GOST R 54570-2011
GOST R 54570−2011 Steel. Methods for evaluating the degree of poloschatosti or orientation of microstructures
GOST R 54570−2011
Group B09
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
STEEL
Methods for evaluating the degree of poloschatosti or orientation of microstructures
Steel. Assessing the degree of banding or orientation of microstructures
OKS 77.080
AXTU 0709
Date of introduction 2012−09−01
Preface
The objectives and principles of standardization in the Russian Federation established by the Federal law of 27 December 2002 N 184-FZ «On technical regulation», and rules for the application of national standards of the Russian Federation — GOST R 1.0−2004 «Standardization in the Russian Federation. The main provisions"
Data on standard
1 PREPARED AND SUBMITTED by the Technical Committee for standardization TC 145 «monitoring Methods of steel products"
2 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology dated 30 November 2011 No. 657-St
3 this standard is modified in relation to the national standard of USA ASTM E 1268−01* «Methods for evaluating the degree of poloschatosti or orientation of microstructures» (ASTM E 1268−01 «Assessing the degree of banding or orientation of microstructures») by modifying its structure to conform with the rules established in GOST R 1.7−2008.
________________
* Access to international and foreign documents mentioned here and below, you can get a link on the website shop.cntd.ru. — Note the manufacturer’s database.
Comparison of the structure of this standard the structure of the specified national standard of USA is given in Annex YES
4 INTRODUCED FOR THE FIRST TIME
Information about the changes to this standard is published in the daily published information index «National standards», and the text changes and amendments — in monthly indexes published information «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet
1 Scope
This standard specifies the methods which allow to describe the appearance of streaky structures and to assess the degree of poloschatosti. The methods used to assess the nature and extent of poloschatosti microstructures of metals and other materials that result from deformation and other technological operations are of banded or oriented structure. The most common example of poloschatosti is a banded ferritic-pearlitic structure of deformed carbon steels. Other examples of poloschatosti carbide banding in hypereutectoid tool steels and martensite banding in heat-treated alloy steels. The methods can also be used for features which do not poloschatosti microstructures with second phase particles, oriented (stretched) in different degrees in the warp direction.
Banded or oriented microstructures can be formed in a single-phase, two-phase or multiphase metals and materials. On the exterior orientation or poloschatosti influenced by such technological factors as the rate of crystallization, degree of segregation, degree of hot or cold deformation, the nature of the used deformation process, heat treatment and other factors.
Microstructural banding or orientation affect the uniformity of the mechanical properties determined at different orientations of the samples in relation to the direction of deformation.
The results obtained by test methods, can be used for quality control of material in accordance with standards agreed upon between consumer and manufacturer, for comparison of different processes or variants of the same process, as well as to retrieve the desired data in the study of the relationship between structure and properties.
2 Normative references
This standard uses the regulatory references to the following standards:
GOST 9450−76 the microhardness measurements by indentation of the diamond tips
ASTM E 140−01* conversion chart hardness values for metals (ASTM E 140−01, Hardness Conversion Tables for Metal)
_______________
* The table of conformity of national standards with international, mentioned hereinafter, please click the link. — Note the manufacturer’s database.
370−03 And ASTM test Methods and definitions for mechanical testing of steel products (ASTM A 370−03, Test Methods and Definitions for Mechanical Testing of Steel Products)
ASTM E 384−01 Methods of testing metals on the microhardness (ASTM E 384−01, Test Method for Microhardness of Materials)
ASTM E 562−02 Manual point method of determining the volume fraction of phases (ASTM E 562−02, Determining Volume Fraction by Systematic Manual Point Count)
3 Terms, definitions and symbols
3.1 Definitions
3.1.1 banded microstructure (banded microstructure): the Separation of one or more phases or structural constituents in two-phase or multiphase microstructure, or segregation of parcels in single-phase or single-structural component microstructure into two distinct layers, parallel to the axis of deformation, as a result of lengthening sections of microliquation. On the formation of streaky structures can influence other factors, such as the temperature of the end of hot deformation, the magnitude of compression when cold or hot deformation, partial transformation of austenite due to limited hardenability, or inadequate rate of cooling.
