CN111830229B - Metallographic corrosive agent for primary strip-shaped structure of steel and metallographic display method - Google Patents

Metallographic corrosive agent for primary strip-shaped structure of steel and metallographic display method Download PDF

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CN111830229B
CN111830229B CN202010666073.XA CN202010666073A CN111830229B CN 111830229 B CN111830229 B CN 111830229B CN 202010666073 A CN202010666073 A CN 202010666073A CN 111830229 B CN111830229 B CN 111830229B
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steel
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温娟
来萍
贾惠平
鞠新华
严春莲
张莉霞
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Shougang Group Co Ltd
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Abstract

The invention belongs to the technical field of metallographic detection, and particularly relates to a metallographic corrosive agent for a primary strip-shaped structure of steel and a metallographic display method. The metallographic etchant comprises: water, methanol, copper chloride and hydrochloric acid; wherein the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: (25-35) ml (20-30) g (1-3) ml. The metallographic corrosive and the metallographic display method are mainly applicable to hot rolled steel products after rolling deformation, can also be used for steel products after heat treatment after rolling, are convenient to operate, have stable corrosion effect, can clearly display the primary banded structure of a steel sample, and can be used for evaluating the quality and performance of the steel products.

Description

Metallographic corrosive agent for primary strip-shaped structure of steel and metallographic display method
Technical Field
The invention belongs to the technical field of metallographic examination, and particularly relates to a metallographic corrosive agent for a primary strip-shaped structure of steel and a metallographic display method.
Background
Generally, the band structure is caused by dendrite segregation of the steel ingot. Because the molten steel is selectively crystallized during solidification, the components on the branches are purer, and impurities such as carbon, alloy elements, phosphorus, sulfur and the like are enriched among the branches. When the ingot is deformed by forging, the stem and dendrite are rolled and elongated into a fibrous structure, thereby forming a so-called primary band structure, which is an original band formed by dendrite segregation extending in the hot working direction. The root cause of the secondary banded structure is that carbon and other alloy elements are segregated and enriched among branches in the solidification process of the continuous casting billet, and Ar3 point temperatures of all areas in steel are inconsistent due to element segregation during hot rolling and heating. When cooling the hypoeutectoid steel from the austenitic state at the time of finish rolling, first, the pro-eutectoid ferrite starts to precipitate at the Ar3 point temperature, and pearlite starts to form when cooling to Ar1, thereby forming a band structure of ferrite+pearlite. The microstructure bands generated by the solid-state phase transition are secondary bands, and the band tissues usually seen after the corrosion of the nitrate alcohol are secondary bands. The primary banded structure is dendrite segregation formed in the solidification process of molten steel, has relative stability, primary grains disappear after heating, but dendrite segregation still remains, and the dendrite segregation is rolled, deformed and extended to form a fiber banded structure. The primary band-like structure cannot be exhibited with ordinary nital. The secondary band structure can be formed on the basis of the primary band structure, but the steel with the primary band structure does not necessarily have the secondary band structure, which has close relation with processes such as rolling control and cooling control during rolling. The strip-shaped structure leads the mechanical property of the steel to generate directionality, so that the transverse toughness index of the steel is reduced, and the machinability of the steel is deteriorated.
Generally, we regard the secondary band structure as a microstructure defect of steel, but the secondary band structure is a product of solid phase transformation, and is a primary band structure in essence, which has a negative effect on the material application performance, so how to improve the morphology and distribution of the primary band structure from the metallurgical process is of great importance. However, the corrosion and display of primary band structures has been a problem, and it is not yet possible to corrode and display clear primary band structures.
Disclosure of Invention
In view of the above problems, the present invention provides a metallographic etchant for a primary band structure of a steel material and a metallographic display method. The metallographic corrosive and the metallographic display method are mainly applicable to hot rolled steel products after rolling deformation, can also be used for steel products after heat treatment after rolling, are convenient to operate, have stable corrosion effect, can clearly display the primary banded structure of a steel sample, and can be used for evaluating the quality and performance of the steel products.
The technical scheme for achieving the purpose is as follows:
the invention provides a metallographic etchant for a primary strip-shaped structure of steel, which comprises the following components: water, methanol, copper chloride and hydrochloric acid;
wherein the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: (25-35) ml (20-30) g (1-3) ml.
