ASNT Level II Study Guide: Magnetic Particle Testing (MT), 2nd ed.

Description ASNT study guides provide prospective ASNT Level III examinees with enough technical knowledge to pass an ASNT NDT Level III examination. Intended to be used with a comprehensive NDT text, such as volumes from the Nondestructive Testing Handbook series. This magnetic particle testing (MT) book was updated in 2013 to align with the new ASNT Standard Topical Outlines for Qualification of Nondestructive Testing Personnel (ANSIASNT CP1052011). Several sections have been expanded including the sections on UV light, indications, surface discontinuities, welding discontinuities, subsurface discontinuities and interpretations, and on UV light hazards. Many new chapter review questions were added. Details Resource Type: ASNT Level III Study Guides, StudyTraining Material Method: Magnetic Particle Testing Year: 2013 ISBN: 9781571172471 Pages: 122 Digital Product Code: 2253e Print Product Code: 2253 Table of Contents Cover ASNT Level III Study Guide Magnetic Particle Testing i Copyright Information iii Foreword iv Acknowledgements v References vi Table of Contents viii Chapter 1 Introduction to Magnetic Particle Testing 1 History 1 Chapter 2 Materials and the Theory of Magnetism 3 Introduction 3 Material Characteristics 3 Magnetic Field Characteristics 4 Magnetic Hysteresis Curve —Induction by Coil 5 Magnetic Flux and Flux Density 7 Magnetization of Ferromagnetic Material 8 Review Questions 10 Chapter 3 Currents Used in the Magnetic Particle Testing Inspection Process 13 Magnetizing Current 13 Magnetization 14 Review Questions 17 Chapter 4 Field Strength and Distribution 19 Magnetization 19 Review Questions 30 Chapter 5 Magnetic Field Direction and Intensity 35 Direction and Intensity 35 External Magnetic Field Measurement 35 Review Questions 38 Chapter 6 Magnetic Particle Testing Equipment 39 Introduction 39 HeavyDuty Equipment 41 Light 42 Review Questions 45 Chapter 7 Magnetic Particle Testing Materials 47 Inspection Materials 47 Characteristics and Control of Magnetic Particles 47 Characteristics and Control of Petroleum Suspensions 49 Characteristics and Control of Water Suspensions 49 Characteristics and Control of Rubber Suspensions 50 Review Questions 51 Chapter 8 Magnetic Particle Testing Practices 53 Magnetic Particle Test Fundamentals 53 Choice of Equipment and Application 57 Effects of Test Object Variables 59 Review Questions 60 Chapter 9 Indications and Interpretations 65 Overview 65 Discontinuities 66 Review Questions 70 Chapter 10 Probability of Detection 75 Detectability versus Probability of Detection 75 Probability of Detection 75 Review Questions 77 Chapter 11 Process and Equipment Controls 79 Control and Verification of Equipment Functions 79 Suspension Control Test 80 Light Intensity and Integrity 81 Review Questions 82 Chapter 12 Specifications, Procedures, Techniques and Standards 85 Introduction 85 Other Types of Controlling Documents 87 Review Questions 88 Chapter 13 Safety 91 Introduction 91 APPENDIX 1 Test Procedure Example 93 APPENDIX 2 Magnetization Chart 96 APPENDIX 3 Materials Properties 97 APPENDIX 4 Discontinuities Found Using Magnetic Particle Testing 98 APPENDIX 5 Glossary 99 APPENDIX 6 Figure Sources

Second Edition MT LECTURE GUIDE Written for ASNT by: Duane Badger NDT Assistance for Nondestructive Testing Copyright © 2015 by The American Society for Nondestructive Testing Inc The American Society for Nondestructive Testing Inc (ASNT) is not responsible for the authenticity or accuracy of information herein Published opinions and statements not necessarily reflect the opinion of ASNT Products or services that are advertised or mentioned not carry the endorsement or recommendation of ASNT No part of this publication may be reproduced or transmitted in any form, by means electronic or mechanical including photocopying, recording or otherwise, without the expressed prior written permission of The American Society for Nondestructive Testing Inc IRRSP, NDT Handbook, The NDT Technician, and asnt.org are trademarks of The American Society for Nondestructive Testing Inc ACCP, ASNT, ASNT Daily, Chat NDT with ASNT, Level Ill Study Guide, Materials Evaluation, Nondestructive Testing Handbook, Research in Nondestructive Evaluation, and RNDE are registered trademarks of The American Society for Nondestructive Testing Inc Second Edition first printing 02/15 second printing 06/18 third printing 04/22 Errata, if available for this printing, may be obtained from ASNT's website, asnt.org Ebooks contain all corrections and updates, including the latest errata ISBN: 978-1-57117-350-8 Printed in the United States of America Published