GOST 5640-68
GOST 5640−68 Steel. Metallographic method for the evaluation of microstructure of sheets and strips
GOST 5640−68
Group B09
STATE STANDARD OF THE USSR
STEEL
Metallographic method for the evaluation of microstructure of sheets and strips
Steel. Method for Metallographic determination of microstructure of sheets and bands
Date of introduction 1970−01−01
APPROVED by Resolution of the Committee of standards, measures and measuring devices under Council of Ministers of the USSR dated 31 October 1968, N 63. The validity period is set from
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* Expiration removed Protocol MGS N 7−95 (ICS 11−95).
REPLACE GOST 5640−59
REPRINTING. September 1988
This standard applies to sheets and strips of mild and carbon steel, and sets metallographic method of evaluating structural-free cementite, perlite, and poloschatosti widmanstatten structure.
Application of the method provided for in the standards and technical conditions for steel products, which establishes technical requirements for it.
1. SAMPLING AND FABRICATION OF MICRO-SECTIONS
1.1. Evaluation of the microstructure produced on the micro-sections of size 30x40 mm. Samples for micro-sections needs to be cut out cold in a mechanical way so that their plane coincides with the direction of the fibers (samples must be longitudinal). Place tenderloin and the number of samples from a batch should be specified in the relevant standards and specifications.
1.2. A method of manufacturing a micro-sections not regulated. To remove work-hardened from machining layer applied re-polishing.
2. METHOD FOR DETERMINATION OF MICROSTRUCTURE
2.1. Etching of the samples produced in 4% strength solution of nitric acid in alcohol. The detection of structurally free cementite, the samples shall poison all that time clearly revealed only particles of cementite, and grain boundaries can be identified weakly.
2.2. To evaluate structural-free cementite and pearlite in the low carbon steels used microscopes with magnification 360−400, to assess poloschatosti and widmanstatten structure — microscopes with magnification of about 100
.
2.3. The standard diameter of fotoatele — 80 mm.
2.4. When using the standard scales you need to specify the number of points and letter number, e.g., 1A, 3B, etc.
Scale 1. Structurally-free cementite
2.5. Scale for the assessment of structural-free cementite in annealed low-carbon steel with carbon content up to 0.15% based on the number, shape and location cementite particles and consists of three rows and six points.
A number And based on the principle of formation of cementite lattice at the grain boundaries. For quantitative characteristics is used, the proportion of the perimeter of individual grains of ferrite is covered by a grid of cementite.
A number B is constructed in ascending order of particle sizes of structural-free cementite, forming a single layer, double layer and multilayer chain of different lengths.
A number of In built on the principle of transition of a uniformly distributed point of the rash in irregular banded structure. In table.1 (Annex 1) provides descriptions of the microstructures according to the points scale 1 (Annex 2).
Scale 2. Pearlite in mild steel deformed
2.6. Scale to assess the number and nature of the arrangement of pearlite in the low carbon deformed steel with a carbon content of 0.10 to 0.30 percent is based on the structure of pearlite (granular or orbituary), its quantity and the nature of the distribution and consists of two rows and six points.
Range And is designed for evaluation of granular pearlite in the cold rolled steel with a carbon content of 0.1−0.2%. With increasing numbers of points increases the size of cementite particles and the tendency to the formation of bands.
Series B is designed to assess sarbatoarea of pearlite in hot rolled steel with a carbon content of 0.1−0.2%. With increasing numbers of points of the granular perlite goes in the plate with the formation of differentiated bands.
The series In intended for evaluation of pearlite in hot rolled steel with a carbon content of 0.21 and 0.30%. With increasing numbers of points the microstructure with small uniformly sized and evenly distributed parts of perlite becomes inhomogeneous banded structure, with the assessment of the microstructure is necessary to produce phase separation zone consisting of clusters of perlite in the form of wide continuous bands.
In table.2 (Annex 1) provides descriptions of the microstructures according to the points scale 2 (Annex 2).
Scale 3. Banding of ferrite-pearlite structure
2.7. Scale for assessment of poloschatosti in the structure of pearlitic steels is built on the principle of increasing the number of ferrite strips taking into account their degree of continuity and the degree of ravnodusnost grains in the bands and consists of three rows and six points.