3.1.2 the number of intersections of particles (feature interceptions): the Number of particles (or clusters of particles) of the phase or structural component intersected by the lines of the measuring grid (figure 1).
Figure 1 — Illustration of the calculation of the intersections of particles N and border crossings P for oriented microstructure
Notes
1 Shows a line measurement of the grid oriented perpendicular to the axis of deformation (A) and parallel to the axis of deformation (In). Shows the scheme of calculating ,
,
and
for calculations carried out from top to bottom (A) and left-to-right (In).
2 T indicates touch particles, and f indicates that the measuring line ends inside the particle; both cases are evaluated as shown in the figure.
Figure 1 — Illustration of the calculation of the intersections of particle and border crossings
for an oriented microstructure
3.1.3 the number of border crossings (feature interseptions): Number of boundaries between the matrix and the phases or structural component intersected by the lines of the measuring grid (see figure 1). For individual particles distributed in the matrix, the number of border crossings will be twice greater than the number of intersections of particles.
3.1.4 oriented structural components (oriented constituents): One or more redundant phases (structural components), extending parallel to the axis of deformation is not in the form of a strip (i.e. randomly distributed); the degree of elongation varies depending on the size and the deformability of the phases or the structural component and the degree of compression during hot or cold deformation.
3.1.5 stereological methods (stereological methods): the Methods used to characterize the three-dimensional components of the microstructure on the basis of measurements performed on two-dimensional planes of sections.
Notes
1 Although the assessment of poloschatosti or orientation are used stereological methods of measurements, these measurements are performed only on planes parallel to the direction of deformation (i.e. longitudinal plane) and three-dimensional characteristics of poloschatosti or orientation are not determined.
2 In Appendix A. 1 shows examples of microstructures to illustrate the terminology used for qualitative descriptions of the nature and extent of poloschatosti or orientation. Figure 2 shows the schema of quality classification.
Figure 2 — diagram of the qualitative classification for banded or oriented microstructures
Length/width.
Or structural component.
Figure 2 — diagram of the qualitative classification for banded or oriented microstructures
3.2 Notation — the number of intersections of particles measuring lines perpendicular to the direction of deformation.
— the number of intersections of particles measuring lines parallel to the direction of deformation.
— increasing.
— the true length of the measuring line, i.e. the line length, divided by M.
— the number of intersections of the boundaries of the measurement lines that are perpendicular to the direction of deformation.
— the number of intersections of the boundaries of the measuring lines parallel to the direction of deformation.
— the number of measured fields or the number of prints of the microhardness.
the mean value of (
,
,
,
).
the estimate of the standard deviation (
).
— the multiplier depending on the number of investigated fields and used together with the standard deviation of the measurements to determine the 95% CI.
95% CI — 95% confidence interval.
95% CI 
% RA — relative accuracy, %.
% RA = 
— the average distance between the centers of the strips.
— the volume fraction of lamellar phase (the structural component).
— the average distance between the edges of the strips, the mean free path (the distance).
— the coefficient of anisotropy.
— degree of orientation of partially oriented linear elements of the structure on the two-dimensional plane of Polish.
4 the Essence of the methods
4.1 Methodology qualitative descriptions of the nature of banded or oriented microstructures based on the morphological features of the microstructure
4.1.1 To study the microstructure of the samples used metallographic microscope. Banding or orientation is best seen at low magnifications, for example from 50to 200
.
4.1.2 the Degree of microstructural poloschatosti or orientation describe qualitatively, using the micro-sections cut parallel to the warp direction of the product. The schema of quality classification for banded or oriented microstructures shown in figure 2. In Appendix A. 1 shows examples of microstructures to illustrate the terminology used for qualitative descriptions of the nature and extent of poloschatosti or orientation.