In some preferred embodiments, in the steel primary band structure metallographic etchant of the present invention, the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: 30ml:25g:2ml.
In some embodiments, the mass percentage concentration of the hydrochloric acid in the metallographic etchant of the primary strip structure of the steel is 36-38 w%.
In some embodiments, the preparation steps of the steel primary band structure metallographic etchant of the invention are as follows: the water, the methanol, the copper chloride and the hydrochloric acid are uniformly mixed according to the proportion of the invention, and the steel primary band-shaped structure metallographic corrosive agent is obtained.
The invention also provides a metallographic display method of the primary band-shaped structure of the steel, which comprises the following steps:
polishing the steel sample (or grinding the steel sample before polishing) to obtain a polished surface of the steel sample;
adopting the steel primary band structure metallographic corrosive agent to carry out corrosion treatment on the polished surface of the steel sample to obtain a metallographic corrosion sample;
washing and drying the metallographic corrosion sample to obtain a metallographic observation sample;
and (5) placing the metallographic observation sample under a metallographic microscope for observation, and collecting pictures.
In some embodiments, the method for displaying the metallographic phase of the primary band-shaped structure of the steel material comprises the following steps:
polishing the steel sample to obtain a polished surface of the steel sample;
immersing the polished surface of the steel sample into the metallographic corrosive agent of the primary strip-shaped structure of the steel, and carrying out corrosion treatment to obtain a metallographic corrosion sample;
washing and drying the metallographic corrosion sample to obtain a metallographic observation sample;
and (5) placing the metallographic observation sample under a metallographic microscope for observation, and collecting pictures.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, immersing the polished surface of the steel material sample in the metallographic etchant of a primary band structure of a steel material according to the present invention comprises: the polished surface of the steel sample is perpendicular to the liquid surface of the metallographic corrosive of the primary strip-shaped structure of the steel.
In some embodiments, the etching treatment of the present invention may also be a variety of metallographic etching treatment methods known to those skilled in the art, such as etching, wiping, and dripping.
In some embodiments, in the method for displaying a metallographic structure of a steel material primary band structure according to the present invention, the steel material sample is a longitudinal section sample parallel to a rolling direction.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the polishing treatment of the steel material sample includes: and embedding, grinding and polishing the steel sample until the polished surface of the steel sample is smooth and has no obvious scratches or stains.
In some embodiments, the polishing treatment may be electrochemical polishing, mechanical polishing, and chemical polishing; after the polishing treatment, a flat polished surface was obtained on the steel sample.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the etching treatment is performed for 1 to 10 seconds.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the method for etching includes: etching, wiping or dripping.
In some embodiments, in the method for displaying a metallographic structure of a steel primary band structure according to the present invention, the polished surface of the steel sample is brownish red after the polished surface of the steel sample is subjected to the corrosion treatment.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the washing includes: washing with water for 3-8 seconds, and washing with absolute ethyl alcohol for 3-8 seconds.
In some embodiments, the metallographic microscope adopts a 50-200 times magnification view field in the method for displaying the metallographic structure of the steel primary band structure.
In some embodiments, in the method for displaying a metallographic phase of a primary band-shaped structure of a steel material, the metallographic observation sample is placed under a metallographic microscope (a 50-200 times magnification view field is adopted) for observation, and obvious white bands appear in the acquired picture, namely the primary band-shaped structure of the steel material.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the steel material is a rolled steel material;
in some preferred embodiments, the steel material according to the present invention is a rolled steel material that has been heat-treated.
In some embodiments, the steel material of the present invention is 20CrMnTi steel material or Q420 steel material.
One or more technical embodiments of the present invention have at least the following technical effects or advantages:
(1) The metallographic corrosive provided by the invention is simple and convenient in preparation method, can be used at room temperature, and does not need heating treatment; the metallographic corrosive has good corrosion effect, can clearly display the primary band-shaped structure of the steel sample, and solves the problems that the primary band-shaped structure of the rolled steel is difficult to display and difficult to display clearly;
(2) Compared with the prior art, the metallographic corrosive and the metallographic display method can enable the primary strip-shaped structure in rolled steel to be easily distinguished, and are beneficial to evaluating the quality of rolled steel products.
