Anti-Pore Agent
Pore prevention agents are additives in the weld metal that bind gases in the melt or reduce their solubility. This prevents bubble formation in the solidified structure and increases strength.
Physical-Chemical Mechanism of Action
Porosity-preventing agents react with gases like oxygen or nitrogen in the molten pool. They chemically bind these gases and prevent them from forming bubbles in the solidified metal.
Metallurgical Relevance & Welding Risks
Without porosity-preventing agents, gas bubbles can form in the melt and remain as pores in the structure upon cooling. This leads to reduced strength, increased stress concentration, and possible cracking. However, too high a content of porosity-preventing agents can over-alloy the weld pool and make the weld uneven.
Workshop Practice & Instructions
Use porosity-preventing agents in the right amount, depending on the metal type and welding process. For steel with a high oxygen content (e.g., HSS), a content of 0.1 to 0.2 % of silicon or titanium is normal. Pay attention to proper volatilization and the right time of addition to the melt. If the dosage is too high, the metal can become over-alloyed and the weld uneven.