Range And is designed to assess poloschatosti in steel with carbon content up to 0.15%.
Series B is designed to assess poloschatosti in steels with a carbon content of 0.16−0.30 percent.
The Number In designed to assess poloschatosti in steels with a carbon content 0,31−0,50%.
In table.3 (Appendix 1) provides descriptions of the microstructures according to the points scale 3 (Appendix 2).
Scale 4. Widmanstatten structure
2.8. Scale for assessment of development widmanstatten structure in pearlitic steels after heating based on the principle of increasing the number and size of needle precipitates of ferrite and the grain size, ferritic determined by a grid corresponding to the amount of actual austenite grain, and consists of two rows and six points.
Range And is designed to evaluate the microstructure in steels with a carbon content of 0.15 and 0.30%.
Series B is designed to evaluate the microstructure in steels with a carbon content 0,31−0,50%.
In table.4 (Annex 1) descriptions of microstructures on the scale of 4 points (Annex 2).
2.9. Evaluation of the microstructure is made by comparing the microstructure with the standards of the relevant scales. Thus the estimation of structural-free cementite, perlite, and poloschatosti widmanstatten structure produced by the highest score found in at least three sections of the cone. Surface layer of metal to a depth of about 10% of the sheet thickness on each side is not taken into account.
ANNEX 1
Table 1
Scale 1. Structurally-free cementite
| The number of points | Description of the microstructure | ||
| The Number And |
A Number Of B | The Number In | |
| 0 | Uniformly distributed point or melkopomolotyj rash from cementite particle size of 1−2 mm |
Point or melkopomolotyj rash from cementite particles having a tendency to the formation of single-layer chains |
Point or melkopomolotyj rash, evenly distributed across the cone and has a certain orientation in the warp direction |
| 1 | Neravnovesnye inclusions of cementite with sizes up to 5 mm, are uniformly distributed in the bulk of grains and their joints |
Cementite particle size of 1−2 mm, forming a single layer of the chain |
Melkopomolotyj rash with a particle size of 1−2 mm, oriented in the warp direction |
| 2 | Relatively evenly distributed cementite particles with sizes greater than 5 mm, having a tendency to occurrence in the form of a grid at the grain boundaries and covering no more than |
Single and double chains of cementite particles with sizes up to 3 mm |
Small clusters of cementite particles size 1−2 mm, oriented in the warp direction |
| 3 | The inclusion of cementite occurring in the form of a grid at the grain boundaries and covering to |
Single and double chains of particles with sizes up to 5 mm |
Globular particles with a size of 2−3 mm, located in clusters and broken bands extending in the warp direction |
| 4 | The inclusion of cementite occurring in the form of a grid at the grain boundaries and covering to |
Double and triple chains, running through the entire field of view and consisting of particles of cementite is larger than 5 mm |
The structure corresponds to score 4 row B |
| 5 | The inclusion of the cementite, forming solid or nearly solid mesh at the grain boundaries of the ferrite |
Wide layered chain passing through the entire field of view and consisting of large (5 mm) particles |
The structure corresponds to a score of 5 series B |
Table 2
Scale 2. Pearlite in mild steel deformed
| The number of points | Description of the microstructure | ||
| The Number And |
A Number Of B | The Number In | |
| 0 | Uniformly or relatively uniformly distributed granular perlite with particle sizes from 1−2 mm to melkoplodnogo |
Uniformly distributed in the field of view areas of the grains of perlite | Uniformly distributed within a field of view small areas of lustrous perlite |
| 1 | Small strokefest granular perlite in the warp direction | A small number of sites sarbatoarea perlite, poorly oriented in the warp direction |
Relatively evenly distributed over large areas of pearlite, poorly oriented in the warp direction |
| 2 | Uneven distribution of granular pearlite, arranged in clusters, oriented in the warp direction |
Larger areas sarbatoarea perlite, oriented in the warp direction | Inhomogeneous largest portions of the perlite having a stroke distribution |
| 3 | Larger aggregations of granular perlite, oriented in the warp direction | Larger areas sarbatoarea perlite having a stroke distribution |
The accumulation of pearlite in large areas having a stroke distribution |
