Metric Flat Washer Dimensions are shown in the following chart according to
ANSI B18.22M and various ISO standards. Metric flat washer dimensions for nominal washer size from 1.6 mm to 64 mm are covered in the chart.
Some important notes from the ANSI B18.22M:
- Two types of washers are specified in the ANSI standard, Soft and Hardened. Soft washers are generally used in low
strength applications to distribute bearing load, to
provide a uniform bearing surface, and to prevent
damage of the work surface. Hardened washers are intended primarily
for use in high-strength joints to minimize embedment,
to provide a uniform bearing surface, and to
bridge large clearance holes and slots.
Some important notes from the ISO standards:
An overview of suitable combinations of ISO metric plain (flat) washers and bolts, screws or nuts in respect of property (hardness)
classes and product grades is given in the following chart.
|
Washers |
Hardness class |
100 HV |
200 HV |
300 HV |
|
Product grade |
C |
A |
A |
|
Bolts, screws, nuts |
Product grade |
A |
no |
yes |
yes |
|
B |
no |
yes |
yes |
|
C |
yes |
no |
no |
|
Bolts, screws |
Property class |
≤ 6.8 |
yes |
yes |
yes |
|
8.8 |
no |
yes |
yes |
|
9.8, 10.9 |
no |
no |
yes |
|
12.9 |
no |
no |
no |
|
Nuts |
Property class |
≤ 6 |
yes |
yes |
yes |
|
8 |
no |
yes |
yes |
|
9, 10 |
no |
no |
yes |
|
12 |
no |
no |
no |
|
Case-hardened thread rolling screws |
yes |
yes |
yes |
|
Stainless - steel bolts, screws and nuts |
- |
yes |
- |
