MMET 402 Exam 1

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Which type of penetrant is most sensitive?
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Which type of penetrant is a fluorescent penetrant?Type IWhat is an advantage of visible dye penetrants over fluorescent penetrants?Visible dye penetrants do not require ultraviolet lightWhich of the following discontinuities would be impossible to detect using a liquid penetrant test?Nonmetallic internal inclusionsWhich of the following physical properties, more than any other, determines what makes a material a good penetrant?No one single property determines if a material will or will not be a good penetrantPT can be used to test most materials provided the surface of the part is:Is not extremally rough or porousThe total time the penetrant is in contact with the part surface is called the:Penetrant dwell timeAll of the following parts can be tested by the liquid penetrant method except:A sintered brass component A part made from porous plastic materialThe speed with which a penetrant penetrants a surface flaw is influenced to the greatest extent by which of the following properties?Capillary actionWhen using a postemfulsifiable penetrant, the fluor time should be:Only as long as necessary to remove the interfering backgroundThe ability to locate a small discontinuity is called:SensitivityBefore conducting a liquid penetrant test, it is important to ensure that the surface of the part is free of:Oil or grease, acids or chemicals, and traces of waterWhich penetrant method is easiest to use in the field?Visible dye solvent removableThe type of emulsifier which acts as a detergent to make the penetrant water washable is called ________.Hydrophilic emulsifierFilter for ultraviolet lights effectively remove:Visible light from the energy given off by the mercury arcMagnetic particle testing is a nondestructive testing method for detecting discontinuities in magnetized materials. This method can detect:Surface and near surface discontinuitiesA hysteresis hoop shows the relationship between the:Induced magnetic flux density in the test object and the magnetizing forceFor detecting subsurface (not too close to the surface) defects using head shot, which current type should be used:DC CurrentWhen using direct current an indication is detected. What is the next logical step to determine if the indication results from a surface or subsurface condition:Reinspect using alternate currentWhat kind of material will have their magnetic property characterized by a hysteresis loop?Ferromagnetic materialsA property of material that describes that ease with which a magnetic flux is established in a component is called:PermeabilityMagnetic particle inspection has several advantages over liquid penetrant inspections which includes:Components with thin coating can be inspected without removing the coating. Components can be inspected more rapidly.Inspecting a part by magnetizing, removing the current flow, then applying the medium is called the:Residual methodWhen all things are equal (some magnetizing field strength, same type of magnetic particles, etc), the following MT methods has a better sensitivity?Continuous methodMagnetic particle inspection can be performed on parts made from which material?Iron/steel, nickel, or cobaltWhen an external magnetizing force is removed, some of the magnetic domains remain preferentially oriented. The additional force required to return them to their original random orientation is commonly referred to as:Coercive forceWhen is the magnetic field strongest in an object being inspected by the magnetic particle method?While the magnetizing current is appliedThe only type of material that can be tested by magnetic particle testing is:FerromagneticWhich type has the so called "skin effect" that dictates the penetration of current and its associated magnetic field?AC CurrentThe best detection of defects occurs:When the lines of magnetic force are perpendicular to the longest dimension of the defectWhen an magnetic field cuts across a crack:Magnetic poles form at the edges of the crackWhen testing parts with magnetic particles, it is best to magnetize the part:In two directions at right angles to each otherWhen the magnetizing current is stopped, a ferromagnetic material will:Retain a residual magnetic field within the componentWhen using the direct induction (also called current flow) method:Good electrical contact must be established between the test equipment and test componentThe settling test of magnetic particles suspension is used to check the...Concentration and degrading of the particlesA simple method of demagnetizing of small test objects is by:Passing them through an alternating current coilMagnetic particles should have the:Highest possible permeability and lowest possible retentivelyMagnetic particles are available in different colors:For color contras with part surface thereby enhancing detection of indicationsThe unit usually used to denote flux density (or field strength) is:GaussBelow the saturation, the magnitude of the residual magnetic field in a specimen is dependent on:The strength of the applied magnetizing forceThe strongest magnetic field in a coil is at the:Inside edgeThe area of maximum induced field strength using a yoke is:The area directly between the polesThe main sensing element of an eddy current probe is a _____.Winding coilWhat type of discontinuities is the target for ET inspection?Surface (including near surface)For ET inspection, the test objects have to be:Electric conductorsFor ET inspection, increasing the probe frequency will result in:Decreasing the depth of penetration of the eddy currentWhat type of current is used to operate the ET probe to induce the eddy currents in the test object?High frequency AC (1 kHz - 1 MHz)The skin depth or the standard depth of penetration of the eddy current induced in a test object is the depth which its density has decreased to ______ of its maximum value which occurs at the surface of the test object.1/eThe effective depth of penetration of the eddy current is the depth at which the eddy current density (word that starts with "d") of surface density and reaches the limit of its flaw detectability.5%The effective range of an eddy current inspection is equal to _______ times the skin depth.3Which of the following tasks can ET not do?a. Metal sorting b. Crack detection c. Corrosion detection d. Measurement of electric conductivity ->e. None of the above<-For a given test workpiece, to increase the depth of penetration of the eddy current for deeper flaws we have to ___________Reduce the frequency of the probeFor a given ET probe and instrument, which material has the shallowest depth that can be inspected?SteelEddy current is induced by a coil which produces a varying magnetic field. This induction of eddy current is a physical phenomenon describes by ________.Faraday's lawWhich parameter plays no roles in ET inspections?Test piece's modulus of elasticityToday's mainstream ET flaw detectors, like the one we used in our lab, detect flaws by monitoring the change in ___________ of the ET system.ImpedanceA test block made with the same material and dimensions as the workpiece to be inspected and embedded artificial defect(s) is referred to as a:Reference standardAssuming that a shop, stationary magnetizing equipment is used (i.e., this part will not be inspected by a yoke or probe), describe the two methods that you would use in combination to detect all the cracks in the part shown in the figure. Assuming flaw C is 45° incline to the horizon. Crack E is on the ID surface of a through hole and oriented along the long axis of the part. Crack B is on the flange surface and oriented along the radial direction.Method 1: Direct Headshot for B&E Method 2: Coil for A, C, & D