Noritake

MENU

PRODUCTS

Grain

1. Types

Grains used for grinding and polishing tools can be broadly divided into (1) general grain and (2) extra-abrasive grain.
The materials used can be categorized (1) as alumina and silicon carbide, and (2) as diamond and cubic boron nitride, with further sub-categories according to differences in properties and structure. The grain categories here are coded according to JIS standards.

Features of abrasive grain

Abrasive Grain A

This is the most usable abrasive grain and it is used for the cut off wheel, free grinding wheel and for grinding general metallic material that strength tensile is high and it is comparatively extended since its toughness is high.

Abrasive Grain WA

Since the toughness of abrasive grain WA is less than the abrasive grain A and hardness is high, the abrasive grain itself is crushed during grinding work and sharp edges are newly and continuously made. As a result, this is suitable to light grinding for high strength tensile quenched steel, special steel, etc.

Abrasive Grain GA

Though the chemical composition of abrasive grain is the same as the abrasive A, this is suitable to the rough grinding of high strength tensile quenched steel, special steel, etc.

Abrasive Grain PA

This is the pink abrasive grain made by adding a little quantity of chromic oxide. Since the toughness is adequately adjusted, it is effective for preventing burn marks and suitable to tool grinding.

Abrasive Grain SA

This is the abrasive grain that releasing the boundary of crystal after hydrated collapse individually separates crystal. The toughness is top ranking among A-system abrasive grains for precision grinding. Consequently, this is suitable for grinding the intricate materials of stainless steel, super heat-resistant steel, etc., and cast iron, various quenched steels, etc., at a high efficiency rate.

Abrasive Grain KA

This abrasive grain contains titanium oxide more than A-acid grain and the toughness is high. Thus, it is suitable for free grinding and heavy load grinding of steel.

Abrasive Grain RG

This is the most complex oxide abrasive grain having strong and microstructure dendrite crystal which is made by melting and cooling under special condition after mixing zirconia of about 25% to alumina. Thus, it is suitable to remove flaw or scratch on steel billet and rolled steel of special steels except stainless steels by the super heavy grinding.

Abrasive Grain 6A

This is the sintered abrasive grain of column type. Since the toughness is extremely high though hardness is low, it is suitable to remove flaw scratch on steel billet and rolled steel of stainless steels by the super heavy grinding.

Abrasive Grain VA

This is the abrasive grain sintering the high purity alumina microstructure crystal in column type. The toughness is slightly lower even though it is more harder than abrasive grains 6A and RG. Therefore, the abrasive grains bite into hard material by heavy load grinding, thus improving efficiency of grinding.

Abrasive Grain HF

This is the abrasive grain mixing the zirconia of about 25% as well as abrasive grain RG. Since grain shape is sharper than the abrasive grain RG, it displays an excellent performance for deburring of cast iron and free grinding of steels.

Abrasive Grain HN

This is the abrasive grain mixing zirconia of about 40%. Since it has unique friability that occurs for anisotropic crystal, it displays an excellent performance for light grinding to work with the grinder such as portable grinder, offset grinder, etc.

Abrasive Grain C

This abrasive grain is harder than A-system abrasive grain and the toughness is low. It is suitable for grinding a soft and less-extension material and a hard easily broken material.

Abrasive Grain GC

This is as hard as the abrasive grain C, but its toughness is lower than that of abrasive grain C. Since each grain from is very sharp, it is suitable for grinding the crustaceous materials of non-ferrous metals and nonferrous materials for carbide, stone materials, etc., and the soft materials for aluminum, rubber, urethane, etc.

Mixing Abrasive Grain
  • 19A: A+WA
  • C/GC: C+GC
  • HA: GA+WA
  • A/C: A+C (only resinoid bonded grinding wheel)
  • EA: GA+PA
Abrasive Grain made together with Cardner Co., associated

79A, 80A, 81A, 82A, 83A, 84A, 86A, 91A

Diamond Abrasive Grain

The diamond abrasive grain is divided into two (i.e. natural diamond and composite diamond). This is the hardest material in the world that knoop hardness is 7000 ~ 8000. It is suitable for grinding the crustaceous materials such as the nonferrous materials and non-ferrous metals for carbide, cermet, ceramics, glass, ferrite, stone, refractory materials, etc. However, this diamond abrasive grain is unsuitable for less carbon content of general steels since the abrasive grain is dipped because carbon that is the constituent of diamond abrasive grain will disperse into iron at a high temperature. Also, since it is weak for heat, oxidation occurs at 600 ~ 700℃ into air and its hardness is lost.

