Electromagnetic Testing Chapter 3- Electromagnetic Testing

More documents

Recommendations

Info

These sudden discontinuous jumps in magnetism were detected by a coil of wire wound on a ferromagnetic core that amplified, producing a series of clicks in a loudspeaker. These sudden jumps in magnetism were interpreted as sudden changes in the size or rotation of magnetic domains. There are a large number of potential applications for BN. Qualitative results can be obtained for determining steel composition along with hardening, grinding, turning, annealing, and tempering effects. However, because of the large number of variables that can be evaluated, simultaneous changes by more than one variable can be confusing. Charlie Chong/ Fion Zhang
3.17.2 Early Applications Stresses in rolling mill rolls are induced during manufacture and in-plant service. Casting, forging, heat treatment, and cooling all produce substantial compressive stresses in the case of the roll that are balanced by tensile stresses in the core. Some factors affecting mechanical stresses induced in rolling mill rolls are listed in Figure 3.37. Because of these mechanical factors and thermal stress factors that can be introduced, it is difficult if not impossible to predict stress on a theoretical basis. Charlie Chong/ Fion Zhang
Page 1 and 2:
Electromagnetic Testing Chapter 3-
Page 3 and 4:
Submarine Applications Charlie Chon
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Fion Zhang at Shanghai 6th April 20
Page 13 and 14:
IVONA TTS Capable. Charlie Chong/ F
Page 15 and 16:
Chapter 3. ELECTROMAGNETIC TESTING
Page 17 and 18:
Barkhausen effect The Barkhausen ef
Page 19 and 20:
Barkhausen Noise Charlie Chong/ Fio
Page 21 and 22:
Figure 3.1 Eddy current principle.
Page 23 and 24:
Figure 3.2 Schematic diagram of bas
Page 25 and 26:
Figure 3.3 The effect of conductivi
Page 27 and 28:
Figure 3.3 The effect of conductivi
Page 29 and 30:
Another important influence on coil
Page 31 and 32:
If the conductivity of the material
Page 33 and 34:
Figure 3.5 The effect of a crack on
Page 35 and 36:
FIGURE 8-49 Conductivity curve: (a)
Page 37 and 38:
So far, we have described how eddy
Page 39 and 40:
Figure 3.6 The effects of (a) condu
Page 41 and 42:
3.1.2 Limiting Frequency f g of Enc
Page 43 and 44:
Figure 3.7 The effect of degree of
Page 45 and 46:
Charlie Chong/ Fion Zhang
Page 47 and 48:
Eddy Current Heating Charlie Chong/
Page 49 and 50:
Eddy Current Heating Charlie Chong/
Page 51 and 52:
Eddy currents weaken the original m
Page 53 and 54:
3.2 MAGNETIC FLUX LEAKAGE THEORY Wh
Page 55 and 56:
3D Magnetic Field Charlie Chong/ Fi
Page 57 and 58:
3D Magnetic Field Fig.1 THE PRINCIP
Page 59 and 60:
Based on what we have learned about
Page 61 and 62:
Charlie Chong/ Fion Zhang Figure 3.
Page 63 and 64:
Magnetic Field - Simple Semi Ellipt
Page 65 and 66:
Flux leakage sensors have small dia
Page 67 and 68:
The frequency of the alternating fi
Page 69 and 70:
Figure 3.14 Rotating magnet arrange
Page 71 and 72:
3.3 EDDY CURRENT SENSING PROBES For
Page 73 and 74:
As the probe moves over the defect,
Page 75 and 76:
Figure 3.17 Differential surface co
Page 77 and 78:
Figure 3.19 shows an encircling coi
Page 79 and 80:
The application of eddy current sen
Page 81 and 82:
Baffles and tube sheets. Charlie Ch
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Another important consideration for
Page 91 and 92:
3.4.1 Induction Coils For an induct
Page 93 and 94:
If the diameter of a surface coil i
Page 95 and 96:
3.4.2 Hall Effect Sensors Hall effe
Page 97 and 98:
Figure 3.21 illustrates the Hall ef
