CE compliant – Regulation (EU) No. 305/2011
Standard: DIN EN ISO 13918 – Type MD-DUO (formerly MPF-DUO)
Combined material: Steel 4.8 welding tip + stainless steel threaded section
Cold-rolled thread: Tolerance 6g
Bimetallic design: Two materials in one stud
Product description – MD-DUO
The BEARFIX® MD-DUO bimetallic threaded stud is designed for drawn arc stud welding with ceramic ferrule. It combines steel 4.8 at the welding tip, optimised for weldability, with stainless steel in the threaded section for corrosion resistance.
Formerly known as MPF-DUO, this design has nearly full thread down to the welding tip. The unthreaded section corresponds approximately to the thread pitch diameter, producing a weld bead around 3–4 mm larger than the external thread diameter.
The aluminium ball at the steel welding tip helps provide stable ignition, while the supplied ceramic ferrule protects the weld pool.
Main applications
- Marine and offshore construction
- Chemical plants and wastewater treatment
- Food and pharmaceutical industries
- Structures exposed to aggressive environments
- Carbon-steel structures requiring a stainless threaded fastening point
- Bridges and coastal structures
Technical advantages
- Bimetallic design – optimised weldability and corrosion resistance
- Cost efficiency – only the threaded section is stainless steel
- Nearly full thread – maximum usable thread length
- Cold-rolled thread – high strength and accuracy
- Standard weld bead – approximately 3–4 mm larger than the external thread diameter
Available material combinations
- 78-14: steel 4.8 tip + stainless steel 1.4571 threaded section
- 78-12: steel 4.8 tip + A2-50 stainless steel threaded section
Standard dimensions – MD-DUO
| Thread | l2 (mm) | y (mm) | d2 (mm) | d3 (mm)* | h (mm)* | 4.8 + 1.4571 article No. | 4.8 + A2-50 article No. | Ceramic ferrule |
|---|---|---|---|---|---|---|---|---|
| M8 | 15–100 | 6 | 7.1 | 10 | 3 | 78-14-08-XXX-PF | 78-12-08-XXX-PF | KSP-F 8 |
| M10 | 20–100 | 6.5 | 8.9 | 12.5 | 3.5 | 78-14-10-XXX-PF | 78-12-10-XXX-PF | KSP-F 10 |
| M12 | 20–100 | 7.5 | 10.8 | 14.5 | 4.5 | 78-14-12-XXX-PF | 78-12-12-XXX-PF | KSP-F 12 |
| M16 | 30–100 | 11 | 14.6 | 17.8 | 5.8 | 78-14-16-XXX-PF | 78-12-16-XXX-PF | KSP-F 16 |
* d3 and h are approximate. Replace XXX with the required length in mm. Other lengths and threads are available on request.
Mechanical properties
- Steel 4.8 tip: yield strength ≥ 340 N/mm², tensile strength ≥ 420 N/mm², elongation ≥ 14%
- A2-50 threaded section: Rp0.2 ≥ 210 N/mm², Rm ≥ 500 N/mm²
- 1.4571 threaded section: Rp0.2 ≥ 210 N/mm², Rm ≥ 500 N/mm²
Standards and certificates
- CE marking according to Regulation (EU) No. 305/2011
- DIN EN ISO 13918 – Type MD-DUO
- DIN EN ISO 14555 – Stud welding
- DIN EN 10204 inspection certificates on request
Return to Bimetallic Threaded Studs.