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Bonded Abrasives 101
Abrasive Grains 101
Types of Abrasives
Manufacture of Abrasives
National and Int'l Standards
UAMA Supported Standards
Standard Sands
Coated Abrasives 101
Superabrasives 101


Unified Abrasives
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Cleveland, OH 44145-1967

Unified Abrasives Manufacturers' Association

National and International Size Standards


Despite these problems, standards have been issued for full ranges of macrogrit and microgrit sizes by ANSI, FEPA, and JIS. (ANSI is of course the American National Standards Institute; FEPA is the European Federation of Abrasives Producers; and JIS is the Japanese Standardization Organization.) For macrogrits, these standards are all but identical, and differ only in a few of the sizes covered and the range of applications covered. ANSI standard B74.12-2001 gives two separate specifications, one for abrasives to be used for grinding wheel and general industrial applications, one for abrasives to be used for blasting. For the sizes covered, the only difference is material used for blasting need not be as tightly sized. Comparing ANSI B74.12-2001 with FEPA 43GB-1984R1991 and JIS R6001-1987, the size requirements for sizes defined are identical. FEPA includes two sizes, F22 and F40, not covered by ANSI or JIS. JIS does not cover the four coarsest sizes, 4, 5, 6 and 7, covered by ANSI and FEPA.

ANSI B74.18-1996, currently under revision, covers coated abrasives. These sizing requirements are quite different from those for bonded and loose abrasives. (For brevity, the differing standards will be referred to as "bonded" and "coated.") In general, it is entirely possible that any particular abrasive that meets the requirements for a coated size will meet the requirements for the same bonded size (that is, an ANSI bonded 180 may also be acceptable as an ANSI coated 180), and vice-versa. It is also entirely possible that a FEPA F120 (bonded) will not meet the requirements of a FEPA P120 (coated), and vice-versa. This is because the standards specify different sieve sizes to be used for testing, allow or require different percentages of retained material on the various sieves, and in general state the requirements in a manner which frustrates direct comparison of the sizes.

Without entering into a detailed comparison of the standards, which the interested user is encouraged to do, one example will hopefully suffice. For FEPA P80 (coated), FEPA GB43-1991 requires all of the material to pass through a 355 micron sieve, and a maximum of 3% be retained on a 255 micron sieve. For FEPA F80 (bonded), FEPA 42GB-1984R1993 requires all the material to pass through a 300 micron sieve. There is no requirement with regard to a 255 micron sieve, and up to 25% of the material may be retained on a 212 micron sieve. Clearly, a single abrasive with no particles over 255 microns would meet both these standards. But an abrasive with no particles over 355 microns, 1% from 300 to 355 microns, and 2% from 255 to 300 microns would meet the coated standard and fail the bonded one. An abrasive with no particles over 300 microns but 4% from 255 to 300 microns would meet the bonded standard and fail the coated one.

With regard to ANSI B74.18-1996, direct comparison is even more difficult, since the standard in general does not specify what percentages may or must be retained. Instead, the sieves themselves are first calibrated with a standard sand (see Appendix 3). The requirements for the material to be tested are then expressed in terms of the performance of the sieve with regards to the standard sand. Thus, for a coated ANSI 120, the maximum percentage allowed to be retained on a 133 micron sieve is 1.2 times the percentage of standard sand retained on that same sieve. The 133 micron sieve must have retained from 9.9 to 17.9 percent of the 120 standard sand. That same sieve is then used as a fines control sieve for coated 100 grade. The percentage of material which passes through that sieve must be within +10%/ -7% of the percentage of the 100 grade standard sand which passed through it.

In comparing coated with bonded macrogrits, the most that can be said is that the sizes are approximately the same, but the specified requirements differ sufficiently to require individual appraisal of batches of material.

Exhibits 2 and 3 show the approximate size range of the standard sizes of macrogrits by FEPA, ANSI, and JIS requirements. For all sizes, the standards require that at least 70% to 85% (depending on the size in question) of the abrasive pass through a coarse control sieve and at least cumulatively 60% to 70% of the abrasive be retained on two or three finer sieves. The size range for each size given in Exhibits 1 and 2 is from the opening of the finest sieve to the opening of the control sieve.

Thus, for ANSI grade 80 (FEPA F80, JIS 80), a total of 65% of the sample must be retained on sieves with openings of 150 and 180 microns. At least 75% of the size must pass through a sieve with an opening of 212 microns. The range shown for size 80 is thus 150 to 212 microns: at least 65% of the sample, including the median size, will fall within this range.

For a complete listing of grit specification and comparison to other standards click on a grit bar.

Exhibit 2

Exhibit 3


Comparison of standards for microgrits is not as straightforward. ANSI standards for coated and bonded grains differ substantially, as do the FEPA standards for coated (called "FEPA P") and bonded (called "FEPA F") grains. The JIS standard is also quite different. For the most part, the standards specify a) a minimum value which 94% of the abrasive must be coarser than, b) a maximum value that 97% of the abrasive must be finer than, and c) the range in which the midpoint must fall.

Exhibits 4, 5 6 and 7 show the required midpoint ranges when measured by electrical resistance as specified in the various standards. Exhibits 8, 9, 10 and 11 show the full size range (from 3% to 94%, 95% for FEPA P) of the same sizes. The relevant standards are ANSI B74.10-2001 (bonded and loose grain, shown as "ANSI" in the exhibits), ANSI B74.18-1996 (shown as "Coated" in the exhibits), FEPA 42-D-1984R1993 and ISO 8486 (for bonded and loose grain, shown as "FEPA" in the exhibits), FEPA 43-GB-1983R1993 (for coated abrasives, shown as FEPA P in the exhibits), and JIS R 6001-1987 (shown as "JIS" in the Exhibits).

In all cases, the shaded area under the size label shows the size range of interest. Where the specifications are identical (for example, for JIS and ANSI-Coated, sizes 4000 and finer), the label shows both sizes. ANSI coated sizes 240 to 500 are not specified by electrical resistance measurement in ANSI B74.18-1996, and thus were not included in the exhibits. In general, they are close to the JIS sizes. FEPA P (coated) microgrits are not specified by electrical resistance, but by sedimentometer. The values given in the exhibits are based on electrical resistance equivalents of the sedimentometer values.

An important point to remember about the microgrits is that the same size number may refer to very different sizes, depending on the standard being used. Thus, a JIS 600 has an average particle size of 18.5-21.5 microns. A FEPA F600 has an average size of 8.3-10.3 microns.

Exhibit 4

Exhibit 5

Exhibit 6

Exhibit 7

Exhibit 8

Exhibit 9

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