CN114910500A - Method for analyzing and positioning crack defect reasons of steel for automobile outer plate - Google Patents
Method for analyzing and positioning crack defect reasons of steel for automobile outer plate Download PDFInfo
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- 230000007547 defect Effects 0.000 title claims abstract description 252
- 238000000034 method Methods 0.000 title claims abstract description 49
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 30
- 239000010959 steel Substances 0.000 title claims abstract description 30
- 238000004458 analytical method Methods 0.000 claims abstract description 125
- 238000005211 surface analysis Methods 0.000 claims abstract description 62
- 238000005336 cracking Methods 0.000 claims abstract description 27
- 239000003973 paint Substances 0.000 claims description 16
- 238000001228 spectrum Methods 0.000 claims description 12
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 11
- 239000011701 zinc Substances 0.000 claims description 11
- 229910052725 zinc Inorganic materials 0.000 claims description 11
- 230000003595 spectral effect Effects 0.000 claims description 8
- 238000004140 cleaning Methods 0.000 claims description 4
- 239000000843 powder Substances 0.000 claims description 4
- 229920001342 Bakelite® Polymers 0.000 claims description 3
- 239000004637 bakelite Substances 0.000 claims description 3
- 238000007781 pre-processing Methods 0.000 description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 238000010183 spectrum analysis Methods 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 4
- 238000007747 plating Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000012795 verification Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
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- 239000012535 impurity Substances 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 235000010299 hexamethylene tetramine Nutrition 0.000 description 2
- 239000004312 hexamethylene tetramine Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 125000001997 phenyl group Chemical class [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 230000002522 swelling effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000009210 therapy by ultrasound Methods 0.000 description 1
- 238000004506 ultrasonic cleaning Methods 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/225—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion
- G01N23/2251—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion using incident electron beams, e.g. scanning electron microscopy [SEM]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/2202—Preparing specimens therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
- G01N33/204—Structure thereof, e.g. crystal structure
- G01N33/2045—Defects
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
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Abstract
The invention particularly relates to an analysis and positioning method for crack defect reasons of steel for an automobile outer plate, belonging to the technical field of defect analysis, and the method comprises the following steps: measuring the defects of the defect plate to be analyzed to obtain defect information; preparing a sample of a defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample; pretreating a sample to obtain a sample body; carrying out defect surface analysis on the sample body to obtain a surface analysis result; inlaying the sample body, and then performing cross section analysis to obtain a cross section analysis result; performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result; determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result; through the combination of defect surface analysis, cross section analysis and metallographic analysis, the source of the defect can be accurately judged, and the problem that the source of the defect cannot be traced at present is solved.
Description
Technical Field
The invention belongs to the technical field of defect analysis, and particularly relates to an analysis and positioning method for crack defect reasons of steel for an automobile outer plate.
Background
With the development of the automobile industry towards light weight, higher requirements are put on the quality of the automobile outer plate, on one hand, the thickness of the automobile plate is thinner and thinner, and on the other hand, the thinning rate of the automobile plate is larger and larger, which leads to the defect of cracking in the stamping process. As is known, defects may occur in any link of a production process from slab to hot rolling, acid rolling to cold rolling, the number of processes for forming and going through the defects is large, the process is long, the period is long, the factors are large, and the defects caused by the previous and subsequent processes are interwoven, so that the defects are difficult to identify and judge, and the defect sources cannot be traced.
Disclosure of Invention
The application aims to provide an analysis and positioning method for the cracking defect reasons of the steel for the automobile outer plate, so as to solve the problem that the defect source cannot be traced at present.
The embodiment of the invention provides a method for analyzing and positioning the causes of cracking defects of steel for an automobile outer plate, which comprises the following steps:
measuring the defects of the defect plate to be analyzed to obtain defect information;
preparing a sample of a defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
pretreating a sample to obtain a sample body;
carrying out defect surface analysis on the sample body to obtain a surface analysis result;
inlaying the sample body, and then performing cross section analysis to obtain a cross section analysis result;
performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
Optionally, the preset ratio is 1: 15-20.
