CN112881117A - Stress corrosion test method for high-strength steel material - Google Patents
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/32—Polishing; Etching
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0003—Steady
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
- G01N2203/024—Corrosive
Abstract
A stress corrosion test method for high-strength steel material includes electrochemical hydrogen charging test of tensile specimen, and selecting 3 g/L NH with solution temperature not lower than 28 deg.C4The introduction and balance of hydrogen in the material are ensured under the condition that the hydrogen charging time is more than or equal to 70h by using the SCN +3% NaCl aqueous solution, wherein the strength of the material of the tensile test piece is more than or equal to 1200MPa, and the current density is 10-50A/m2The hydrogen charging current seal is reduced along with the increase of the material strength of the tensile test piece, and after the hydrogen charging test, the tensile rate of the tensile test piece after the hydrogen charging is more than or equal to 10‑2s‑1The tensile testing machine performs tensile test, the tensile time is less than 5min, and the stress corrosion test is completed. Is suitable for the rapid test of hydrogen induced stress corrosion cracking of steel materials with the tensile strength of more than or equal to 1200MPa, and realizes the rapid, high-efficiency and high-reliability of high-strength and ultrahigh-strength steelAnd (6) evaluating.
Description
Technical Field
The invention belongs to the field of steel material performance test and failure research, and particularly relates to a high-strength steel material stress corrosion test method.
Background
In order to save resources, reduce cost, meet requirements of lightweight design and the like, the strength of steel structural materials is continuously improved. However, in practical application, it is found that after the strength of the high-strength structural steel exceeds a certain level, a stress corrosion cracking phenomenon occurs under the combined action of a service environment, wherein the loading stress is far lower than the yield strength, as shown in fig. 1, so that the practical significance of engineering application is lost in the ultra-high strength of the structural material. Generally, the steel material with the strength of more than 1200MPa belongs to ultrahigh-strength steel, and the traditional ultrahigh-strength steel is rarely applied as structural material engineering except for being widely applied in the special fields of aerospace, mining machinery wear-resistant parts and the like. In recent years, with the progress of steel material design and manufacturing technology and the increase of the demand of engineering design for application of ultra-high-strength materials, the application of ultra-high-strength steel materials is gradually tried in the fields of civil construction, machinery and other industries. The high strength and ultrahigh strength of steel materials are hot research spots, and ultrahigh strength steel is developed in large quantities. However, the test methods for evaluating the stress corrosion of ultra-high strength steels are slow to develop.
Numerous stress corrosion test methods have been developed to evaluate the reliability of high strength steel and ultra high strength steel engineering applications and the susceptibility of materials to delayed fracture. The current general standard mainly used is ISO 7539, ASTM G series and other standards. A plurality of stress corrosion test evaluation standards with industrial application characteristics are established in the fields of aerospace, oil and gas exploitation, prestressed structures and the like, such as NACE TM 0177, ISO 15630-3, ECSS-Q-70-37A and the like. The series of GB/T15970 corrosion-stress corrosion test of metals and alloys in China is equal to ISO 7539 standard. In the ISO 7539 standard, the method can be classified into: constant displacement, constant load, slow strain rate stretching, and gradual displacement/load method. These processes are all carried out at a strain-free rate or a slow strain rate to achieve sufficient diffusion and accumulation of hydrogen, which is a core factor contributing to hydrogen-induced stress corrosion cracking of high-strength, ultra-high-strength ferrous materials. Although the delayed fracture sensitivity of the steel material can be better evaluated by adopting a non-strain rate test or a slow strain rate test, the test period is long, the equipment occupancy rate is high, and the test under the large-scale and multi-state condition of the material is difficult to implement. And because many influencing factors, test process control are complicated in the long-period test, the test data is discrete, the test data samples are few, and a large amount of truncated data exists. The test cost is high, the data analysis difficulty is high, and the stress corrosion sensitivity of the high-strength material is difficult to efficiently and accurately evaluate.
