Bimetallic Threaded Studs for Drawn Arc Welding with Ceramic Ferrule
CE compliant – Regulation (EU) No. 305/2011
Standard: DIN EN ISO 13918 – Types MD-DUO, RD-DUO, PD-DUO, ID-DUO
Combined materials: Steel 4.8 + A2-50 / Steel 4.8 + 1.4571
Bimetallic design: Two materials in one stud
What are bimetallic threaded studs?
BEARFIX® bimetallic threaded studs combine two different materials in a single component:
- Welding area (tip): steel 4.8 – optimised for weldability.
- Threaded area: stainless steel A2-50 or 1.4571 – for corrosion resistance.
This configuration is ideal where a corrosion-resistant fastening point is required but welding is carried out on a carbon-steel structure, combining weldability, corrosion resistance and cost efficiency.
Available types
BEARFIX® offers four bimetallic configurations:
MD-DUO – Nearly full thread
Main feature: Thread extends almost to the welding tip. The unthreaded section corresponds approximately to the thread pitch diameter. The weld bead is approximately 3–4 mm larger than the external thread diameter.
Ideal application: Maximum usable thread length with a conventional weld bead.
RD-DUO – Reduced shank
Main feature: Thread extends almost to the welding tip, with the shank reduced approximately to the thread core diameter. The weld bead is only 0.5–1 mm larger than the external thread diameter.
⚠️ Note: The reduced tip lowers bearing strength by approximately 15%. Select the next diameter if required.
Ideal application: Restricted spaces where the smallest possible weld bead is required.
PD-DUO – Partial thread (on request)
Main feature: Partial external thread with a plain welding section. The weld bead is approximately 3–4 mm larger than the external thread diameter.
Ideal application: Flexible thread-length requirements.
📌 Available on request.
ID-DUO – Internal thread (on request)
Main feature: Internal thread for a flush fastening point without a projecting external thread.
Ideal application: Clean, flat fastening surfaces.
📌 Available on request.
Available material combinations
- Combination 1: Steel 4.8 welding tip + stainless steel 1.4571 threaded section.
- Combination 2: Steel 4.8 welding tip + stainless steel A2-50 threaded section.
Advantages of bimetallic studs
- Material optimisation – weldability plus corrosion resistance.
- Cost efficiency – only the threaded/body section uses stainless steel.
- Cold-rolled thread – high mechanical strength.
- Excellent weldability – aluminium ball at the steel 4.8 tip.
- Four configurations for different application requirements.
Standards and certificates
- CE marking according to Regulation (EU) No. 305/2011
- DIN EN ISO 13918 – Types MD-DUO, RD-DUO, PD-DUO and ID-DUO
- DIN EN ISO 14555 – Stud welding
- DIN EN 10204 inspection certificates on request
Ordering information
When ordering bimetallic threaded studs, specify the type, material combination, thread size and total length.
The corresponding ceramic ferrule is supplied with each stud.
BEARFIX® – Fastening and welding solutions for structural engineering.