Optionally, the preprocessing includes: the samples were subjected to a dirty wash, which was noted to be incapable of being treated with ultrasound.
Optionally, the preprocessing further includes: and (4) performing paint removing treatment on the sample.
Optionally, when the sample body is a galvanized sheet, the sample body is subjected to defect surface analysis to obtain a surface analysis result, and the method specifically includes:
performing first defect surface analysis on the sample body to obtain a first analysis result;
removing the zinc layer of the sample body to obtain a zinc layer-free sample;
performing second defect surface analysis on the zinc layer-free sample to obtain a second analysis result;
and obtaining a surface analysis result according to the first analysis result and the second analysis result.
Optionally, the first defect surface analysis adopts a mode including energy spectrum point analysis and/or energy spectrum plane analysis; and the second defect surface analysis is performed in a manner including spectral point analysis and/or spectral surface analysis.
Optionally, in the energy spectrum point analysis, the number of analysis points at the defect position is more than or equal to 10.
Optionally, the inlaid inlay is bakelite powder.
Optionally, the cross-section analysis includes spectral point analysis and/or spectral surface analysis.
Optionally, the set multiple includes 50 times, 100 times, 150 times, 200 times, 250 times and 300 times.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
according to the method for analyzing and positioning the cracking defect reasons of the steel for the automobile outer plate, provided by the embodiment of the invention, the source of the defect can be accurately judged by combining the defect surface analysis, the section analysis and the metallographic analysis, and the problem that the source of the defect cannot be traced at present is solved.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a flow chart of a method provided by an embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
according to an exemplary embodiment of the present invention, there is provided a method for analyzing and locating causes of crack defects in steel for an outer panel of an automobile, the method including:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
specifically, after the defect plate is taken back, the relative position of the crack in the steel plate is determined, whether a falling foreign body exists or not is observed, the crack surface is observed, macroscopic measurement is carried out on the defect, the macroscopic measurement comprises information such as length and width, and the defect plate is shot with a scale to obtain defect information.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
in some embodiments, the predetermined ratio is 1: 15-20.
The control area is too large, the analysis space is occupied, and the analysis efficiency is influenced; the control area is too small, and partial defects are embedded in the matrix, so that the integrity of the defects can be damaged, and the accuracy of analysis is influenced.
Specifically, the size of the prepared sample is proportional to the defect, and the area ratio of S is more than or equal to 15 and less than or equal to 20.
S3, preprocessing a sample to obtain a sample body;
in some embodiments, the pre-processing comprises: and carrying out dirt cleaning on the sample.
It should be noted that the cleaning process cannot be performed by ultrasonic treatment, which easily shakes off the defect embedded in the substrate, so that the real reason of the defect cannot be determined.
In some embodiments, the pre-processing further comprises: and (4) performing paint removing treatment on the sample.
When the sample is a paint coating sample, the paint coating sample needs to be subjected to paint stripping, wherein the paint stripping agent is formed by mixing solvents such as chlorohydrocarbon, ketone, ester, alcohol, benzene series and the like, the paint on the surface is effectively removed by utilizing the penetrating swelling effect of the solvents on the covering, and the surface is cleaned after being maintained for 1min after each coating until the paint on the surface is completely removed.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
in some embodiments, when the sample body is a galvanized sheet, the performing a defect surface analysis on the sample body to obtain a surface analysis result specifically includes:
s4.1, performing first defect surface analysis on the sample body to obtain a first analysis result;
the first defect surface analysis specifically comprises: taking a picture of the surface, and taking a picture of the defect appearance under the conditions of 50 times, 100 times, 200 times and 500 times of magnification in the electron microscope back scattering visual field respectively, and storing; performing energy spectrum point analysis on the surface: in a backscattering mode, comparing and analyzing components at the defect and the normal position, wherein the number of analysis points at the defect is not less than 10, and performing surface scanning component analysis on the abnormal particle dense region; scanning and analyzing the surface opening surface: and amplifying the defects to proper times (200-1000 times are different), and carrying out scanning analysis on the energy spectrum surface.