(3) In order to prove that the white strip corroded by the method is a strip-shaped tissue, the invention performs microhardness and electron probe element surface scanning tests. The metallographic observation sample is subjected to microhardness test, the hardness of the corroded strip is obviously higher, and the hardness of the general element segregation region is higher than that of the matrix, so that the element segregation region is the element casting blank solidification position; meanwhile, when the electronic probe device scans the element surface, the high-low area of the element content can be displayed by different colors according to the content of the alloy element, so that the element segregation zone is represented. After a metallographic erosion strip sample is subjected to alloy element surface scanning by an electronic probe, the element segregation distribution obtained by scanning by the electronic probe is found to be consistent. The hardness test and the electron probe test prove that the strip corroded by the method is an element segregation site when the element casting blank is solidified, namely the strip corroded and displayed by the test method adopted by the invention is an alloy element segregation zone and is a primary banded structure.
(4) In the invention, the metallographic observation sample is placed under a metallographic microscope (with 50-200 times of amplified view field) for observation, a gray mode of the microscope can be adopted, the acquired picture is black and white, and obvious white strips appear; color mode may also be used, the acquired picture is reddish brown, and light bands appear in the reddish brown field of view.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIGS. 1 (a) and (b) show a primary band-like tissue picture obtained in example 1 of the present invention;
FIGS. 2 (a) and (b) show a primary band-like tissue picture obtained in example 3 of the present invention;
FIG. 3 shows a photograph of a metallographic structure obtained in comparative example 1 of the present invention;
fig. 4 (a) and (b) show the metallographic structure pictures obtained in comparative example 2 of the present invention.
Detailed Description
The advantages and various effects of the present invention will be more clearly apparent from the following detailed description and examples. It will be understood by those skilled in the art that these specific embodiments and examples are intended to illustrate the invention, not to limit the invention.
Throughout the specification, unless specifically indicated otherwise, the terms used herein should be understood as meaning 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. In case of conflict, the present specification will control.
Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or may be prepared by existing methods.
The technical scheme provided by the embodiment of the invention aims to solve the technical problems, and the overall thought is as follows:
the invention provides a metallographic etchant for a primary strip-shaped structure of steel, which comprises the following components: water, methanol, copper chloride and hydrochloric acid;
wherein the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: (25-35) ml (20-30) g (1-3) ml.
The inventor of the application finally determines the proportioning relation of water, methanol, copper chloride and hydrochloric acid through a large number of screening tests, so that the metallographic corrosive has good corrosion effect, can clearly display the primary strip-shaped structure of a steel sample, solves the problems of difficult and clear display of the primary strip-shaped structure of rolled steel, and realizes good technical effect.
In some preferred embodiments, in the steel primary band structure metallographic etchant of the present invention, the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: 30ml:25g:2ml.
For the metallographic display method of the primary strip structure of the steel, which proportioning relationship is most suitable for water, methanol, copper chloride and hydrochloric acid, the inventor further performs screening and optimization, and discovers that when the ratio of the volume of water to the volume of methanol to the volume of copper chloride to the volume of hydrochloric acid is as follows: 30ml:25g:2ml, the primary band structure of the steel sample was most favorably displayed.
The invention also provides a metallographic display method of the primary band-shaped structure of the steel, which comprises the following steps:
polishing the steel sample to obtain a polished surface of the steel sample;
adopting the steel primary band structure metallographic corrosive agent to carry out corrosion treatment on the polished surface of the steel sample to obtain a metallographic corrosion sample;
washing and drying the metallographic corrosion sample to obtain a metallographic observation sample;
and (5) placing the metallographic observation sample under a metallographic microscope for observation, and collecting pictures.
The invention obtains the metallographic display method of the primary band-shaped structure of the steel through a large number of experiments, thereby leading the primary band-shaped structure in the rolled steel to be easy to distinguish and being beneficial to evaluating the quality of the rolled steel product.
