NONDESTRUCTIVE INSPECTION - TEST METHODS
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TABLE OF CONTENTS INTRODUCTION. SAFETY SUMMARY. 1 NONDESTRUCTIVE INSPECTION METHODS, GENERAL INFORMATION .1-1 SECTION I NONDESTRUCTIVE INSPECTION NDI METHODS .1-1 1.1 Why We Do Nondestructive Inspection NDI.1-1 1.1.1 Nondestructive Inspection Data .1-1 1.1.2 Structural Management Programs.1-1 1.1.3 Mechanisms for Using NDI Data .1-1 1.1.4 Tools for Gathering NDI Data.1-2 SECTION II PERSONNEL TRAINING QUALIFICATION CERTIFICATION .1-3 1.2 Personnel TrainingQualificationCertification .1-3 1.2.1 Training Introduction.1-3 1.2.2 Training Requirements .1-3 1.2.3 Certification Requirements.1-3 1.2.4 Physical Requirements .1-3 1.2.5 Requirement for Special Task Certification and Recurring Training.1-3 SECTION III REPORTING NEW OR IMPROVED NDI TECHNIQUES .1-5 1.3 Reporting NewImproved Nondestructive Inspection Techniques .1-5 1.3.1 Need for Reporting New and Improved Techniques .1-5 1.3.2 Authority .1-5 1.3.3 AFTO Form 242.1-5 1.3.4 Scope.1-5 1.3.5 Responsibilities for Updating Techniques .1-5 1.3.6 AFTO Form 242 Entries .1-6 SECTION IV NDI EQUIPMENT .1-9 1.4 Procuring NDI Equipment AIR FORCE Only .1-9 1.4.1 Centrally Procured NDI Equipment.1-9 1.4.2 Weapon System SpecificSpecial Purpose Equipment.1-9 1.4.3 Local Purchase Equipment.1-9 SECTION V PROCESS CONTROL.1-10 1.5 Process Control.1-10 1.5.1 Reason for Controlling the Process .1-10 1.5.2 Scope of Process Control .1-10 1.5.3 Process Control Documentation Requirements .1-12 1.5.4 Establishing a Documentation Method.1-12 1.5.5 Suggested Documentation Method .1-12 SECTION VI LABORATORY INFORMATION .1-13 1.6 General Laboratory Information .1-13 1.6.1 Constructing a Nondestructive Inspection Laboratory.1-13 1.6.2 Building Requirements .1-13 1.6.3 Electrical and Mechanical Requirements.1-14 1.6.4 Room Identification.1-15 2 LIQUID PENETRANT INSPECTION METHOD .2-1 SECTION I LIQUID PENETRANT INSPECTION METHOD .2-1 2.1 General Capabilities of Liquid Penetrant Inspection .2-1 2.1.1 Introduction to Liquid Penetrant Inspection.2-1 2.1.2 Background of Liquid Penetrant Inspection.2-1 2.1.3 Why Use Liquid Penetrant Inspection.2-1 2.1.4 Limitations of Liquid Penetrant Inspection .2-1 2.1.5 Advantages of Liquid Penetrant Inspection.2-2 2.1.6 Disadvantages of Liquid Penetrant Inspection .2-2 2.1.7 Basic Penetrant Inspection Process.2-3 2.1.8 Personnel Requirements .2-4 2.1.9 Understanding Penetrant Classification and Processes .2-4 2.1.10 Qualification of Penetrant Material .2-9 2.1.11 Qualification of Penetrant Sensitivity.2-9 2.1.12 Penetrant Material Performance.2-9 SECTION II PRINCIPLES AND THEORY OF LIQUID PENETRANT INSPECTION.2-11 2.2 Principles and Theory of Liquid Penetrant Inspection .2-11 2.2.1 General.2-11 2.2.2 Characteristics of a Penetrant.2-11 2.2.3 Mechanisms of Penetrant Action .2-11 2.2.4 How Liquid Penetrant Enters Discontinuities .2-17 2.2.5 Mechanisms and Principles of Penetrant Removal .2-17 2.2.6 Mechanisms of