CWB Level 2 Exam Questions with Correct Answers

CWB Level 2 Exam Questions with Correct Answers What are the 5 main categories for LP indications - Answer-1. Continuous Line 2. Intermittent Line 3. Rounded 4. Small Dots 5. Diffused or weak surface tension - Answer-property of a liquid that tends to reduce the area of the surface contact angle - Answer-the angle that the base of a drop of water makes with the surface it is on If a Liquid has good wetting it has a Contact Angle - Answer-Small Contact Angle capillary action - Answer-tendency of water to rise in a thin tube How are LP Procedures/Techniques Qualified - Answer-Comparator Block False Indications - Answer-Indications not associated with a discontinuity of any kind Nonrelevent Indications - Answer-Indications cause by features or design of material What Standard are CGSB inspectors certified to? - Answer-CAN/CGSB 48.9712 MP can not be used on what types of materials? - Answer-1. Non Ferrous 2. Austenitic Stainless 3. Copper 4. Aluminum flux leakage field - Answer-a path created between 2 new polls as a result of an indication Lines of force must run to the crack, for the crack to appear. - Answer- perpendicular induced magnetism - Answer-the influence of a external magnetic field on a piece of iron, which makes the iron a temporary magnet Flux density - Answer-A measure of the density of the field lines around a magnet Permeability - Answer-the ability for a material to hold its magnetism. Magnetic saturation - Answer-When the flux reaches a maximum and the material can no longer be further magnetized. Magnetic Retentivity - Answer-the ability of a material to stay magnetized How do inspectors remove a materials retained flux? - Answer-apply field in opposite direction Coercive Force - Answer-the strength of the reverse field necessary to bring the induced flux to zero. what range should the applied filed be applied to avoid saturation of a material? - Answer-30 to 70% electric current produces what kind of magnetic field? - Answer-circular the lines of force are the strength of the applied current? a. proportional b. 2x bigger c. 2x smaller - Answer-a. proportional Adding a coil does what to the magnetic field? - Answer-increase. it adds to the strength of the others Ampere-turns - Answer-the relative strength of a field from a coil 2 types of magnetization in MP inspection? - Answer-1. longitudinal, and circular. 2 methods of MP inspection? - Answer-1. direct magnetization - current passes through the part 2. indirect magnetization - either a permanent or electromagnet is placed directly on the part or the part is placed in and electromagnet. how are arc strikes avoided when using Prods for MP inspection? - Answer-current is not applied until both prods are on the part. current applied during MT inspection using prods is calculated by amps for every mm - Answer-4 amps per mm or 100 amps per inch (90 to 125 amps for each 25 mm or 1 in) typical amp output from a yoke is? - Answer-5 to 10 amps during MT inspection an AC will magnetize the of the part. - Answer-surface (skin effect) Direct current applied during MT Inspection has the ability to penetrate how far into the material? - Answer-2- 3 mm During MT inspection which methods is more sensitive? a. wet b. dry - Answer-a. wet variations in permeability can arise from? - Answer-1. composition 2. micro structure 3. hardness 4. heat treatment 5. work hardening how may a part be demagnetized? - Answer-by reversing and reducing the magnetic field