by: The American Society for Nondestructive Testing Inc 1711 Arlingate Lane Columbus, OH 43228-0518 asnt.org Edited by: Bob Conklin, Educational Materials Editor Assisted by: Cynthia M Leeman, Educational Materials Supervisor Tim Jones, Senior Manager of Publications ASNT Mission Statement: ASNT exists to create a safer world by advancing scientific, engineering, and technical knowledge in the field of nondestructive testing ASNT Code of Ethics: The ASNT Code of Ethics was developed to provide members of the Society with broad ethical statements to guide their professional lives In spirit and in word, each ASNT member is responsible for knowing and adhering to the values and standards set forth in the Society's Code More information, as well as the complete version of the Code of Ethics, can be found on ASNT's website, asnt.org Lecture Quide | Introduction to the Magnetic Particle Testing Lecture Guide The materials in this training package are designed to provide basic knowledge of the fundamentals of magnetic particle testing The training program that you are teaching will contain the following classroom hours of instruction to present the information suggested in the ASNT publication Recommended Practice No SNT-TC-1A: Personnel and Qualification in Nondestructive Testing Level I training will include lectures on chapters through in the Magnetic Particle Classroom Training Book, with an average of approximately 1-2 hours per lesson Level II training will include lectures on all 15 chapters with an average of approximately 1-2 hours per lesson, with emphasis on chapters through 15 If the training program is aimed at meeting the guidelines for Level I, the instructor can follow the lecture guide closely with very little elaboration or explanation If Level II guidelines are to be met, the instructor should encourage additional outside reading and classroom discussions and should present personal information to elaborate on the lecture guideline Each program can be easily expanded based on the instructor's experience and expertise The material in this course is formatted for use in a typical classroom training setting with an ideal class size of to 25 students The instructor will lecture on all lessons with the aid of the PowerPoint’ lecture presentation Il Contents of Training Package The instructor should be familiar with all materials before attempting to teach the course This course is designed to provide a maximum amount of learning with a minimum amount of preparation by the instructor The following breakdown of the materials and their functions should be carefully studied 1, Student Guide Each package will contain the following: A Student Guide that will describe the course and provide a lesson outline B Magnetic Particle Testing Classroom Training Book that will serve as the major text for the training course Magnetic Particle Testing Lecture Guide | FOREWORD TO LECTURE GUIDE A printed copy of the PowerPoint’ lecture, which includes 15 lessons of lecture material (one lesson corresponding with each chapter in the Classroom Training Book), providing an outline of the fundamentals of magnetic particle instruction Note: Contents of the printed lecture may differ from the content of the PowerPoint’ slides D Quizzes — A quiz will be furnished for each lesson Lecture Guide Each package will contain the following: A Lecture Guide introduction that will provide instructions in preparing for and administering this course B Magnetic Particle Testing Classroom Training Book that will be used by the instructor as the main source text C An online registration code to download the electronic PowerPoint” lectures of Level I and Level II magnetic particle testing through asnttutorials.org PowerPoint” capabilities are necessary to run the lecture The presentation includes 15 lessons, as well as additional lecture notes that help explain the content of each slide These notes are found at the bottom of each slide and cannot be viewed by the students The PowerPoint* presentation will be used by the instructor as a basis for the lectures (See Part III of this guide.) Suggested Use of the Electronic Lecture Guide The downloadable zip file containing the PowerPoint” lecture can be used on any computer with PowerPoint’ support and an overhead projector connected to the computer The PowerPoint* presentation is intended to serve as a memory jogger for the instructor and should not be used as a strict outline or script A The instructor should ensure clear understanding by the students of each PowerPoint’ slide before continuing to the next B The instructor should elaborate and relate personal information whenever it is pertinent C