Dowel Pins manufactured in Grade 8.8 Steel (class 8.8) are dimensioned to ISO 8734 / DIN 6325. 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 Dowel Pins
The workhorse medium-carbon alloy grade for structural joints. For dowel pins, 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 dowel pins 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 Dowel Pins, 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 Dowel Pins Available in Grade 8.8 Steel
| Nominal diameter (mm) | Diameter tolerance | Common length range (mm) | Material | Hardness | Reference standard | Notes |
|---|---|---|---|---|---|---|
| 1.0 | h6 | 4~10 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 1.2 | h6 | 4~12 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 1.5 | h6 | 4~16 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 2.0 | h6 | 6~20 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 2.5 | h6 | 6~24 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 3.0 | h6 | 8~30 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 4.0 | h6 | 8~40 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 5.0 | h6 | 10~50 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 6.0 | h6 | 12~60 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 8.0 | h6 | 16~80 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 10.0 | h6 | 20~100 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 12.0 | h6 | 25~120 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 16.0 | h6 | 30~160 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 20.0 | h6 | 35~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 25.0 | h6 | 45~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 30.0 | h6 | 50~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 40.0 | h6 | 60~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 50.0 | h6 | 80~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |

