CN102033026A - Method for judging sample cracking through stress corrosion U-bend test - Google Patents
Method for judging sample cracking through stress corrosion U-bend test Download PDFInfo
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- CN102033026A CN102033026A CN2009101966494A CN200910196649A CN102033026A CN 102033026 A CN102033026 A CN 102033026A CN 2009101966494 A CN2009101966494 A CN 2009101966494A CN 200910196649 A CN200910196649 A CN 200910196649A CN 102033026 A CN102033026 A CN 102033026A
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Abstract
The invention belongs to the field of stress corrosion tests and in particular to a method for judging sample cracking through the stress corrosion test. The method comprises the following steps: firstly, fixing an acoustic emission probe of an acoustic emission instrument on a U-bend sample; secondly, coating an anti-corrosive layer outside the acoustic emission probe; thirdly, immersing the U-bend sample into test solution and starting the acoustic emission instrument to monitor the signal; and finally, waiting until the signal of the acoustic emission probe mutates, obtaining the generation time of the crack and completing the test. Through stress corrosion U-bend test, in the method, the generation time of the stress corrosion crack of the U-bend sample and the sample cracking time can be rapidly and accurately obtained, the experiment efficiency is greatly improved, the test workload is reduced, the acoustic emission instrument of the multichannel signal can be adopted to simultaneously carry out multiple parallel tests and vast time and energy in the work of periodical evaluation of the stress corrosion sensitivity of the ultrahigh strength steel automobile sheets is saved.
Description
Technical field
The invention belongs to the stress corrosion (cracking) test field, relate in particular to a kind of sample cracking determination methods of stress corrosion (cracking) test.
Background technology
U type bending test is a kind of constant strain stress corrosion (cracking) test method commonly used, and this method has advantages such as test is simple, sample is compact, can carry out synchronously in batches, is fit to very much factory and testing laboratory and uses.Its main process is that the length rectangular metal thin plate is processed into the U type and uses bolt, then sample is positioned over all after dates that are exposed to regulation in the particular environment medium, whether break to determine according to sample whether metal counter stress corrosion failure under specific environment is responsive, perhaps judge the difference of different materials Sensitivity of Stress Corrosion in specific environment, also can differentiate the susceptibility that stress corrosion takes place certain material in varying environment according to the time length that crackle occurs according to the time length that crackle occurs.
Sheet metal is curved U type sample needs special equipment and method, has mentioned the preparation method of U type bend specimen among the GB GB/T15970.3-1995, comprises that single-stage loads and the two-stage loading method.These two kinds of methods all are sheet metal to be placed on exert pressure with machine on the specific mould or pulling force carries out moulding, this forming method complicated operation, and will on particular machines equipment, carry out.
Whether whether sample stress corrosion takes place mainly crackle occurs according to specimen surface and judges, usually with the naked eye or low-power microscope in process of the test, sample is carried out routine observation and determines.There is the shortcoming of following four aspects in this method: the one, and must end test and just can observe; The 2nd, be discontinuity owing to observe, can not accurately judge the time that crackle produces; The 3rd, to some trickle crackles with the naked eye or low-power microscope often be not easy to find, thereby influence the judgement of counter stress corrosion susceptibility; The 4th, make regular check on the specimen surface crackle, loaded down with trivial details bothersome, workload is big.
Summary of the invention
Technical matters to be solved by this invention provides a kind of sample cracking determination methods of stress corrosion U type bending test, the acoustic emission signal of sending when monitoring sample cracking and fracture in real time by the instrument generation time that ruptured accurately.
A kind of sample cracking determination methods of stress corrosion U type bending test may further comprise the steps:
1) the acoustic emission probe with Acoustic radiating instrument is fixed on the U type bend specimen;
2) coating anticorrosive coat outside the acoustic emission probe;
3), open Acoustic radiating instrument and carry out signal monitoring with in the U type bend specimen immersion test solution;
4) sudden change appears in the signal up to the acoustic emission probe, and the time that obtains the crackle generation is finished test.
Also comprise step before the described step 1 with bolt U type bend specimen opening part.
In test can the corresponding Acoustic radiating instrument that adopts multi channel signals, synchronization monitoring is organized test more, obtains simultaneously that each parallel sample crackle produces and the situation of fracture.
The anticorrosive coat material is 704 bonding agents, epoxy resin, organosilicon bonding agent or AB glue in the described step 2.
Described U type bend specimen is the thick steel plate of 1～5mm, and U type bend radius is 8～15mm.
Described steel plate is high-strength steel Automobile Plate, 304 stainless steels, high-strength line-pipe steel.
Testing liquid is selected from tap water, 3.5～5% NaCl solution, 5% HCl solution, 5% H in the described step 3
2SO
4A kind of in the solution.
