Tack weld design
Tack weld construction: temporary fixation through short weld spots to maintain the desired geometry. Must be stable against shrinkage forces.
Physical-chemical mechanism of action
The tack weld construction consists of short-lived weld spots that are used before the main welding process. These spots hold the parts at the correct distance and prevent distortion during the lengthy hardening sequence of the main weld.
Metallurgical relevance & risks when welding
If the tack weld is too short or not stable enough, parts can distort and no longer maintain the desired geometry. This leads to inaccurate weld seam positions and possible cracks in the finished component.
Workshop practice & action instructions
The tack weld must be at least 5 mm long and made of a metal with the same or similar hardness as the main weld material. The weld spots should be evenly distributed and apply a stress of at least 10 N/mm². For severe distortion, an additional support weld may be required.