TPT January 2012
A rticle
ASTM E112
GОSТ 5639
DIN 50601
Parameters
Parameters
Parameters
Grain No.
Grain No.
Grain No.
d– , mm
N , 1/mm 2 A
d , mm m
m , 1/mm 2 nom
d , mm m
m , 1/mm 2
-7 -6 -5 -4 -3 -2 -1
4
0.0625
2.828
0.125
2
0.25 0.50
1.414
-3 -2 -1
1
1 2 4 8
1
1 2 4 8
0.707 0.500 0.353 0.250 0.177 0.125 0.088 0.062 0.044 0.031 0.022 0.015 0.011
0.707 0.500 0.354 0.250 0.177 0.125
00
0.508 0.359 0.254
3.88 7.75
0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9
15.50
16 32 64
16 32 64
0.1796 0.1270 0.0898 0.0635 0.0449 0.0318 0.0225 0.0159 0.0112 0.0079 0.0056 0.0040 0.0028
31 62
124 248 496 992
128 256 512
0.0884 0.0625 0.0442 0.0312 0.0221 0.0156 0.0110 0.0078 0.0055 0.0039 0.0028 0.0020 0.0014 0.0010
128 256 512
1024 2048 4096 8192
1024 2048 4096 8192
1984 3968 7936
10 11 12 13 14
10 11 12 13 14
10 11 12 13 14 15 16 17
15872
0.0079 0.0056 0.0039
16384 32768 65536
16384 32768 65536 131072 262144 524288 1048576
31744.1 63488.1 126976.3
0.0027 131072
In all, 16 х) Nos.
In all, 18 Nos.
In all, 25 Nos.
х) Only whole numbers are given in the Table. The standard contains 30 numbers
Table 2 : Соmparative analysis of grain structure parameter values determined by three standards (magnification ×100)
• shape factor and index of asymmetry of the grain structure • grain number according to GOST 5639 and АSТМ Е112 The main advantage of the new method is the possibility of assessment of grain anisotropy in the examined structures using the variation coefficient of grain distribution in the product volume generally used in the assessment of grain structure unhomogeneity. All above-mentioned parameters are determined in commonly used units to ensure higher accuracy of design strength calculation of new materials as there is no need in conversion of conventional numbers into commonly used units. The new method was taken as a basis for a proposed standard. The new standard features a condition that each number is a monodisperse system of spheres (equiaxed grains). In the proposed standard, value of the grain diameter within the monodisperse system of spheres in which grain anisotropy is absent
and not the quantity of grains in a form of cubes in 1 mm 2 as in GOST 5639-88 is taken as the grain number. Then, the number of equiaxed grains in a unit of volume is determined by the following equation:
3 2
N
V = m pcs/mm 3
Тhis approach will ensure a clear-cut assessment of material grain anisotropy by the variation coefficient of grain distribution by sizes. If the obtained variation coefficient in the examined structure is 0.28 in a plane or -0.36 in a line, it will be the evidence of structure homogeneity in a volume. And the more this value differs from the above values, the higher anisotropy is in the volume of the examined structure. The new standard features: 1. The standard series is set for 3D structure objects 2. Spatial spherical model of structural components
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