Developer Action .2-21 2.2.7 Cleaning and Surface Preparation.2-22 2.2.8 Surface Conditions Affecting Penetrant Inspection .2-22 2.2.9 Contaminants and Soils.2-22 2.2.10 Coatings .2-27 2.2.11 Effects of Surface Deformation, Wear, and Surface Roughness on Penetrant Inspection .2-29 SECTION III LIQUID PENETRANT INSPECTION EQUIPMENT.2-31 2.3 Equipment.2-31 2.3.1 General.2-31 2.3.2 Portable Equipment .2-31 2.3.3 Stationary Inspection Equipment - General Purpose .2-31 2.3.4 Small Parts Inspection Systems .2-31 2.3.5 Automated Inspection Systems .2-31 2.3.6 Inspection Lamps.2-31 2.3.7 Process Control Equipment.2-35 SECTION IV LIQUID PENETRANT APPLICATION METHODS .2-36 2.4 Application Method.2-36 2.4.1 General.2-36 2.4.2 Basic Penetrant Processes .2-36 2.4.3 Pre-Testing.2-41 2.4.4 Pre-Cleaning Preformed by NDI Personnel .2-41 2.4.5 Penetrant Application .2-42 2.4.6 Temperature Limitations .2-44 2.4.7 Penetrant Dwell .2-47 2.4.8 Penetrant Removal.2-53 2.4.9 Water WashingRinsing Technique .2-64 2.4.10 Drying .2-65 2.4.11 Application of Developers .2-67 2.4.12 Post-Cleaning After Penetrant Inspection.2-76 2.4.13 Protection of Parts Following Penetrant Inspection.2-77 SECTION V INTERPRETATION OF LIQUID PENETRANT INSPECTION .2-78 2.5 Interpretation of Indications .2-78 2.5.1 General.2-78 2.5.2 Importance of Understanding the Interpretation Process .2-78 2.5.3 Personnel Requirements .2-78 2.5.4 Lighting.2-78 2.5.5 Inspection Conditions .2-83 2.5.6 Evaluating Indications .2-83 SECTION VI PROCESS CONTROL OF LIQUID PENETRANT INSPECTION.2-92 2.6 Liquid Penetrant Process Control .2-92 2.6.1 General.2-92 2.6.2 Need for Process Quality .2-92 2.6.3 Why Test New Materials .2-92 2.6.4 Why Test In-Use Materials.2-92 2.6.5 Causes of Material Degradation.2-92 2.6.6 Establishing Work Center Process Control Intervals.2-93 2.6.7 Process Control Equipment.2-93 2.6.8 Process Control Requirement.2-96 2.6.9 Control of New Materials .2-101 2.6.10 Testing In-Use Materials.2-102 SECTION VII SPECIAL PURPOSE LIQUID PENETRANTS .2-118 2.7 Special Purpose Liquid Penetrant .2-118 2.7.1 General.2-118 2.7.2 Liquid Oxygen LOX Compatible Penetrants.2-118 2.7.3 Low Sulfur, Low Chlorine Penetrant Systems.2-119 2.7.4 High Temperature Penetrant Materials.2-119 2.7.5 Dye Precipitation Penetrant Systems .2-119 2.7.6 Reversed Fluorescence Method .2-119 2.7.7 Thixotropic Penetrant .2-120 2.7.8 Dilution Expansion Developers .2-120 2.7.9 Plastic-Film Developers .2-120 SECTION VIII LIQUID PENETRANT INSPECTION SAFETY.2-121 2.8 Liquid Penetrant Inspection Safety.2-121 2.8.1 Safety Requirements.2-121 2.8.2 General Precautions.2-121 2.8.3 Personal Protection Equipment .2-121 2.8.4 Ventilation.2-121 2.8.5 Matting.2-122 2.8.6 UV-A Black Light Hazards.2-122 3 MAGNETIC PARTICLE INSPECTION METHOD .3-1 SECTION I MAGNETIC PARTICLE INSPECTION METHOD .3-1 3.1 General Capabilities of Magnetic Particle Inspection.3-1 3.1.1 Introduction to Magnetic Particle Inspection MPI .3-1 3.1.2 Benefit of Magnetic Particle Inspection .3-1 3.1.3 Basic Concept of Magnetic Particle Inspection .3-1 SECTION II MAGNETIC PARTICLE PRINCIPLES AND THEORY.3-2 3.2 Principles and Theory of Magnetic Particle Inspection .3-2 3.2.1 Principles of Magnetization .3-2 3.2.2 Basic Terminology .3-2 3.2.3 Magnetic Field Characteristics.3-3 3.2.4 Currents Used to Generate Magnetic Fields .3-9 3.2.5 Ferromagnetic Material Characteristics .3-10 SECTION III MAGNETIC PARTICLE INSPECTION EQUIPMENT .3-14 3.3 Magnetic Particle Inspection Equipment and Materials .3-14 3.3.1 Selection of Magnetic Particle Inspection Equipment .3-14 3.3.2 Categories of Magnetic Particle Inspection Equipment.3-14 3.3.3 Inspection Equipment Accessories.3-17 3.3.4 Special Purpose Equipment.3-17 3.3.5 Field Strength Measurement Devices .3-18 3.3.6 Understanding and Selecting Magnetic Particle Inspection Materials .3-20 SECTION IV MAGNETIC PARTICLE INSPECTION APPLICATIONS.3-27 3.4 Magnetic Particle Inspection Application Methods .3-27 3.4.1 Inspection Preparation .3-27 3.4.2 Magnetic Particle Inspection Techniques .3-29 3.4.3 Selecting a Magnetizing Current .3-30 3.4.4 Magnetic Field.3-33 3.4.5 Field Strength Measurement Techniques.3-39 3.4.6 Methods of Particle Application .3-41 3.4.7 Wet Fluorescent Inspection Technique.3-50 3.4.8 Portable Magnetic Particle Inspection .3-51 3.4.9 Special Magnetization Techniques.3-53 3.4.10 Multidirectional Magnetization .3-55 3.4.11 Demagnetization .3-55 3.4.12 Post Inspection Cleaning.3-62 3.4.13 Magnetic Rubber Inspection .3-63 SECTION V MAGNETIC PARTICLE INSPECTION INTERPRETATIONS .3-73 3.5 Magnetic Particle Inspection Interpretation.3-73 3.5.1 Formation of Discontinuities and their Indications.3-73 3.5.2 Definition of Terms.3-75 3.5.3 Basic Steps of Inspection .3-75 3.5.4 Classes of Discontinuities .3-80 3.5.5 Non-Relevant Indications .3-98 3.5.6 Interpretation and Elimination of Non-Relevant Indications.3-103 3.5.7 Methods of Recording MPI Indications .3-103 SECTION VI PROCESS CONTROL OF MAGNETIC PARTICLE INSPECTION .3-106 3.6 Magnetic Particle Process Control.3-106 3.6.1 Purpose and Scope .3-106 3.6.2 General.3-106 3.6.3 Causes of System Degradation .3-106 3.6.4 Frequency of Process Control.3-107 3.6.5 Evaluating the Magnetic Particle Process .3-107 3.6.6 Evaluating Equipment Effectiveness .3-107 3.6.7 Evaluating Material Effectiveness .3-113 3.6.8 Additional Tests for Water Baths .3-118 3.6.9 Disposition for Nonconformance Materials.3-119 3.6.10 Magnetic Particle Process Checklist.3-119 SECTION VII MAGNETIC PARTICLE INSPECTION EQUATIONS .3-121 3.7 Magnetic Particle Equations.3-121 3.7.1 Rule-of-Thumb Formulas.3-121 3.7.2 Cross-Sectional Area .3-121 3.7.3 Calculating Coil Current .3-122 SECTION VIII MAGNETIC PARTICLE INSPECTION SAFETY.3-126 3.8 Magnetic Particle Safety .3-126 3.8.1 Safety Requirements.3-126 3.8.2 General Precautions.3-126 3.8.3 Floor Matting.3-126 3.8.4 Wet Suspension Precautions .3-126 3.8.5 Arcing Precautions .3-126 3.8.6 Head Stocks .3-126 3.8.7 UV-A Black Light Hazards.3-126 