S4.2, removing a zinc layer from the sample body to obtain a zinc layer-free sample;
specifically, the dezincification reagent used for removing the zinc layer comprises a hydrochloric acid solution and a corrosion agent hexamethylenetetramine, wherein the ratio of concentrated hydrochloric acid to water is 1: 1, 3.5g of hexamethylenetetramine per liter of diluted hydrochloric acid solution are added.
S4.3, performing second defect surface analysis on the zinc layer-free sample to obtain a second analysis result;
the second defect surface analysis specifically includes: taking a picture of the surface, and taking a picture of the defect appearance under the conditions of 50 times, 100 times, 200 times and 500 times of magnification in the electron microscope back scattering visual field respectively, and storing; performing energy spectrum point analysis on the surface: in a backscattering mode, comparing and analyzing components at the defect and the normal position, wherein the number of analysis points at the defect is not less than 10, and performing surface scanning component analysis on the abnormal particle dense region; surface open surface scan analysis: and amplifying the defects to proper times (200-1000 times are different), and carrying out scanning analysis on the energy spectrum surface.
And S4.4, obtaining a surface analysis result according to the first analysis result and the second analysis result.
S5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
specifically, the section inlay adopted by inlaying is bakelite powder, and the temperature is kept for 8-15min at the temperature of 130-.
The cross-sectional analysis specifically includes: cutting the steel substrate along the rolling direction at the position near the defect to ensure parallel cutting and parallel grinding and polishing, and inlaying by using inlaying powder; gradually grinding off the steel substrate to expose the defects, observing in an electron microscope, and detecting the defects by using energy spectrum point analysis and surface scanning; and grinding the steel substrate layer by layer until the defects completely disappear, and detecting the defects by using energy spectrum point analysis and surface scanning according to requirements in the process.
S6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
the metallographic analysis specifically comprises: the structure, grain size, and zinc layer distribution in the vicinity of the defect of the sample were observed at 50 times, 100 times, 150 times, 200 times, 250 times, and 300 times, respectively.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The method for analyzing and locating the cause of the crack defect in the steel for the outer panel of the automobile according to the present application will be described in detail with reference to examples, comparative examples, and experimental data.
Example 1
A method for analyzing and locating causes of cracking defects of steel for an automobile outer panel comprises the following steps:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the defective plate is painted and is a galvanized plate. The defect is a cracked strip without dropped foreign matter, and the length and width of the defect are about 1.5mm and 1mm, respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
about 1.5mm and 1mm depending on the length and width of the defect, respectively, and 30mm for the sheared test piece 2 。
S3, preprocessing a sample to obtain a sample body;
the sample was cleaned for smudgy around it and 10 times with a paint stripper.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
s5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
s6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and (3) observing the defects under a scanning electron microscope by magnifying the defects to 1000 times, and performing energy spectrum analysis on the defects to find that the defects are calcium aluminate components.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The defects can be judged to be from the steel ladle slag according to the calcium aluminate component, and the judgment result is accurate through verification.
Example 2
A method for analyzing and locating causes of cracking defects of steel for an automobile outer panel, the method comprising:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the defect plate is free of plating paint and is a galvanized plate. The defect is in the shape of a cracked ellipse without falling foreign matter, and the major axis and the width axis of the ellipse defect are about 1mm and 0.8mm, respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
about 1mm and 0.8mm in length and width depending on the defect, respectively, and 12mm in the sheared sample 2 。
S3, preprocessing a sample to obtain a sample body;
the periphery of the sample was cleaned from dirt.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
s5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
s6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
the defects are observed under a scanning electron microscope by magnifying the scanning electron microscope to 900 times, and the defects are subjected to energy spectrum analysis and are found to be aluminum oxide components.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The defect can be judged to come from the falling of the water gap plug according to the alumina component, and the result is accurate through verification.