Stereological 4.2 methods for the quantitative measurement of the degree of poloschatosti or orientation of microstructures
4.2.1 These methods are used to measure the number of strips per unit length, the distance between the strips or particles and the degree of anisotropy or orientation (parameters ,
,
,
,
,
, etc.).
4.2.2 Stereological methods can be used to determine the nature and extent of microstructural poloschatosti or orientation of any metal or material.
4.2.3 Stereological methods are not suitable for measuring structural features in separate zones of phase separation present in the rest of the fairly homogeneous microstructure. Instead, they should use standardized methods of measurement to determine the size of such zones. For such structures it is also possible to use a method of measurement of microhardness.
4.2.4 Stereological the rate is measured by the overlay measuring grid consisting of a series of closely spaced parallel lines of known length deposited on a transparent plastic overlay or ocular insertion, for the projected images of the microstructure or on the MicroDot. The rate is measured by the overlay measuring lines parallel and perpendicular to the direction of deformation. The total length of the lines of the measuring grid should be at least 500 mm. examples of the measurement of banded or oriented structures is given in Appendix A. 1.
4.2.5 For microstructures with sufficient contrast between the banded or oriented structural components of the calculation can be performed on the automatic analyzer of images.
4.3 Method of measurement of microhardness
4.3.1 Method of measurement of microhardness should be used only to determine the differences in the hardness in heat treated metals with a lamellar structure, mainly in steels.
4.3.2 hardness testing of strips of each type in heat-treated steels or other metals use hardness. For such measurements is particularly well suited indenter of Copa.
4.3.3 For a fully martensitic carbon and alloy steels (0,10%-0,65%) after quenching the carbon content in the matrix and segregated area can be estimated by the values of microhardness.
5 Sampling
5.1 Normally, the samples should be collected from the final product after all manufacturing operations, especially those that may affect the nature and extent of poloschatosti. Since the degree of poloschatosti or orientation can change the thickness of the cross section of the investigated plane must pass through all cross-section. If the size of the product is too large for the manufacture of a microsection across the cross section, the samples should be collected in standard plots, for example at the surface, mid-radius (or the distance equal to ¼ of the thickness of the surface) and in the center or in certain areas specified in the agreements between manufacturer and user.
5.2 Degree present poloschatosti or orientation determine the longitudinal samples, i.e. the samples with the plane of Polish parallel to the direction of deformation. For the sheet metal may also be the tested sample oriented in the rolling plane (i.e. the plane of the thin section parallel to the surface of the sheet), prepared beneath the surface, mid-thickness or the center of the sheet depending on the nature of the use of the products.
5.3 Banding or orientation can be evaluated on intermediate products, such as billets or rods, for the purpose of material specifications or quality control. However, the results of such tests may not show a direct connection with the results of the tests of the final product. Samples for testing should be made in accordance with 5.1 and 5.2, but subject to the additional requirements for the location of the samples relative to the ingot or continuous cast slab and a stream of continuous casting. The date and place of taking such samples needs to be specified in the agreement between the manufacturer and the customer.
5.4 the Area of the polished surface of a metallographic specimen of the individual should cover all the cross section, if possible. Length of the samples made in the full cross-section in the warp direction should be at least 10 mm. If too big size of products allows to prepare a thin section across the cross section, the minimum area of the polished surface of the samples prepared in the required locations shall be 100 mmwhen the length of the sample in the longitudinal direction at least 10 mm.
6 sample Preparation
6.1 Methods of sample preparation must provide identification of the microstructure and to eliminate undue influence arising in the process of making the deformation or smoothing of asperities.
6.2 depending on the type of sample or, if necessary for processing on automatic polishing machines, can be used to mount the samples.
6.3 For the identification* of the microstructure necessary to achieve a significant contrast through the use of appropriate method of chemical or electrolytic etching, colored etching or oxidation, etc. For some materials, the etching may be optional if naturally occurring the difference in the reflectivity of the structural components can provide sufficient contrast.
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* The text of the document matches the original. — Note the manufacturer’s database.
7 Method
7.1 Polished and treated with the sample placed on the microscope stage, choose a suitable low magnification, for example, 50or 100
, and study the microstructure. Set the pattern so that the direction of deformation on the projection screen was horizontal.
