Electromagnetic Testing - Eddy Current Testing Applications Chapter 5 & 6

More documents

Recommendations

Info

Generally, to detect small flaws, coils with a small diameter, no greater than the length of flaw required to be detected, need to be used. In addition, inservice cracking most often occurs in a change of section, slot, or thread root. Therefore, small diameter pencil probes give good access to such test surfaces and are most commonly used, although spot probes with a small diameter coil can be used on flat surfaces or where the curvature of the test surface is constant and not too great. If only relatively large flaws are sought, larger diameter probes can be used, with a consequent reduction in the number of passes required to scan a given test area. Absolute probes are almost always used for surface flaw detection, with differential probes being used only for special applications such as testing holes, discussed later. The probe can be shielded or unshielded. Shielded probes should be used for testing around holes. Keywords: Absolute probes are almost always used for surface flaw detection Charlie Chong/ Fion Zhang
If the fastener is not removed, cracks will normally be detected only if they extend beyond the fastener. To detect cracks under fasteners, a ring probe or sliding probe should be used. These are discussed later under the heading ‘Detection of subsurface flaws’. Shielded probes should also be used for testing near edges, at changes in the section, such as in slots, grooves, and thread roots, and, if testing non-ferromagnetic material, where there is an adjacent ferromagnetic material. Also, because the eddy current field of shielded probes is much more confined than that of an unshielded probe with the same diameter coil, shielded probes are capable of detecting smaller cracks, and so should be used whenever very small cracks are required to be detected. Unshielded probes can be used in other situations, and have the advantage that, because of the greater lateral spread of the eddy currents, fewer passes are required to scan a given test area. Charlie Chong/ Fion Zhang
Page 1 and 2:
Electromagnetic Testing - Eddy Curr
Page 3 and 4:
http://igor113.livejournal.com/5121
Page 5 and 6:
Charlie Chong/ Fion Zhang
Page 7 and 8: 同桌的你 Charlie Chong/ Fion
Page 9 and 10: Fion Zhang at Shanghai 2014/Novembe
Page 11 and 12: 5.0 APPLICATIONS 5.1. Surface testi
Page 13 and 14: FIG. 5.1. Schematic diagram showing
Page 15 and 16: Eddy current field extends laterall
Page 17 and 18: Depth of Penetration & Current Dens
Page 19 and 20: Please also comment on this illustr
Page 21 and 22: FIG. 5.2 Directional properties of
Page 23 and 24: The depth of surface flaws (the dis
Page 25 and 26: Case Discussion: The corresponding
Page 27 and 28: 5.1.2.2 Types of standard surface t
Page 29 and 30: (b) Spot probes Spot probes are pro
Page 31 and 32: FIG. 5.6. A spring loaded probe. Ch
Page 33 and 34: FIG. 5.5. (a) The core and coil of
Page 35 and 36: Although it is usually evident by i
Page 37 and 38: FIG. 5.7. Effects of cores and shie
Page 39 and 40: 5.1.2.3 Other types of surface prob
Page 41 and 42: FIG. 5.8. A tangential probe showin
Page 43 and 44: Compare vertical probe with the FIG
Page 45 and 46: Discussion Topic- Why in the tangen
Page 47 and 48: FIG. 5.9. A gap (horseshoe) probe.
Page 49 and 50: Horseshoe probe - maximum sensitivi
Page 51 and 52: A gap (horseshoe) probe - Magnetic
Page 53 and 54: 5.1.3 Testing for surface-breaking
Page 55 and 56: Eddy Current Testing over painted s
Page 57: Testing Frequency: • 200 kHz to 5
Page 61 and 62: Following are some examples of spec
Page 63 and 64: Threaded Probe Charlie Chong/ Fion
Page 65 and 66: Eddy Current Testing- Hole fatigue
Page 67 and 68: Hand operated or manual hole probes
Page 69 and 70: If motor driven probes are to be us
Page 71 and 72: FIG. 5.12. Typical rotating hole pr
Page 73 and 74: Bolt hole probes Charlie Chong/ Fio
Page 75 and 76: (c) Aircraft wheels: Aircraft wheel
Page 77 and 78: Aircraft wheels Charlie Chong/ Fion
Page 79 and 80: Automated equipment which will perf
Page 81 and 82: Tangential probe - used in electron
Page 83 and 84: FIG. 5.3 Charlie Chong/ Fion Zhang
Page 85 and 86: Although these blocks can be used f
Page 87 and 88: (f) Scan over the appropriate disco
Page 89 and 90: 4.1.3.5 Testing in-service welds in
Page 91 and 92: FIG. 5.14 a. Typical weld testing p
Page 93 and 94: Since the eddy currents produced at
Page 95 and 96: For testing, the instrument should
Page 97 and 98: Charlie Chong/ Fion Zhang
Page 99 and 100: Charlie Chong/ Fion Zhang
Page 101 and 102: Keywords: Typically, the magnetic f
Page 103 and 104: Multilayer structures - of flaws in
Page 105 and 106: 5.1.4.2 Probe and frequency selecti
Page 107 and 108: An acceptable compromise which give
Page 109 and 110:
FIG. 5.15. Eddy current signals fro
