CN102778457A - Method for detecting toughness of bainite steel welding point - Google Patents
Method for detecting toughness of bainite steel welding point Download PDFInfo
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- CN102778457A CN102778457A CN2012102693176A CN201210269317A CN102778457A CN 102778457 A CN102778457 A CN 102778457A CN 2012102693176 A CN2012102693176 A CN 2012102693176A CN 201210269317 A CN201210269317 A CN 201210269317A CN 102778457 A CN102778457 A CN 102778457A
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Abstract
The invention discloses a method for detecting toughness of bainite steel welding point. The method includes the following steps: a) supplying samples of the bainite steel welding point; b) corroding the samples through picric acid corrosion solution, and performing polishing and washing on the corroded samples; c) shooting metallographical pictures on the washed samples; d) performing image processing and data statistics on the metallographical pictures to obtain the area parameters of the black areas in the metallographical pictures; and e) comparing the area parameters of different samples to obtain the relative toughness values of the different samples. The method for detecting toughness of the bainite steel welding point aims at M-A components, can totally corrode the areas high in carbon content and is wide in application range compared with a two-step electrolytic etching method, and the corrosion process is simple and easy to operate and can be used in experiment research and actual production.
Description
Technical field
The present invention relates to the mechanical property technical field, more specifically, the present invention relates to a kind of detection method of bainitic steel welding joint toughness.
Background technology
The steam turbine low-pressure welded disc turbine rotor adopts the bainitic steel welding mostly, and toughness is the important mechanics parameter of bainitic steel welding joint, is a key factor that influences the turbine rotor security.Along with rotor develops to high parameter, maximization direction, the importance of toughness is increasing; And the rotor brittle fracture accident that is caused by the toughness deficiency has in history highlighted the importance of toughness more.
In the submerged arc welding process of rotor, the heat affecting coarse grain zone of weldering welding bead can receive the complicated heat effect of follow-up multiple tracks welding bead earlier, thereby forms relative weak link--the interlayer of toughness in the welding joint, and interlayer is restricting the raising of the toughness of whole rotor.Existing experimental study shows, is prone to the M-A constituent element at the interlayer of bainitic steel weld seam.The M-A constituent element contains higher carbon content, and than ferrite matrix, its hardness is higher, so toughness important influence of butt junction all such as size of M-A constituent element, distribution.Corresponding relation between research M-A constituent element and the welding joint toughness extremely has realistic meaning.
Known existing research method mainly is to amplify between weld layer through the method for thermal simulation, uses the corrosion of two one-step electrolysis to demonstrate the M-A constituent element and carries out software statistics afterwards.Available research achievements is that the toughness of finding shape, size and the distribution butt junction of M-A constituent element has material impact at present.This method can comparatively accurately must erode away the M-A constituent element, adds up also more accurate; But two one-step electrolysis etch need plurality of reagents, need energising, and etching process is also comparatively complicated, is fit to the laboratory and uses, and is also inapplicable in actual production.
Summary of the invention
The present invention one of is intended to solve the problems of the technologies described above at least to a certain extent or provides a kind of useful commerce to select at least.
For this reason, one object of the present invention be to propose that a kind of etching process is simple, the detection method of the bainitic steel welding joint toughness of easy operating and suitable actual production.
Detection method according to the bainitic steel welding joint toughness of the embodiment of the invention may further comprise the steps: the bainitic steel weld joint samples a) is provided; B) sample is used the corrosion of picric acid etchant solution, and the sample after will corroding polishes, cleans; C) will clean sample afterwards and take metallograph; D) said metallograph is carried out the area parameters that Flame Image Process and data statistics obtain black region in the metallograph; E) area parameters with various sample compares, and obtains the relative size of various sample toughness.
According to the detection method of the bainitic steel welding joint toughness of the embodiment of the invention, than two one-step electrolysis etch, this method is not only to the M-A constituent element; Come out in zone that can also carbon content is higher all corrosion; Applied widely, and etching process is simple, easy operating; Not only can be used for laboratory study, also can in actual production, use.
In addition, the detection method of bainitic steel welding joint toughness according to the above embodiment of the present invention can also have following additional technical characterictic:
According to one embodiment of present invention, wherein said area parameters comprises average area.
According to one embodiment of present invention, step a) comprises:
A-1) the bainitic steel weld joint samples is provided, sample is carried out thermal simulation to amplify the interlayer of said sample;
A-2) sample after the thermal simulation is carried out grind away with first to the 6th section sand paper successively;
A-3) sample behind the grind away is polished, remove specimen surface cut and pit.