Prior to the lecture, the instructor may wish to record some additional information on the instructor's print copy of the PowerPoint* presentation D Students should be encouraged to follow along in their copy of the Student Guide and write additional information when it is given Discussions and questions should be encouraged as the instructor proceeds through the PowerPoint” presentations IV Use of the Magnetic Particle Testing Classroom Training Book dự The Magnetic Particle Testing Classroom Training Book is the major source of information for this training course, Reading assignments should be given to the students to correlate with the instructor's lecture The Magnetic Particle Testing Classroom Training Book follows the lessons in this training course in the following order: Chapter 1: Principles of Magnetic Particle Testing Chapter 2: Effects of Discontinuities on Materials Chapter 3: Magnetization Chapter 4: Principles of Demagnetization Chapter 5: Equipment Chapter 6: Discontinuities Chapter 7: Magnetic Principles Chapter 8: Flux Fields Chapter 9: Magnetic Particles and Methods of Application Chapter 10: Magnetization by Means of Electric Current Chapter 11: Advanced Principles of Demagnetization Chapter 12: Magnetic Particle Testing Equipment Chapter 13: Types of Discontinuities Chapter 14: Evaluation Techniques Chapter 15: Quality Control V Suggested Use of Quizzes and Quiz Keys The instructor may decide to remove the lesson quizzes from the Student Guide before the student is issued the package of training materials Quizzes can be given at the end of each lecture and then reviewed and discussed before moving to the next lecture This will give time for discussion and to ensure student comprehension of material before moving to the next chapter The quiz questions in this package are not intended for use in total certification of nondestructive testing personnel They are simply teaching tools to aid the instructor in presenting the material If examination for certification is needed, it is suggested that the instructor obtain a copy of SNT-TC-1A, CP-105, or ANSI/ASNT CP-189 as applicable and follow those requirements If the instructor so chooses, the quiz results could be used to arrive at a percentage score that could be recorded on the student's certificate of completion along with the number of course hours and/or continuing education unit credits Magnetic Particle Testing Lecture Guide | FOREWORD TO LECTURE GUIDE VI Demonstration and/or Lab Exercises It is highly recommended that the instructor make every effort to provide the student with some practical experience in magnetic particle testing The depth of practical exercises will depend on time, equipment, and facilities available to the instructor The instructor should use whatever resources are available to collect sample parts that will represent a variety of discontinuities If time, equipment, and facilities are available, each student should be given as much hands-on experience as possible Where practical, a variety of lab stations should be set up, each with a different magnetic particle testing process The student should then be rotated through each station with as many resource people as possible and/or available to help answer specific questions Where the instructor finds that all students are from a specific type of industry (for example, aircraft, foundry, or welding), the demonstrations and lab work should be designed accordingly VII Continuing Education Units (CEUs) ASNT recommends that the instructor consider offering CEUs to participants using this nondestructive training program A form must be filled out requesting CEU credit each time this course is given, and must include specific details regarding performance evaluation and contact hours One CEU is given for every 10 contact hours of participation in an approved nondestructive testing training program Please contact ASNT at (614) 274-6003 or (800) 222-2768 for additional information regarding CEUs VIII Note about the MT Student Guide What immediately follows is the MT Student Guide This is the material that is available to the student However, the Student Guide does not contain the Quiz Keys that are found at the end of this publication Nor does the Student Guide contain the PowerPoint’ presentation on the USB flash drive MT STUDENT GUIDE Written for ASNT by: Duane Badger NDT Assistance The American Society for Nondestructive Testing Student Guide | Introduction to the Magnetic Particle Testing Student Guide The materials in this training package are designed to provide basic knowledge of the fundamentals of magnetic particle testing The training program that you are participating in