Grain Size Measurement

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Grain Size Measurement

" Comparison Method

" Planimetric Method

" Intercept Method

(ASTM = American Society of Testing Materials)(ASTM = American Society of Testing Materials)

Comparison Method

" 4��56�789:;�:<�;�=>6�9?�@กB�>C;D5�5 100x H><�IB�� � :�5J�?�5JกCJ6�789:;�:<�;�=>6�9��K:L�I

" �>M�ก6�7��K:L�I?�@��DI���ก:I�ก><�9�5;กCJDI���ก:ID�;�NOI;�I?���J?�@�=�

" 6�7��K:L�I�������5�>DกB�กCJ�:�5ก��� ASTM Grain Size Number 5N@;���5�>D��ก �ก:I5N@;��DI��>����5�

" ������B��:CJ89:;�:<�;�=>6�9?�@���ก:I���I����� RIHJJ EquiaxedGrain

Comparison Method

"ASTM Grain Size Number ����:49B�I�U��<�C;I�O

ICJ�B�I�I�ก:I�I 1 K�:�;INO���ก6�74��589:;�:<�;�=>6�9?�@กB�>C;D5�5 100x H><�� 9B�I�U ASTM Grain Size Number ��ก�VK:

12 −= GN

N = N = �B�I�I�ก:I�I�IW@;K�:�;INO�?�@กB�>C;D5�5�B�I�I�ก:I�I�IW@;K�:�;INO�?�@กB�>C;D5�5 100x100xG = ASTM grainG = ASTM grain--size numbersize number

�������� �7M@���DI���ก:IK����K:L�I ASTM D�;KC��5��;8>���IN��IW@; 6�74��589:;�:<�;�=>6�9?�@กB�>C;D5�5 100 �?�� 4Vก4��5H>�ICJ�B�I�I�ก:I��< 64 �ก:I�I�IW@;K�:�;INO� DI���ก:IK����K:L�I ASTM D�;8>���NOII�O�?��กCJ�?����?

7

)301.0)(1(806.1

)2)(log1(64log

2 1

=

−=

−=

= −

G

G

G

N G

DI���ก:IK����K:L�I ASTM D�;8>���NOII�O�?��กCJ 7

88 9977

Comparison Method

" ��ก89:;�:<�;�=>6�9>����5���ก 6�74��589:;�:<�;�=>6�9?�@กB�>C;D5�5 100x H><��������:4ICJ�B�I�I�ก:I��<����ก

" ��<4��56�789:;�:<�;�=>6�9?�@กB�>C;D5�5�V;DWOI H><�9B�I�U Correction Factor (Q) ��ก�VK:

" ��M@� M 9M�กB�>C;D5�5?�@��<4��56�789:;�:<�;�=>6�9" IB� Q � 9VUกCJ ASTM Grain size number ?�@��<��ก6�7�W;����< ASTM

Grain size number ?�@H?<�:N;

=

=

100log64.6

100log2 102

MMQ

Planimetric Method

" ����;ก>�7MOI?�@ 5000 mm2 (��<Ia��IbVI5cก>�; 79.8 mm) JI6�789:;�:<�;�=>6�9 9�:����<6�5�I�;ก>����ก:I�5��;I<�5 50 �ก:I

" ICJ�B�I�I�ก:I6�5�I�;ก>� ��ก�ก:I4VกD�J�;ก>�KC�a��I��<ICJ� RI ½ �ก:I

" ��ก�B�I�I�ก:I��<IB�� 9VU�<�5 Jeffriesi Multiplier jW@;DWOI�5V�กCJกB�>C;D5�5?�@��<4��56�7 (�C;K�:�;)

" 9����<��� RI�B�I�I�ก:IK���IW@;K�:�;�N>>N��K:" ������B��:CJ89:;�:<�;�=>6�9?�@���ก:I���I����HJJ EquiaxedGrain

+=

2

int ercept

insideA

NNfN

NA = number of grain per mm2

f = Jeffriesi MultiplierNinside = number of grains inside the test circleNintercept =number of grains that intercept the test circle

200.01000x50.0500x8.0200x2.0100x0.550x0.0210x0.00021x

Jeffries� MultiplierMagnification

5000

2Mf =

95.2)(log322.3 −= ANG

����:49B�I�U�� ASTM Grain Size Number ��<��ก�VK:

KC��5��; Planimetric Method

��ก6�7ICJ�B�I�I�ก:I6�5�I�;ก>���< 44 �ก:IICJ�B�I�I�ก:I?�@4Vก�;ก>�KC�a��I��< 25 �ก:IJeffriesi Multiplier = (1002)/5000 = 2.0

2113

2

25440.2

mm

grains

N A

=

+=

87.3

95.2)113(log322.3

=

−=G

Intercept Method

" �����<I?�@:V<9���5��JI6�74��589:;�:<�;�=>6�9?�@:V<กB�>C;D5�5 8�5?C@�� ��<�;ก>� 3 �; ?�@����<Ia��IbVI5cก>�; 79.58, 53.05 H>� 26.53 mm K��>B��CJ jW@;��9���5����<I:���?��กCJ 500 mm 7���

" ICJ�B�I�ID�J�ก:I?�@4Vก��<IKC�a��I ��ก��<IKC�a��I�=�?�@� RI:�5K��:�����; 3 �ก:I (Tripole Junction) ��<ICJ� RI 1.5

" IB�a>:���B�I�ID�J�ก:I?�@��<��:�<�59���5��H?<�:N;?�@กB�>C;D5�5D�;6�74��5 (K5. 500 mm ?�@ 1x = 1 mm ?�@ 500 x)

" 9��?�@��<9M� PL (Number of point intersections per unit length of test line)

288.31

log644.6 −

−=

lPG

����:49B�I�U�� ASTM Grain Size Number ��<��ก�VK:

KC��5��; Intercept Method

��ก6�7ICJ�B�I�I intersections ��< 60 �=�ICJ Tripole Junction ��< 7 �=�

9N�� RI 60 + (1.5)(7) = 70.5 �=�

15.70

500

500

5.70

−=

=

mm

mmPl

98.8

298.3)5.70

1(log6457.6

=

−−=G

กB�>C;D5�5 500 x

9���5����<I:�J�;

Intercept pattern �B��:CJ8>��?�@��>CกpU��ก:IDWOI�5V�กCJ?Nb?�;

9���5��D�;��<IK:;?CO;��� = 500 mm

9���5����<I:�J�;?CO;��� = 500 mm