Abrasive Grain CBN

This is the cubic boron nitride abrasive grain and its hardness is next to that of diamond since Knoop hardness is 4700. CBN does not react with steel chemically since it differs from the diamond. Since temperature converting to soften hexagonal metal is high as 1400℃, it is suitable for grinding the quenched steel.

2. Grain size

There are different standards for the grain size of abrasive grain according to whether it’s for (1) grinding wheels, (2) abrasive cloth and sandpaper, or (3) extra- abrasive grain.
The JIS standards are described below.

(1) Grain size of grains for grinding wheels

1. Coarse particle grain size distribution
Grain size Test sieve 
that 100% 
of particles 
must pass 
through
(stage 1)
Test sieve 
that may stop 
a set amount of 
particles and the 
resulting amount 
(stage 2)
Test sieve 
that must stop 
a set minimum 
amount of 
particles and 
the resulting amount 
(stage 3)
Two test sieves 
that, when combined, 
must stop a set 
minimum amount of 
particles and 
the resulting amount 
(stage 3 + stage 4)
Test sieve 
that may allow 
a maximum of 
3% of particles 
to pass through 
(stage 5)
mm μm mm μm % mm μm % mm μm % mm μm
F4 8.00 5.60 20 4.75 40 4.75 4.00 70 3.35
F5 6.70 4.75 20 4.00 40 4.00 3.35 70 2.80
F6 5.60 4.00 20 3.35 40 3.35 2.80 70 2.36
F7 4.75 3.35 20 2.80 40 2.80 2.36 70 2.00
F8 4.00 2.80 20 2.36 45 2.36 2.00 70 1.70
F10 3.35 2.36 20 2.00 45 2.00 1.70 70 1.40
F12 2.80 2.00 20 1.70 45 1.70 1.40 70 1.18
F14 2.36 1.70 20 1.40 45 1.40 1.18 70 1.00
F16 2.00 1.40 20 1.18 45 1.18 1.00 70 850
F20 1.70 1.18 20 1.00 45 1.00 - - 850 70 710
F22 1.40 1.00 20 850 45 850 710 70 600
F24 1.18 850 25 710 45 710 600 65 500
F30 1.00 710 25 600 45 600 500 65 425
F36 850 600 25 500 45 500 425 65 355
F40 710 500 30 425 40 425 355 65 300
F46 600 425 30 355 40 355 300 65 250
F54 500 355 30 300 40 300 250 65 212
F60 425 300 30 250 40 250 212 65 180
F70 355 250 25 212 40 212 180 65 150
F80 300 212 25 180 40 180 150 65 125
F90 250 180 20 150 40 150 125 65 106
F100 212 150 20 125 40 125 106 65 75
F120 180 125 20 106 40 106 90 65 63
F150 150 106 15 75 40 75 63 65 45
F180 125 90 15 63 40 63 53 65
F220 106 75 15 53 40 53 45 60

Source: JIS R6001 “Bonded abrasive grain sizes”

2. Fine particulate and sedimentation test method for general polishing (units: μm)
Grain size Particle diameter 
at 3% cumulative 
height 
(ds-3 value)
Particle diameter 
at 50% cumulative 
height 
(ds-50 value)
Particle diameter 
at 95% cumulative 
height 
(ds-95 value)
F230 77 or less 55.7±3.0 38 or more
F240 68 or less 47.5±2.0 32 or more
F280 60 or less 39.9±1.5 25 or more
F320 52 or less 32.8±1.5 19 or more
F360 46 or less 26.7±1.5 14 or more
F400 39 or less 21.4±1.0 10 or more
F500 34 or less 17.1±1.0 7 or more
F600 30 or less 13.7±1.0 4.6 or more
F800 28 or less 11.0±1.0 3.5 or more
F1000 23 or less 9.1±0.8 2.4 or more
F1200 20 or less 7.6±0.5 2.4 or more (1)