In some embodiments, the method for displaying the metallographic phase of the primary band-shaped structure of the steel material comprises the following steps:
polishing the steel sample to obtain a polished surface of the steel sample;
immersing the polished surface of the steel sample into the metallographic corrosive agent of the primary strip-shaped structure of the steel, and carrying out corrosion treatment to obtain a metallographic corrosion sample;
washing and drying the metallographic corrosion sample to obtain a metallographic observation sample;
and (5) placing the metallographic observation sample under a metallographic microscope for observation, and collecting pictures.
The inventors found through experiments that the polished surface of the steel sample was immersed in the metallographic etchant to perform etching treatment (etching method), the obtained etching effect was good, and the obtained metallographic observation sample clearly showed a band-like structure once.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the steel material sample is a longitudinal section sample parallel to a rolling direction; the strip-shaped structure can be deformed along the rolling direction, and the strip-shaped structure is not obvious in the cross section direction.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the etching treatment is performed for 1 to 10 seconds; the etching time is too long, so that the etching surface is blackened, and the definition of the sample tissue is affected.
In some embodiments, in the method for displaying a metallographic structure of a steel primary band structure according to the present invention, the polished surface of the steel sample is reddish brown after the polished surface of the steel sample is subjected to the etching treatment. In the present invention, since copper chloride is contained in the etchant, a chemical reaction occurring during etching causes copper to appear on the polished surface, and thus the color appearing on the etched surface is the same as that of copper and is reddish brown.
In some embodiments, in the method for displaying a metallographic phase of a primary band structure of a steel material according to the present invention, the washing includes: washing with water for 3-8 seconds. The washing time is too long, which is not beneficial to the drying of the sample; washing with absolute ethyl alcohol for 3-8 seconds; the time is too long, ethanol is not favorable for volatilization, and the polished surface is not clean.
In some embodiments, the metallographic microscope adopts a 50-200 times magnification view field in the method for displaying the metallographic structure of the steel primary band structure. If the multiple is too large, the observation area is too small, which is not beneficial to observing the macroscopic morphology of the banded tissue.
The metallographic etchant for the primary band structure of the steel material and the metallographic display method described in the present application will be described in detail with reference to examples, comparative examples and experimental data.
Example 1:
preparing the metallographic corrosive agent for the primary strip-shaped structure of the steel: mixing water 25ml, methanol 25ml, copper chloride 20g and hydrochloric acid 1ml with the mass percent concentration of 36w percent uniformly to obtain the steel primary band-shaped structure metallographic corrosive agent, and placing the steel primary band-shaped structure metallographic corrosive agent into a container for standby.
(1) Taking a 20CrMnTi steel (heat treatment, namely heating to an austenite region of 930 degrees, preserving heat for 30 minutes, and then performing water cooling treatment), obtaining a longitudinal section along a rolling direction parallel to the steel to obtain a 20CrMnTi steel sample, and inlaying, grinding and polishing the sample until the polished surface is bright and clean and has no obvious scratches and stains;
(2) The polished surface of the steel sample obtained in the step (1) is rubbed and etched for 10 seconds by adopting the prepared steel primary band-shaped structure metallographic corrosive agent, and the polished surface is brownish red to obtain a metallographic corrosive sample;
(3) Immediately washing the metallographic corrosion sample obtained in the step (2) with water for 3 seconds, rapidly putting the metallographic corrosion sample into ethanol for washing for 3 seconds, and drying (blow-drying) the metallographic corrosion sample to obtain a metallographic observation sample for later use;
(4) Placing the metallographic observation sample obtained in the step (3) under a metallographic microscope for observation, amplifying a field of view by 50 times, and collecting pictures; the apparent bands appear in the picture as primary bands, some of which are thicker, throughout the field of view, as shown in fig. 1.
Example 2:
preparing the metallographic corrosive agent for the primary strip-shaped structure of the steel: mixing water 35ml, methanol 35ml, copper chloride 30g and hydrochloric acid 3ml with mass percent concentration of 38w percent uniformly to obtain the steel primary band structure metallographic corrosive agent, and placing the steel primary band structure metallographic corrosive agent into a container for standby.
