Etching

From GAWDAwiki

Etching is when a weld specimen is cut through a weld and an acid or similar solution can be applied to the weld area to bring out the features of the weld. These include the deposited weld metal, heat affected zone, penetration and weld profile. Many different etching solutions and techniques exist for the various kinds of metals.^[1]

References

1. http://www.millerwelds.com/interests/instructors/pdf/Glossary.pdf