Page 111 and 112:
FIG. 5.16. Spot probes testing a la
Page 113 and 114:
) Sliding probes Sliding probes are
Page 115 and 116:
5.1.4.4 Reference samples Reference
Page 117 and 118:
5.1.5 Conductivity testing and mate
Page 119 and 120:
5.1.5.3 Factors which affect conduc
Page 121 and 122:
(b) Alloying. Dissolving any elemen
Page 123 and 124:
(d) Cold work Plastic deformation o
Page 125 and 126:
(b) Test part thickness The conduct
Page 127 and 128:
(c) Edge effect Probes dedicated to
Page 129 and 130:
5.1.5.6 Frequency selection The fre
Page 131 and 132:
FIG. 5.19. Impedance diagrams and t
Page 133 and 134:
Page 135 and 136:
The Characteristic Parameter (PC) i
Page 137 and 138:
Example: Calculate the optimum freq
Page 139 and 140:
When eddy current conductivity mete
Page 141 and 142:
(d) Perform conductivity measuremen
Page 143 and 144:
5.1.5.9 Heat treatment of aluminium
Page 145 and 146:
5.1.5.10 Sorting materials by magne
Page 147 and 148:
5.1.6 Thickness measurement of non-
Page 149 and 150:
FIG. 5.22. Methods of obtaining sta
Page 151 and 152:
Non-conducting coating thickness me
Page 153 and 154:
A typical operating frequency to me
Page 155 and 156:
5.1.6.4 Measurement procedure (a) C
Page 157 and 158:
(k) (l) Alternatively, if the measu
Page 159 and 160:
5.1.7 Thickness measurement of cond
Page 161 and 162:
5.1.7.2 Probe and frequency selecti
Page 163 and 164:
5.1.7.3 Signals from variations in
Page 165 and 166:
FIG. 5.26. Part of the display show
Page 167 and 168:
5.1.7.5 Measurement procedure (a) C
Page 169 and 170:
(j) (k) Alternatively, if the measu
Page 171 and 172:
5.1.8 Thickness measurement of cond
Page 173 and 174:
FIG. 5.28 shows the impedance curve
Page 175 and 176:
5.2.1.1 Tube testing probes and the
Page 177 and 178:
The coil(s) in bobbin probes produc
Page 179 and 180:
Bobbin probe eddy current the orien
Page 181 and 182:
To obtain adequate sensitivity to f
Page 183 and 184:
As for surface testing, the test se
Page 185 and 186:
5.2.1.2 Selection of test frequency
Page 187 and 188:
The basis for the selection of test
Page 189 and 190:
FIG. 5.32. Impedance diagram showin
Page 191 and 192:
5.2.1.4 Flaw signals from absolute
Page 193 and 194:
At f 90 , all flaw signals appear i
Page 195 and 196:
5.2.1.5 Absolute probe signals from
Page 197 and 198:
Wobble - A-go-go Charlie Chong/ Fio
Page 199 and 200:
Discussion Topic- Discuss on the fo
Page 201 and 202:
(c) Ferromagnetic conditions at the
Page 203 and 204:
A signal from a ferromagnetic condi
Page 205 and 206:
FIG. 5.36 shows the signal from a f
Page 207 and 208:
Tube Sheet: Baffle Plate Charlie Ch
Page 209 and 210:
Tube Sheet: Baffle Plate Charlie Ch
Page 211 and 212:
(e) Non-ferromagnetic support or ba
Page 213 and 214:
This signal will be modified by any
Page 215 and 216:
(f) Ferromagnetic support or baffle
Page 217 and 218:
FIG. 5.37. The signals from a carbo
Page 219 and 220:
FIG. 5.38. Absolute and differentia
Page 221 and 222:
5.2.1.7 Correlating flaw depth and
Page 223 and 224:
FIG. 5.39. Graph showing the correl
Page 225 and 226:
5.2.1.8 Correlating flaw depth and
Page 227 and 228:
5.2.2 Bar and tube testing using en
Page 229 and 230:
Discussion Topic: This means that p
Page 231 and 232:
FIG. 5.41. The eddy current intensi
Page 233 and 234:
5.2.2.2 Selection of frequency For
Page 235 and 236:
Associated with the f/f g concept i
Page 237 and 238:
The optimum operating point depends
Page 239 and 240:
5.2.2.3 Specific test applications
Page 241 and 242:
(c) Flaw detection Surface flaw ind
Page 243 and 244:
5.2.2.4 Testing ferromagnetic bars
Page 245 and 246:
Ferromagnetic material can be teste
Page 247 and 248:
5.3.2 Equipment Most modern eddy cu
Page 249 and 250:
These standards cover such topics a
Page 251 and 252:
The following example is taken from
Page 253 and 254:
The content of written procedures d
Page 255 and 256:
Page 257 and 258:
6.5. Records and reports 6.5.1 Test
Page 259 and 260:
6.5.2 Test reports A formal test re
Page 261 and 262:
Records Charlie Chong/ Fion Zhang
Page 263 and 264:
Calibration Standard A test standar
Page 265 and 266:
Coil, probe A small coil or coil as
Page 267 and 268:
Discontinuity Artificial Reference
Page 269 and 270:
Electromagnetic Testing That non de
Page 271 and 272:
IACS σ IACS . International Anneal
Page 273 and 274:
Material, Diamagnetic A material ha
Page 275 and 276:
Parameter A material property or in
Page 277 and 278:
Phase Lag β (beta), radians or deg
Page 279 and 280:
Resistivity ρ (ro), microhm centim
Page 281 and 282:
Signal A change in eddy current ins
Page 283 and 284:
Space Station Charlie Chong/ Fion Z
Page 285 and 286:
Charlie https://www.yumpu.com/en/br
Page 287:
Good Luck! Charlie Chong/ Fion Zhan
show all

Electromagnetic Testing - Eddy Current Testing Applications Chapter 5 & 6

Create successful ePaper yourself

Delete template?

Save as template?