GOST 21073.2-75

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  ГОСТ 21073.2-75

GOST 21073.2−75 ferrous Metals. Determination of grain size by the method of counting beans (with Change No. 1)

GOST 21073.2−75

Group B09

INTERSTATE STANDARD

METALS NONFERROUS

Determination of grain size by the method of counting beans

Non-ferrous metals. Determination of grain size bu grain calkulation method

AXTU 1709

Date of introduction 1976−07−01

Resolution The state Committee of standards of Ministerial Council of the USSR from 15 August 1975 N 2164 the introduction of set with 01.07.76

Restriction expiration removed by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)

EDITION with Change No. 1, approved in December 1983 (ICS 3−84).


This standard applies to non-ferrous metals and sets the method of counting the grains to determine the grain size.

The method is applied to the quantitative characteristics of grain size in research or experimental work, etc.

The method of counting the grains should not be used to determine the value of neravnovesnykh beans.

The standard complies ST SEV 1959−79 in a method of counting beans.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for test method — according to GOST 21073.0−75.

2. TESTING

2.1. For the determination of grain size the surface of the thin section view, and choose at least three cases, and in determining the statistical characteristics (, , ) — at least 15 cases and produce the corresponding number of measurements.

2.2. To determine the amount of grain used for controlling the area of the counting.

2.3. The determination of the amount of grain produced at this magnification to within the control area was entirely 30−100 grains.

2.4. The image of the measured locations, observed on the frosted glass the microscope, on photomicrographs, or directly in the eyepiece of the microscope (if the eyepiece is provided with image contours control area calculation) applied outline of the control area count.

2.5. As a control square calculation using the following figures in 100-fold (linear) increase, limiting the cone area of 0.5 mm :

a circle with a diameter 79,8±0.4 mm;

square or rectangles with dimensions of 70,7х70,7; 65х77; 60х83,3; 55х91; 50x100 mm with limit deviation ±0,4 mm.

These dimensions take internal contours of the figures.

2.6. At magnifications other than 100-fold, allowed to apply square counting other sizes in the form of a circle or rectangle an aspect ratio of from 1:2 to 2:1.

2.7. The grain size is determined by counting the number of grains that are wholly contained within the control area of calculation, and , dissected inner contour of the control area count excluding grain, located on the corners of the control area count as a square or rectangle.

The difference in counting the number of grains in one thin section should not be more than 50%.

(Changed edition, Rev. N 1).

3. PROCESSING OF THE RESULTS

3.1. The result of the test take one or several values:

a) the average number of grains per 1 mmsquare sections;

b) the average cross-sectional area of the grain , mm;

C) minimum and maximum cross-sectional area of grain and , respectively, mm;

d) the standard deviation of individual measurements of cross-sectional area of the grain , mm

.

3.2. The calculation is made according to the formulas:

a) in the control area of the counting circle

,

where .

In the control area of the counting in the form of a circle with a diameter of 79,8 mm the value of the coefficient depending on the number of grains given in the table.

b) in the control area of the counting in the form of a square or rectangle

;

C) when the inspection area calculate any of the figures:

.

Under the conditions of claim 2.5 and 100 times magnification

.

Under the conditions of claim 2.5, but when you zoom other than 100-fold

.

The value of the coefficient for the most applicable increases provided in the Appendix.

3.3. As reference values characterizing the grain size at determining the method of counting grains, can be computed average grain diameter according to the formula

.

3.1−3.3. (Changed edition, Rev. N 1).

APPLICATION (reference). The value of the COEFFICIENT f FOR the MOST APPLICABLE INCREASES

APP
Reference

THE VALUE OF THE COEFFICIENT FOR THE MOST APPLICABLE
INCREASES