Grade 12.9 Steel Slotted Pan Head Screw — GB/T 67 / ISO 1580 (Series 040) pairs the standard GB/T 67 / ISO 1580 with a Grade 12.9 Steel base material. The sections below cover why engineers select this grade for slotted pan head screw — gb/t 67 / iso 1580 (series 040), its corrosion and temperature behavior, and the sizes available.
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 |
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.
Comparable Grades
For Slotted Pan Head Screw — GB/T 67 / ISO 1580 (Series 040), class 8.8 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 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 |