will contain the following classroom hours of instruction to learn the information suggested in the ASNT publication Recommended Practice No SNT-TC-1A: Personnel and Qualification in Nondestructive Testing Level I training will include lectures on chapters through in the Magnetic Particle Classroom Training Book, with an average of approximately 1-2 hours per lesson Level II training will include lectures on all 15 chapters with an average of approximately 1-2 hours per lesson, with emphasis on chapters through 15 The student shall assume the responsibility for reading all assignments to include the Magnetic Particle Testing Classroom Training Book, as well as additional reference materials associated with the Student Guide, attending all lectures, and participating in classroom discussions Short exams will be administered after each lesson to provide students with an indicator of their progress and to stimulate study Il Contents of Training Package Your training package contains the following materials with specific instructions and assignments to be given by the course instructor 1, Student Guide A Student Guide Introduction that outlines the purpose, content, and use of the training material B Magnetic Particle Testing Classroom Training Book that will serve as the major text for the training course C A printed copy of the PowerPoint’ lecture, which includes 15 lessons of lecture material (one lesson corresponding with each chapter in the Classroom Training Book), providing an outline of the fundamentals of the magnetic particle instruction During the lecture, the student should use the Student Guide to make additional notes, and it will also be valuable to study at a later date Note: Contents of the printed lecture may differ from the content of the PowerPoint’ slides D Quizzes The instructor may elect to remove the quizzes from your packet prior to starting the course and administer them as each lesson is completed A quiz will be furnished for each of the lessons in the training course vii Magnetic Particle Testing Lecture Guide | FOREWORD TO STUDENT GUIDE Outline of Lessons and Related Reading Assignments The reading assignments will be made by the instructor and will correlate with the lectures, The Magnetic Particle Testing Classroom Training Book published by ASNT follows the lessons/lectures in the training course in the following order: Chapter 1: Principles of Magnetic Particle Testing Chapter 2: Effects of Discontinuities on Materials Chapter 3: Magnetization Chapter 4: Principles of Demagnetization Chapter 5: Equipment Chapter 6: Discontinuities Chapter 7: Magnetic Principles Chapter 8: Flux Fields Chapter 9: Magnetic Particles and Methods of Application: Chapter 10: Magnetization by Means of Electric Current Chapter 11: Advanced Principles of Demagnetization Chapter 12: Magnetic Particle Testing Equipment Chapter 13: Types of Discontinuities Chapter 14: Evaluation Techniques Chapter 15: Quality Control Ill Optional Reference Material The following materials are available from ASNT and are suggested where the student wants additional depth in the magnetic particle testing method Nondestructive Testing Handbook, third edition: Volume 6, Magnetic Particle Testing ASNT Level II Study Guide: Magnetic Particle Testing Method, latest edition ASNT Level III Study Guide: Magnetic Particle Testing Method, latest edition 4, ASNT Questions & Answers Book: Magnetic Particle Testing Method, latest edition viii Magnetic Particle Testing Lecture Guide | QUIZ KEYS Half-wave current has sensitivity aoe for detecting subsurface discontinuities than alternating current 10 One disadvantage of direct current in magnetic particle testing is: less equal unique a it must be purchased directly from the electric company and is costly b it provides the greatest sensitivity for detecting subsurface discontinuities greater c the current does not reverse so it cannot easily be used for demagnetizing Three-phase full-wave current has the advantage of: a 10% lower energy costs compared to single phase b 50% lower energy costs compared to single phase c equivalent energy costs compared to single phase d no energy costs compared to single phase 128 d it requires a considerably higher skill level, compared to alternating current, and is difficult to work with Quiz Key a high permeability and low retentivity method, which is more sensitive than the method b low permeability and high retentivity c high permeability and high retentivity d low coercive force and high residual field oP Most specifications require the Magnetic particle formulations contain ao Magnetic particles should have: residual; continuous residual; discontinuous