Visual inspection
Visual inspection is the oldiest and more easy of non-destructive inspection, which is used for survey of defects on surface of checked parts.
We survey possible presence of defects as inadmisible unevenesses, weld deviations – size, spatters, cracks, cold welds in the are of weld root.
Visual inspection is used for verification of condition for next MDT inspections.
The principle of operation method
Inspector could evaluate all above mentioned with sufficient lighting. The main inspector tools are good lighting, eyes and brain.
We split visual method on direct and indirect according to accessibility and on the way of observation. Direct visual inspection is done by eye, sometimes we use simple optical tools as 3x6x magnifying loupe. During indirect visual inspection we use more complicated optical tools as solid or flexible endoscope etc.
Requirements on visual inspection should be all time during production – during weld preparation, welding and on finished weld.
Testing and resulting
Conclusion and results of this inspection are very important and should precede to all other exams. Experienced NDT worker is able to assess quality of welder’s work acc. to individual layer of weld and is able to provide good conclusions about possible internal defects (for example weld surface is irregular, clearly visible connection of welds, different weld widht, very dissimilar weld surface in different position etc).
During visual inspection we work according to rule ČSN EN ISO 17637 (Nondestructive testing – Visual inspection of tusible welds) and rating ussualy acc. to ČSN EN ISO 5817 (Welding – welds of steel, nickel, titanium and their alloys – determination of quality grades).
