Manganese Deoxidation Effect
Manganese reduces oxygen in the weld pool and forms manganese silicates that float out, suppressing carbon monoxide bubbles.
Physical-chemical mechanism of action
Manganese reacts with oxygen in the molten steel bath and forms manganese silicates. These compounds settle well, meaning they easily separate during solidification and don't get trapped as pores in the weld.
Metallurgical relevance & risks when welding
The manganese deoxidation effect prevents the formation of carbon monoxide bubbles, which can cause porosity and weak spots. Too little manganese can leave oxygen in the melt and cause pores. Too much manganese can coarsen the grain structure and hurt the steel's toughness.
Workshop practice & instructions
Add 0.1 to 0.3 % manganese in the molten pool. Watch the temperature and oxygen content closely. If manganese is too low, increase it slowly; if too high, reduce it. Make sure the melt settles well to get a homogeneous manganese distribution.