DIN 912 M20 Socket Head Cap Screw Class 10.9
Socket Head Cap Screw · M20 × 2.5 · Class 10.9 · Alloy steel, class 10.9
- Key facts
- Standard
- DIN 912
- Size
- M20
- Thread designation
- M20 × 2.5
- Pitch
- 2.5 mm
- Class
- Class 10.9
- Material
- Alloy steel, class 10.9
- Finish
- Black oxide / Zinc plated / Dacromet
Dimensions
Values are taken as published on our spec sheet, not recalculated; tolerances follow the standard execution class.
| Thread size | M20 × 2.5 |
| Pitch P | 2.5 mm |
| Head diameter dk | 30 mm |
| 头部高度 k | 20.0 mm |
| Hex socket across flats s | 17 mm |
| Counterbore diameter | dk + 0.5 ~ 1 mm（约 30.5 – 31 mm） |
| Length | 10 – 500 mm, all lengths available; non-standard lengths and fine pitches to drawing |
Mechanical properties
Per GB/T 3098.1 / ISO 898-1 class definitions (stainless per ISO 3506).
| Nominal tensile strength | 1000 MPa |
| Min. yield strength | 940 MPa |
| Hardness range | 32 – 39 HRC |
| Common material | Medium-carbon alloy steel (35CrMo) |
| Quenching & tempering required | Yes |
| Fracture toughness | Medium |
| Relative price | ≈ 1.2 – 1.4 |
Recommended tightening torque
Coarse thread · dry assembly · μ ≈ 0.14 · estimated at 70% of yield strength — reference only; critical joints follow the design document
Factors that change the actual torque: lubrication, finish, washer and bearing surface, re-use.
DIN / GB / ISO cross reference
Match on the standard number: similarly named parts can differ in width across flats, and superseded DIN standards need an agreed inspection basis.
Applications & mating parts
Machine the counterbore to dk + 0.5 ~ 1 mm; when screwed into a tapped hole, effective depth in steel ≥ 1×d.
Supply information
Multiple diameters and classes can be mixed in one order; batch mill test reports ship with the goods.
- MOQ: 500 pcs (mixed containers accepted)
- Lead time: 3–7 days in stock / 15–25 days custom
- Documents: packing list, invoice, certificate of origin (CO / FORM E / RCEP)
- Terms: FOB Ningbo / Shanghai · CIF · EXW
- Ships with: mill test certificate and inspection report per batch
Adjacent sizes & other classes
Changing class on the same diameter changes material and heat treatment — thread and head dimensions stay the same. Re-check the joint design before substituting.
Other classes, same diameter
Adjacent sizes, same class
Request a quote: DIN 912 M20 Socket Head Cap Screw Class 10.9
Send the standard, diameter, class and quantity — price, lead time and a sample MTC within 24 hours.