Cap reinforcement
The excess of the surface of the filler metal above the component surface. It compensates for volume changes and ensures the cross-section is correct.
Physicochemical Mechanism of Action
The excess weld metal forms through melting of the filler material and expansion of the metal during welding. This leads to an increase in volume that sticks out above the original surface.
Metallurgical Relevance & Welding Risks
Too much excess weld metal can cause stress build-up and cracks. It can also damage the outside of the component surface or hurt the visual quality. Too little excess can mean the cross-section is not correct and the mechanical properties suffer.
Workshop Practice & Instructions
The excess weld metal should lie in the range of 0.1 to 0.3 mm. This can be achieved through careful selection of the filler metal and the right welding parameters. If the excess values are too high, rework or adjustment is required.