(1) Taking Q420 steel, obtaining a longitudinal section along a direction parallel to the rolling direction of the steel to obtain a Q420 steel sample, and inlaying, grinding and polishing the sample until the polished surface is smooth and clean and has no obvious scratches or stains;
(2) Adopting the prepared steel primary band-shaped structure metallographic corrosive agent, performing drip etching treatment on the polished surface of the steel sample obtained in the step (1) for 8 seconds, wherein the polished surface is red, and obtaining a metallographic corrosive sample;
(3) Immediately washing the metallographic corrosion sample obtained in the step (2) with water for 8 seconds, rapidly putting the metallographic corrosion sample into ethanol for washing for 8 seconds, and drying (blow-drying) the metallographic corrosion sample to obtain a metallographic observation sample for later use;
(4) Placing the metallographic observation sample obtained in the step (3) under a metallographic microscope for observation, amplifying a field of view by 100 times, and collecting pictures; the image has distinct bands, primary band tissue, which is less spaced, thin and dense (some of the primary bands are thicker), and the bands extend mostly through the field of view.
Example 3:
preparing the metallographic corrosive agent for the primary strip-shaped structure of the steel: mixing water 30ml, methanol 30ml, copper chloride 25g and hydrochloric acid 2ml with the mass percent concentration of 36w percent uniformly to obtain the steel primary band-shaped structure metallographic corrosive agent, and placing the steel primary band-shaped structure metallographic corrosive agent into a container for standby.
(1) Taking Q420 steel, obtaining a longitudinal section along a direction parallel to the rolling direction of the steel to obtain a Q420 steel sample, and inlaying, grinding and polishing the sample until the polished surface is smooth and clean and has no obvious scratches or stains;
(2) Immersing the polished surface of the steel sample obtained in the step (1) into the metallographic etchant of the primary strip structure of the steel, wherein the polished surface of the steel sample is perpendicular to the liquid surface of the metallographic etchant of the primary strip structure of the steel, carrying out etching treatment for 1 second, and the polished surface is red to obtain a metallographic etching sample;
(3) Immediately washing the metallographic corrosion sample obtained in the step (2) with water for 5 seconds, rapidly putting the metallographic corrosion sample into ethanol for washing for 5 seconds, and drying (blow-drying) the metallographic corrosion sample to obtain a metallographic observation sample for later use;
(4) Placing the metallographic observation sample obtained in the step (3) under a metallographic microscope for observation, amplifying a view field by 200 times, and collecting pictures; the visible bands in the picture are primary bands of tissue that are less spaced, thin and dense bands (some of which are thicker), with the majority of the bands extending across the field of view as shown in fig. 2.
Comparative example 1:
(1) Taking a 20CrMnTi rolled material sample (heat treatment: heating to an austenite region of 930 ℃ C., preserving heat for 30min, and then performing water cooling treatment), inlaying, grinding and polishing the sample until the polished surface is smooth and has no obvious scratches or stains;
(2) Carrying out corrosion treatment on the polished surface of the steel sample obtained in the step (1) for 2 seconds by adopting 4% nitroalcohol to obtain a metallographic corrosion sample;
(3) Washing the metallographic corrosion sample obtained in the step (2) with water and ethanol immediately, and drying to obtain a metallographic observation sample for later use;
(4) Placing the metallographic observation sample obtained in the step (3) under a metallographic microscope for observation, amplifying a view field by 200 times, and collecting pictures; the metallographic structure is shown as a martensitic structure in the picture, and no obvious band shape is shown in figure 3.
Comparative example 2:
(1) Taking a Q420 rolled material sample, inlaying, grinding and polishing the sample until the polished surface is smooth and has no obvious scratches or stains;
(2) Carrying out corrosion treatment on the polished surface of the steel sample obtained in the step (1) for 2 seconds by adopting 4% nitroalcohol to obtain a metallographic corrosion sample;
(3) Washing the metallographic corrosion sample obtained in the step (2) with water and ethanol immediately, and drying to obtain a metallographic observation sample for later use;
(4) Placing the metallographic observation sample obtained in the step (3) under a metallographic microscope for observation, amplifying a view field by 200 times, and collecting pictures; the metallographic structure is shown as bainite structure in the picture, and no obvious band shape is shown in figure 4.
Example 4: process optimization experiment
And (3) examining the influence of the proportion relation of each component in the steel primary strip structure metallographic corrosive on the primary strip structure display definition:
method 1: the procedure is followed as described in example 1, except that the metallographic etchant comprises: 22ml of water, 23ml of methanol, 18g of copper chloride and 4ml of hydrochloric acid.