3.8.8 Hazards of Aerosol Cans .3-127 3.8.9 Magnetic Rubber Precautions .3-127 4 EDDY CURRENT INSPECTION METHOD.4-1 SECTION I EDDY CURRENT TESTING ET METHOD .4-1 4.1 General Capabilities of ET.4-1 4.1.1 Introduction to ET .4-1 4.1.2 Definition of Eddy Current .4-2 4.1.3 Inspection With Eddy Current .4-2 4.1.4 Limitations of Eddy Current Method .4-2 4.1.5 Variables Affecting Eddy Currents.4-2 4.1.6 Eddy Current Techniques.4-3 4.1.7 Effect of Conductivity on Eddy Currents.4-4 4.1.8 Crack Detection in Non-Ferromagnetic Materials .4-9 4.1.9 Phase Lag at Depth .4-11 SECTION II EDDY CURRENT PRINCIPLES AND THEORY.4-13 4.2 Principles and Theory of ET.4-13 4.2.1 Materials and Processes .4-13 SECTION III EDDY CURRENT EQUIPMENT TYPES.4-27 4.3 ET Equipment.4-27 4.3.2 Components of an ET System .4-27 4.3.3 Eddy Current Subsystems .4-28 4.3.4 Functions of the Eddy Current Instrument.4-31 4.3.5 General Requirements .4-31 4.3.6 Specific Instrumentation Requirements .4-31 4.3.7 Special Circuits and Processes.4-33 4.3.8 Amplitude Detection.4-33 4.3.9 Multi-Frequency Eddy Current Systems .4-33 4.3.10 Pulsed Eddy Current Techniques.4-33 4.3.11 Metal Thickness Measurements .4-33 4.3.12 Presentations and Displays.4-33 4.3.13 Meters .4-33 4.3.14 Cathode Ray Tube CRT Display .4-33 4.3.15 Digital Display.4-33 4.3.16 Linear Time Base Display .4-34 4.3.17 Recorders .4-34 4.3.18 Impedance Plane Eddy Current Test Equipment .4-34 4.3.19 Digital Equipment.4-34 4.3.20 Mechanical Scanning.4-34 4.3.21 Multi-Frequency Testing Techniques .4-34 4.3.22 Dual Frequency Testing .4-34 4.3.23 Pulsed Eddy Current Testing .4-34 4.3.24 Low Frequency ET.4-35 4.3.25 Barkhausen Noise Testing of Ferromagnetic Materials.4-35 4.3.26 Alpha-Case on Titanium .4-35 4.3.27 Titanium Aluminide .4-35 4.3.28 Magneto-Optic Imaging MOI.4-35 4.3.29 Application of Advanced Techniques.4-35

SECTION IV APPLICATION OF ET.4-36 4.4 General.4-36 4.4.1 Operating Point.4-36 4.4.2 Filters .4-36 4.4.3 Modulation Analysis.4-37 4.4.4 Frequency Response.4-38 4.4.5 Inspection of Fastener Holes.4-40 4.4.6 Fastener Hole Inspection Equipment .4-40 4.4.7 Lift-Off Compensation for Bolt-Hole Inspection.4-40 4.4.8 Sensitivity Settings .4-41 4.4.9 Scanning Speed.4-41 4.4.10 Bolt Hole Preparation.4-41 4.4.11 Probe to Edge Spacing .4-41 4.4.12 Fixtures and Guides.4-42 4.4.13 Fastener Holes Non-Removable Fasteners .4-42 4.4.14 Probe Selection .4-42 4.4.15 Standards for Nonremovable Fastener Holes .4-42 4.4.16 Fillets and Rounded Corner .4-42 4.4.17 Impedance Diagrams .4-43 4.4.18 Corrosion.4-47 4.4.19 Frequency Selection .4-48 4.4.20 Probe Selection .4-48 4.4.21 Corrosion Reference Standards.4-48 4.4.22 Inspection Procedure-Corrosion Detection .4-48 4.4.23 Part Preparation .4-48 4.4.24 Field Measurement of Conductivity .4-48 4.4.25 Conductivity of Aluminum Alloys .4-48 4.4.26 Heat Treatment Effects on Aluminum Conductivity .4-49 4.4.27 Discrepancies in Aluminum Alloy Heat Treatment.4-49 4.4.28 Applications of Conductivity Measurement .4-49 