Surface pore
Surface porosity is gas inclusions that reach the surface and can introduce corrosive media. They appear as craters or open blisters and are unacceptable in high assessment groups.
Physicochemical mechanism of action
Surface pores form due to the entrapment of gases like oxygen or hydrogen during the welding process. These gases get trapped in the molten pool or during cooling in the weld and cannot fully escape, so they remain as pores.
Metallurgical relevance & risks in welding
Surface pores are a serious problem in welding because they allow corrosive media like moisture and salt acids to enter. This leads to corrosion and reduced component life. Additionally, pores can be visually unappealing and affect aesthetic quality.
Workshop practice & instructions
To avoid surface pores, it is important to ensure a clean welding environment and a good deoxidation process. Use high-quality shielding gases like argon or helium to support gas escape during welding. Also pay attention to proper cooling steps to ensure a homogeneous grain structure and minimal pore formation.