounting hole of the bracket 6, and tighten the nut 9 with a wrench to achieve the preload level required for the test.

[0038] Step 3: At this time, the preload required for the test measured by the tension-compression sensor 7 is displayed in real time on the display instrument 11 through the data output line 10.

[0039] Step 4: Place the sample assembly 5 consisting of the bracket 6, tension-compression sensor 7, bolt sample 8, nut 9, data output line 10, display instrument 11 and cathode terminal 12 in the electrolytic cell 3, and connect the wire 2 to the cathode terminal 12 as a cathode.

[0040] Step 5: Connect the wire 2 to the anode plate 4 as an anode.

[0041] Step 6: Connect the respective wires 2 connecting the anode and the cathode to the positive and negative electrodes of the DC power supply 1, and pour an appropriate amount of sodium hydroxide aqueous solution (500g NaOH+3L H2O) into the electrolytic cell 3 as an electrolyte solution.

[0042] Step 7: Turn on the DC power supply 1, and adjust the current and voltage appropriately. Under the action of electrolysis, the sodium hydroxide aqueous solution in the electrolytic cell 3 releases oxygen at the anode end and hydrogen at the cathode end.

[0043] Step 8: After the simulated hydrogen embrittlement test is completed, turn off the DC power supply 1, disassemble the corresponding device, take out the bolt sample 8, and use non-destructive testing, stereo microscope or scanning electron microscope to check whether the bolt sample 8 has hydrogen embrittlement cracks.

[0044] The present invention proposes a test device and method for simulating hydrogen embrittlement, which can transmit the preload level of the prepared standard bolt sample by tightening in real time through a tension-compression sensor. According to the principle of electrolyzing sodium hydroxide aqueous solution, the anode releases oxygen, and the cathode releases hydrogen, an electrolysis method is used to provide a hydrogen-filled environment for the prepared standard bolt sample. The sample is simulated under conditions where hydrogen embrittlement occurs, and the load level of hydrogen embrittlement occurring in the hydrogen-filled environment can be monitored and recorded in real time.

[0045] The third embodiment of the present invention is to provide a test device and method for simulating hydrogen embrittlement, which are applied to the study of reversible hydrogen embrittlement of the containment ring of TC4 titanium alloy. Through the test device, the relationship between the static stress and hydrogen embrittlement of the containment ring of TC4 titanium alloy under each heat treatment state and each organizational morphology is studied, and the critical value of hydrogen embrittlement stress intensity under various organizational morphologies is found.

[0046] Step 1: First, the containment ring of the TC4 titanium alloy to be subjected to the hydrogen embrittlement simulation test is machined into a bolt specimen.

[0047] Step 2: Pass the bolt specimen through the center hole of the tension-compression sensor and the mounting hole of the bracket, and tighten the nut with a wrench to achieve the preload level of 12.3 kN required for the test.

[0048] Step 3: At this time, the preload required for the test measured by the tension-compression sensor is displayed in real time on the display instrument through the data output line.

[0049] Step 4: Place the sample assembly consisting of the bracket, tension-compression sensor, bolt specimen made of TC4 titanium alloy containing ring, nut, data output line, display instrument and cathode terminal in the electrolytic cell, and connect the wire to the cathode terminal as the cathode.

[0050] Step 5: Connect the wire to the anode plate as the anode.

[0051] Step 6: Connect the wires connecting the anode and cathode to the positive and negative electrodes of the DC power supply, and pour an appropriate amount of sodium hydroxide aqueous solution (500g NaOH+3L H2O) into the electrolytic cell as an electrolyte solution.

[0052] Step 7: Turn on the DC power supply and adjust the current and voltage appropriately. Under the action of electrolysis, the sodium hydroxide aqueous solution in the electrolytic cell releases oxygen at the anode end and hydrogen at the cathode end.

[0053] Step 8: After the 24-hour simulated hydrogen embrittlement test is completed, turn off the DC power supply, disassemble the corresponding device, take out the bolt sample, and use a scanning electron microscope to check whether the bolt sample has hydrogen embrittlement cracks. If cracks are found ( Figure 3 ), confirming that hydrogen embrittlement has occurred.

[0054] The fourth embodiment of the present invention provides a test device and method for simulating hydrogen embrittlement, which are applied to the research of 15-5PH. Before the chrome plating treatment of the 15-5PH piston rod, the test device is used to evaluate and inspect its hydrogen embrittlement sensitivity and tendency. It is ensured that the chrome plating treatment of the 15-5PH piston rod does not produce hydrogen embrittlement.

[0055] Step 1: First, machine the 15-5PH precipitation hardened stainless steel piston rod to be subjected to the hydrogen embrittlement simulation test into a bolt specimen.

[0056] Step 2: Pass the bolt specimen through the center hole of the tension-compression sensor and the mounting hole of the bracket, and tighten the nut with a wrench to achieve the preload level of 20kN required for the test.

[0057] Step 3: At this time, the preload required for the test measured by the tension-compression sensor is displayed in real time on the display instrument through the data output line.

