GOST 3443-87

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  ГОСТ 3443-87

GOST 3443−87 cast iron Castings with graphite of different form. Methods of determining the structure

GOST 3443−87
Group В89

INTERSTATE STANDARD

CAST IRON CASTINGS WITH GRAPHITE OF DIFFERENT FORM

Methods of determining the structure

Cast iron castings with graphite of different form. Methods of structure determination

ISS 77.140.80
OKP 41 1100

Date of introduction 1988−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of power engineering

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 26.02.87 N 614

3. The standard corresponds to the international standard ISO 945−75* in part of the method of constructing scales to assess the shape, size and distribution of inclusions of graphite

4. REPLACE GOST 3443−77

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

7. REPRINTING. August 2005


This standard applies to castings made of cast iron for structural purposes with graphite of different form and establishes methods of determining the structure of grey cast iron with lamellar graphite spheroidal cast iron with spheroidal and vermicular graphite iron and malleable cast iron with compact graphite.

The standard is designed to assess the structure of unalloyed and low-alloyed cast iron as-cast and subjected to annealing for removal of internal stress, high temperature annealing, normalizing or other heat treatment to obtain the desired structure.

The standard does not apply to high-alloy cast iron.

The standard corresponds to the international standard ISO 945−75 in respect of the method of constructing scales to assess the shape, size and distribution of inclusions of graphite (see Annex 1).

1. GENERAL PROVISIONS

1.1. The structure of cast iron is determined by the graphite and the metal base.

In determining the estimate should be graphite: form, distribution, size, number of inclusions of graphite.

In determining the metallic base evaluation subject: view of the structure, the form of pearlite, the content of pearlite (or ferrite), pearlite dispersity, structure, distribution, sizes of the grid cells and the area of the inclusions fosrenol eutectic, the number and size of inclusions of cementite (cementite or of ledeburite).

1.2. To denote the components of the structure and their characteristic features used the notation keys indicated in the table.1.

Table 1

2. SELECTION AND PREPARATION OF SAMPLES

2.1. Samples for preparation of thin section studies of the structure machined from castings, tidal or specially cast samples as well as cast billets, used to manufacture samples for mechanical testing.

Not allowed to use specimens cut from the riser, heaving or profit.

Allowed preparation of thin section on the working surface of the casting without cutting out the special sample.

2.2. Sampling and making thin sections for structure determination is carried out in such a way as not to disturb them in the structure of cast iron.

If the technical conditions specified casting heat treatment, the samples to analyze the structure taken after heat treatment.

Specially molded blanks, tides or sample for samples subjected to heat treatment together with the casting.

2.3. The selection and number of samples for structure determination, as well as requirements on the structure of cast iron are specified in the technical specifications for the casting.

2.4. When cutting samples from the cast should take into account the heterogeneity of the structure of cast iron depending on wall thickness and length of the casting.

Samples are taken of such size and cross-section to provide a complete view of the structure of castings.

For thick-walled castings, the sample should be measuring at least 3 cmbut not more than 9 cm, for thin-walled castings in the area of the cone not less than 0.2 cm. For small parts (such as individual piston rings) is allowed for sections smaller. The height of the cone should not be more than 15−20 mm.

Place cuttings samples from the cast must be defined in the drawing.

When you structure on the samples cut from the tides to the casting or separately cast samples, it is necessary that the wall thickness and crystallization conditions of the tide (or sample) and the castings were the same.

The size of the tide and its location on the casting must be indicated on the drawing.

In determining the structure directly on the working surface of the casting cone is made to a depth equal to the allowance for machining. It allowed the production of thin section after machining of the casting.

3. TESTING

3.1. The surface of the cone needs to be mirrored without any scratches from the operations of grinding and polishing, oxides and other contaminants.

3.2. The study of graphite is carried out on netravlenoy the cone, and metallic substrates — thin sections after etching.

For etching the surface of the cone used reagents is given in Appendix 2.

