ASNT Level III- Visual & Optical Testing
My Level III Self Study Notes Reading 4 Section 4B
My Level III Self Study Notes Reading 4 Section 4B
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7.3 Etching<br />
7.3.1 Choice of Etchant<br />
The etchant, its strength, the material and the discontinuity<br />
all combine to determine surface finish requirements (see<br />
Table 15). Properly selected etchants chemically attack the<br />
test material and reveal welds (Fig. 70), pitting (Fig 71),<br />
grain boundaries, segregation, laps, seams, cracks aria heat<br />
affected zones. The indications are highlighted or contrasted<br />
with the surrounding base material.<br />
Charlie Chong/ Fion Zhang