Appendix A
h. VARIABLES AFFECTING TEST RESULTS
(1) Instrument performance variations
(2) Search unit performance variations
(3) Inspected part variations
(a) Entry surface condition
(b) Part size and geometry
(c) Metallurgical structure
(4) Discontinuity variations
(a) Size and geometry
(b) Distance location from entry surface
(c) Orientation to entry surface
(d) Type of discontinuity-reflecting characteristics
i. FINAL WRITTEN/PRACTICAL EXAMINATION
TOTAL TIME (HOURS): 40
8. LIQUID PENETRANT TRAINING COURSE
a. INTRODUCTION
(1) Brief history of nondestructive testing and liquid penetrant testing
(2) Purpose of liquid penetrant testing
(3) Basic principles of liquid penetrant testing
(4) Types of liquid penetrants commercially available
b. LIQUID PENETRANT PROCESSING
(1) Preparation of parts
(2) Application of penetrant to parts
(3) Removal of surface penetrant
(4) Developer application and drying
(5) Inspection and evaluation
(6) Post-cleaning
c. SELECTION OF PENETRANT TEST METHODS
(1) Advantages of various methods
(2) Disadvantages of various methods
d. LIQUID PENETRANT TEST EQUIPMENT
(1) Liquid penetrant test units
(2) Lighting for liquid penetrant inspection
(3) Materials for liquid penetrant testing
(4) Precautions in penetrant inspection
e. LIQUID PENETRANT INDICATIONS
(1) General
(a) Reason for indications
(b) Appearance of indications
(c) Time for indications to appear
(d) Persistence of indications Page 12
Appendix A
(2) Factors affecting indications
(a) Penetrant used
(b) Technique used
(3) Establishing acceptance standards
(a) Lack of “standards”
(b) Standards for repetitive inspection
(4) Indication from cracks
(a) Cracks occurring during solidification
(b) Cracks occurring during processing
(c) Cracks occurring during service
(5) Indications from laminar discontinuities
(a) Cold shut or fold
(b) Forging laps
(c) Extrusion defect
(d) Seams
(6) Indications from porosity
(7) Nonrelevant indications
f. INSPECTION PROCEDURES AND STANDARDS
(1) Inspection procedures
(2) Standards
g. FINAL WRITTEN/PRACTICAL EXAMINATION
TOTAL TIME (HOURS): 16
9. EDDY CURRENT TESTING TRAINING COURSE
a. INTRODUCTION
(1) Brief history of eddy current testing
(2) Basic principles of eddy current testing
b. EDDY CURRENT THEORY
(1) Generation of eddy currents by means of an A-C field
(2) Effect of fields created by ededy currents (impedance changes)
(3) Effect of change of impedence on instrumentation
(4) Properties of eddy current
(a) Travel in circular direction
(b) Strongest on surface of test material
(c) Zero value at center of solid conductor placed in an eddy current field
(d) Strength, time relationship, and orientation as function of test system parameters and test part characteristics
(e) Have properties of compressible fluids
(f) Small magnitude of current flow
(g) Relationship of frequency and plane with current in coil
(h) Effect of irrelevant permeability variations when induced in magnetic particles
(i) Effect of discontinuity orientation
(j) Power losses
Appendix A
c. TYPES OF SENSING ELEMENTS
(1) Probes
(a) Types of arrangement
(i) Absolute
(ii) Differential
(iii) Reflectance
(b) Lift-off
(c) Theory of operation
(d) Applications
(e) Advantages
(f) Limitations
(2) Through, Encircling, or Annular Coils
(a) Types or arrangements
(i) Absolute
(ii) Differential
(b) Lift-off
j. READ-OUT MECHANISM
(1) Calibrated or uncalibrated meter
(2) Null meter with dial indicator
(3) Oscilloscope
(4) Alarm, lights, etc.
(5) Sorting gates and tables
(6) Strip chart recorder
k. APPLICATIONS
(1) Flaw detection
(2) Sorting for properties related to conductivity
(3) Sorting for properties related to permeability
(4) Thickness evaluation
(5) Measurement of magnetic characteristic values
l. REFERENCE STANDARDS AND OPERATING PROCEDURES
(1) Explanation of standards and specifications used in eddy current testing
(2) Explanation of operating procedures used in eddy current testing
m. FINAL WRITTEN/PRACTICAL EXAMINATION
TOTAL TIME (HOURS): 40