The MT systems used for in-service inspection of pressure vessels employ an electric current to magnetize the area of the vessel shell being examined. Either…
A bar of ferromagnetic material can be magnetized by placing it in contact with the north and south poles of a horseshoe magnet, as depicted…
MT can be used to detect surface and near surface flaws in ferromagnetic materials. MT cannot be used for austenitic stainless steel pressure vessels, because…
PT can be used to detect cracks that have occurred due to stress-corrosion (environmental) cracking, creep, mechanical or thermal fatigue, and hydrogen attack. However, it…
The developer should be applied to the surface of the workpiece immediately after the excess liquid penetrant is removed from the surface. The developers used…
The liquid used for a dye-penetrant must both wet the surface of the workpiece and have a high surface tension to cause a sufficient quantity…
Surface preparation is very important. The surface must be both clean and dry to enable the liquid penetrant to wet the surface completely, and to…
The dye-penetrant examination system that is the most useful is referred to as the solvent-removable system. This system employs an oil-base penetrant that is removed…
Figure 700-6 illustrates the physical principles of PT. A liquid (referred to as a penetrant) is applied to the surface of the part being examined,…
PT is used to detect flaws that are open to the surface of a workpiece. It is a relatively simple NDE procedure that requires a…