Note (1): Particle diameter at 80% cumulative height (ds-80 value)

Source: JIS R6001 “Bonded abrasive grain sizes”
Some standards also taken from “Sedimentation Methods for Light Transmission”

3. Fine particulate and dispersal test method for precision polishing (units: μm)
Grain size Maximum particle 
diameter
(ds-0)
Particle diameter
at 3% cumulative 
height 
(ds-3 value)
Particle diameter 
at 50% cumulative 
height 
(ds-50 value)
Particle diameter 
at 94% cumulative 
height 
(ds-94 value)
#240 127 or less 90 or less 60.0±4.0 48 or more
#280 112 or less 79 or less 52.0±3.0 41 or more
#320 98 or less 71 or less 46.0±2.5 35 or more
#360 86 or less 64 or less 40.0±2.0 30 or more
#400 75 or less 56 or less 34.0±2.0 25 or more
#500 65 or less 48 or less 28.0±2.0 20 or more
#600 57 or less 43 or less 24.0±1.5 17 or more
#700 50 or less 39 or less 21.0±1.3 14 or more
#800 46 or less 35 or less 18.0±1.0 12 or more
#1000 42 or less 32 or less 15.5±1.0 9.5 or more
#1200 39 or less 28 or less 13.0±1.0 7.8 or more
#1500 36 or less 24 or less 10.5±1.0 6.0 or more
#2000 33 or less 21 or less 8.5±0.7 4.7 or more
#2500 30 or less 18 or less 7.0±0.7 3.6 or more
#3000 28 or less 16 or less 5.7±0.5 2.8 or more

Source: JIS R6001 “Bonded abrasive grain sizes”
Some standards also taken from “Testing Methods for Electrical Resistance”

(2) Grain size of abrasives for abrasive cloth and sandpaper

1. Coarse particle grain size distribution
Grain size Amount trapped 
by stage 
1
Cumulative amount 
trapped by stages 
1+2
Cumulative amount 
trapped by stages 
1+2+3
Cumulative amount 
trapped by stages 
1+2+3+4
Cumulative amount 
trapped by stages 
1+2+3+4+5
Amount not 
trapped 
by stage 
5 sieve
⊿Q
Aperture 
for stage 
1 sieve
Q1 Aperture 
for stage 
2 sieve
Q2 Aperture 
for stage 
3 sieve
Q3 Aperture 
for stage 
4 sieve
Q4 Aperture 
for stage 
5 sieve
Q5
mm μm % mm μm % mm μm % mm μm % mm μm % %
P12 3.35 0 2.36 1
or less
2.00 14
±4
1.70 61
±9
1.40 92
or more
8
or less
P16 2.36 0 1.70 3
or less
1.40 26
±6
1.18 75
±9
1.00 96
or more
4
or less
P20 1.70 0 1.18 7
or less
1.00 42
±8
850 86
±6
710 96
or more
4
or less
P24 1.40 0 1.00 1
or less
850 14
±4
710 61
±9
600 92
or more
8
or less
P30 1.18 0 850 1
or less
710 14
±4
600 61
±9
500 92
or more
8
or less
P36 1.00 0 710 1
or less
600 14
±4
500 61
±9
425 92
or more
8
or less
P40 710 0 500 7
or less
425 42
±8
355 86
±6
300 96
or more
4
or less
P50 600 0 425 3
or less
355 26
±6
300 75
±9
250 96
or more
4
or less
P60 500 0 355 1
or less
300 14
±4
250 61
±9
212 92
or more
8
or less
P80 355 0 250 3
or less
212 26
±6
180 75
±9
150 96
or more
4
or less
P100 300 0 212 1
or less
180 14
±4
150 61
±9
125 92
or more
8
or less
P120 212 0 150 7
or less
125 42
±8
106 86
±6
90 96
or more
4
or less
P150 180 0 125 3
or less
106 26
±6
90 75
±9
75 96
or more
4
or less
P180 150 0 106 2
or less
90 15
±5
75 62
±12
63 90
or more
10
or less
P220 125 0 90 2
or less
75 15
±5
63 62
±12
53 90
or more
10
or less