7.1.1 Use a stage micrometer to determine the increase in the projection plane of the image or in the plane of the photograph. To determine the length of lines on a measuring grid plate in millimeters using a ruler.
7.1.2 Initial field chosen by arbitrary displacement of the table and install without any additional adjustment of its position.
7.1.3 most measurements used brightfield illumination. However, depending on the investigated alloy or material may be used other types of lighting, such as polarized light or differential interference contrast.
7.1.4 Measurement can also be performed by measuring overlay grid on photomicrographs of randomly selected fields of view under appropriate magnifications.
7.2 Qualitatively define the nature and extent of present poloschatosti or orientation in accordance with subsequent instructions. For identification and classification of the present structural components may require study at higher magnifications. Used classification scheme is shown in figure 2.
7.2.1 Determine whether banding or orientation due to changes in the intensity of etching of one phase or the structural component, as it can occur as a result of segregation in the samples tempered martensitic alloy steel or as a consequence of preferential orientation of one or more phases or structural constituents in two-phase or multiphase sample.
7.2.2 in the presence of orientation or poloschatosti in a two-phase or multiphase sample to determine whether only the primary orientation contained in a smaller amount of phase or structural component in the matrix phase. In other cases, can be oriented both phases, and none of them is a matrix phase.
7.2.3 For the two-phase (containing two structural components) or multiphase (containing many of the structural components) of the microstructures to determine whether a lamellar second phase (structural component) layers or represents a randomly distributed oriented particles, not forming bands.
7.2.4 In cases where the second phase or structural component has the form of strips or oriented in neprostoi, undirected matrix, determine whether banded or oriented structural component in the form of discrete particles (which may be globular or elongated) or in a continuous oriented structural component.
7.2.5 Describe the distribution of the second phase (lighter or darker areas of the etched single-phase microstructure) on the basis of the observed pattern, such as: isotropic (undirected or nefolosita), almost isotropic, partially stripped, partially oriented, blurred stripes, narrow stripes, wide stripes, mixed narrow and wide stripes, fully focused, etc.
7.2.6 Examples of microstructures are given in Appendix A. 1 illustrate the use of such terminology for the qualitative description of the nature and extent of poloschatosti or orientation. Figure 2 shows the pattern approach to the classification of the microstructures.
7.3 Place the measuring grid on projected image or a photomicrograph randomly selected fields (7.1) so that the grid lines are perpendicular to the direction of deformation. The mesh should be set by the operator without shifting. Determine which phase or structural component is stripped. In that case, if the stripe are both of the phase or structural components in the absence of discernible matrix phase, choose one of the phases for counting. It is usually better to count for the phase which is present in smaller amounts. Depending on the purpose of measurement or in accordance with the technical requirements can be measured by the value of or
or both of these values (the technique of definition 7.3.1−7.3.4), using the orientation measurement grid perpendicular (
) or parallel (||) the direction of deformation.
7.3.1 Measurement — applied measurement grid perpendicular to the warp direction and count the number of discrete particles or clusters of particles that crossed the measuring lines. For the two-phase structure count all crossings of the phase considered, i.e. the ones that clearly are part of bands, and those that are not. If two or more adjacent particles, grains or clusters of particles of the considered phase or structural component intersected by a grid line, i.e. between such particles, grains or clusters do not present different phases or structural component, this should be considered as one intersection (
1). Touch the measurement line is counted as half of the intersection. Cases where the ends of the line lie inside particles, clusters of particles or granules, are also counted as half of the intersection. Table 1 shows the scoring rules, and figure 1 illustrates the method of calculation. Calculate the number of intersections of particles per unit length of the line perpendicular to the cosine of deformation
, according to the formula
where — the number of intersections;
— the true length of the measuring line, i.e. the line length, divided by
.