In recent years, on the basis of a standard stress corrosion method, a large number of novel stress corrosion test methods are developed to meet the detection requirements of special environment working conditions and applications, but most of the patents are improved and optimized on a stress loading tool structure or an environment loading device, such as adding a cathode protection device, adopting a high-temperature high-pressure kettle and a fluid control system to adjust the experiment environment, designing an experiment loading device and the like, and the problems of overlong stress corrosion test period and the like caused by ensuring sufficient diffusion and aggregation of hydrogen in the experiment process are not solved. For example, a constant displacement stress corrosion test method using nut loading is introduced in a CN101109691A metal rod material stress corrosion test device and a test method thereof. CN105954179A introduces a test method for measuring the sensitivity of elemental sulfur stress corrosion cracking of a metal material, which adopts a bending method to load a sample and belongs to a constant displacement method for loading. The steel hydrogen embrittlement test device and the test method under the cathodic protection in CN105987847A marine environment introduce the constant stress method for loading; CN105987847A an interior balanced prestressed anchorage cable stress corrosion test system and introduced in the test method also carry out loading through a nut by a constant displacement method.
In the current stress corrosion test method, in order to obtain the stress corrosion performance related data of high-strength steel and ultrahigh-strength steel in a short time, the acceleration test is usually performed by means of increasing stress, making a notch to intensify local stress concentration, making a crack, increasing the concentration of a corrosion medium, and adopting a poisoning agent to intensify hydrogen adsorption. However, the diffusion adsorption of hydrogen and the sample loading are carried out synchronously or a slow strain rate tensile test is carried out after hydrogen is pre-charged, so that the test result is greatly influenced. The hydrogen diffusion adsorption and the sample loading are carried out synchronously, so that the experimental result is inaccurate due to the uneven and insufficient hydrogen diffusion. Particularly, in the case of a material having a high hydrogen trap, the uneven and insufficient diffusion of hydrogen is further accelerated. In the slow strain rate tensile test after hydrogen pre-charging, because the time is long in the subsequent tensile test, the phenomenon of surface hydrogen escape exists, and the accuracy of the test result is not high. The traditional high-strength steel material stress corrosion test method is not only used for material screening and research, but also difficult to be used as a large-scale industrial production application test method.
According to the existing research, the mechanical property of the hydrogen induced stress corrosion cracking of the high-strength and ultrahigh-strength steel is closely related to the fracture morphology, and the fracture strength, elongation and reduction of area of the material can be greatly reduced along with crystal cracking. In engineering application, the stress corrosion cracking crack source region of the high-strength and ultrahigh-strength material is basically in the shape of a crystal fracture, so that the identification of the fracture shape has important significance for judging the delayed fracture sensitivity of the material.
For high-strength and ultrahigh-strength steel materials with the tensile strength of more than or equal to 1200MPa, the material is in a hydrogen induced cracking type due to stress corrosion cracking, has high hydrogen induced stress corrosion sensitivity, and is the main solution direction for the research on the hydrogen induced stress corrosion cracking of the steel materials.
Disclosure of Invention
The invention provides a high-strength steel material stress corrosion test method, which is suitable for the rapid test of hydrogen-induced stress corrosion cracking of steel materials with the tensile strength of more than or equal to 1200MPa, and realizes the rapid, efficient and high-reliability evaluation of high-strength and ultrahigh-strength steel.
In order to realize the technical purpose, the adopted technical scheme is as follows: a stress corrosion test method for high-strength steel material includes electrochemical hydrogen charging test of tensile specimen, and selecting 3 g/L NH with solution temperature not lower than 28 deg.C4The introduction and balance of hydrogen in the material are ensured under the condition that the hydrogen charging time is more than or equal to 70h by using the SCN +3% NaCl aqueous solution, wherein the strength of the material of the tensile test piece is more than or equal to 1200MPa, and the current density is 10-50A/m2The hydrogen charging current seal is reduced along with the increase of the material strength of the tensile test piece, and after the hydrogen charging test, the tensile rate of the tensile test piece after the hydrogen charging is more than or equal to 10-2s-1The tensile testing machine performs tensile test, the tensile time is less than 5min, and the stress corrosion test is completed.