4.4.29 Conductivity Measurement.4-50 4.4.30 Equipment for Magnetic Materials .4-50 4.4.31 Effects of Variations in Material Properties.4-50 4.4.32 Effects of Variations in Test Conditions .4-51 4.4.33 Flaw Detection.4-52 4.4.34 Inspection Material .4-52 4.4.35 Accessibility.4-52 4.4.36 Crack Detection .4-52 4.4.37 Probe Selection .4-52 4.4.38 Lift-Off Effects .4-56 4.4.39 Lift-Off Compensation Methods.4-56 4.4.40 Effects of Crack Location on Detectability.4-60 4.4.41 Effects of Scanning Techniques on Detection .4-62 4.4.42 Reference Standards for Cracks.4-64 4.4.43 Thickness Measurement .4-70 4.4.44 Measurement of Total Metal Thickness .4-71 SECTION V INTERPRETING EDDY CURRENT SIGNALS.4-76 4.5 ET Interpretation.4-76 4.5.1 Flaw Detection.4-76 4.5.2 Evaluation of Crack Indications.4-76 4.5.3 Effect of Scan Rate and Pattern.4-77 4.5.4 Openings, Large Holes, and Cutouts .4-78 4.5.5 Conductivity Measurement.4-78 4.5.6 Inspection Procedures.4-78 4.5.7 Calibration for Measuring Conductivity Values .4-79 SECTION VI EDDY CURRENT PROCESS CONTROL.4-80 4.6 ET Process Control.4-80 4.6.1 General.4-80 4.6.2 Probe Test .4-80 4.6.3 Slot Test.4-80 SECTION VII EDDY CURRENT EQUATIONS .4-81 4.7 Tables and Equations .4-81 4.7.1 Resistance .4-88 4.7.2 Inductance .4-89 4.7.3 Fill Factor .4-90 4.7.5 Permeability .4-91 4.7.6 Depth of Penetration .4-92 4.7.7 Limit Frequency, 4.7.8 Characteristic Frequency .4-93 4.7.10 Calculating Flaw Frequency for Setting Filters .4-93 4.7.11 Measurement of Conductivity.4-94 SECTION VIII EDDY CURRENT SAFETY.4-95 4.8 ET Safety .4-95 4.8.1 Safety Requirements.4-95 4.8.2 General Precautions.4-95 4.8.3 ET.4-95 5 ULTRASONIC INSPECTION METHOD .5-1 SECTION I GENERAL CAPABILITIES OF ULTRASONIC INSPECTION .5-1 5.1 Introduction.5-1 5.1.1 Introduction to Ultrasonic Inspection .5-1 5.1.2 Development of Ultrasonics.5-1 5.1.3 Ultrasonic Testing.5-1 SECTION II PRINCIPLES AND THEORY OF ULTRASONIC INSPECTION.5-2 5.2 Introduction.5-2 5.2.1 Characteristics of Ultrasonic Energy .5-2 5.2.2 Generation and Receiving of Ultrasonic Vibrations .5-2 5.2.3 Modes of Ultrasonic Vibration .5-3 5.2.4 Refraction and Mode Conversion .5-5 5.2.5 Ultrasonic Inspection Variables .5-7 5.2.6 Sound Beam Characteristics.5-8 SECTION III ULTRASONIC INSPECTION EQUIPMENT AND MATERIALS .5-12 5.3 Introduction.5-12 5.3.1 Ultrasonic Instruments.5-12 5.3.2 Transducers .5-20 5.3.3 Specialized Transducers .5-24 5.3.4 Wedges and Shoes.5-25 5.3.5 Couplants .5-33 5.3.6 Inspection Standards.5-34 5.3.7 Bonded Structure Reference Standards .5-34 5.3.8 Thickness Measurement Equipment .5-36 SECTION IV ULTRASONIC INSPECTION APPLICATION .5-38 5.4 Introduction.5-38 5.4.1 Guidelines for Inspector Familiarization .5-38 5.4.2 Basic Ultrasonic Inspection.5-38 5.4.3 Ultrasonic Reflections .5-39 5.4.4 Data Presentation Methods.5-40 5.4.5 Relationship of a Scan Waveform Display to Distance.5-42 5.4.6 Common Inspection Techniques.5-42 5.4.7 Ultrasonic Technique Development.5-47 5.4.8 Distance Amplitude Correction DAC