This standard specifies the instructive method for penetrant inspection of steel forgings. This standard applies to liquid penetrant testing of materials. It can be effectively used for process inspection, final inspection and maintenance inspection of workpieces made of non-porous metals (including ferrous and non-ferrous metals), ceramics, plastics, glass and other materials. This method can be used to display open surface defects such as cracks, seams, heavy skin, delamination, penetration leakage and incomplete welding.