3.3. To define the structure of cast iron of the cone examined under the microscope at the magnifications listed on the reference scales. of Annex 3.

To assess the structure choose parts of the cone located away from the edges a minimum distance or thickness or diameter of the specimen.

3.4. Evaluation of structure of cast iron is carried out visually by comparison of the structures visible in the microscope, the structure of the Etalon corresponding to the scale.

For a more accurate assessment of the structure should be applied to linear, point, or planimetric methods of quantitative metallography, as well as special automatic installation Quantimet, Epiquant etc.

3.5. Determination of graphite

3.5.1. Depending on the type of graphite cast iron in its structure is determined by the scales 1−4 Annex 3: cast iron with lamellar graphite — 1 scale, cast iron with vermicular graphite — a scale 2, the spheroidal graphite cast irons — 3 scale, cast iron with compact graphite — 4 scale.

3.5.2. Form of inclusions of graphite in structure of cast iron is assessed: for cast iron with lamellar graphite — according to the scale 1A, with vermicular graphite — a scale 2A, nodular — scale 3A and with a compact graphite — 4A scale.

If the structure of cast iron has graphite in different forms, it is necessary to visually estimate the percentage of each form and specify it in the designation of a structure.

3.5.3. Depending on the size (length or diameter) of inclusions of graphite structure of cast iron is estimated in the table.2 and scales: for cast iron with lamellar graphite scale 1B, nodular — scale 3B, with a compact graphite — scale 4B.

Table 2

Determining the size of inclusions of graphite is conducted at an average length or diameter of the three largest inclusions in the microsection, measured in at least three fields of view.

If the structure of cast iron has graphite in various shapes, sizes of its inclusions are defined for each form.

3.5.4. Depending on the distribution of inclusions of graphite structure of cast iron is assessed: for cast iron with lamellar graphite according to the scale 1B, compacted graphite iron on a scale 2B, the spheroidal graphite cast irons — 3V scale.

If the structure of cast iron inclusions of graphite in various types of distribution, covering an area of up to 1.0% of the total area of the cone, they should be viewed as «footprints».

3.5.5. Depending on the number of inclusions of graphite structure of cast iron with lamellar graphite is evaluated on a table.3 and a scale of 1G, nodular at the table.3 scale and 3G.

Table 3

The number of inclusions of graphite is estimated the average percentage of the area occupied on the microsection, and is determined not less than 3 fields of view.

3.5.6. The number of globular graphite in the structure of cast iron with vermicular graphite is evaluated on a table.4 and the scale 2B.

Table 4

The proportion of spherical graphite relative to iron is estimated the average percentage of the area occupied by the specified graphite on a polished section and defined at least 3 fields of view.

3.6. The definition of metal base

3.6.1. Depending on the type of the metal base structure of cast iron is determined on a scale of 5.

3.6.2. Depending on the amount of pearlite or ferrite percentage (pearlite + ferrite = 100%) structure of cast iron is estimated in the table.5 and a scale 6 of Annex 3; for large and medium castings of cast iron with lamellar graphite at a low speed of cooling Bank 1, for thin-walled castings made of cast iron with lamellar graphite at high velocity cooling — a number 2, for castings made of cast iron with vermicular graphite — 3 range, for castings from cast iron with nodular graphite — series 4, casting of malleable cast iron — number 5.

Table 5

The amount of pearlite or ferrite is estimated the average percentage of the area occupied by these structural components in thin section and defined at least 3 fields of view.

3.6.3. View regional zones in samples of ductile cast iron determined by the scale 7.

3.6.4. Depending on the degree of dispersion of lamellar pearlite structural cast iron is evaluated in the table.6 and the scale 8 of Annex 3.

Table 6

Dispersion of lamellar pearlite is determined by the average distance between the plates of cementite. This distance is measured in grains of pearlite, the greatest dispersion, where the cementite plate is perpendicular to the plane of the thin section.

