Hi
porosity is the gas pores (or) gas pocket travel deep in the solidified weld bead.
Major causes
$ Inadequate shielding gas
$ Poor welding technique
$ Damaged welding accessories
$ Natural effects like wind flow
Porosity is the formation of bubbles in the weld.
Porosity is caused by molten puddle problems: oil, dirt, etc near weld, lack of shielding gas (tank is empty, or wind is blowing away gas. local vaccums for ventilation also can cause gas problems.) If mig welding, if you don't balance wire speed to amps, you may see porosity. Lastly, long arc'ing (too much distance from end of mig wire, to material) can cause bubbling.
what must be done to prevent this from happening
Weld porosity is gas formations that did not escape prior to the weld solidification. These gases can be formed from water (which breaks down to hydrogen and oxygen atoms), oil, paint, rust or many other contaminants. The welding contamination can be on your welding materials as well as on the base metal (damp welding electrodes, etc.).
Porosity in stainless steel welds is primarily caused by the entrapment of gas bubbles during the solidification of the weld metal. This can occur due to contamination from moisture, oils, or other impurities on the base material or filler metal. Additionally, improper welding parameters, such as excessive heat or inadequate shielding gas coverage, can contribute to porosity. Ensuring clean surfaces and optimal welding conditions can help minimize this defect.
Porosity is the formation of bubbles in the weld.
Porosity is nothing more than bubbles in the weld. Surprisingly a weld can contain quite a bit of porosity without affecting the strength.
Porosity is caused by molten puddle problems: oil, dirt, etc near weld, lack of shielding gas (tank is empty, or wind is blowing away gas. local vaccums for ventilation also can cause gas problems.) If mig welding, if you don't balance wire speed to amps, you may see porosity. Lastly, long arc'ing (too much distance from end of mig wire, to material) can cause bubbling.
High wind velocity can potentially cause porosity in welds by introducing contaminants, such as oxygen and moisture, to the welding area. These contaminants can react with the molten metal and create gas pockets or porosity in the weld bead. It is important to shield the welding area from strong winds or drafts to prevent porosity.
what must be done to prevent this from happening
Weld porosity is gas formations that did not escape prior to the weld solidification. These gases can be formed from water (which breaks down to hydrogen and oxygen atoms), oil, paint, rust or many other contaminants. The welding contamination can be on your welding materials as well as on the base metal (damp welding electrodes, etc.).
Porosity in stainless steel welds is primarily caused by the entrapment of gas bubbles during the solidification of the weld metal. This can occur due to contamination from moisture, oils, or other impurities on the base material or filler metal. Additionally, improper welding parameters, such as excessive heat or inadequate shielding gas coverage, can contribute to porosity. Ensuring clean surfaces and optimal welding conditions can help minimize this defect.
Porosity in welding is a result of dissolved gases or gases released during the welding process, being trapped in the metal when there is insufficient time to escape prior to solidification. If in the shape of rounded holes, the gas is called spherical porosity or just porosity. However, if elongated the terminology is wormholes or piping. Causes of porosity are;excessively long or short arc lengthwelding current too highinsufficient or moist shielding gastravel speed to fastbase metal covered with oil, grease, moisture etc.wet, unclean or damaged electrodes.
Electrodes with too much moisture may lead to cracking or porosity.
Check the shielding gas & its flow rate.
Sub arc welding is a process in which the welding actually occurs while submerged under a layer of flux. Not only does this prevent oxygen from entering the weld and thus porosity, but it also keeps the dangerous arc from sputtering and spattering from the weld.
J. Littleton has written: 'Gas-metal reactions and porosity in the inert gas arc welding of copper'