Table 1 — Rules for counting values and
| 1 |
|
| 2 |
|
| 3 | If two or more adjacent particles, grains or clusters of particles of the considered phase or structural component intersected by the grid lines (no other phases or between the structural component traversed by the particle is not present), then this case should be considered as one intersection ( |
| 4 | If the measuring line for the considered particles, grains or clusters of particles, that is |
| 5 | If the measuring line ends inside the particle, |
| 6 | If the entire measuring line is fully placed inside the phase or the object in question (this may occur when the parallel position of the measuring line relative to the axis of deformation in materials with strongly pronounced banding), it |
| |
7.3.2 Measurement — turn off measurement grid relative to the same field location, which was measured
, so that measurement lines were oriented parallel to the direction of deformation. Do not install the measuring grid on any specially chosen feature or features of the microstructure. Calculate all intersections of the particles
with measuring lines (as described in 7.3.1), regardless of whether they are a distinct part of the portion of the band or not. Calculate the number of intersections of particles per unit length of the line parallel to the axis of deformation
, according to the formula
where is the true length of the measuring line (see 7.3.1).
7.3.3 Measurement — applied measurement grid perpendicular to the warp direction and count the number of crossings measuring border lines of particles, phase, or structural component,
irrespective of the particle, the phase or structural component of a distinct part of the band or not. Do not consider the boundaries between the phase or the structural component, and similar particles, grains or clusters of particles. Consider only the intersection of the boundaries of phase or structural component with different particles, grains or clusters of particles. Touch borders with the measuring line is counted as one intersection. Table 1 shows the scoring rules, and figure 1 illustrates the method of calculation. Calculate the number of intersections of particles per unit length of the line perpendicular to the axis of deformation
, according to the formula
where is the true length of the measuring line (see 7.3.1).
7.3.4 Measurement — turn off measurement grid relative to the field location, which was measured
, so that the lines were oriented parallel to the warp direction and count the number of intersections of the boundaries of the particles, phase, or structural component
, for the considered objects (as described in 7.3.3). Computes the number of border crossings per unit length of the line parallel to the axis of deformation
, according to the formula
where is the true length of the measuring line (see 7.3.1).
7.3.5 Measurement should be repeated at least five fields for each sample or site selected by the operator arbitrarily. If the picture of poloschatosti varies considerably in thickness in the longitudinal sample, the measurements can be carried out in certain places, for example beneath the surface, mid thickness and the centre or in some places in thickness to evaluate possible modifications to different parts of the sample.
7.3.6 Examples of the use of these methods of measurement are given in Appendix A. 1.
7.4 For stripped heat-treated microstructures, especially for alloy steels, the above-described measurement of the microstructure can be complemented by the definition of the average microhardness of the bands. Determine the nature of the present bands, for example, are light and dark stripes travesias martensite or martensite and Bantam.
7.4.1 Hardness of each strip measured, using Copa indenter or Vickers. The load is selected so that the imprint was fully inside the lines. If possible, you should use a load of 500 g, especially if it needs to be evaluated is equivalent to the hardness scale Rockwell (HRC). Measurement of microhardness should be performed in accordance with GOST 9450.
7.4.2 To determine the average hardness should be not less than five measurements in each type of strips (light and dark truesense the martensite or martensite and bainite depending on nature strips). For small sections of the plant receive five or more prints of the microhardness may not be possible.
Note — If the difference in the microhardness values of Kopu between the bands is negligible, it is possible to determine the statistical significance of this difference using the criterion as described in most textbooks on statistics.
7.4.3 the Transfer of hardness values for Knope (NK) in equivalent hardness values on a scale From Rockwell (HRC) requires great care and may be accompanied by significant error, especially if used in the test loads were less than 500 g of the Table in ASTM E 140 do not include transfer values of NK in the HRC (or other scales) for steels with a hardness of more than 251 of the tax code; however, the standard of ASTM A 370 allows such a transfer for a range of values of hardness of the covering of heat-treated steel. To translate the values of NK at HRC you can also use the formulas given in Appendix A. 2.
