MEGA LAB PROPOSAL

Stephanie Nystrom

TEST PIECE: CIRCUIT BREAKER

Made of three different materials:

• Copper base• Silver-Tungsten Contact

(graphite)• Galvanized Steel

TEST PIECE: CIRCUIT BREAKER

Three Material Identification (Resistivity)

Three Material Thicknesses

Matrix Structure-Homogeneity of the PM Contact

Join Integrity-Lack of Fusion

OBJECTIVES

Three Material Identification (Resistivity)

Copper Thickness

Change in Microstructure of the Steel due to Heat Damage

Theory

%IACS Calibration: 1st try

17, 35, 37• Copper: NA• Steel: 29.035-30.826

• 30.42• PM: 34.47-34.53

MATERIAL ID: %IACS

%IACS Calibration: 2nd try

17, 37, 60• Copper: 63.8-70.29

• 69.57• Steel: -5.01• PM: 56.46Tungsten: 30-31.4

Graphite: 0.22Silver: 105.00-6.00 (%18 Ni))

MATERIAL PROPERTIES

Copper Steel Ag/W PM%IACS 69.57% ¿30.42%? 34.47%Gain 15 dB 15 dB 15 dBR 1.097 [V] 0.022 [V] 1.135 [V]X -1.734 [V] 2.212 [V] 1.531 [V]θ -57.68° 89.43° 53.45°Z 2.052 2.212 1.906σ 40.351

[MS/m]17.644 [MS/m]

19.993 [MS/m]

Ω [Ωm] 2.478x10^-8

5.668x10^-8

5.002x10^-8

Ultrasonic

Calibration Blocks

Calibrate machine: 4682 m/s

Calipers: 2.01mm

UT: 2.01-2.03mm

COPPER THICKNESS

PM THICKNESS & MICROSTRUCTURE

??? Or $$$

A bit big…

Heat Damage->Microstructure

Heat Gun-> Heat, not deform

MICRO STR U CTUR E:HEAT DAMAGE

Fried

Before Heat Damaged

X: -9.0102 V

Y: 14.2993 V

COPPER

After Heat Damaged

X: -9.1158 V

Y: 14.4780 V

Before Heat Damage

X: -.7324 V

Y: -14.8754 V

GALVANIZED STEEL

After Heat Damaged

X: -1.2922 V

Y: -14.8754 V

By Heating the Steel:• Decreased

Resistivity• -.5598

• Increased Conductivity

• Annealing

Example: Circuit Overload

GALVANIZED STEEL

Measured Thickness: 1.65mm

UT: Time-.23μs

Sound Velocity= distance/time=

1.65mm/.23μs=7.174 mm/μs

SOU ND VELO CITY:TU NGSTEN/S ILVER

INTERFACE??? THEORY

QUESTIONS?