CN106018046A - Method for etching surface crack defect of sample - Google Patents
Method for etching surface crack defect of sample Download PDFInfo
- Publication number
- CN106018046A CN106018046A CN201610567954.XA CN201610567954A CN106018046A CN 106018046 A CN106018046 A CN 106018046A CN 201610567954 A CN201610567954 A CN 201610567954A CN 106018046 A CN106018046 A CN 106018046A
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- China
- Prior art keywords
- etchant
- sample
- specimen
- precracked
- crack defect
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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
Abstract
The invention provides a method for etching a surface crack defect of a sample. The method comprises the following steps: (I) conducting electrolytic polishing with the voltage of 50 to 60v on the cracked sample for 65 to 75s, and socking the polished cracked sample in an etchant for 20 to 120s, wherein the etchant is a 2 to 5% nitric alcohol solution; (II) slightly moving the sample in the etching process to ensure that the etchant flows slowly on the ground surface of the sample to promote overflow of bubbles, and taking out the sample after the ground surface turns dark; (III) soaking the sample into anhydrous ethanol, and moving an observation surface slightly, wherein the step (III) can be carried out repeatedly for cleaning till foul and impurities near cracks are removed; (IV) after cleaning, taking out the sample, and finally, carefully wiping the etched surface with medical absorbent cotton. The method provided by the invention has the advantages that the accuracy and the reliability of a test result are greatly improved; the operation is simple; the time consumption is low; the method is one of effective methods for re-test of samples with crack defects.
Description
Technical field
The present invention relates to etching pit method, a kind of method that specimen surface crack defect is corroded.
Background technology
Metallographic Analysis is one of important means of check analysis material, it is intended to disclose the real structure of material, in the industrial production, owing to a variety of causes can produce damage to hardware and machine components, these damages are by along with the use of hardware and part develops into micro-crack or expands to macroscopic cracking, part breaking is caused to lose efficacy, so analysis on cracks is the important content of parts failure cause analysis and deduction the most at last.
In metallographic is tested, the sample preparation for crackle is generally divided into two kinds, i.e. polishing state and corrosion state, the purpose that polishing state sample corrodes further is to observe its microscopic structure, thus analyzes fracture origin and propagation direction and the load condition of fracture process；The caustic solution that laboratory is conventional at present is: by sample burnishing surface upwards, is completely immersed in etchant (general steel sample commonly uses the nital that etchant is 2-5%) and stops certain time taking-up, then through rinsing, drying up.But for precracked specimen, because there is the gap of different depth in its surface, when though sample takes out through rinsing and drying up from etchant, owing to crackle gap still remaining a part of chemical reagent and moisture, and prolongation over time, residue can the most outwards ooze out, and causes the sightingpiston near crackle to get rusty and cannot observe its tissue original appearance；It can thus be seen that the metallographic sample preparation level of precracked specimen, decide the degree that failure analysis conclusion is correct to a great extent.
The many disadvantages existed in view of existing cracking corrosion method, people are improved at a lot of aspects, such as changed, by traditional cold water flush, the sample taken out from etchant into hot water injection, shorten the etching time of precracked specimen in the lab as far as possible, that finds and improve sample most preferably dries up angle etc., but solves the most well to blend the key issues such as crackle periphery gets rusty outside residue near crackle.
Summary of the invention
The technical problem to be solved is:
(1) the most well solve to blend outside residue near crackle the key issues such as crackle periphery gets rusty；
(2) how particularly in the step of etch and cleaning, sample to be isolated entirely from water in whole corrosion process, improving accuracy and the reliability of experimental result；
The present invention solves the technical scheme of above technical problem:
A kind of method corroding specimen surface crack defect, comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 50-60v, and polishing time is 65-75s, is immersed in etchant by the precracked specimen completing polishing, and etchant is the nital of 2-5%, stops the time of 20-120s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
The technical scheme that the present invention further limits as:
The aforesaid method corroding specimen surface crack defect, structural alloy steel selected by sample.
The aforesaid method corroding specimen surface crack defect, comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 50v, and polishing time is 65s, is immersed in etchant by the precracked specimen completing polishing, and etchant is the nital of 2%, stops the time of 20s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
The aforesaid method corroding specimen surface crack defect, comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 60v, and polishing time is 75s, is immersed in etchant by the precracked specimen completing polishing, and etchant is the nital of 5%, stops the time of 120s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
The invention has the beneficial effects as follows: in the process particularly etch and cleaning step of whole corrosion, owing to sample is completely separated with water, reduce the probability blending periphery generation corrosion near crackle outside residue to a great extent, can preferably retain original tissue topography, thus substantially increase accuracy and the reliability of experimental result, and the method is simple to operation, expending the time few, conventional efficient is high.