Example 3
A method for analyzing and locating causes of cracking defects of steel for an automobile outer panel, the method comprising:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the defect plate is free of plating paint and is a galvanized plate. The defect is in the shape of a cracked round pit, the defect is fallen off, and the length and the width of the round defect are about 1mm and 1mm respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
the cut specimens were 18mm according to the length and width of the defect being about 1mm and 1mm, respectively 2 。
S3, preprocessing a sample to obtain a sample body;
the smudges around the sample were cleaned.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
s5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
s6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and (3) observing the defects under a scanning electron microscope by magnifying to 800 times, and performing energy spectrum analysis on the defects to find that the defects are Fe components and are free of inclusion components.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The cross section is only Fe without iron oxide; metallographic analysis shows that obvious grain deformation exists at the edge of the defect, and the grain deformation is obviously different from the uniform grain of the matrix grain.
According to the results of the section and the metallographic phase, the defect can be judged to come from the pressing-in of foreign matters after cold rolling and galvanizing, and the judgment result is proved to be accurate.
Comparative example 1
A method for analyzing and locating causes of cracking defects of steel for an automobile outer panel, the method comprising:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the defect plate is painted and is a galvanized plate. The defect is a cracked strip without dropped foreign matter, and the length and width of the defect are about 1.5mm and 1mm, respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
the length and width of the defect were about 1.5mm and 1mm, respectively, and the cut specimen was 10mm 2 。
S3, preprocessing a sample to obtain a sample body;
the sample was cleaned for smudgy around it and 10 times with a paint stripper.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
s5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
s6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and (3) observing the defects under a scanning electron microscope by magnifying the defects to 1000 times, and performing energy spectrum analysis on the defects, wherein the defects are Fe and have no impurity components.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The cross section is only Fe without iron oxide; metallographic analysis, no decarburized layer and no grain deformation.
Based on the above analysis, the source of the defect cannot be determined.
And (3) carrying out interception analysis again on corresponding samples except for the intercepted sample:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the defective plate is painted and is a galvanized plate. The defect is a cracked strip without dropped foreign matter, and the length and width of the defect are about 1.5mm and 1mm, respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
about 1.5mm and 1mm depending on the length and width of the defect, respectively, and 25mm for a sheared specimen 2 。
S3, preprocessing a sample to obtain a sample body;
the sample was cleaned of dirt around its periphery and 10 times with a paint remover.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
s5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
s6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and (4) observing the defects under a scanning electron microscope by magnifying the defects to 1000 times, and performing energy spectrum analysis on the defects to find the defects to be aluminum oxide components.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The defect can be judged to come from the falling of the water gap plug according to the alumina component, and the defect reason can not be clearly analyzed due to the fact that the first analysis process is wrong after verification.
Comparative example 2
A method for analyzing and locating causes of cracking defects of steel for an automobile outer panel, the method comprising:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the plate to be detected is free of plating paint and is a galvanized plate. The defect is in the shape of a cracked ellipse without falling foreign matter, and the major axis and the width axis of the ellipse defect are about 1mm and 0.6mm, respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
about 1mm and 0.6mm in length and width depending on the defect, respectively, and 12mm in the sheared sample 2 。
S3, preprocessing a sample to obtain a sample body;
the smudges around the sample are cleaned, and the ultrasonic vibration cleaning is not suitable.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
the defect is an alumina component.
S5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
the cross section is alumina component.
S6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and (3) observing the defects by magnifying the defects to 950 times under a scanning electron microscope, and performing energy spectrum analysis on the defects, wherein the defects are Fe and have no impurity components.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
Based on the above analysis, the source of the defect cannot be determined.
Another defect was reanalyzed:
a method for analyzing and locating causes of cracking defects of steel for an automobile outer panel, the method comprising:
s1, measuring the defects of a defect plate to be analyzed to obtain defect information;
the sample plate for analyzing the defects of the defect plate is free of plating paint and is a galvanized plate. The defect is in the shape of a cracked ellipse without falling foreign matter, and the major axis and the wide axis of the ellipse defect are about 1.2mm and 0.6mm, respectively.
