Property Class 8.8 Steel (ISO 898-1 property class 8.8) is the workhorse medium-carbon alloy class for structural joints. When hexalobular socket pan head screws are specified in this grade, the dimensions remain per ISO 14583; the material determines corrosion behavior (requires plating (zinc) for corrosion protection) and the service temperature range (commonly limited to approx. +300 °C; confirm against the coating and the load). Both are covered below with the size table.
Why Choose Property Class 8.8 Steel for Hexalobular Socket Pan Head Screws
The workhorse medium-carbon alloy class for structural joints. For hexalobular socket pan head screws, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Galvanic & Galling Considerations
For hexalobular socket pan head screws 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 Hexalobular Socket Pan Head Screws, 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 Hexalobular Socket Pan Head Screws Available in Property Class 8.8 Steel
| Size | Pitch P (mm) | a_max (mm) | b_min (mm) | d_a_max (mm) | Head diameter dk (mm) | Head height k (mm) | r_min (mm) | rf (mm) | x_max (mm) | tt (mm) | t (mm) | A_ref (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M2 | 0.4 | 0.8 | 25 | 2.6 | 4 | 1.6 | 0.1 | 3.2 | 1 | T6 | 0.7 | 1.75 | 3~20 | ISO 14583 |
| M2.5 | 0.45 | 0.9 | 25 | 3.1 | 5 | 2.1 | 0.1 | 4 | 1.1 | T8 | 0.975 | 2.4 | 3~25 | ISO 14583 |
| M3 | 0.5 | 1 | 25 | 3.6 | 5.6 | 2.4 | 0.1 | 5 | 1.25 | T10 | 1.14 | 2.8 | 4~30 | ISO 14583 |
| (M3.5) | 0.6 | 1.2 | 38 | 4.1 | 7 | 2.6 | 0.1 | 6 | 1.5 | T15 | 1.2 | 3.35 | 5~35 | ISO 14583 |
| M4 | 0.7 | 1.4 | 38 | 4.7 | 8 | 3.1 | 0.2 | 6.5 | 1.75 | T20 | 1.465 | 3.95 | 5~40 | ISO 14583 |
| M5 | 0.8 | 1.6 | 38 | 5.7 | 9.5 | 3.7 | 0.2 | 8 | 2 | T25 | 1.715 | 4.5 | 6~50 | ISO 14583 |
| M6 | 1 | 2 | 38 | 6.8 | 12 | 4.6 | 0.25 | 10 | 2.5 | T30 | 2.22 | 5.6 | 8~60 | ISO 14583 |
| M8 | 1.25 | 2.5 | 38 | 9.2 | 16 | 6 | 0.4 | 13 | 3.2 | T45 | 2.985 | 7.95 | 10~60 | ISO 14583 |
| M10 | 1.5 | 3 | 38 | 11.2 | 20 | 7.5 | 0.4 | 16 | 3.8 | T50 | 3.82 | 8.95 | 12~60 | ISO 14583 |
Dimensions are independent of the material: every size above is available in Property Class 8.8 Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
Grade 8 8 Steel is one of the grades the catalog describes. Lengths and thread lengths outside the standard table are the commonest request, followed by a drive the standard does not offer and a head marked with your own part number. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
