Visual testing (VT)

Visual testing is one of methods of non-destructive testing of optical type. It is based on obtaining information about the tested material with the help of visual observation or of optical and measuring instruments. Visual testing method allows detecting discontinuities, deviations of the size and shape from the specified ones for more than 0.1 mm when using instruments with magnification up to 10x.

Visual testing is usually performed with the naked eye or with magnifying glasses (magnifiers) with magnification up to 7x. In doubtful cases and in course of technical diagnostics magnifiers can be used with magnification up to 20x. Before performing visual testing surface of the material in the control area should be cleaned of rust, scale, dirt, paint, oil, metal spray and other impurities that prevent inspection.