Curve .5-49 5.4.9 Attenuation Correction Transfer.5-50 5.4.10 Inspection of Bonded Structures.5-56 5.4.11 Thickness Measurement .5-56 5.4.12 Calibration and Thickness Measurement.5-57 SECTION V ULTRASONIC INSPECTION INTERPRETATION.5-59 5.5 Introduction.5-59 5.5.1 Evaluation of Discontinuity Indications .5-59 5.5.2 Types of Discontinuity Indications.5-59 5.5.3 Test Part Variables .5-65 5.5.4 Discontinuity Variables .5-68 5.5.5 Inspection Coverage of Bonded Structures .5-68 5.5.6 Inspection Methods for Bonded Structures .5-70 5.5.7 Techniques Associated With Instruments Dedicated to Bond Inspection.5-78 5.5.8 Thickness Measurement Test Part Preparation .5-82 5.5.9 Thickness Measurement Considerations.5-82 SECTION VI ULTRASONIC INSPECTION PROCESS CONTROLS.5-83 5.6 Introduction.5-83 5.6.1 Ultrasonic Process Control Requirements .5-83 5.6.2 Reference Standard Configuration .5-83 5.6.3 System Equipment Checks .5-87 5.6.4 Transducer Verifications .5-96 SECTION VII ULTRASONIC INSPECTION EQUATIONS .5-101 5.7 Introduction.5-101 5.7.1 General.5-101 5.7.2 Snell’s Law .5-101 5.7.3 Determining the Angle of Incidence in Plastic to Generate 45-Degree Shear Wave in Aluminum .5-101 5.7.4 Near Field .5-101 5.7.5 Beam Spread.5-102 5.7.6 Calculating Acoustic Impedance.5-102 5.7.7 Thickness Measurement Correlation Factor .5-105 SECTION VIII ULTRASONIC INSPECTION SAFETY.5-107 5.8 Introduction.5-107 5.8.1 Safety Requirements.5-107 5.8.2 General Precautions.5-107 5.8.3 Ultrasonic Inspection.5-107 6 RADIOGRAPHIC INSPECTION METHOD.6-1 SECTION I RADIOGRAPHIC INSPECTION METHOD .6-1 6.1 General Capabilities of Radiographic Inspection.6-1 6.1.1 Introduction to Radiographic Inspection .6-1 6.1.2 History of X- and Gamma Radiation .6-2 6.1.3 Factors of Radiographic Inspection .6-3 6.1.4 The Physics of X-rays.6-3 6.1.5 Properties of X- and Gamma Radiation .6-5 6.1.6 Differential Absorption of Radiation in Matter.6-5 6.1.7 Exposure of Film to Radiation.6-7 6.1.8 When to use Radiography.6-8 6.1.9 Unique Properties of Gamma Radiation.6-8 SECTION II PRINCIPLES AND THEORY OF RADIOGRAPHIC INSPECTION.6-10 6.2 How X-rays Are Produced.6-10 6.2.1 Generating X-Radiation.6-10 6.2.2 Type of Radiation Produced by a Tube Head.6-11 6.2.3 Effects of Voltage and Amperage on X-ray Production.6-12 6.2.4 X-ray Generators .6-13 6.2.5 Intensity and Distribution of an X-ray Beam.6-15 6.2.6 Interaction of Radiation With Matter .6-18 6.2.7 Radiation Energy .6-22 6.2.8 Scatter Radiation.6-23 6.2.9 Material Contrast .6-24 6.2.10 Understanding Radiographic Film .6-24 6.2.11 Fundamentals of Digital Radiography .6-29 SECTION III RADIOGRAPHIC EQUIPMENT .6-33 6.3 Radiographic Inspection Equipment .6-33 6.3.1 Types of X-ray Generators.6-33 6.3.2 Types of X-ray Tubes .6-33 6.3.3 Considerations in Choosing Equipment.6-33 6.3.4 Considerations When Operating X-ray Equipment.6-35 6.3.5 Standard Industrial X-ray Equipment in the DoD .6-36 6.3.6 Isotope Source Equipment .6-37 6.3.7 Radiographic Film .6-39 6.3.8 Film Holders, Film