Page 99 and 100:
Hall voltage Charlie Chong/ Fion Zh
Page 101 and 102:
Since a 1 gauss (G) field produces
Page 103 and 104:
Figure 3.22 Effect of magnetic fiel
Page 105 and 106:
3.5 FACTORS AFFECTING FLUX LEAKAGE
Page 107 and 108:
Defect & Flux Distribution Charlie
Page 109 and 110:
The distance between adjacent defec
Page 111 and 112:
3.6 SIGNAL-TO-NOISE RATIO The signa
Page 113 and 114:
With flux leakage testing, signal-t
Page 115 and 116:
As shown in Eq. (3.6), test frequen
Page 117 and 118:
The characteristic frequency for a
Page 119 and 120:
Charlie Chong/ Fion Zhang
Page 121 and 122:
Figure 3.23 Magnetization or magnet
Page 123 and 124:
By taking the product of B and H fo
Page 125 and 126:
The rate of change of the opposing
Page 127 and 128:
Figure 3.25 Encircling coils establ
Page 129 and 130: Figure 3.27 DC-MFL sensor illustrat
Page 131 and 132: Fill factors apply only to encircli
Page 133 and 134: For best results with encircling co
Page 135 and 136: 3.11 INSTRUMENT DESIGN CONSIDERATIO
Page 137 and 138: Charlie Chong/ Fion Zhang Figure 3.
Page 139 and 140: TABLE 3.2. Comparison of Instrument
Page 141 and 142: Some general categories of equipmen
Page 143 and 144: Figure 3.29 UniWest-454 EddyView mu
Page 145 and 146: Scanner operation uses a separate c
Page 147 and 148: Figure 3.30 E-Lab model US-450 full
Page 149 and 150: 3.12.3 ETC-2000 Scanner Because of
Page 151 and 152: ETC-2000 scanner features include:
Page 153 and 154: 3.13 INSTITUT DR. FOERSTER Institut
Page 155 and 156: It is possible to provide 100% eddy
Page 157 and 158: Figure 3.33 ET testing of hot coppe
Page 159 and 160: For maximum sensitivity, the Circog
Page 161 and 162: 3.14 MAGNETIC FLUX LEAKAGE TESTING
Page 163 and 164: ASTM E 570 describes magnetic flux
Page 165 and 166: Charlie Chong/ Fion Zhang Figure 3.
Page 167 and 168: Applications involving physical par
Page 169 and 170: Inexpensive 60 Hz eddy current comp
Page 171 and 172: 4. Measure the length of nonwelded
Page 173 and 174: Some general applications for the f
Page 175 and 176: Permanent magnets are the preferred
Page 177 and 178: Robot Charlie Chong/ Fion Zhang
Page 179: 3.17.1 Introduction In 1911, Dr. He
Page 183 and 184: Typical roll failures are caused by
Page 185 and 186: This technique has been found to be
Page 187 and 188: Figure 3.38 A comparison of Barkhau
Page 189 and 190: Figure 3.39 Three-channel Rollscan
Page 191 and 192: The appropriate depth of measuremen
Page 193 and 194: 3.17.5 Calibration and Testing Bark
Page 195 and 196: Comparative studies by Kirsti Titto
Page 197 and 198: 3.17.6 Current Applications Barkhau
Page 199 and 200: 3.17.9 Pipe/Tubing/Sheet/Plate Manu
Page 201 and 202: EMATs overcome many common ultrason
Page 203 and 204: 3.18.1 EMATs Advantages Over Piezoe
Page 205 and 206: 3.18.3 Recent Applications And Deve
Page 207 and 208: Figure 3.44 Courtesy of Weld Inspec
Page 209 and 210: 3.19 ALTERNATING CURRENT FIELD MEAS
Page 211 and 212: 3.19.1 Acfm Principles Of Operation
Page 213 and 214: Figure 3.45 Current flow and induce
Page 215 and 216: 3.19.2 Bx and Bz Components The pre
Page 217 and 218: 3.19.3 Butterfly Plot To aid interp
Page 219 and 220: 3.19.4 Probe Design Standard ACFM p
Page 221 and 222: Figure 3.48 Flowchart selection of
Page 223 and 224: 3.31 APPLICATIONS One active encode
Page 225 and 226: Other applications include: • Ins
Page 227 and 228: Eddy Current Testing at High Temper
Page 229 and 230: Good Luck Charlie Chong/ Fion Zhang
show all

Electromagnetic Testing Chapter 3- Electromagnetic Testing

Create successful ePaper yourself

Delete template?

Save as template?