Porosity

Physico-chemical mechanism of action

Pores form when gas bubbles in the molten pool or weld metal cannot escape in time. This can be caused by too high a temperature or too slow cooling.

Metallurgical relevance & risks in welding

Porosity reduces the tightness and mechanical integrity of the weld, which can lead to cracking, wear, and reduced strength. It can also lead to water channels and corrosion.

Workshop practice & instructions

To avoid porosity, the molten pool must be well shielded to minimize gas bubbles. Cooling should be controlled and not too fast. For highly porous materials, post-weld heat treatment can help.