Emulsifier
An emulsifier mixes water-insoluble penetrants with water so that they can be washed off as a liquid. This prevents excess medium and improves cleanliness.
Physical-chemical mechanism of action
An emulsifier forms a stable mixture of water-soluble and water-insoluble parts by splitting the surface of the penetrant into water. This prevents the penetrant from clumping together into large lumps and makes it easier to wash off.
Metallurgical relevance & risks in welding
A missing or incorrect emulsifier can lead to the formation of pores and cracks, as the penetrant is not properly removed. This impairs the strength and toughness of the weld.
Workshop practice & instructions for use
Use the emulsifier in the prescribed dose, usually 1-2% of the penetrant content. Mix it well with water and let the liquid sit for at least 5 minutes before applying it to the material to be welded. Make sure all excess emulsifier residues are washed off after welding.