When the strength of the tensile test piece material is 1200-1300 MPa, the current density is 50A/m2。
When the strength of the tensile test piece material is 1300-1400 MPa, the current density is 40A/m2。
When the strength of the tensile test piece material is 1200-1300 MPa, the current density is 30A/m2。
When the strength of the tensile test piece material is 1500-1700 MPa, the current density is 20A/m2。
When the strength of the tensile test piece material is not less than 1700MPa, the current density is 10A/m2。
The solution temperature is 30 ℃, and the hydrogen charging time is 72 h.
The stretching speed of the tensile testing machine is 0.5 mm/min-25 mm/min.
Fracture morphology was analyzed by SEM inspection.
The invention has the beneficial effects that:
the invention can greatly improve the stress corrosion test efficiency of the high-strength material, and solve the problems of long test period, complex process influence factors and the like of constant displacement, constant load, slow strain rate stretching and the like. By implementing the method, the loading test period is shortened to be within 5min from more than 200h of conventional constant displacement and constant load and more than 48h of slow strain rate tensile test, and the test efficiency is greatly improved.
The evaluation method adopts the hydrogen charging and notch type samples with different current densities, has short hydrogen diffusion path and high hydrostatic stress level at the front edge of the notch, effectively ensures the saturation of the local hydrogen content of the material, and simulates the full accumulation of hydrogen under the stress induction action in engineering application. And the fracture mode can be fully identified by combining SEM inspection, and the accuracy of the test is effectively improved.
Drawings
FIG. 1 is a graph showing delayed fracture sensitivity of a conventional steel material according to tensile strength;
FIG. 2 is a schematic view of a stress-etched tensile notch specimen.
Detailed Description
Since the hydrogen-material-stress interaction belongs to the essential property of the material, and the diffusion and accumulation of hydrogen belongs to the process influence factor, the stress corrosion intrinsic sensitivity of the high-strength material is not reflected. The hydrogen induced stress corrosion cracking of high-strength materials in engineering application basically occurs at the level below the yield strength, and is not essentially connected with the macroscopic plastic deformation after loading, which is shown in that the fracture morphology is that a stress corrosion cracking source region basically presents the crystal-following cracking characteristic. The invention fully identifies the essential characteristics of hydrogen induced stress corrosion cracking of high-strength steel, innovatively adopts a standard tensile test bar, adopts an electrochemical method to introduce hydrogen with certain concentration into a tensile sample (test bar), adopts a conventional tensile test method to carry out tensile test, and carries out a material delayed fracture sensitivity evaluation test for confirming the fracture morphology of a material by observing a fracture through a scanning electron microscope, and the main invention contents are as follows:
adopting a tensile sample with a notch structure:
as shown in figure 2, the tensile sample adopted by the invention has the advantages that the diameter of the rod part of the working section is phi 7, and the diameter of the bottom of the notch position R is phi 5. The selection of a smaller rod part diameter is beneficial to the diffusion and homogenization of hydrogen in the subsequent electrochemical hydrogen charging process, the introduction and balance of hydrogen can be realized in a shorter time, a multidirectional tensile stress state can be established at the front edge position of the tip end of a notch by adopting a notch structure, the plastic deformation of a material is effectively restrained, the hydrogen-induced stress corrosion sensitivity of the material is improved, the critical hydrogen content of the material along crystal cracking is reduced, the sealing of threads of a clamping section can be conveniently realized by selecting a longer straight edge section at the clamping section of threads at two ends, the uniform hydrogen charging of the rod part in the electrochemical hydrogen charging process is ensured, the hydrogen charging current is reduced, the failure of the threads at the clamping end caused by the tip end effect is avoided, a shorter sample can be selected according to the actual blank condition, but the end sealing in the hydrogen charging process needs to be ensured, the notch selects a 60-degree included angle and the radius of the bottom of the R0.25 notch, and the, meanwhile, the size of the notch is a universal notch angle, related machining cutters and inspection tools can be conveniently selected, machining efficiency is improved, machining cost is reduced, the problems that the notch stress concentration coefficient is too high, discreteness caused by machining errors is too large and the like can be solved by selecting a fillet radius of R0.25, proper rigidity of a sample can be effectively guaranteed by selecting the specification of the phi 7/phi 5 working section, and additional stress caused by subsequent tensile test due to test bending in the machining and other processes is avoided. The sample structure of the invention is a preferable sample structure according to the characteristics of the high-strength material, and samples with other specifications can also be adopted.
