Slotted Terminal Screws manufactured in Property Class 12.9 Steel (ISO 898-1 property class 12.9) are dimensioned to DIN 84. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose Property Class 12.9 Steel for Slotted Terminal Screws
The highest common strength class, for high-load machine assembly. For slotted terminal screws, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating or black-oxide protection |
Corrosion Behavior in Service
Carbon and alloy steel slotted terminal screws 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 Slotted Terminal Screws, 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 Terminal Screws Available in Property Class 12.9 Steel
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Slot width n (mm) | Slot depth t (mm) | Common material | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|
| M2.5 | 0.45 | 4.5 | 1.8 | 0.6 | 1.1 | Brass CW614N | 4~20 | DIN 84 |
| M3 | 0.5 | 5.5 | 2.0 | 0.8 | 1.2 | Brass CW614N | 4~25 | DIN 84 |
| M3.5 | 0.6 | 6.0 | 2.4 | 1.0 | 1.5 | Brass CW614N | 5~30 | DIN 84 |
| M4 | 0.7 | 7.0 | 2.6 | 1.2 | 1.6 | Brass CW614N | 5~35 | DIN 84 |
| M5 | 0.8 | 8.5 | 3.3 | 1.2 | 2.0 | Brass CW614N | 6~40 | DIN 84 |
| M6 | 1.0 | 10.0 | 3.9 | 1.6 | 2.4 | Brass CW614N | 8~50 | DIN 84 |