Source: JIS R6010 “Coated abrasive grain sizes”

2. Fine particulate (P240–P1200) and dispersal test method (units: μm)
Grain size Maximum 
particle diameter 
(ds-0 value)
Particle diameter 
at 3% cumulative 
height 
(ds-3 value)
Particle diameter 
at 50% cumulative 
height
(ds-50 value)
Particle diameter 
at 95% cumulative 
height 
(ds-95 value)
P240 110 or less 81.7 or less 58.5±4.0 44.5 or more
P280 101 or less 74.0 or less 52.2±3.0 39.2 or more
P320 94 or less 66.8 or less 46.2±2.5 34.2 or more
P360 87 or less 60.3 or less 40.5±2.0 29.6 or more
P400 81 or less 53.9 or less 35.0±2.0 25.2 or more
P500 77 or less 48.3 or less 30.2±2.0 21.5 or more
P600 72 or less 43.0 or less 25.8±1.5 18.0 or more
P800 67 or less 38.1 or less 21.8±1.0 15.1 or more
P1000 63 or less 33.7 or less 18.3±1.0 12.4 or more
P1200 58 or less 29.7 or less 15.3±1.0 10.2 or more

Source: JIS R6010 “Coated abrasive grain sizes”

3. Fine particulate (P1500–P2500) and dispersal test method (units: μm)
Grain size Maximum particle 
diameter 
(ds-0 value)
Particle diameter 
at 3% cumulative 
height 
(ds-3 value)
Particle diameter 
at 50% cumulative 
height 
(ds-50 value)
Particle diameter 
at 95% cumulative 
height 
(ds-95 value)
P1500 58 or less 25.8 or less 12.6±1.0 8.3 or more
P2000 58 or less 22.4 or less 10.3±0.8 6.7 or more
P2500 58 or less 19.3 or less 8.4±0.5 5.4 or more

Source: JIS R6010 “Coated abrasive grain sizes”
Some standards also taken from “Testing Methods for Electrical Resistance”

(3) Grain Size of diamond and abrasive grain CBN

Standard 
type
Sieve 
type
Grain size type Aperture dimension of sieve used
Table 
for 
method 
A
Table 
for 
method 
B
Sieve 1 Sieve 2 Sieve 3 Sieve 4
Sieve through 
which 99.9% 
must pass
Sieve that 
must not stop 
a set amount 
and the resulting
amount
Sieve that 
must stop 
a set amount, 
and that 
amount
Maximum amount 
that may 
pass through
Sieve through 
which a maximum 
of  2% may pass
μm μm % μm % % μm
Narrow-range Net 
sieve
16/18 1181 1700 1180 8 1000 90 8 710
18/20 1001 1400 1000 8 850 90 8 600
  851 1180 850 8 710 90 8 500
  711 1000 710 8 600 90 8 425
  601 850 600 8 500 90 8 355
  501 710 500 8 425 90 8 300
Electric 
sieve
426 600 455 8 360 90 8 255
356 500 384 8 302 90 8 213
50/60 301 455 322 8 255 90 8 181
251 384 271 8 213 90 8 151
213 322 227 8 181 90 8 127
80/100 181 271 197 10 151 87 10 107
100/120 151 227 165 10 127 87 10 90
120/140 126 197 139 10 107 87 10 75
140/170 107 165 116 11 90 85 11 65
170/200 91 139 97 11 75 85 11 57
200/230 76 116 85 11 65 85 11 49
230/270 64 97 75 11 57 85 11 41
270/325 54 85 65 15 49 80 15
325/400 46 75 57 15 41 80 15
Wide-range Net   1182 1700 1180 8 850 90 8 600
20/30 852 1180 850 8 600 90 8 425
30/40 602 850 600 8 425 90 8 300
Electric 40/50 427 600 455 8 302 90 8 213
60/80 252 384 271 8 181 90 8 127

Source: JIS B4130 “Diamond/CBN products-Grain sizes of diamond or cubic boron nitride”