Wedge / Taper Washer manufactured in Grade 8.8 Steel (class 8.8) are dimensioned to GB/T 852. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose Grade 8.8 Steel for Wedge / Taper Washer — GB/T 852 (Series 084)
The workhorse medium-carbon alloy grade for structural joints. For wedge / taper washer — gb/t 852 (series 084), this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Corrosion Behavior in Service
Carbon and alloy steel wedge / taper washer — gb/t 852 (series 084) require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Wedge / Taper Washer — GB/T 852 (Series 084), class 10.9 or 12.9 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Wedge / Taper Washer — GB/T 852 (Series 084) Available in Grade 8.8 Steel
| For bolt size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Mean thickness t (mm) | Slope | Reference standard |
|---|---|---|---|---|---|
| M3 | 3.5 | 6 | 1.2 | 1:6 | DIN 6917 / GB/T 853 |
| M4 | 4.5 | 8 | 1.6 | 1:6 | DIN 6917 / GB/T 853 |
| M5 | 5.5 | 11 | 2.0 | 1:6 | DIN 6917 / GB/T 853 |
| M6 | 6.5 | 13 | 2.4 | 1:6 | DIN 6917 / GB/T 853 |
| M8 | 8.5 | 17 | 3.2 | 1:6 | DIN 6917 / GB/T 853 |
| M10 | 10.5 | 22 | 4.0 | 1:6 | DIN 6917 / GB/T 853 |
| M12 | 12.5 | 26 | 4.8 | 1:6 | DIN 6917 / GB/T 853 |
| M14 | 14.5 | 30 | 5.6 | 1:6 | DIN 6917 / GB/T 853 |
| M16 | 16.5 | 35 | 6.4 | 1:6 | DIN 6917 / GB/T 853 |
| M18 | 18.5 | 39 | 7.2 | 1:6 | DIN 6917 / GB/T 853 |