Cassettes, and Radiographic Screens .6-44 6.3.9 Quality Indicators .6-47 6.3.10 Radiation Monitoring Devices and Instruments.6-50 6.3.11 Radiographic Processing Equipment .6-53 6.3.12 Film Evaluation Equipment .6-53 6.3.13 Digital Radiographic Viewing, Storage, Archival, and Printing Systems.6-54 SECTION IV APPLICATION OF RADIOGRAPHIC INSPECTION.6-55 6.4 Effective Radiographic Inspections .6-55 6.4.1 Introduction.6-55 6.4.2 Factors Affecting Image Quality .6-55 6.4.3 Radiographic Sensitivity.6-67 6.4.4 Improving Radiographic Sensitivity .6-71 6.4.5 Darkroom Design .6-76 6.4.6 Radiographic Film .6-79 6.4.7 Film Handling Problems .6-80 6.4.8 Preparation for Manual Processing.6-83 6.4.9 Storage of Radiographs .6-83 6.4.10 Processing Chemicals .6-84 6.4.11 Processing Radiographic Film .6-86 6.4.12 Manual Film Processing Procedure .6-94 6.4.13 Automatic Film Processing .6-97 6.4.14 Silver Recovery .6-100 6.4.15 Film Reproduction Technique.6-100 6.4.16 Film Artifacts.6-101 6.4.17 Special Radiographic Techniques .6-102 6.4.18 Digital Radiographic Techniques.6-111 SECTION V INTERPRETATION OF RADIOGRAPHIC INSPECTION.6-112 6.5 Radiographic Interpretation.6-112 6.5.1 General.6-112 6.5.2 Radiographic Image Quality .6-112 6.5.3 Sensitivity .6-112 6.5.4 Definition or Detail .6-112 6.5.5 Density .6-114 6.5.6 Contrast .6-115 6.5.7 Fog .6-115 6.5.8 Distortion and Magnification .6-116 6.5.9 Kilovoltage and Processing.6-116 6.5.10 Viewing Radiographs .6-116 6.5.11 Reading Interpreting Radiographs.6-118 6.5.12 Typical Use of Radiography .6-118 6.5.13 Castings.6-118 6.5.14 Casting Defects.6-120 6.5.15 Welds .6-128 6.5.16 Welding Defects and Conditions .6-128 6.5.17 In-Service Inspections .6-145 6.5.18 Assemblies .6-146 6.5.19 Radiographic Standards.6-146 6.5.20 Digital Radiographic Image Analysis.6-146 SECTION VI PROCESS CONTROL OF RADIOGRAPHIC INSPECTION.6-149 6.6 Radiographic Process Control.6-149 6.6.1 Scope and Purpose .6-149 6.6.2 Radiographic Process Control Requirements .6-149 6.6.3 Process Control in the Darkroom .6-149 6.6.4 Controlling the Development Process .6-153 SECTION VII RADIOGRAPHIC INSPECTION EQUATIONS .6-155 6.7 Radiographic Equations.6-155 6.7.1 General.6-155 6.7.2 Inverse Square Law.6-155 6.7.3 Source-to-Film Distance SFD .6-155 6.7.4 Film Density .6-156 6.7.5 Logarithms for Density and Exposure Calculations .6-156 6.7.6 Material Contrast Factor.6-159 6.7.7 Image Unsharpness.6-159 6.7.8 Heel Effect.6-160 SECTION VIII RADIOGRAPHIC INSPECTION SAFETY.6-161 6.8 Scope and Purpose of Radiation Protection .6-161 6.8.1 General.6-161 6.8.2 Responsibilities .6-161 6.8.3 ALL Qualifications of Civilian Industrial Radiographers.6-166 6.8.4 ALL Industrial Radiographic Safety Training.6-167 6.8.5 ALL Radiation Protection .6-169 6.8.6 Industrial Radiographic Operations .6-180 6.8.7 Industrial Radiographic Installation Classifications .6-181 6.8.8 Mandatory Operating Procedures.6-187 6.8.9 NDI Facility Design and Modification.6-193 GLOSSARY. LIST OF ILLUSTRATIONS