7.4.4 For hardened carbon and alloy steels with a mass fraction of carbon from 0.10% to 0.65% measuring the hardness in a state after hardening, allow us to estimate the carbon content in the matrix and segregated stripes or spots. Like the matrix and segregated areas should be fully martensitic (except for the usual slight amount of residual austenite), and in the condition after quenching. The values of microhardness on Knuu (at a load of 500 g) for the matrix and phase separation sections are translated into values of HRC (formula (A. 2.1) and (A. 2.3) of Annex A. 2), the carbon content depending on the hardness values determined by the formula (A. 2.4) application A. 2.
8 Calculation of results
8.1 After measurements at the required number of fields or dimensions of a certain number of prints of the microhardness
calculate the average value of each dimension by dividing the sum of measurements
for the determination of srednesrochnoi
,
,
,
or the average value of microhardness for Knopw for bands of every type. For microstructures with a very pronounced banding
(a dash over the number indicates the mean value) is a measure of the number of strips at 1 mm (½
approximately equal
).
8.2 Next calculate the standard deviation these measurements for
fields or prints of the microhardness from the expression
where the results of measurements of individual fields;
the average value.
8.3 Next calculate the 95 percent confidence interval 
where is the standard deviation;
varies depending on the number of measurements (table 2).
The value for each dimension is expressed as mean ±
8.4 Further calculate the relative precision in percent 
where — the average value of each dimension.
Relative accuracy is the error estimate for each measurement in % related to the change in values when moving from one field to another. Usually sufficient accuracy is 30% or less. If 
Table 2 — Values for computing the 95% confidence interval
| 2 |
4,303 |
| 3 |
3,182 |
| 4 |
2,776 |
| 5 |
2,571 |
| 6 |
2,447 |
| 7 |
2,365 |
| 8 |
2,306 |
| 9 |
2,262 |
| 10 |
2,228 |
Note 1 — | |
8.5 the Average distance (center to center) for banded or oriented phase (or structural component), can be defined as the inverse
You can also calculate the mean free path (from edge to edge). It is necessary to determine the volume fraction of banded or oriented phase (structural component) method of point counting (ASTM E 562) or other suitable methods. The mean free path
is determined from the expression
where the volume fraction (not percentage).
The difference between the average distance and the mean free path allows us to estimate the average width of banded or oriented phase or structural component.
8.6 Calculate the anisotropy factor , using an average from the values defined in 8.1, from the expression
These two coefficients should be approximately equal, because if you do not consider the effects of touching particles and boundaries, as well as calculation errors for such structures 
8.7 the Degree of orientation of partially oriented linear elements of the structure on the two-dimensional plane of the thin section can be calculated using values
or
defined in 8.1, according to the formula
These two values should be approximately equal, because if you do not consider the impact of touching particles and boundaries, as well as calculation errors for such structures 
9 test report
9.1 the Protocol should contain complete information about the tested sample: its origin, location, product, type of product, date of analysis, the number of measured fields or prints of the microhardness, used grow, etc.
9.2 Describe the nature and extent of poloschatosti or orientation, present in the microstructure.
9.3 depending on the measurements indicate the average value, standard deviation, 95% confidence interval and % relative accuracy for each dimension (,
,
,
and NK for each strip). Then, depending on made banding, specify values for the distances
and
calculated in 8.5.
9.4 For samples, which was determined by microhardness of the bands, calculate the difference in the values of hardness Knopw between the bands, if required. The translation of NK in HRC values (or other scales) may contain significant error (especially for loads less than 500 g).
9.4.1 For hardened carbon and alloy steels with a martensitic matrix structure and phase separation sections is possible to estimate the carbon content in the matrix and phase separation plot based on the values of hardness in a state after quenching, using the methodology described in Appendix A. 2. This method is applicable only for steels with a mass fraction of carbon from 0.10% to 0.65%, which segregated to the site and the matrix needs to have a martensitic structure. For these samples it is possible to estimate and specify in the Protocol the degree of segregation of carbon.
10 Precision and accuracy
10.1 Standards, allowing to reliably determine the accuracy of the measurement of poloschatosti and to detect measurement error, missing.
