SEMS Screws with Captive Conical Spring Washers manufactured in Property Class 8.8 Steel (ISO 898-1 property class 8.8) are dimensioned to DIN 6900-5 Z9 and DIN 6908. 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 8.8 Steel for SEMS Screws with Captive Conical Spring Washers
The workhorse medium-carbon alloy class for structural joints. For sems screws with captive conical spring washers, 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 sems screws with captive conical spring washers 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 SEMS Screws with Captive Conical Spring Washers, 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 SEMS Screws with Captive Conical Spring Washers Available in Property Class 8.8 Steel
| Thread size | Pitch (mm) | Washer inside diameter (mm) | Washer outside diameter (mm) | Washer thickness (mm) | Material options | Reference standard |
|---|---|---|---|---|---|---|
| M2.5 | 0.45 | 2.25~2.35 | 5.7~6.0 | 0.5 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M3 | 0.5 | 2.75~2.85 | 6.64~7.0 | 0.6 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M4 | 0.7 | 3.6~3.72 | 8.64~9.0 | 1.0 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M5 | 0.8 | 4.55~4.67 | 10.57~11.0 | 1.2 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M6 | 1.0 | 5.5~5.62 | 13.57~14.0 | 1.5 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M8 | 1.25 | 7.4~7.55 | 17.57~18.0 | 2.0 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M10 | 1.5 | 9.3~9.45 | 22.48~23.0 | 2.5 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
| M12 | 1.75 | 11.0~11.18 | 28.48~29.0 | 3.0 | steel or A2 stainless | DIN 6900-5 Z9 and DIN 6908 |
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. Head form and drive can be specified to the assembly rather than to a standard: a larger bearing face, a security drive, or a socket sized for the tool already on the bench. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