(II) sample hydrogen filling is carried out by adopting an electrochemical hydrogen filling method:
the invention adopts an electrochemical method to charge hydrogen, and the electrochemical charging can effectively simulate the entry of corrosive hydrogen in the application process of the steel material. And can realize higher hydrogen charging efficiency, can introduce the hydrogen content meeting the test requirement in shorter time, especially for the invention, the material microcell hydrogen content level needs to reach the microcell gathered hydrogen content level under the stress induced concentration action, can be realized simply and conveniently through the electrochemical method. Meanwhile, under the influence of electrochemical cathode protection, the sample is not corroded to be damaged in the hydrogen charging process, and the size of the sample, particularly the stability of the fine size of the notch micro-area can be ensured. Other charging modes such as high-temperature gaseous charging and the like can be considered according to actual conditions.
The hydrogen filling test parameters of the present invention are shown in table 1 below:
TABLE 1 electrochemical Hydrogen Charge test parameters
Selecting 3 g/L NH4The SCN +3% NaCl water solution can realize good hydrogen charging efficiency and conductivity, and 3 g/L NH is adopted4The SCN serving as a hydrogen charging poisoning agent can ensure the stability of the cathode polarization process in the hydrogen charging process and reduce the influence of different materials.
The solution temperature of 30 ℃ is close to the ambient temperature and slightly higher than the ambient temperature, so that the equilibrium stability of temperature and the like can be realized by adopting a simple control means, and the adsorption and diffusion of cathode hydrogen can be fully ensured. The reduction of the adsorption efficiency caused by overhigh temperature can be avoided, and the problems of low diffusion speed, slow hydrogen homogenization and the like caused by overlow temperature can also be avoided.
The density of the hydrogen charging current is distinguished according to the strength grade of the material, although various optimization and improvement are carried out on the existing material to improve the hydrogen-induced stress corrosion resistance of the material, the trends of dislocation density increase, lattice distortion increase and the like caused by high strength of the material are kept consistent, and the content of sensitive hydrogen of the material is reduced along with the increase of the strength. Different charging current densities are selected according to different strength grades, so that the situation that the difference of different materials cannot be effectively compared due to too harsh tests caused by too high charging current densities can be avoided, and the situation that hydrogen induced stress corrosion cracking cannot be detected, particularly along crystal form cracking, cannot be detected due to too low hydrogen content can be avoided.
The hydrogen filling time is selected to be 72 hours, so that the saturation of the hydrogen content in the sample can be ensured, and the test time can be fully saved. And high efficiency test of the material is realized. Because electrochemical hydrogen charging can select multipath hydrogen charging, a plurality of samples can be charged at one time, and the efficiency is higher.
(III) adopting a common tensile test tensile rate to carry out a tensile test:
the tensile test of the invention does not need to adopt a customized slow tensile testing machine, and the tensile rate is more than or equal to 10-2s-1The conventional tensile testing machine can perform tensile test, so that the equipment investment is greatly saved. The speed of the crossbeam of the testing machine can be controlled within 0.5 mm/min-25 mm/min, the testing time can be completed within 5min, compared with the slow strain rate tensile test which is usually more than or equal to 48h, the testing method greatly saves the testing time and equipment occupation, and because the testing time is short, the diffusion, aggregation and escape of hydrogen can be almost ignored, the influence of factors such as the diffusion, aggregation and escape of hydrogen is greatly reduced, and the testing precision is improved. To avoid hydrogen evolution between the hydrogen charge and the tensile test, the test specimens should complete the tensile test within 10min after the hydrogen charge.