10.2 Since the banding is determined on a longitudinally oriented metallographic specimens cut parallel to the direction of deformation, the departure of the plane polishing, in excess of approximately 5°, will influence the measurement results.
10.3 Improper sample preparation will affect the test results. Etching should provide a strong contrast between the considered phases or structural components. However, it is undesirable to used reagent reveals grain boundaries within the phase.
10.4 the Degree of poloschatosti or orientation, as well as the width of strips can vary according to the thickness of the cross section of the sample. Therefore, you should assess the characteristics of poloschatosti or orientation in certain places.
10.5 the results of the tests may attempt to used increase. It should be high enough to ensure an accurate count of intersections of particles or border crossings between the phases. However, the increase should be as low as possible, so that each test line was crossed by a sufficiently large number of grains or particles of interest.
10.6 To ensure sufficient accuracy of the calculation and determination of ,
,
,
measurement lines must be accurately held perpendicular to parallel to the direction of deformation. Should avoid deviations of the lines from the perpendicular or parallel direction by more than 5°.
10.7 As a rule, with increasing number of fields measured statistical variability of test results decreases.
The relative accuracy of the measurements in the direction parallel to the axis hot deformation, almost always worse than the accuracy of measurements perpendicular to the direction of deformation, as can be seen from the results of the tests are given in Appendix A. 1. For a given number of measured fields, the statistical accuracy is usually better in the case of coarser structures than for smaller structures and the isotropic structures compared to highly oriented lamellar or structures.
10.8 Should strictly follow the rules of counting, because otherwise it will deteriorate the convergence and reproducibility intralaboratory and interlaboratory tests.
10.9 Verbal description of the nature of poloschatosti or orientation is qualitative and somewhat subjective. Currently, there are no absolute principles that allow to associate the measured quantitative parameters and qualitative terms used to describe the microstructure.
10.10 values of the coefficient of anisotropy and the degree of orientation cannot be used to establish whether a microstructure is only oriented parallel to the direction of deformation, or she’s really streaky. To establish this difference it is necessary to use image recognition methods, which are not included in the tasks considered in this standard method.
However, an experienced operator will be able to make a distinction between two forms of orientation, with examples, is given in Appendix A. 1.
10.11 Use the method of measurement of microhardness to determine the difference in hardness between the bands is due to the influence of the same factors that affect the precision and accuracy of the results of such test (ASTM E 384).
10.12 Transfer of hardness values for Kopu at a load of 500 g in the values of HRC introduces another source of uncertainty, which are difficult to determine.
10.13 the Prediction of carbon content in quenched carbon and alloy steels (in the matrix and segregated area) or the difference in carbon content between a segregated phase and matrix should be considered as an approximation due to the variability of the published data for the dependence of hardness after quenching (100% martensite) on the carbon content in carbon and alloy steels.
Appendix 1 (compulsory). Examples of the measurement of banded or oriented microstructures
Appendix A. 1
(required)
A. 1.1 In this Annex examples of single-phase and two-phase microstructures (figures A1.1-A1.17), which illustrate various degrees of poloschatosti or orientation of microstructures. For each microstructure the qualitative description in accordance with the scheme shown in figure 1, and each structure was measured using the appropriate methodology described in 6.3. All measurements were conducted using a two-fold enlargement of the presented photomicrographs. The measuring grid used for these measurements consisted of eight parallel lines, spaced 20 mm apart; each line was measured a length of 125 mm with a total line length of 1000 mm. the Measurement grid was set alternately perpendicular and parallel to the axis of deformation in different randomly selected locations of the photomicrographs with the lowest possible offset. On each micrograph were performed at least five (usually more) of the dimensions in each direction with one or more operators. Each shows a microstructure deform axis corresponds to a horizontal direction.