[0058] Step 4: Place the sample assembly consisting of the bracket, tension-compression sensor, bolt specimen made of 15-5PH precipitation hardened stainless steel piston rod, nut, data output line, display instrument and cathode terminal in the electrolytic cell, and connect the wire to the cathode terminal as the cathode.

[0059] Step 5: Connect the wire to the anode plate as the anode.

[0060] Step 6: Connect the wires connecting the anode and cathode to the positive and negative electrodes of the DC power supply, and pour an appropriate amount of sodium hydroxide aqueous solution (500g NaOH+3L H2O) into the electrolytic cell as an electrolyte solution.

[0061] Step 7: Turn on the DC power supply and adjust the current and voltage appropriately. Under the action of electrolysis, the sodium hydroxide aqueous solution in the electrolytic cell releases oxygen at the anode end and hydrogen at the cathode end.

[0062] Step 8: After the simulated hydrogen embrittlement test is completed for 72 hours, turn off the DC power supply, dismantle the corresponding device, take out the bolt sample, and use a scanning electron microscope to check whether the bolt sample has hydrogen embrittlement cracks. If cracks are found ( Figure 4 ), confirming that hydrogen embrittlement has occurred. This batch of 15-5PH precipitation hardened stainless steel piston rods has large internal stress and is prone to hydrogen embrittlement during the chrome plating process. The heat treatment process needs to be readjusted to reduce its internal stress and avoid hydrogen embrittlement.

Claims

1. A test device for simulating hydrogen embrittlement, characterized in that: The test device comprises: A direct current power supply, a positive electrode and a negative electrode of the direct current power supply; The sample assembly includes a bracket, a tension-compression sensor, a bolt sample, a nut and a cathode terminal. The bolt sample passes through the center hole of the tension-compression sensor and the mounting hole of the bracket. The nut arranged at the end of the bolt sample is tightened to the preload level using a wrench. The cathode terminal is arranged on the bracket and connected to the negative electrode of the DC power supply as a cathode. An electrolytic cell, wherein the sample assembly is placed in the electrolytic cell, and an appropriate amount of sodium hydroxide aqueous solution is poured into the electrolytic cell; An anode plate is placed in the electrolytic cell and connected to the positive electrode of a DC power supply to serve as an anode.

2. The test device for simulating hydrogen embrittlement according to claim 1, characterized in that: The test device further comprises: a display instrument, which is connected to the tension-compression sensor via a data output line and is used to display the pre-tightening force generated after the bolt sample is tightened.

3. The test device for simulating hydrogen embrittlement according to claim 2, characterized in that: The cathode terminal is connected to the negative electrode of the DC power supply through a wire as a cathode, and the anode plate is connected to the positive electrode of the DC power supply through a wire as an anode.

4. The test device for simulating hydrogen embrittlement according to claim 3, characterized in that: The DC power supply is used to convert AC power into DC power and adjust the current and voltage required for electrolysis.

5. The test device for simulating hydrogen embrittlement according to claim 4, characterized in that: The anode plate material is 0Cr18Ni9 austenitic stainless steel plate.

6. The test device for simulating hydrogen embrittlement according to claim 5, characterized in that: The formula of the sodium hydroxide aqueous solution is: 500g sodium hydroxide+3L water.

7. A test method using the test device for simulating hydrogen embrittlement as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: First, the metal material or its workpiece to be subjected to the hydrogen embrittlement simulation test is machined into a bolt specimen; Step 2: Pass the bolt specimen through the center hole of the tension-compression sensor and the mounting hole of the bracket, and tighten the nut with a wrench to achieve the preload level required for the test; Step 3: At this time, the preload required for the test measured by the tension-compression sensor is displayed in real time on the display instrument through the data output line; Step 4: Place the sample assembly consisting of the bracket, tension-compression sensor, bolt sample, nut, data output line, display instrument and cathode terminal in the electrolytic cell, and connect the negative electrode of the DC power supply to the cathode terminal through a wire, which serves as the cathode; Step 5: Connect the positive pole of the DC power supply and the anode plate through a wire to serve as the anode; Step 6: Pour an appropriate amount of sodium hydroxide aqueous solution into the electrolytic cell as an electrolyte solution; Step 7: Turn on the DC power supply, adjust the current and voltage appropriately, and the sodium hydroxide aqueous solution in the electrolytic cell releases oxygen at the anode end and hydrogen at the cathode end under the action of electrolysis. The simulated bolt specimen is kept under the combined action of hydrogen and stress for a period of time; Step 8: After the simulated hydrogen embrittlement test is completed, turn off the DC power supply, remove the nut, take out the bolt sample, and use non-destructive testing, stereo microscope or scanning electron microscope to check whether the bolt sample has hydrogen embrittlement cracks.

8. The test method of the test device for simulating hydrogen embrittlement according to claim 7, characterized in that: In step 7, the simulated bolt specimen is maintained under the combined action of hydrogen and stress for 24 hours or 72 hours.

Images