(IV) analyzing the fracture morphology by adopting SEM (scanning electron microscope)
In a traditional high-strength steel material stress corrosion test, strength, reduction of area or attenuation value of elongation are generally used as parameter indexes for evaluating the stress corrosion sensitivity of the material, but the indexes are closely related to the fracture mode of the material, for example, the material is cracked along crystal, the strength and the reduction of area of the material are sharply reduced, and the relative reduction amplitude of the elongation is smaller; for quasi-cleavage cracking, the strength reduction amplitude of the material is smaller; the elongation and the reduction of area will be reduced properly.
For the high-strength stress corrosion cracking resistant material containing a hydrogen trap developed at present, due to the trapping effect of the hydrogen trap on hydrogen, the concentration of hydrogen in a material grain boundary is difficult to reach a critical level in a short time by adopting a traditional test method, and the crystal-following cracking is difficult to occur, so that the hydrogen-induced stress corrosion sensitivity of the material is difficult to effectively detect by adopting a conventional slow strain rate tensile test, and after a high-current density hydrogen charging test, the hydrogen content of the material tends to be saturated, the hydrogen content in the material grain boundary can effectively reach the critical hydrogen content, the hydrogen-induced stress corrosion sensitivity of the material can be effectively detected, the detection effect is good, and the reliable evaluation of the material is effectively guaranteed.
The fracture is analyzed by adopting the SEM, so that the fracture mode of the notch can be effectively identified, the consistency of the test fracture behavior and the engineering application fracture behavior is ensured, and the accuracy of test evaluation is ensured.
(V) evaluation of Hydrogen induced stress Corrosion sensitivity of Material
And (3) evaluating the hydrogen induced stress corrosion sensitivity of the material by adopting (notch strength before hydrogen filling-notch strength after hydrogen filling)/notch strength before hydrogen filling, wherein the larger the value is, the higher the notch sensitivity is. And identifying the fracture morphology according to the SEM result, wherein the hydrogen induced stress corrosion cracking sensitivity of the material along the crystal fracture morphology is higher than that of the material with mixed morphology and through-crystal quasi-cleavage.
Example 1
The chemical components of the materials adopted in the test are shown in table 2, the materials are general alloy structural steel and ultrahigh-strength steel, the materials are smelted by a 50Kg vacuum furnace, forged into a phi 30 round bar, turned to a phi 25 round and then subjected to heat treatment, and the test bar is quenched and tempered to obtain the performances shown in table 3. And (4) processing the notch sample shown in the figure by adopting linear cutting sampling, and respectively carrying out slow strain rate stretching and normal stretching test after hydrogen charging.
TABLE 2 chemical composition of steel for test
TABLE 3 mechanical properties of the test steels after heat treatment
The slow strain rate tensile test is carried out by adopting a slow strain tensile testing machine, the displacement speed of the tensile testing machine is 0.005mm/min, a sample adopts the notched tensile test bar, and acetone ultrasonic cleaning is adopted before the test bar is loaded, so that oil stains on the surface are removed. In order to avoid the influence of the equipment clearance, the notch stress is loaded to 100MPa in advance, a solution loading groove is fixed on a sample, and 20 percent NH is adopted4The test was carried out with an aqueous SCN solution, the room temperature in the laboratory was kept constant at 25. + -. 2 ℃ and the breaking load of the specimen was recorded and converted to confirm the notched breaking strength. SEM examination is carried out on the fracture after the test, and the fracture morphology is shown in Table 4.