Figure A. 1.1 — an Undirected, nefolosita isotropic two-phase microstructure, in which there is no matrix phase
Deformed corrosion resistant steel AISI 312
|
|
|
|
|||||
| Of 32.30 |
28,71 | 1,13 | 0,074 | 62,02 | 56,50 | 1,10 | 0,059 | |
| 1,409 |
2,316 | 3,208 | 4,117 | |||||
| ±1,06 |
±1,75 | ±2,42 | ±3,10 | |||||
| 3,3 |
6,1 | 3,9 | 5,5 | |||||
| 10 |
Note — Measurements have been performed on austenitic (white) phase. Colored etching.
Figure A. 1.1 — an Undirected, nefolosita isotropic two-phase microstructure, in which there is no matrix phase; ferrite (white), austenite (white)
Figure A. 1.2 — Highly oriented lamellar two-phase microstructure
Deformed corrosion resistant steel AISI 329
|
|
|
|
|||||
| 61,28 |
13,18 | 4,65 | 0,699 | 121,83 | 25, and 58 | 4,76 | 0,705 | |
| 3,828 |
2,390 | 7,231 | 4,557 | |||||
| ±2,57 |
±1,61 | ±4,86 | ±3,06 | |||||
| 4,2 |
12,2 | 4,0 | 12,0 | |||||
| 11 | ||||||||
| ||||||||
0,227 
0,0163 mm
Note — Measurements have been performed on austenitic (white) phase. Colored etching.
Figure A. 1.2 — Highly oriented lamellar two-phase microstructure oriented austenite (white) in oriented lamellar ferritic (from gray to black) matrix
Figure A. 1.3 — Microstructure consisting of two components: oriented, slightly elongated, partially stripped of Delta-ferrite in an undirected, neprostoi matrix of tempered martensite
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| 36,14 | 17,00 | 2,13 | 0,417 | 72,59 | 34,08 |
2,13 | 0,419 | |
| 4,149 | 3,348 | 8,624 | 7,009 |
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| ±2,40 | ±1.93 and | ±4,98 | ±4,05 |
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| Of 6.63 | 11,4 | 6,9 | 11,9 |
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| 14 | ||||||||
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0,490 
0,0277 mm
Note — the Measurements were conducted at the Delta ferrite (white phase). The etching solution of Aqua Regia in glycerol.
Figure A. 1.3 — Microstructure consisting of two components: oriented, slightly elongated, partially banded (wide strip) of Delta-ferrite (white) in an undirected, neprostoi matrix of tempered martensite (black)
Figure A. 1.4 — Microstructure, consisting of two components: the stripe top bainite in a lamellar, equiaxed ferritic (netravlenoy) matrix
Alloy steel AISI 8715
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| 8,50 | Of 2.83 |
3,0 | 0,561 | 17,00 | Of 5.66 | 3,0 | 0,561 | 0,118 | 0,086 | |
| 0,4555 | 0,6506 |
0,911 | 1,3012 | |||||||
| ±0,57 | ±0,81 |
±1,13 | ±1,62 | |||||||
| 6,7 | 28,5 |
6,7 | 28,5 | |||||||
| 5 |
Note — Measurements have been performed on bainite component. Etching in 4% alcoholic solution of picric acid.
Figure A. 1.4 — Microstructure, consisting of two components: the stripe top bainite (dark) in a lamellar, equiaxed ferritic (netravlenoy) matrix
Figure A. 1.5 — Microstructure consisting of two components: nearly isotropic distributed globular pearlite in a matrix of equiaxed ferrite (netrain)
Alloy steel AISI 8620
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| 28,86 |
Of 25.92 | 1,11 | 0,067 | 56,31 | 52,55 | Of 1.08 | 0,047 | |
| 1,6373 |
2,5308 | 4,205 | 4,6425 | |||||
| ±1,72 |
±2,66 | ±4,41 | ±4,87 | |||||
| 6,0 |
10,3 | 7,8 | 9,3 | |||||
| 6 |
Note — the Measurements were conducted on pearlitic component. Etching in 4% alcoholic solution of picric acid.
Figure A. 1.5 — Microstructure consisting of two components: nearly isotropic distributed globular pearlite (dark) in a matrix of equiaxed ferrite (netrain)