continuous; residual discontinuous; residual particles manufactured to specific sizes to decrease increase balance eliminate Bọ a FS dry powder wet powder fluorescent colors invisible wet powder , fluorescent magnetic particles are much easier to see because of the brightness against the dark backgrounds in the ultraviolet testing areas ae white light ultraviolet radiation infrared radiation thermal radiation Lower Unrectified half-wave Higher Milli- A central conductor will produce a circular field with danger of burning or ruining the test object ao Boge Magnetic particles are available in the following form(s) except: When viewed under amperage gives better sensitivity imminent maximal minimal significant During the wet continuous method, the current is normally only required to be on: a for 0.5 s after the solution is applied to the test object b fora maximum of 2s during the entire test ao FP mobility and sensitivity d before solution is applied to the test object, when it is immediately shut off 129 | QUIZ KEYS 10 13 (three to seven turns) around a test object FP may create may not detect ao cannot detect may enhance For maximum detection, a discontinuity should be to the magnetic lines 14, ca 15 ae quality indicator (QI) gage magnetic tape wire penetrameter pie gage A circular magnetic field is generated in a test object whenever current is through the test object or through a central conductor 16 Boge 10 000 A 1000 A 100 A 10A longitudinally circularly polarically ferritically When using a coil, the test object may be laid of the coil where the field is strongest in a test object a at the precise center b on the inner diameter c outside, approximately half the object diameter multiplied by L/D x d anywhere near the center passed impeded resisted imploded 17, 130 unwrapping wrapping Placing a test object inside a coil will magnetize the test object aoges se positioned similarly to the discontinuity typically encountered 12 welding Satisfactory amperage for circular direct no FS ao parallel angulated perpendicular oriented 45° Magnetic flux direction may be verified with a warping magnetization may be as high as per in (25.4 mm) of diameter of force 11 A longitudinal field is generated in a test object by placing it in a coil, or by cables Coil inductance is the ratio of the total: FP ao op The residual method may be useful during interpretation of indications but small discontinuities coil diameter and the current surface area and the current ao Magnetic Particle Testing Lecture Guide flux and the current flux and the voltage Quiz Key The magnetic lines of flux induced by current flow: A circular field induced by a current flow through a test object creates a magnetic field both in the test object and in the ơp surrounding the test object air technician mo positrons of the particles positrons of the antimagnetic particles Prods may be used to induce a magnetic field a longitudinal b circular c bipolar d diagramatic a anorth and south pole at each end b a north and south pole at random locations c anorth and south pole at opposite sides of the circumference d no external poles In order to induce a uniform longitudinal field in a coil, the test object must have a length-to-diameter ratio of at least: 15 The only type of material that can be tested by magnetic particle testing is: yoke FP coil A long, uniform, hollow test object magnetized with a central conductor will have: central conductor head shot ao aos ® An indirect method of inducing a circular magnetic field is with a: coil prod unit central conductor head shot ae c are in the same direction as the grain of the material d are at 90° to the current direction øp b vary with the type of current Bose are in the same direction as current flow mo a An indirect method of inducing a longitudinal magnetic field is with a: diamagnetic paramagnetic ferromagnetic carbon-based 131 Magnetic Particle Testing Lecture Guide | QUIZ KEYS The mathematically calculated starting magnetizing force to use for a test object when 1l using a low fill factor coil is: a, The cross-sectional area ratio of a 20 in (51 cm) coil and a in (13 cm) test object is: ampere turns = 4500/(L/D) b c voltage turns = 4500/(L/D) d b ampere turns = 45 000/(L/D) ce 10 d voltage turns = 45 000/(L/D) 12 10 A(n) fill factor coil/test object combination is when the cross-sectional area of the coil is greater than two and less than 10 times the cross-sectional area of the test object evaluation is necessary to determine whether the discontinuity: a is the result of primary or secondary processing, a low b is surface or subsurface b intermediate c c high d extreme 132 After proper interpretation of an indication, is