Method 2: the procedure is followed as described in example 1, except that the metallographic etchant comprises: 37ml of water, 37ml of methanol, 32g of copper chloride and 0.5ml of hydrochloric acid.
Method 3: the procedure is followed as described in example 1, except that the metallographic etchant comprises: 22ml of water, 40ml of methanol, 35g of copper chloride and 3.5ml of hydrochloric acid.
Method 4: the procedure is followed as described in example 1, except that the metallographic etchant comprises: 40ml of water, 20ml of methanol, 35g of copper chloride and 0.8ml of hydrochloric acid.
Method 5: inventive example 1;
method 6: inventive example 2;
method 7: inventive example 3;
the results are shown in Table 1.
Table 1: the proportion relation of each component in the corrosive agent has influence on the definition of the primary banded tissue
Figure BDA0002580500840000111
Comparison of methods 1-7 can be seen: through the above screening of 7 metallographic etchants, it was found that the primary band structures obtained by methods 1 to 4 showed unclear and no distinct bands. The primary banded tissue obtained by the methods 5 to 7 has high definition and obvious banded tissue appears; in particular, method 7 resulted in the highest definition of primary banding tissue with very pronounced banding.
Through the screening test, the invention finally determines the ratio of the volume of the water, the volume of the methanol, the mass of the cupric chloride and the volume of the hydrochloric acid as follows: (25-35) ml (20-30) g (1-3) ml, and further preferably the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: 30ml:25g:2ml; therefore, the metallographic etchant has good etching effect, can clearly display the primary banded structure of the steel sample, solves the problems of difficult display and clear display of the primary banded structure of rolled steel, and realizes good technical effect.
Finally, it is also 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. It is therefore intended that the following claims be interpreted as including the 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 modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (11)

1. A metallographic etchant for a primary strip structure of steel, the metallographic etchant comprising: water, methanol, copper chloride and hydrochloric acid;
wherein the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: (25-35) ml (20-30) g (1-3) ml;
the mass percentage concentration of the hydrochloric acid is 36-38 w%.
2. The steel primary band structure metallographic etchant according to claim 1, wherein the ratio of the volume of water, the volume of methanol, the mass of copper chloride to the volume of hydrochloric acid is: 30ml:25g:2ml.
3. A method for displaying a metallographic phase of a primary strip-shaped structure of a steel material, comprising the steps of:
polishing the steel sample to obtain a polished surface of the steel sample;
carrying out corrosion treatment on the polished surface of the steel sample by adopting the steel primary band-shaped structure metallographic corrosive agent according to claim 1 or 2 to obtain a metallographic corrosion sample;
washing and drying the metallographic corrosion sample to obtain a metallographic observation sample;
and (5) placing the metallographic observation sample under a metallographic microscope for observation, and collecting pictures.
4. The method of displaying a metallographic structure of a steel material according to claim 3, wherein the steel material sample is a longitudinal section sample parallel to the rolling direction.
5. The method for displaying a metallographic structure of a steel material according to claim 3 or 4, wherein the polishing the steel material sample comprises: and embedding, grinding and polishing the steel sample until the polished surface of the steel sample has no obvious scratches and stains.
6. The method for displaying a metallographic structure of a steel material primary tape according to claim 3 or 4, wherein the etching treatment is carried out for 1 to 10 seconds;
the method for corrosion treatment comprises the following steps: etching, wiping or dripping.
7. The method for displaying a metallographic phase of a steel primary tape structure according to claim 3 or 4, wherein said washing comprises: washing with water for 3-8 seconds, and washing with absolute ethyl alcohol for 3-8 seconds.
8. The method for displaying a metallographic structure of a steel material primary tape according to claim 3 or 4, wherein the metallographic microscope employs a 50-200 magnification view field.
9. The method for displaying a metallographic structure of a steel material according to claim 3 or 4, wherein the steel material is a rolled steel material.
10. The method for displaying a metallographic structure of a steel material according to claim 9, wherein the steel material is a heat-treated steel material after rolling.
11. The method for displaying a metallographic structure of a steel material according to claim 9, wherein the steel material is 20CrMnTi steel material or Q420 steel material.
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