DIN 933 M20 Hex Bolt Class 8.8
Hex Bolt · M20 × 2.5 · Class 8.8 · Carbon steel, class 8.8
- Key facts
- Standard
- DIN 933
- Size
- M20
- Thread designation
- M20 × 2.5
- Pitch
- 2.5 mm
- Class
- Class 8.8
- Material
- Carbon steel, class 8.8
- Finish
- 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 |
| Width across flats S | 30 mm |
| Head height K | 12.5 mm |
| Grip length b (partial thread) | ≈ 2d + 6 mm (DIN931 partial-thread reference) |
| 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 | 800 MPa |
| Min. yield strength | 640 MPa |
| Hardness range | 22 – 32 HRC |
| Common material | Medium-carbon steel (35# / 45#) |
| Quenching & tempering required | — |
| Fracture toughness | Good |
| Relative price | 1 (baseline) |
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Match on the standard number: similarly named parts can differ in width across flats, and superseded DIN standards need an agreed inspection basis.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
Mates with DIN934 hex nuts / DIN985 nylon insert lock nuts.
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 933 M20 Hex Bolt Class 8.8
Send the standard, diameter, class and quantity — price, lead time and a sample MTC within 24 hours.