Grade 12.9 Steel Slotted Pan Head Screw are stocked to GB/T 67 / ISO 1580. The grade provides requires plating or black-oxide protection and is magnetic; the practical service range is up to approx. +300 °C. Property data, grade comparison and the full size table follow.
Why Choose Grade 12.9 Steel for Slotted Pan Head Screw — GB/T 67 / ISO 1580 (Series 040)
The highest common strength class, for high-load machine assembly. For slotted pan head screw — gb/t 67 / iso 1580 (series 040), this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating or black-oxide protection |
Corrosion Behavior in Service
Carbon and alloy steel slotted pan head screw — gb/t 67 / iso 1580 (series 040) 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.
Galvanic & Galling Considerations
For slotted pan head screw — gb/t 67 / iso 1580 (series 040) in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Sizes of Slotted Pan Head Screw — GB/T 67 / ISO 1580 (Series 040) Available in Grade 12.9 Steel
| Size | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Cross recess | Reference standard |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 20 | 5.6 | 1.8 | PH1 | ISO 7045 / GB/T 818 |
| M4 | 0.7 | 25 | 8.0 | 2.4 | PH2 | ISO 7045 / GB/T 818 |
| M5 | 0.8 | 30 | 9.5 | 3.0 | PH2 | ISO 7045 / GB/T 818 |
| M6 | 1.0 | 40 | 12.0 | 3.6 | PH3 | ISO 7045 / GB/T 818 |
| M8 | 1.25 | 50 | 16.0 | 4.8 | PH3 | ISO 7045 / GB/T 818 |
| M10 | 1.5 | 60 | 20.0 | 6.0 | PH4 | ISO 7045 / GB/T 818 |