TABLE 4 test results of slow strain rate tensile testing machine
The invention adopts 3 g/L NH for the sample4SCN +3% NaCl solution, water bath constant temperature 30 ℃ +/-2, using programmable DC voltage-stabilizing current-stabilizing power supply to perform electrochemical hydrogen charging, wherein the hydrogen charging current density is shown in Table 5, and the hydrogen charging time is 72h +/-1 h. And immediately performing a tensile test after the hydrogen charging is finished, wherein the displacement speed of the cross beam of the tensile test tester is 1mm/min, and the tensile test is finished within 10min after the hydrogen charging is finished. After the tensile test, the fracture was examined by SEM, and the notch strength and the morphology after fracture are shown in table 5.
TABLE 5 results of conventional tensile test after electrochemical hydrogen charging of the invention
| Number plate | Current density of hydrogen charging | σbH (empty)/MPa | σbH (charging)/MPa | Fracture morphology |
| 42CrMo | 50A/m2 | 1897 | 1458 | Local grain boundary + transgrain mixing at notch edge |
| 45NiCr1Mo1V | 30A/m2 | 2218 | 1380 | Intergranular + transgranular mixing |
| 40CrNi2Si2NoVA | 10A/m2 | 2482 | 1138 | Mainly along the grain |
It can be seen from the comparison of tables 4 and 5 that the method of the present invention has good hydrogen induced delayed fracture test sensitivity, and for materials with Rm1200MPa addition and low hydrogen induced stress corrosion cracking sensitivity, the slow strain rate tensile test method is adopted to test that the materials are in transgranular cracking due to the difficulty of effective diffusion and aggregation of hydrogen, which is not in accordance with the practical engineering application.
Claims (9)
1. A stress corrosion test method for high-strength steel materials is characterized by comprising the following steps: performing hydrogen charging test on the tensile test piece by adopting an electrochemical method, and selecting 3 g/L NH with the solution temperature being more than or equal to 28 DEG C4The introduction and balance of hydrogen in the material are ensured under the condition that the hydrogen charging time is more than or equal to 70h by using the SCN +3% NaCl aqueous solution, wherein the strength of the material of the tensile test piece is more than or equal to 1200MPa, and the current density is 10-50A/m2The hydrogen charging current seal is reduced along with the increase of the material strength of the tensile test piece, and after the hydrogen charging test, the tensile rate of the tensile test piece after the hydrogen charging is more than or equal to 10-2s-1The tensile testing machine performs tensile test, the tensile time is less than 5min, and the stress corrosion test is completed.
2. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: when the tensile test piece material is strongWhen the temperature is 1200-1300 MPa, the current density is 50A/m2。
3. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: when the strength of the tensile test piece material is 1300-1400 MPa, the current density is 40A/m2。
4. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: when the strength of the tensile test piece material is 1200-1300 MPa, the current density is 30A/m2。
5. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: when the strength of the tensile test piece material is 1500-1700 MPa, the current density is 20A/m2。
6. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: when the strength of the tensile test piece material is not less than 1700MPa, the current density is 10A/m2。
7. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: the solution temperature is 30 ℃, and the hydrogen charging time is 72 h.
8. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: the stretching speed of the tensile testing machine is 0.5 mm/min-25 mm/min.
