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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6.3.7 Pipeline Coatings<br />
Epoxy powders are specially formulated to enhance corrosion<br />
proof resistance of utility pipe: that is, pipe usually buried<br />
underground, where it is subject to widely varying<br />
pipeline operating conditions. Intimately bonded to the<br />
pipe, the bonded epoxy is unaffected by widely varying soil<br />
compaction, moisture penetration, fungus attack, soil acids<br />
and chemical degradation. To achieve a long lasting bond of epoxy coating to<br />
metal pipe, the pipe must be preheated very carefully to the recommended<br />
preheat of 230 °C (450 °F). A spot on the pipe needs to be touched with the<br />
stick; its melting shows that the correct temperature for coating has been<br />
reached.<br />
Charlie Chong/ Fion Zhang