S2, preparing a sample of the defect plate to be analyzed according to the defect information so that the sample size of the prepared sample and the area ratio of the defect meet a set proportion to obtain a sample;
about 1mm and 0.6mm in length and width depending on the defect, respectively, and 15mm in the sheared sample 2 。
S3, preprocessing a sample to obtain a sample body;
the sample was subjected to ultrasonic cleaning.
S4, carrying out defect surface analysis on the sample body to obtain a surface analysis result;
the defect is Fe and has no impurity component.
S5, inlaying the sample body, and then performing section analysis to obtain a section analysis result;
the cross section is Fe without inclusion.
S6, performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and (3) observing the defects by magnifying the defects to 300 times under a scanning electron microscope, and performing energy spectrum analysis on the defects without decarburization, wherein the crystal grains are normal.
And S7, determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
The defect can be judged to come from the falling of the water gap plug according to the alumina component, and the defect reason can not be clearly analyzed due to the fact that the first analysis process is wrong after verification.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
according to the method provided by the embodiment of the invention, through the combination of defect surface analysis, cross section analysis and metallographic analysis, the source of the defect can be accurately judged, and the problem that the source of the defect cannot be traced at present is solved.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for analyzing and positioning the causes of cracking defects of steel for an automobile outer panel is characterized by comprising the following steps:
measuring the defects of the defect plate to be analyzed to obtain defect information;
preparing a sample of a defect plate to be analyzed according to the defect information so as to enable the sample size of the prepared sample and the area ratio of the defects to meet a set proportion, and obtaining a sample;
pretreating the sample to obtain a sample body;
carrying out defect surface analysis on the sample body to obtain a surface analysis result;
inlaying the sample body, and then performing cross section analysis to obtain a cross section analysis result;
performing metallographic analysis on the defects of the sample body under a set multiple to obtain a metallographic analysis result;
and determining the cause of the cracking defect according to the surface analysis result, the section analysis result and the metallographic analysis result.
2. The method for analyzing and locating the causes of the cracking defects of the steel for the automobile outer panel according to claim 1, wherein the preset proportion is 1: 15-20.
3. The method for analyzing and locating the cause of the crack defect of the steel for the automobile outer panel according to claim 1, wherein the pretreatment comprises: and carrying out dirty cleaning on the sample.
4. The method for analyzing and locating the cause of the crack defect of the steel for the automobile outer panel according to claim 3, wherein the pretreatment further comprises: and (4) performing paint removing treatment on the sample.
5. The method for analyzing and locating the cause of the cracking defect of the steel for the automobile outer panel according to claim 1, wherein when the sample body is a galvanized plate, the sample body is subjected to defect surface analysis to obtain a surface analysis result, and the method specifically comprises the following steps:
performing first defect surface analysis on the sample body to obtain a first analysis result;
removing the zinc layer of the sample body to obtain a zinc layer-free sample;
performing second defect surface analysis on the zinc layer-free sample to obtain a second analysis result;
and obtaining a surface analysis result according to the first analysis result and the second analysis result.
6. The method for analyzing and locating the cause of the cracking defect of the steel for the automobile outer panel according to claim 5, wherein the first defect surface analysis adopts a mode comprising energy spectrum point analysis and/or energy spectrum surface analysis; and the second defect surface analysis is performed in a manner including spectral point analysis and/or spectral surface analysis.
7. The method for analyzing and locating the causes of the cracking defects of the steel for the outer panel of the automobile as recited in claim 6, wherein the number of analysis points at the defect position in the energy spectrum point analysis is not less than 10.
8. The method for analyzing and locating the cause of the crack defect of the steel for the automobile outer panel as recited in claim 1, wherein the inlaid inlay is bakelite powder.
9. The method for analyzing and locating the cause of the cracking defect in the steel for the outer panel of the automobile according to claim 1, wherein the cross-sectional analysis includes a spectral point analysis and/or a spectral surface analysis.
10. The method for analyzing and locating the cause of the crack defect in the steel for the outer panel of the automobile according to claim 1, wherein the set times include 50 times, 100 times, 150 times, 200 times, 250 times, and 300 times.
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