| 4 | One solid and a few broken bands of granular perlite | Arbituary, sometimes lamellar pearlite with stroke distribution |
One or more broken bands of perlite, passing through the entire field of view |
| 5 | Pronounced banded distribution of globular pearlite | Large areas sorbirovannoe and grouplisting perlite having a pronounced stroke distribution (the width of the lines is not less than |
A wide continuous band of coarser pearlite structure passing through the entire field of view |
Table 3
Scale 3. Banding of ferrite-pearlite structure
| The number of points | Description of the microstructure | ||
| The Number And |
A Number Of B | The Number In | |
| 0 | Equiaxed grains of ferrite and small amount of pearlite with a complete lack of poloschatosti | Uniform ferrite-pearlitic structure with a complete lack of poloschatosti |
Uniform perlito- ferritic structure with a complete lack of poloschatosti |
| 1 | The General orientation of the structure in the warp direction without distinct bands | The General orientation of the structure in the warp direction without distinct bands |
The orientation of clusters of ferrite in the warp direction |
| 2 | One or two continuous band of ferrite in the background of equiaxed grains | One or two solid and a few broken bands of equiaxed grains of ferrite | One or two solid and a few broken bands of equiaxed grains of ferrite and pearlite |
| 3 | A few bands of ferrite, passing through the entire field of view, against the background of equiaxed grains |
The alternation of ferrite and pearlite strips consisting of equiaxed grains | The alternation of ferrite and pearlite strips consisting of equiaxed grains |
| 4 | Alternating bands of small equiaxed and larger deformed grains of ferrite | Uniform alternation of ferrite and pearlite bands, consisting of equiaxed and some deformed grains |
Uniform alternation of ferrite and pearlite bands, consisting of equiaxed and some deformed grains |
| 5 | Alternating bands of small equiaxed and a large number of larger deformed grains | Irregular alternation of ferrite and pearlite bands, consisting mainly of deformed grains |
Irregular alternation of ferrite and pearlite bands, consisting mainly of deformed grains |
Table 4
Widmanstatten structure
| The number of points | Description of the microstructure | |
| The Number And |
A Number Of B | |
| 0 | Uniform ferrite-pearlitic structure with a complete lack of signs widmanstetter |
Uniform pearlitic-ferritic structure with a complete lack of signs widmanstetter |
| 1 | The presence in the structure of ferritic grains having irregular comminuted form |
The presence in the structure of grains of ferrite comminuted form and a small number of spikes from a grid of ferrite at the grain boundaries |
| 2 | The presence in the structure of individual sections having a needle-like structure |
The presence in the structure of the needles extending from a grid of ferrite at the grain boundaries |
| 3 | Widmanstatten structure with thin needles radiating from a ferrite grid and inside the grains |
Widmanstatten structure with a significant amount of fine needles within the grains and extending from the mesh at the grain boundaries |
| 4 | Pronounced widmanstatten structure |
Pronounced widmanstatten structure with lots of long needle extending from a grid of ferrite at the grain boundaries |
| 5 | Pronounced rough widmanstatten structure with massive needles and ferritic mesh at the grain boundaries |
Pronounced rough widmanstatten structure with massive needles and thick ferritic mesh at the grain boundaries |
ANNEX 2
ANNEX 1*
________________
* Numbering corresponds to the original. — Note the manufacturer’s database
SCALE 1. STRUCTURALLY-FREE CEMENT it (X360−400)
| A number | Score 0 | Score 1 | Score 2 | Score 3 | Score 4 | Score 5 |
| And |
||||||
| * |
||||||
| * |
________________
* The text of the document matches the original. — Note the manufacturer’s database.
SCALE 2. PEARLITE IN MILD STEEL DEFORMED (H360−400)
| A number | Score 0 | Score 1 | Score 2 | Score 3 | Score 4 | Score 5 |
| And |
||||||
| B |
||||||
| In |
SCALE 3. BANDING of FERRITIC-PEARLITIC STRUCTURE (X100)
| A number | Score 0 | Score 1 | Score 2 | Score 3 | Score 4 | Score 5 |
| And |
||||||
| B |
||||||
| In |
SCALE 4. WIDMANSTATTEN STRUCTURE (X100)
| * | Score 0 | Score 1 | Score 2 | Score 3 | Score 4 | Score 5 |
| * |
||||||
| * |
________________
* The text of the document matches the original. — Note the manufacturer’s database.
