Material specification page for square head bolts with collar in Property Class 8.8 Steel. Covers the grade designation (ISO 898-1 property class 8.8), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to DIN 478.
Why Choose Property Class 8.8 Steel for Square Head Bolts with Collar
The workhorse medium-carbon alloy class for structural joints. For square head bolts with collar, 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 |
Corrosion Behavior in Service
Carbon and alloy steel square head bolts with collar 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 Square Head Bolts with Collar, 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 Square Head Bolts with Collar Available in Property Class 8.8 Steel
| Size | Pitch P (mm) | b1 (mm) | b2 (mm) | c (mm) | da (mm) | dc (mm) | Width across corners e (mm) | Head height k (mm) | r (mm) | Width across flats s (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 16 | 16 | 2 | 5.7 | 9.5 | 6.5 | 7 | 0.25 | 5 | 10~30 | DIN 478 |
| M6 | 1 | 18 | 18 | 2 | 6.8 | 10.5 | 8 | 8 | 0.25 | 6 | 10~40 | DIN 478 |
| M8 | 1.25 | 22 | 22 | 2 | 9.2 | 13.5 | 10 | 10 | 0.4 | 8 | 16~45 | DIN 478 |
| M10 | 1.5 | 26 | 32 | 3 | 11.2 | 16.5 | 13 | 13 | 0.4 | 10 | 20~60 | DIN 478 |
| M12 | 1.75 | 30 | 36 | 3 | 13.7 | 19.5 | 17 | 15 | 0.6 | 13 | 25~90 | DIN 478 |
| M16 | 2 | 38 | 44 | 4 | 17.7 | 25 | 22 | 20 | 0.6 | 17 | 30~140 | DIN 478 |
| M20 | 2.5 | 45 | 52 | 5 | 22.4 | 31 | 28 | 25 | 0.8 | 22 | 35~180 | DIN 478 |
| M24 | 3 | 54 | 60 | 6 | 26.4 | 36 | 32 | 28 | 0.9 | 24 | 35~180 | DIN 478 |
Dimensions are independent of the material: every size above is available in Property Class 8.8 Steel.
Custom manufacturing · Made to drawing
Need this bolt in a grade that is not listed?
Grade 8 8 Steel is one of the grades the catalog describes. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
