Metric Property Class 9.8
Class 9.8 sits between 8.8 and 10.9 and applies only to diameters up to 16 mm. It is rarely stocked; most catalogs jump from 8.8 to 10.9.
| Marking | 9.8 plus manufacturer ID |
|---|---|
| Matching nut | ISO 898-2 class 9 (or higher) |
Mechanical properties (ISO 898-1)
| Class | Size | Tensile Rm (min) | Yield Rp0.2 (min) | Proof stress | Hardness |
|---|---|---|---|---|---|
| 9.8 | up to M16 | 900 MPa | 720 MPa | 650 MPa | 290 - 360 HV |
These tables carry the same figures as the printed sheet below.
The printed sheet
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Text version of this sheet
ISO 898-1 · property class 9.8 · sizes up to M16 only
What it is
FIELD IDENTIFICATION
Class 9.8 sits between 8.8 and 10.9 and applies only to diameters up to 16 mm. It is rarely stocked;
most catalogs jump from 8.8 to 10.9.
MFG
9.8
Marking
9.8 plus manufacturer ID
Matching nut
ISO 898-2 class 9 (or higher)
Head stamped 9.8 + manufacturer ID
Mechanical properties (ISO 898-1)
Class
9.8
Size
Tensile Rm (min)
up to M16
Yield Rp0.2 (min)
900 MPa
Proof stress
720 MPa
Hardness
650 MPa
290 - 360 HV
Key points
Above M16 there is no 9.8; the next class up is 10.9.
Do not substitute 8.8 where 9.8 is specified without engineering approval.
Governing standards: ISO 898-1:2013; ISO 898-2:2022. Editions shown are the latest confirmed as of September 2026. The drawing and the governing standard always take
precedence over this sheet.
torquing any fastener. Verify the current governing standard, project documents, OEM requirements, size, thread, coating and lot certification. To the fullest extent permitted by law, The Fastener App disclaims liability
arising from reliance on this reference.
Fastener Guide reference FG-95F0A4 · thefastenerapp.com/fastener-guide/technical-reference/class-9-8 · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