Carry out stress corrosion U type bending test by method of the present invention, judge by the acoustic emission signal that collects in the process of the test, first acoustic emission sudden change peak time corresponding is the time that sample cracks the earliest, stage casing acoustic emission signal sudden change peak shows that the sample crackle expands, and last acoustic emission peak time corresponding of suddenling change was the correct time of sample fracture when fracture took place sample.This method can obtain U type bend specimen stress corrosion cracking (SCC) generation time and sample fracture time fast and accurately, improved conventional efficient greatly, reduced the workload of test, can also carry out the parallel experiments of many groups simultaneously by adopting the multi channel signals Acoustic radiating instrument, in the appraisal of the Sensitivity of Stress Corrosion of cycle evaluation super-high strength steel Automobile Plate, save plenty of time and energy.
Description of drawings
Fig. 1 is the testing equipment synoptic diagram of stress corrosion U type bending test of the present invention;
The acoustic emission signal figure that Fig. 2 obtains for the test among the embodiment 1;
The acoustic emission signal figure that Fig. 3 obtains for the test among the embodiment 2;
The acoustic emission signal figure that Fig. 4 obtains for the test among the embodiment 3;
The acoustic emission signal figure that Fig. 5 obtains for the test among the embodiment 4.
Embodiment
Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used to the present invention is described and be not used in and limit the scope of the invention.Should be understood that in addition those skilled in the art can make various changes or modifications the present invention after the content of having read the present invention's statement, these equivalent form of values fall within the application's appended claims institute restricted portion equally.
A kind of sample cracking determination methods of stress corrosion U type bending test, as shown in Figure 1, choosing thickness is the DP980 shrend high-strength steel Automobile Plate of 3mm, be cut into the rectangular specimen of 150mm * 25mm, bending to radius behind the punching two ends is the U type sample of 10mm, pass the hole at sample two ends with bolt, fixedly U type sample opening part prevents to test resilience, and the acoustic emission probe of Acoustic radiating instrument is fixed on the U type bend specimen; Coating one deck 704 bonding agents outside the acoustic emission probe, prevent the probe corrosion, then in the NaCl solution with U type bend specimen immersion 3.5%, open Acoustic radiating instrument and carry out signal monitoring, as shown in Figure 2, begin to occur acoustic emission signal behind the 33h, stop test behind the 39h, by signal graph time of taking place that obtains ftractureing be 33h.
A kind of sample cracking determination methods of stress corrosion U type bending test, be with the difference of embodiment 1, choosing thickness is the MS1480 shrend high-strength steel Automobile Plate of 3mm, bending to radius behind the punching two ends is the U type sample of 12.5mm, and the acoustic emission of Acoustic radiating instrument is popped one's head in to be fixed on the U type bend specimen; Coating one deck epoxy resin outside the acoustic emission probe, prevent the probe corrosion, then U type bend specimen is immersed in the tap water, open Acoustic radiating instrument and carry out signal monitoring, as shown in Figure 3, begin to occur acoustic emission signal behind the 57h, stop test behind the 63h, obtain first acoustic emission jump signal peak time corresponding by signal graph, can judge that the time that begins to occur crackle is 57h.
A kind of sample cracking determination methods of stress corrosion U type bending test, be with the difference of embodiment 1, choosing thickness is 304 corrosion resistant plates of 1mm, and bending to radius behind the punching two ends is the U type sample of 8mm, and the acoustic emission of Acoustic radiating instrument is popped one's head in to be fixed on the U type bend specimen; Coating one deck organosilicon sealant outside the acoustic emission probe, prevent the probe corrosion, then in the HCl solution with U type bend specimen immersion 5%, open Acoustic radiating instrument and carry out signal monitoring, as shown in Figure 4, begin to occur acoustic emission signal behind the 65h, stop test behind the 118h, sample fracture is judged the rupture time that last acoustic emission sudden change pairing time 105h in peak is a sample, and acoustic emission signal is tending towards 0 and remain unchanged after the sample fracture.
A kind of sample cracking determination methods of stress corrosion U type bending test, be with the difference of embodiment 1, choosing thickness is the X100 pipe line steel of 5mm, and bending to radius behind the punching two ends is the U type sample of 15mm, and the acoustic emission of Acoustic radiating instrument is popped one's head in to be fixed on the U type bend specimen; Coating one deck AB glue outside the acoustic emission probe, prevent the probe corrosion, then in the sulfuric acid solution with U type bend specimen immersion 5%, open Acoustic radiating instrument and carry out signal monitoring, as shown in Figure 5, begin to occur acoustic emission signal behind the 45h, stop test behind the 58h, obtain first acoustic emission jump signal peak time corresponding by signal graph, can judge that the time that begins to occur crackle is 45h.
Need to prove, more than four kinds of embodiment in test can the corresponding Acoustic radiating instrument that adopts multi channel signals, synchronization monitoring can obtain simultaneously that each parallel sample crackle produces and the situation of fracture, improves the efficient of test.
Claims (7)
1. the sample of stress corrosion U type bending test cracking determination methods is characterized in that, may further comprise the steps:
1) the acoustic emission probe with Acoustic radiating instrument is fixed on the U type bend specimen;
2) coating anticorrosive coat outside the acoustic emission probe;
3), open Acoustic radiating instrument and carry out signal monitoring with in the U type bend specimen immersion test solution;
4) sudden change appears in the signal up to the acoustic emission probe, and the time that obtains the crackle generation is finished test.