Detailed description of the invention
Embodiment 1
The present embodiment provides a kind of method corroding specimen surface crack defect, and structural alloy steel 4137MA selected by steel grade, and the method comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 50v, and polishing time is 65s, is immersed in etchant by the precracked specimen completing polishing, and described etchant is the nital of 2%, stops the time of 20s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
Embodiment 2
The present embodiment provides a kind of method corroding specimen surface crack defect, and structural alloy steel 4137MA selected by steel grade, and the method comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 60v, and polishing time is 75s, is immersed in etchant by the precracked specimen completing polishing, and described etchant is the nital of 5%, stops the time of 120s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
Embodiment 3
The present embodiment provides a kind of method corroding specimen surface crack defect, and structural alloy steel 4137MA selected by steel grade, and the method comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 55v, and polishing time is 70s, is immersed in etchant by the precracked specimen completing polishing, and described etchant is the nital of 4%, stops the time of 80s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
In addition to the implementation, the present invention can also have other embodiments.The technical scheme that all employing equivalents or equivalent transformation are formed, all falls within the protection domain of application claims.
Claims (4)
1. the method that specimen surface crack defect is corroded, it is characterised in that the described method corroding specimen surface crack defect comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 50-60v, and polishing time is 65-75s, is immersed in etchant by the precracked specimen completing polishing, and described etchant is the nital of 2-5%, stops the time of 20-120s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
The method that specimen surface crack defect is corroded the most according to claim 1, it is characterised in that: structural alloy steel selected by described sample.
The method that specimen surface crack defect is corroded the most according to claim 1, it is characterised in that: the described method corroding specimen surface crack defect comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 50v, and polishing time is 65s, is immersed in etchant by the precracked specimen completing polishing, and described etchant is the nital of 2%, stops the time of 20s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
The method that specimen surface crack defect is corroded the most according to claim 1, it is characterised in that: the described method corroding specimen surface crack defect comprises the following steps:
(1) precracked specimen is polished by the electrobrightening using voltage to be 60v, and polishing time is 75s, is immersed in etchant by the precracked specimen completing polishing, and described etchant is the nital of 5%, stops the time of 120s in etchant；
(2) at precracked specimen slight mobile sample during etch, try etchant sluggish flow on flour milling, promote bubble to overflow, observe after flour milling becomes ash dead color and take out；
(3) it is dipped in dehydrated alcohol after taking out sample and slightly moves sightingpiston, can repeatedly immerse in dehydrated alcohol and clean, to wash the booty near crackle and foreign material；
(4) it is drawn off after cleaning, then with medical absorbent cotton, erosional surface is carefully dried.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610567954.XA CN106018046A (en) | 2016-07-19 | 2016-07-19 | Method for etching surface crack defect of sample |
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| CN201610567954.XA CN106018046A (en) | 2016-07-19 | 2016-07-19 | Method for etching surface crack defect of sample |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108918568A (en) * | 2018-08-02 | 2018-11-30 | 洛阳Lyc轴承有限公司 | A kind of analysis test method for bearing inner packing harmful element |
| CN110320074A (en) * | 2019-06-27 | 2019-10-11 | 东方电气集团东方锅炉股份有限公司 | A kind of processing method after the metallographic specimen etch with crack defect |
| CN110940580A (en) * | 2018-09-21 | 2020-03-31 | 天津大学 | Method for calculating stress intensity factor of passivated stress corrosion crack tip |
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| JP2010133830A (en) * | 2008-12-04 | 2010-06-17 | Toyota Motor Corp | Method of evaluating solder junction state, and chip component for evaluating solder junction state |
| CN101788413A (en) * | 2010-02-08 | 2010-07-28 | 宁波华舜铝材有限公司 | Method for preparing lead and lead alloy metallic phase samples and exposing texture |
| CN104111230A (en) * | 2014-06-19 | 2014-10-22 | 中国科学院金属研究所 | Classified display and quantitative detection method for martensite and residual austenite in M-A island |
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2016
- 2016-07-19 CN CN201610567954.XA patent/CN106018046A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101058884A (en) * | 2007-05-31 | 2007-10-24 | 中国铝业股份有限公司 | Magnesium alloy etching agent and using method thereof |
| JP2010133830A (en) * | 2008-12-04 | 2010-06-17 | Toyota Motor Corp | Method of evaluating solder junction state, and chip component for evaluating solder junction state |
| CN101581639A (en) * | 2009-06-26 | 2009-11-18 | 西北有色金属研究院 | Method for metallographic corrosion of welding surface of titanium steel plate welded by silver based solder |
| CN101788413A (en) * | 2010-02-08 | 2010-07-28 | 宁波华舜铝材有限公司 | Method for preparing lead and lead alloy metallic phase samples and exposing texture |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108918568A (en) * | 2018-08-02 | 2018-11-30 | 洛阳Lyc轴承有限公司 | A kind of analysis test method for bearing inner packing harmful element |
| CN110940580A (en) * | 2018-09-21 | 2020-03-31 | 天津大学 | Method for calculating stress intensity factor of passivated stress corrosion crack tip |
| CN110940580B (en) * | 2018-09-21 | 2022-05-20 | 天津大学 | Method for calculating stress intensity factor of passivated stress corrosion crack tip |
| CN110320074A (en) * | 2019-06-27 | 2019-10-11 | 东方电气集团东方锅炉股份有限公司 | A kind of processing method after the metallographic specimen etch with crack defect |
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