Visual examination of Welds (VT)



Visual examination is the most extensively used NDE method for welds.
It includes either direct or indirect observation of the exposed surface of the weld and base metal.

Direct visual examination is conducted when access is sufficient to place the eye within 6” to 24” (150mm to 600mm) of the surface to be examined and at an angle not less than 30 degrees to the surface. Mirrors may be used to improve the angle of vision.
Personnel are required to demonstrate annually completion of a J-1 Jaeger-Type eye vision test.

Written procedure is required for VT.

Optical Aids: Lighting: The inspection surface is of extreme importance. Adequate illumination level shall be established in order to ensure and effective visual examination. Lighting levels of 100 foot-candles (1000 Lux) at the examination surface. Inspector must measure the lighting conditions with light meters.

Mirrors- Valuable to the inspector allowing them to look inside piping threaded and bored holes, inside castings and around corners.
Mechanical Aids: Steel ruler, Vernier scale, Combination square sets, Thickness gauge etc.

Welding examination devices:

Inspector’s kit

Bridge gauge – to measure weld preparation angle prior to welding, to measure excess reinforcement, depth of undercut etc


Fillet weld gauge offers quick and precise means of more commonly used fillet weld sizes. Types of fillet weld gauge include: adjustable fillet weld gauge, skew- T fillet gauge etc.

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