Understanding NRT- Reading 1- 2 of 2- Radiogaphic Testing A
Understanding nrt reading 1- 2 of 2- radiogaphic testing a
Understanding nrt reading 1- 2 of 2- radiogaphic testing a
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Radiographic Indications for Casting Repair Welds<br />
Most common alloy castings require welding either in upgrading from<br />
defective conditions or in joining to other system parts. It is mainly for reasons<br />
<strong>of</strong> casting repair that these descriptions <strong>of</strong> the more common weld defects are<br />
provided here. The terms appear as indication types in ASTM E390. For<br />
additional information, see the Nondestructive <strong>Testing</strong> Handbook, Volume 3,<br />
Section 9 on the "Radiographic Control <strong>of</strong> Welds."<br />
Slag is nonmetallic solid material entrapped in weld metal or between weld<br />
material and base metal. Radiographically, slag may appear in various<br />
shapes, from long narrow indications to short wide indications, and in various<br />
densities, from gray to very dark.<br />
Porosity is a series <strong>of</strong> rounded gas pockets or voids in the weld metal, and is<br />
generally cylindrical or elliptical in shape.<br />
Undercut is a groove melted in the base metal at the edge <strong>of</strong> a weld and left<br />
unfilled by weld metal. It represents a stress concentration that <strong>of</strong>ten must be<br />
corrected, and appears as a dark indication at the toe <strong>of</strong> a weld.<br />
Charlie Chong/ Fion Zhang
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