Grade 12.9 Steel Phillips Pan Head Machine Screw — GB/T 818 / ISO 7045 (Series 035) pairs the standard GB/T 818 / ISO 7045 with a Grade 12.9 Steel base material. The sections below cover why engineers select this grade for phillips pan head machine screw — gb/t 818 / iso 7045 (series 035), its corrosion and temperature behavior, and the sizes available.
Why Choose Grade 12.9 Steel for Phillips Pan Head Machine Screw — GB/T 818 / ISO 7045 (Series 035)
The highest common strength class, for high-load machine assembly. For phillips pan head machine screw — gb/t 818 / iso 7045 (series 035), 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 phillips pan head machine screw — gb/t 818 / iso 7045 (series 035) 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 phillips pan head machine screw — gb/t 818 / iso 7045 (series 035) 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 Phillips Pan Head Machine Screw — GB/T 818 / ISO 7045 (Series 035) 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 |