According to one embodiment of present invention, said first section to the 6th section sand paper is respectively 400#, 600#, 800#, 1000#, 1500# and 2000# sand paper.
According to one embodiment of present invention, used antiscuffing paste is No. 2.5 and No. 0.5 antiscuffing paste step a-3).
According to one embodiment of present invention, step b) comprises:
B-1) preparation picric acid etchant solution;
B-2) with corroding in the immersion of the specimen surface after the thermal simulation picric acid etchant solution, wait the complete blackening of specimen surface to take out afterwards;
B-3) with carrying out polishing behind the absorbent cotton removal specimen surface atrament;
B-4) sample after will polishing carries out ultrasonic cleaning in alcohol;
B-5) repeating step b-2)-b-4) 4-5 time.
According to one embodiment of present invention, said picric acid etchant solution is the supersaturation picric acid solution, and its solvent is 95 ℃ a distilled water.
According to one embodiment of present invention, contain liquid detergent in the said picric acid etchant solution, the volume ratio of said liquid detergent and said solvent is 3:200.
According to one embodiment of present invention, step b-3) used antiscuffing paste is No. 0.5 antiscuffing paste in, and polishing time is 5s.
Additional aspect of the present invention and advantage part in the following description provide, and part will become obviously from the following description, or recognize through practice of the present invention.
Description of drawings
Above-mentioned and/or additional aspect of the present invention and advantage obviously with are easily understood becoming the description of embodiment from combining figs, wherein:
Fig. 1 is the schematic flow sheet according to the detection method of the bainitic steel welding joint toughness of the embodiment of the invention.
Embodiment
Describe embodiments of the invention below in detail, the example of said embodiment is shown in the drawings.Be exemplary through the embodiment that is described with reference to the drawings below, only be used to explain the present invention, and can not be interpreted as limitation of the present invention.
At first with reference to the flow process of figure 1 description according to the detection method of the bainitic steel welding joint toughness of the embodiment of the invention.
Particularly, the detection method according to the bainitic steel welding joint toughness of the embodiment of the invention may further comprise the steps:
A) the bainitic steel weld joint samples is provided;
B) sample is used the corrosion of picric acid etchant solution, and the sample after will corroding polishes, cleans;
C) will clean sample afterwards and take metallograph;
D) said metallograph is carried out the area parameters that Flame Image Process and data statistics obtain black region in the metallograph;
E) area parameters with various sample compares, and obtains the relative size of various sample toughness.
Thus, according to the detection method of the bainitic steel welding joint toughness of the embodiment of the invention, than two one-step electrolysis etch; This method is not only to the M-A constituent element, and come out in zone that can also carbon content is higher all corrosion, applied widely; And etching process is simple; Easy operating not only can be used for laboratory study, also can in actual production, use.
In step a), the source of said bainitic steel weld joint samples does not have particular restriction, adopts the common joint through the bainitic steel welding to get final product.For the ease of detecting the toughness of said bainitic steel weld joint samples, can sample be carried out thermal simulation to amplify the interlayer of said sample, said thermal simulation method can adopt conventional thermal modeling test to use method.
Considering needs to take metallograph, so need the sample after the thermal simulation be carried out grind away; Consider that cut and pit can influence the subsequent corrosion effect of sample, can sample be carried out polishing after polishing.
Method and sand paper about grind away do not have particular restriction, as long as can specimen surface be polished flat.Preferably; Can the sample after the thermal simulation be carried out grind away with first to the 6th section sand paper successively; Said first section to the 6th section sand paper is respectively 400#, 600#, 800#, 1000#, 1500# and 2000# sand paper, guarantees behind the grind away that the polishing scratch of back one section sand paper can cover the polishing scratch of the preceding paragraph sand paper fully.
Polishing can be removed cut and the pit through the specimen surface behind the grind away, does not have particular restriction about said finishing method, selects for use suitable antiscuffing paste to polish and gets final product.Preferably, used antiscuffing paste is No. 2.5 and No. 0.5 antiscuffing paste.
Particularly, step a) can may further comprise the steps:
A-1) the bainitic steel weld joint samples is provided, sample is carried out thermal simulation to amplify the interlayer of said sample;
A-2) sample after the thermal simulation is carried out grind away with first to the 6th section sand paper successively;
A-3) sample behind the grind away is polished, remove specimen surface cut and pit.
In step b), the sample that will pass through after grind away and the polishing carries out corrosion treatment, and the sample after will corroding polishes and cleans.