If necessary, a more accurate determination of dispersion of perlite should be used assessment method is given in Appendix 2.

3.6.5. Depending on the structure fosrenol eutectic structure of cast iron is assessed on a scale 9A: the etching of the cone is 4.0% alcohol solution of nitric acid is number 1, the etching of the thin section is heated to 70−80 °With a solution of Murakami — the number 2.

3.6.6. Depending on the nature of the distribution of values fosrenol eutectic structure of cast iron is assessed on a scale 9B.

3.6.7. Depending on the diameter of the grid cells fosrenol eutectic structure of cast iron is estimated in the table.7 and a scale 9 of Annex 3.

Table 7

The diameter of the grid cell is determined by the average value of the diameters of the three largest cells.

3.6.8. Depending on the size of isolated inclusions fosrenol eutectic determined by the average area of the three largest inclusions, structure of cast iron is estimated in the table.8 and 9G scale required applications 3.

Table 8

3.6.9. Depending on the number of cementite or cementite of ledeburite structure of cast iron is estimated in the table.9 and 10A scale required applications 3.

Table 9

The amount of cementite or cementite of ledeburite estimated average percentage of the area occupied by these inclusions on a polished section and define at least three fields of view.

If the structure of cast iron inclusions of cementite in the amount of less than 1.0% (one or two include an area of less than 2000 micronsin two or three fields of view) they should be viewed as «footprints».

3.6.10. Depending on the size of isolated inclusions of cementite or cementite of ledeburite defined by the average area of the three largest inclusions, structure of cast iron is estimated in the table.10 and the scale 10B of Annex 3.

Table 10

Examples record the results of structure determination

The structure of cast iron with evenly distributed graphite plate of rectilinear shape with a length of 60−120 mm; metal base: pearlite plate in an amount of from 30 to 60% with megaplatinum distance of 0.5 microns; fosfina the eutectic triple needle structure in the form of separate inclusions:

ПГф1-ПГр1-ПГд90-Пт1-P45-Пд0,5-ФЭ3-ФЭр1

The structure of the spheroidal graphite cast irons correct shape with a diameter from 30 to 60 µm; the metal shell: 60% of lamellar perlite, granular perlite:

ШГф5-ШГд45-Пт1-П70-Пт2

The structure of malleable cast iron with inclusions of graphite compact shape with a diameter of 40−50 microns; metal shell: 60% of lamellar pearlite with megaplatinum a distance of 0.8 µm, and 40% ferrite.

КГф3-КГд45-Пт1-П70-Ф30-Пд1,0

The structure of cast iron with vermicular graphite thickened shape, unevenly distributed, the number of vermicular graphite 85%; metal base 80% ferrite.

ВГф3-ВГр2-ВГ85-F80.

ANNEX 1 (reference)

ANNEX 1
Reference

Table 11

Compliance notation standards for evaluation in the form of graphite in scales of this standard and the ISO standard 945−75

Table 12

Compliance designations of the standards to estimate the distribution of graphite in scales of this standard and the ISO standard 945−75

Table 13

Compliance designations of the standards to estimate the size (length and diameter) of inclusions of graphite in scales of this standard and the ISO standard 945−75

APPENDIX 2 (recommended)

ANNEX 2
Recommended

The composition of the reagents for the etching of thin sections and identify the overall structure of cast iron and a separate structural components

________________
* The text of the document matches the original. — Note the manufacturer’s database.

Assessment of the dispersion of perlite

Determination of the dispersion of the perlite is conducted using the following method: in the plane of the thin section under the microscope using ocularocular on an arbitrary straight section length of 1000 µm count the number of crossing it under the arbitrary corners of the plates of cementite . Then the true mean between the plates of cementite distance () in micrometers is calculated by the formula

.