9. The stress corrosion test method of a high-strength steel material according to claim 1, characterized in that: fracture morphology was analyzed by SEM inspection.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115096727A (en) * | 2022-06-16 | 2022-09-23 | 中船双瑞(洛阳)特种装备股份有限公司 | Method for rapidly determining hydrogen embrittlement mechanism and sensitivity of high-strength steel |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104502196A (en) * | 2014-12-16 | 2015-04-08 | 东风商用车有限公司 | Device and method for detecting hydrogen embrittlement sensibility in high-strength steel surface treatment process |
| CN105300874A (en) * | 2015-09-11 | 2016-02-03 | 中国民航大学 | Stress corrosion and hydrogen measuring electrochemical in-situ measurement device under slow strain speed condition |
| JP2016057163A (en) * | 2014-09-09 | 2016-04-21 | 新日鐵住金株式会社 | Evaluation method of hydrogen embrittlement characteristic of steel material |
| JP2017044477A (en) * | 2015-08-24 | 2017-03-02 | 東京電力ホールディングス株式会社 | Hydrogen embrittlement test solution and test method for steel material with use of ammonium thiocyanate |
| CN107764663A (en) * | 2016-08-23 | 2018-03-06 | 张宇 | A kind of hydrogen embrittlement evaluation method |
| CN107764721A (en) * | 2016-08-23 | 2018-03-06 | 张宇 | Metal material delayed crack sensitivity evaluation method |
| CN107966362A (en) * | 2017-10-10 | 2018-04-27 | 中国科学院金属研究所 | A kind of metal plate-like sample dynamic is flushed with hydrogen tensile stress etching experimental rig |
| CN110006751A (en) * | 2019-04-10 | 2019-07-12 | 北京交通大学 | The appraisal procedure of high-intensitive nonmetallic inclusionsin steel |
-
2021
- 2021-01-13 CN CN202110043245.2A patent/CN112881117A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016057163A (en) * | 2014-09-09 | 2016-04-21 | 新日鐵住金株式会社 | Evaluation method of hydrogen embrittlement characteristic of steel material |
| CN104502196A (en) * | 2014-12-16 | 2015-04-08 | 东风商用车有限公司 | Device and method for detecting hydrogen embrittlement sensibility in high-strength steel surface treatment process |
| JP2017044477A (en) * | 2015-08-24 | 2017-03-02 | 東京電力ホールディングス株式会社 | Hydrogen embrittlement test solution and test method for steel material with use of ammonium thiocyanate |
| CN105300874A (en) * | 2015-09-11 | 2016-02-03 | 中国民航大学 | Stress corrosion and hydrogen measuring electrochemical in-situ measurement device under slow strain speed condition |
| CN107764663A (en) * | 2016-08-23 | 2018-03-06 | 张宇 | A kind of hydrogen embrittlement evaluation method |
| CN107764721A (en) * | 2016-08-23 | 2018-03-06 | 张宇 | Metal material delayed crack sensitivity evaluation method |
| CN107966362A (en) * | 2017-10-10 | 2018-04-27 | 中国科学院金属研究所 | A kind of metal plate-like sample dynamic is flushed with hydrogen tensile stress etching experimental rig |
| CN110006751A (en) * | 2019-04-10 | 2019-07-12 | 北京交通大学 | The appraisal procedure of high-intensitive nonmetallic inclusionsin steel |
Non-Patent Citations (5)
| Title |
|---|
| Y.S. DING ET AL.: "Gaseous hydrogen embrittlement of PH 13-8 Mo steel", 《JOURNAL OF NUCLEAR MATERIALS》, vol. 385, pages 538 - 544, XP026013794, DOI: 10.1016/j.jnucmat.2008.12.048 * |
| 张敬强等: "基于预充氢拉伸法的焊接接头氢致裂纹敏感性评价", 《焊接学报》, vol. 36, no. 05, 31 May 2015 (2015-05-31) * |
| 王毛球等: "氢对高强度钢缺口拉伸强度的影响", 《材料热处理学报》, vol. 27, no. 04, pages 57 - 60 * |
| 肖娜等: "高洁净度齿轮钢中非金属夹杂物的检测方法", 《工程科学学报》, vol. 42, no. 07, pages 912 - 921 * |
| 谌康等: "2000 MPa 级马氏体钢的氢脆敏感性", 《材料热处理学报》, vol. 38, no. 08, pages 76 - 82 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115096727A (en) * | 2022-06-16 | 2022-09-23 | 中船双瑞(洛阳)特种装备股份有限公司 | Method for rapidly determining hydrogen embrittlement mechanism and sensitivity of high-strength steel |
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