acceptable or rejectable d occurred before service or during service Quiz Key A simple method of demagnetization of small test objects is by: passing them through an alternating current coil, passing them through a direct current coil c placing them with the principal axis east to west Demagnetization is not normally required in low carbon materials when: a they are cooled below the curie point b they are not used in navigational system components c, they are heated above the curie point d the NDT written practice permits higher magnetic permeability placing them with the principal axis north to south ø it is important to prevent the residual field from interfering with subsequent manufacturing operations b magnetometer readings exceed 200 mSy gauss meter readings exceed mSy instructed by the Level III normally require demagnetization to an absolute value of less than G (0.0003 T) a b & d Engineers Specifications Level IIIs Allowable stress tables Which scenario below typically requires demagnetization? a When the test object will be heat-treated above its curie point b When the residual magnetic field is found to be too low for chips to cling to the test object during machining c, When the residual magnetism may interfere with nearby instruments d When inspecting a welded assembly with low retentivity Demagnetization is required in the part that: aoe The main reason to demagnetize is when: is made of low carbon steels is made of medium carbon steels is made of high carbon steels will be machined into a precise shape with a focused electric arc 133 Magnetic Particle Testing Lecture Guide QUIZ KEYS Ifa test object has a residual field and is The magnetic field strength at the start of the demagnetization cycle the residual magnetic field strength heat-treated above the curie temperature it will: require demagnetization after cơ? a p0 heat-treatment b require demagnetization before Aa heat-treatment c have a higher residual field after heat-treatment d have no residual field after 10 must be equal to the L/D ratio of must be less than the L/D ratio of must be higher than must be less than A test object too large to fit in a coil that has a residual field may be demagnetized by: heat-treatment aoe Before or during each demagnetization, the coercive force must be: calculated counteracted measured reconnected left sitting east and west for five days so it will lose its residual field wrapping with cables with an alternating current running through the cables and amperage reduced from a high current to Zero wrapping with cables running through the reduced from a high putting the part on a with a direct current cables and amperage current to zero turntable and spinning it in the Earth’s magnetic field 134 Quiz Key 200 - 600 V 2000 - 6000 V 200 - 600 A 2000 - 6000 A aos Mobile or stationary units will usually supply voltage alternating or half-wave direct magnetizing current zero low medium high Magnetic particle testing should be performed if possible The Level II technician will have a standard company procedure or technique that specifies the type of suspension and particles, and may select a with the test object background a minimal color contrast b good allowable color retentivity c good color contrast d minimal color retentivity If wet suspensions are used from portable containers, they should be checked for particle concentrations before use and the solution must be agitated thoroughly: = pose current aos Versatile, mobile testing units will usually supply up to about alternating current or half-wave direct magnetizing before each use every 4h every 8h every time when there is a change of technician a before painting or other coatings b before painting but after other coatings c after painting or other coatings to provide background contrast d both before and after painting or other coatings 135 The wet suspension concentration should be mL/100 L for visible and mL/100 L for fluorescent ao e® 136 | QUIZ KEYS 0.1 1.2 0.1 1.2 to to to to 0.4; 2.4; 1.2; 2.4; 1.2 0.1 1.2 0.1 to to to to 2.4 0.4 2.4 1.2 For wet magnetic particle testing, additives usually are added to water These include antifoaming materials, corrosion inhibitors, and: Roos Magnetic Particle Testing Lecture Guide anti-freezing agents anti-fouling agents anti-bubbling agents wetting agents, Quiz Key eo TS Inherent discontinuities are: just a property of the alloy of metal all removed by cropping formed when molten metal solidifies discontinuities that exist inside the material below the surface A burst may be found in a: a casting b forging c ingot d weld A common discontinuity in a weld or casting imperfections that cause the test object to fail An