ANNEX 3 (required)

APPENDIX 3
Mandatory

SCALE 1. DEFINITION OF GRAPHITE IN STRUCTURE OF CAST IRON WITH LAMELLAR GRAPHITE

SCALE 1. DEFINITION OF GRAPHITE IN STRUCTURE OF CAST IRON WITH LAMELLAR GRAPHITE

A. Form of inclusions of graphite

A. Form of inclusions of graphite

Magnified 100 times

B. the Length of graphite inclusions (µm)

B. the Length of graphite inclusions (µm)

V. the Distribution of inclusions of graphite

V. the Distribution of inclusions of graphite

G. Number of inclusions of graphite (%)

G. Number of inclusions of graphite (%)

SCALE 2. DEFINITION OF GRAPHITE IN STRUCTURE OF CAST IRON WITH VERMICULAR GRAPHITE

A. Form of inclusions of graphite

A. Form of inclusions of graphite

Magnified 100 times

B. Distribution of inclusions of graphite

B. Distribution of inclusions of graphite

Magnified 100 times

Isolated inclusions

Midentity

V. the Number of inclusions of vermicular graphite (%)

SCALE 3. DEFINITION OF GRAPHITE IN THE STRUCTURE OF HIGH-STRENGTH CAST IRON WITH SPHERICAL GRAPHITE

A. Form of inclusions of graphite

A. Form of inclusions of graphite

Magnified 100 times

B. the Diameter of nodule (mm)

V. the Distribution of inclusions of graphite

V. the Distribution of inclusions of graphite

Magnified 100 times

G. Number of inclusions of graphite (%)

G. Number of inclusions of graphite (%)

SCALE 4. DEFINITION OF GRAPHITE IN THE STRUCTURE OF MALLEABLE CAST IRON WITH COMPACT GRAPHITE

A. Form of inclusions of graphite

A. Form of inclusions of graphite

Magnified 100 times

B. the Diameter of nodule (mm)

B. the Diameter of nodule (mm)

SCALE 5. THE LAYOUT OF THE METALLIC BASE OF CAST IRONS

Magnified about 500 times

SCALE 6. THE CONTENTS OF PEARLITE AND FERRITE IN THE STRUCTURE OF CAST IRON (%)

A. Cast iron with lamellar graphite. Number 1

A. Cast iron with lamellar graphite. Number 1

Magnified 100 times

B. Cast iron with lamellar graphite. Number 2

B. Cast iron with lamellar graphite. Number 2

B. vermicular graphite Iron. Number 3

B. vermicular graphite Iron. Number 3

G. ductile Iron. Number 4

G. ductile Iron. Number 4

D. Cast iron with compact graphite. Number 5

D. Cast iron with compact graphite. Number 5

Magnified 100 times

SCALE 7. VIEW REGIONAL ZONES OF DUCTILE IRON

Magnified 100 times

SCALE 8. THE DISPERSION OF PERLITE IN THE STRUCTURE OF CAST IRON

Magnified about 500 times

SCALE 9. FOSFINA THE EUTECTIC IN THE STRUCTURE OF CAST IRONS

A. the structure of the inclusions of eutectic fosrenol

A. the structure of the inclusions of eutectic fosrenol

Magnified about 500 times

B. Distribution of inclusions fosrenol eutectic

B. Distribution of inclusions fosrenol eutectic

Increased 20 times

Enlarged 50 times

V. the Diameter of the grid cell fosrenol eutectic (µm)

V. the Diameter of the grid cell fosrenol eutectic (µm)

Increased 20 times

Magnified 100 times

G. the area of the inclusions of eutectic fosrenol

G. the area of the inclusions of eutectic fosrenol

Magnified 100 times

The SCALE 10. DEFINITION OF CEMENTITE OR CEMENTITE OF LEDEBURITE IN THE STRUCTURE OF CAST IRON

A. the Content of cementite or cementite of ledeburite

A. the Content of cementite or cementite of ledeburite

Magnified 100 times

B. the area of the inclusions of cementite or cementite of ledeburite

B. the area of the inclusions of cementite or cementite of ledeburite

Magnified 100 times

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M.: STANDARTINFORM, 2005