Said corrosion treatment agents useful for same is the picric acid etchant solution, preferably, adopts supersaturation picric acid etchant solution.Said supersaturation picric acid etchant solution adopts 95 ℃ distilled water as solvent, can increase picric meltage.Can also contain liquid detergent in the said supersaturation picric acid etchant solution, the volume ratio of said liquid detergent and said solvent is 3:200.
The method of said corrosion treatment does not have particular restriction, as long as can reach the effect with the specimen surface corrosion.In order to guarantee that corrosion fully; Preferably, can the specimen surface after the thermal simulation be immersed in the picric acid etchant solution and corrode, wait the complete blackening of specimen surface to take out afterwards; After the taking-up, use clean absorbent cotton in the water that flows, to wipe the specimen surface atrament.
After treating that the specimen surface atrament is wiped, it is polished and cleans.Because sample has just passed through corrosion treatment, in order to prevent polishing process sample is produced damage, the light throwing adopted in polishing here, and gently throwing used antiscuffing paste is No. 0.5 antiscuffing paste, and gently the throwing time is 5s.After the polishing sample is put into and carries out ultrasonic cleaning in the alcohol, scavenging period is 2min.
In order to guarantee corrosive effect, can repeat above-mentioned burn into polishing and cleaning step 4-5 time.
Particularly, step b) can may further comprise the steps:
B-1) preparation picric acid etchant solution;
B-2) with corroding in the immersion of the specimen surface after the thermal simulation picric acid etchant solution, wait the complete blackening of specimen surface to take out afterwards;
B-3) with carrying out polishing behind the absorbent cotton removal specimen surface atrament;
B-4) sample after will polishing carries out ultrasonic cleaning in alcohol;
B-5) repeating step b-2)-b-4) 4-5 time.
With the sample after cleaning take low power (100 *, 200 *, 500 * etc.) under metallograph, and said metallograph carried out the area parameters that Flame Image Process and data statistics obtain black region in the metallograph.Said image processing software does not have particular restriction, for example can adopt OpenCV etc.The area parameters of various sample is compared, obtain the relative size of various sample toughness.Wherein, said area parameters is mainly the average area value.
Specifically describe detection method with reference to embodiment below according to bainitic steel welding joint toughness of the present invention.
Embodiment 1
The bainitic steel weld joint samples is provided, sample is carried out the interlayer that said sample is amplified in thermal simulation.Sample after the thermal simulation is carried out grind away with 400#, 600#, 800#, 1000#, 1500# and 2000# sand paper successively, then the sample behind the grind away is polished, remove specimen surface cut and pit.
Excessive picric acid is dissolved in the distilled water of 95 ℃ of 200ml, and the preparation of interpolation 3ml liquid detergent obtains supersaturation picric acid etchant solution.With corroding 3min in the immersion of the specimen surface after the thermal simulation supersaturation picric acid etchant solution, wait the complete blackening of specimen surface to take out afterwards; Use clean absorbent cotton in the water that flows, to wipe the specimen surface atrament, use No. 0.5 antiscuffing paste that light throwing of sample is 5s, be put into and carry out ultrasonic cleaning 2min in the alcohol.Repeat above-mentioned burn into polishing and cleaning step 4-5 time.
With the sample after cleaning take low power (100 *, 200 *, 500 * etc.) following metallograph, and said metallograph employing OpenCV carried out the area parameters that Flame Image Process and data statistics obtain black region in the metallograph.The area parameters of various sample is compared, obtain the relative size of various sample toughness.
In the description of this instructions, the description of reference term " embodiment ", " some embodiment ", " example ", " concrete example " or " some examples " etc. means the concrete characteristic, structure, material or the characteristics that combine this embodiment or example to describe and is contained at least one embodiment of the present invention or the example.In this manual, the schematic statement to above-mentioned term not necessarily refers to identical embodiment or example.And concrete characteristic, structure, material or the characteristics of description can combine with suitable manner in any one or more embodiment or example.
Although illustrated and described embodiments of the invention; Those having ordinary skill in the art will appreciate that: under the situation that does not break away from principle of the present invention and aim, can carry out multiple variation, modification, replacement and modification to these embodiment, scope of the present invention is limited claim and equivalent thereof.
Claims (9)
1. the detection method of a bainitic steel welding joint toughness is characterized in that, may further comprise the steps:
A) the bainitic steel weld joint samples is provided;
B) sample is used the corrosion of picric acid etchant solution, and the sample after will corroding polishes, cleans;
C) will clean sample afterwards and take metallograph;
D) said metallograph is carried out the area parameters that Flame Image Process and data statistics obtain black region in the metallograph;
E) area parameters with various sample compares, and obtains the relative size of various sample toughness.