example of a processing discontinuity that is the result of an inherent discontinuity changing shape during rolling is a: a b c d cooling crack burst lap lamination aos A common processing indication in rolled bar stock is a: seam, lap a a crack, b porosity c shrinkage d lamination Grinding cracks may occur during: oP always classified as primary or secondary So mo either acceptable or rejectable machining welding quenching heat-treating A weld discontinuity that always occurs at the root of a weld is: Pp always defects and usually rejected that is difficult to detect by magnetic particle testing is: lack of fusion ao Discontinuities are: slag inclusions lack of penetration undercut hot tear cold shut 137 Magnetic Particle Testing Lecture Guide | QUIZ KEYS Fatigue cracking is a fracture mechanism induced by: 11 Hydrogen will cause which one of the following discontinuities, if present during heat-treating or welding? a a single overloading, b cyclic loading c cyclic loading with the aid of corrosion or a Slag inclusions, c Incomplete fusion b Cold cracks d Porosity 138 Hydrogen embrittlement d Delayed hydrogen cracking 12 A slag inclusion in a weld may be found at the: FS cavities or pores that form when some constituent within the molten weld metal vaporizes and forms a small pocket of entrapped gas? c ao d a preexisting discontinuity Which type of discontinuity is composed of Hydrogen-induced lack of penetration b Hydrogen-induced lack of fusion heat cycle 10 a weld crater root ofa gas tungsten arc weld root of an SMAW weld heat-affected zone of a GMAW weld Quiz Key Before magnetic particle testing, a reference standard may be used to verify the of a testing system operation criticality € retentivity always relies on aoe the sensitivity is satisfactory for a particular part subsurface indications will be detected permeability — A technician empirical rules for establishing magnetic particle testing procedures The standard tool steel ring is used to verify that: Which of the following is a reference standard test block? a may start with never uses considers developing A daily system performance check should include: Retired part with a crack Flux leakage test block d Centrifuge tube Hall effect meters measure: aoe Bose a standard test object with known discontinuities magnetic flux lines in the part magnetic field strength in the part residual field strength in the part magnetic flux lines outside the part What are used to determine adequate field strength and to avoid excess flux while 7p achieving accurate indications? ao head shot pressure Prism steel test block with an artificial discontinuity suspension pump pressure line voltage the system is working the suspension and fluorescence are satisfactory oF ao Ff Hall effect meters Reference standards Feedback controls Knobs on equipment 139 Quiz Key b procedure Properly calibrated equipment and material Proper material and a good technique/procedure d Instinctively developed procedure and previously used equipment a Properly calibrated material and sound The settling test is performed once for new mixtures of solutions and: before each use successful magnetic particle test? in the first shift of every week ao Which of the following are key elements for a c, If manufacturer's instructions for storage are followed, materials should not degrade except by: a aging b contamination, c loss of permeability d loss of sensitivity Ultraviolet radiation intensity used for testing must be a minimum of at 15 in (38 cm) a b c d fc (20 Ix) 20 fc (200 Ix) 100 IW/cm? 1000 W/cm? because the lamps lose intensity as they age aoe hourly weekly monthly before testing begins oF Bf Too much current will produce indications or background ao procedures d done once every two months measured The ultraviolet radiation intensity is normally measured with a light meter Checking new material prior to use is: a necessary b a waste of resources c not recommended but required by certain in the first shift of every month in the first and last shift of every week relevant; excessive nonrelevant; excessive nonrelevant; minimal allowable; minimal 141 Magnetic Particle Testing Lecture Guide | QUIZ KEYS New test objects usually require half- or full-wave direct current to detect subsurface discontinuities and may also use alternating current for: a b c d 142 9, The residual method should only be used as an aid in evaluating indications detected with the continuous method and for information tests of materials with high: the availability of equipment a permeability better surface sensitivity b coercive force c retentivity d inductance better subsurface sensitivity better surface and subsurface sensitivity