Top tips for HD welding
Recommendations for the spot welding of galvanized ahss high-ductility steels
Galvanized ahss high-ductility steels are a joy for forming specialists. They are highly corrosion-resistant, high-strength and exhibit excellent formability. Welding specialists see this in a more differentiated way, especially with respect to liquid metal embrittlement. Liquid zinc penetrates the grain boundaries of the steel and damages the joint. Such penetration can be avoided.
Generally, the following applies:
- voestalpine ahss high-ductility steels (complex-phase and dual-phase steels) in strength classes 600 and 800 MPa do not differ significantly from others in their resistance to liquid metal embrittlement. Weldability is guaranteed.
- Proper welding equipment that meets all pertinent requirements must be used in the welding of high-strength steels. Such equipment is mandatory, especially with respect to liquid metal embrittlement.
Tips for tip-top results: These special recommendations from a welding expert have been proven in practice and are frequently used by OEMs.
- Use high electrode forces,preferably between 4 and 5 kN.
- Enlarge electrode contact areas,for example 8 mm instead of 6 mm, or use flat electrode caps.
- Use highly rigid C spot welding electrode holders.
What will the future bring?
ahss, HD dual-phase and complex-phase steels with tensile strengths in excess of 1000 MPa are particularly interesting in lightweight automotive design. voestalpine is a leader in the development of these high-quality steels and is working to reduce liquid metal embrittlement.