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Italian Grades

Grade Diameter (mm) Sphericity (µm) Diameter Variation (µm) Shipment Diameter (µm) Maximum Roughness (µm) ISO* Grade DIN* Grade AFBMA* Grade
AAAA 0-3 inc 0.15 0.3 ± 1.5 0.010 5 - 5
over 3-6 inc 0.2 0.4 ± 2 0.013 10 - 10
over 6-10 inc 0.2 0.4 ± 3 0.015 10 I 10
over 10-20 inc 0.4 0.8 ± 4 0.020 16 - 16
over 20-30 inc 0.6 1.2 ± 5 0.023 - II 24
over 30-50 inc 0.9 1.8 ± 6 0.028 - - 24
AAA 0-3 inc 0.2 0.5 ± 2 0.012 10 I 10
over 3-6 inc 0.3 0.6 ± 3 0.015 16 I 16
over 6-10 inc 0.4 0.8 ± 4 0.018 16 II 16
over 10-20 inc 0.5 1 ± 5 0.022 20 II 16
over 20-30 inc 0.8 1.5 ± 6 0.025 28 - 24
over 30-50 inc 1 2 ± 8 0.030 40 - 48
AA 0-3 inc 0.4 0.8 ± 4 0.015 16 II 16
over 3-6 inc 0.5 1 ± 5 0.018 28 II 24
over 6-10 inc 0.6 1.2 ± 6 0.022 28 III 24
over 10-20 inc 0.8 1.5 ± 7.5 0.025 28 III 24
over 20-30 inc 1 2 ± 10 0.030 40 III 48
over 30-50 inc 1.5 3 ± 12

0.035

- III 48
A 0-3 inc 0.8 1.2 ± 6 0.020 28 III 24
over 3-6 inc 1 1.5 ± 7.5 0.023 40 III 48
over 6-10 inc 1.2 2 ± 8 0.026 40 - 48
over 10-20 inc 1.5 2.5 ± 10 0.030 40 IV 48
over 20-30 inc 2 3 ± 15 0.035 100 IV 100
over 30-50 inc 2 4 ± 20 0.040 100 IV 100
B 0-3 inc 1.2 2.5 ± 7.5 0.040 40 III 48
over 3-6 inc 1.5 3 ± 9 0.050 100 III 100
over 6-10 inc 2 4 ± 12 0.060 100 IV 100
over 10-20 inc 2.5 5 ± 15 0.080 100 IV 100
over 20-30 inc 3 6 ± 24 0.100 200 IV 200
over 30-50 inc 4 8 ± 32

0.120

200 IV 200
C 0-3 inc 3 6 ± 12 - 100 IV 100
over 3-6 inc 4 8 ± 16 - - IV 100
over 6-10 inc 5 10 ± 20 - 200 IV 200
over 10-20 inc 8 15 ± 30 - 200 V 200
over 20-30 inc 10 20 ± 40 - - V 300
over 30-50 inc 12 25 ± 50 - - V 300
D 0-3 inc 30 30 ± 50 - - V 500
over 3-6 inc 30 30 ± 50 - - V 1000
over 6-10 inc 40 40 ± 75 - - V 1000
over 10-20 inc 50 50 ± 125 - - V 1000
over 20-30 inc 50 50 ± 125 - - V 1000