2. the sample cracking determination methods of stress corrosion U type bending test as claimed in claim 1 is characterized in that: also comprise the step with bolt U type bend specimen opening part before the described step 1.
3. the sample cracking determination methods of stress corrosion U type bending test as claimed in claim 2, it is characterized in that: in test can the corresponding Acoustic radiating instrument that adopts multi channel signals, synchronization monitoring is organized test more, obtains the situation that each parallel sample crackle produces and ruptures simultaneously.
4. the sample cracking determination methods of stress corrosion U type bending test as claimed in claim 3, it is characterized in that: the anticorrosive coat material is 704 bonding agents, epoxy resin, organosilicon bonding agent or AB glue in the described step 2.
5. as the sample cracking determination methods of the described stress corrosion U of any claim type bending test in the claim 1～4, it is characterized in that: described U type bend specimen is the thick steel plate of 1～5mm, and U type crooked position radius-of-curvature is 8～15mm.
6. the sample cracking determination methods of stress corrosion U type bending test as claimed in claim 5, it is characterized in that: described steel plate is high-strength steel Automobile Plate, 304 stainless steels, high-strength line-pipe steel.
7. as the sample cracking determination methods of the described stress corrosion U of any claim type bending test in the claim 1～4, it is characterized in that: testing liquid is selected from tap water, 3.5～5% NaCl solution, 5% HCl solution, 5% H in the described step 3
2SO
4A kind of in the solution.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102706792A (en) * | 2012-05-18 | 2012-10-03 | 中国航空工业集团公司北京航空材料研究院 | Method for testing aging change of polymer material |
| CN103913393A (en) * | 2014-04-17 | 2014-07-09 | 南通大学 | Method for quickly calculating steel stress corrosion cracking time applicable to ocean engineering |
| CN104062196A (en) * | 2014-01-08 | 2014-09-24 | 中国石油大学(华东) | Corrosion fatigue life prediction method based on damage evolution |
| CN106442280A (en) * | 2016-08-27 | 2017-02-22 | 中石化炼化工程（集团）股份有限公司 | Device and method for detecting stress corrosion resistance |
| CN106596729A (en) * | 2016-12-22 | 2017-04-26 | 北京航空航天大学 | Method for monitoring fatigue crack propagation and evaluating hydrogen brittleness of 2.25Cr-1Mo steel based on sound emission |
| CN107219119A (en) * | 2017-04-25 | 2017-09-29 | 河海大学 | Acoustic emission detection cable corrosion of coating fatigue crack initiation and the test method of extension |
| CN107290213A (en) * | 2017-05-31 | 2017-10-24 | 江苏金钿实业有限公司 | A kind of wrist-watch corrosion-resistant detection method of steel bracelet |
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2009
- 2009-09-28 CN CN2009101966494A patent/CN102033026A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102706792A (en) * | 2012-05-18 | 2012-10-03 | 中国航空工业集团公司北京航空材料研究院 | Method for testing aging change of polymer material |
| CN104062196A (en) * | 2014-01-08 | 2014-09-24 | 中国石油大学(华东) | Corrosion fatigue life prediction method based on damage evolution |
| CN103913393A (en) * | 2014-04-17 | 2014-07-09 | 南通大学 | Method for quickly calculating steel stress corrosion cracking time applicable to ocean engineering |
| CN103913393B (en) * | 2014-04-17 | 2016-03-09 | 南通大学 | The quick projectional technique of a kind of Marine Engineering Steel stress corrosion crack time |
| CN106442280A (en) * | 2016-08-27 | 2017-02-22 | 中石化炼化工程（集团）股份有限公司 | Device and method for detecting stress corrosion resistance |
| CN106596729A (en) * | 2016-12-22 | 2017-04-26 | 北京航空航天大学 | Method for monitoring fatigue crack propagation and evaluating hydrogen brittleness of 2.25Cr-1Mo steel based on sound emission |
| CN106596729B (en) * | 2016-12-22 | 2019-03-29 | 北京航空航天大学 | 2.25Cr-1Mo the monitoring of steel crack Propagation and hydrogen embrittlement evaluation method |
| CN107219119A (en) * | 2017-04-25 | 2017-09-29 | 河海大学 | Acoustic emission detection cable corrosion of coating fatigue crack initiation and the test method of extension |
| CN107219119B (en) * | 2017-04-25 | 2020-04-21 | 河海大学 | Test method for detecting corrosion fatigue crack initiation and propagation of cable coating by acoustic emission |
| CN107290213A (en) * | 2017-05-31 | 2017-10-24 | 江苏金钿实业有限公司 | A kind of wrist-watch corrosion-resistant detection method of steel bracelet |
| CN107290213B (en) * | 2017-05-31 | 2019-08-20 | 江苏金钿实业有限公司 | A kind of corrosion-resistant detection method of wrist-watch steel bracelet |
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Application publication date: 20110427 |