2. the detection method of bainitic steel welding joint toughness according to claim 1 is characterized in that wherein said area parameters comprises average area.
3. the detection method of bainitic steel welding joint toughness according to claim 1 is characterized in that step a) comprises:
A-1) the bainitic steel weld joint samples is provided, sample is carried out thermal simulation to amplify the interlayer of said sample;
A-2) sample after the thermal simulation is carried out grind away with first to the 6th section sand paper successively;
A-3) sample behind the grind away is polished, remove specimen surface cut and pit.
4. the detection method of bainitic steel welding joint toughness according to claim 3 is characterized in that, said first section to the 6th section sand paper is respectively 400#, 600#, 800#, 1000#, 1500# and 2000# sand paper.
5. the detection method of bainitic steel welding joint toughness according to claim 3 is characterized in that step a-3) in used antiscuffing paste be No. 2.5 and No. 0.5 antiscuffing paste.
6. the detection method of bainitic steel welding joint toughness according to claim 1 is characterized in that step b) comprises:
B-1) preparation picric acid etchant solution;
B-2) with corroding in the immersion of the specimen surface after the thermal simulation picric acid etchant solution, wait the complete blackening of specimen surface to take out afterwards;
B-3) with carrying out polishing behind the absorbent cotton removal specimen surface atrament;
B-4) sample after will polishing carries out ultrasonic cleaning in alcohol;
B-5) repeating step b-2)-b-4) 4-5 time.
7. the detection method of bainitic steel welding joint toughness according to claim 6 is characterized in that, said picric acid etchant solution is the supersaturation picric acid solution, and its solvent is 95 ℃ a distilled water.
8. the detection method of bainitic steel welding joint toughness according to claim 7 is characterized in that, contains liquid detergent in the said picric acid etchant solution, and the volume ratio of said liquid detergent and said solvent is 3:200.
9. the detection method of bainitic steel welding joint toughness according to claim 6 is characterized in that step b-3) in used antiscuffing paste be No. 0.5 antiscuffing paste, polishing time is 5s.
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| CN201210269317.6A CN102778457B (en) | 2012-07-30 | 2012-07-30 | Method for detecting toughness of bainite steel welding point |
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| CN201210269317.6A CN102778457B (en) | 2012-07-30 | 2012-07-30 | Method for detecting toughness of bainite steel welding point |
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Cited By (4)
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| CN107860621A (en) * | 2017-10-23 | 2018-03-30 | 东方电气集团东方锅炉股份有限公司 | Examine T/P91 or T/P92 steel and Cr Mo low alloy ferritic Heat Resistant Steel Welded Joints etchant preparation methods |
| CN108225872A (en) * | 2018-01-29 | 2018-06-29 | 攀钢集团攀枝花钢铁研究院有限公司 | For detecting the detection method of the corrosive agent of weld seam macrostructure, preparation method and caustic solution and weld seam macrostructure |
| CN109355661A (en) * | 2018-08-29 | 2019-02-19 | 东风汽车有限公司 | Corrosive agent for steel plate welding area, corrosion method and application |
| CN113504093A (en) * | 2021-07-09 | 2021-10-15 | 大冶特殊钢有限公司 | Grain size display method for alloy containing cobalt element not easy to corrode |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107860621A (en) * | 2017-10-23 | 2018-03-30 | 东方电气集团东方锅炉股份有限公司 | Examine T/P91 or T/P92 steel and Cr Mo low alloy ferritic Heat Resistant Steel Welded Joints etchant preparation methods |
| CN107860621B (en) * | 2017-10-23 | 2020-11-17 | 东方电气集团东方锅炉股份有限公司 | Preparation method of etchant for testing welding joint of T/P91 or T/P92 steel and Cr-Mo low-alloy ferritic heat-resistant steel |
| CN108225872A (en) * | 2018-01-29 | 2018-06-29 | 攀钢集团攀枝花钢铁研究院有限公司 | For detecting the detection method of the corrosive agent of weld seam macrostructure, preparation method and caustic solution and weld seam macrostructure |
| CN109355661A (en) * | 2018-08-29 | 2019-02-19 | 东风汽车有限公司 | Corrosive agent for steel plate welding area, corrosion method and application |
| CN113504093A (en) * | 2021-07-09 | 2021-10-15 | 大冶特殊钢有限公司 | Grain size display method for alloy containing cobalt element not easy to corrode |
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