Thermite!

You wouldn’t like it when it’s angry!

Drew Moug, Ginny Raymond, Michael “Miguel” Schantz, Lorenzo TulipanoENGR 45, 11 May 2009, SRJC

The Basics

Thermite is a combination of Iron Oxide (rust) and Aluminum that, when it reacts, creates an unstoppable reaction that produces molten metal at temperatures reaching 2500˚C. The reaction is as follows:

Fe2O3 + 2Al --> Al2O3 + 2Fe

A Little History

• The Thermite reaction was discovered, and later patented, by German chemist Dr. Hans Goldschmidt.

• The Doctor realized the application in welding, and the first commercial use of Thermite was welding two pieces of train track together in 1899.

• This would serve to be the primary use of Thermite

About Thermite Welding

• Ideal for welding train tracks• No track removal necessary• Very portable

Raw Data

Weld type:SMAW (7018) Weld type: MIG Weld type: TIG Weld type: Thermite

b, width (in): 2.9940 b, width (in): 2.9955 b, width (in): 2.9945 b, width (in): 2.9930

d, depth (in): 0.2490 d, depth (in): 0.2415 d, depth (in): 0.2410 d, depth (in): 0.2440

L, support span (in): 4.7255

L, support span (in): 5.8735

L, support span (in): 4.2750

L, support span (in): 5.8735

Fmax (lbf): 3540 Fmax (lbf): 2860 Fmax (lbf): 3180 Fmax (lbf): 280

Deflection (in) Force (lbf) Deflection (in) Force (lbf) Deflection (in) Force (lbf) Deflection (in) Force (lbf)

0.000 70 0.000 310 0.000 0 0.000 0

0.002 110 0.002 730 0.002 40 0.002 10

0.004 160 0.004 750 0.004 70 0.004 30

0.006 220 0.006 780 0.006 110 0.006 50

0.008 280 0.008 810 0.008 140 0.008 70

0.010 320 0.010 830 0.010 180 0.010 90

0.012 380 0.012 860 0.012 210 0.012 120

0.014 430 0.014 890 0.014 250 0.014 130

0.016 480 0.016 920 0.016 290 0.016 150

0.018 540 0.018 940 0.018 320 0.021 180

0.020 600 0.020 970 0.020 360 0.026 210

0.030 910 0.030 1110 0.030 540 0.036 240

0.040 1230 0.040 1250 0.040 740 0.046 260

0.050 1520 0.050 1390 0.050 970 0.066 280

0.060 1740 0.060 1520 0.060 1180 0.076 280

0.070 1910 0.070 1620 0.070 1390 0.086 280

0.080 2000 0.080 1710 0.080 1550 0.111 270

0.090 2080 0.090 1800 0.090 1690 0.136 260

0.100 2150 0.100 1880 0.100 1820 0.161 250

0.150 2340 0.150 2120 0.150 2150 0.236 210

0.200 2410 0.200 2220 0.200 2240 0.386 180

0.300 2580 0.300 2340 0.300 2400 0.586 110

0.400 2790 0.400 2440 0.400 2780 0.786 70

0.500 2950 0.450 2490 0.450 2910 0.886 60

MIGSMAW TIG Thermite

Problems with Thermite Welds

• The weld can be porous, resulting in weaker welds than traditional welding, as seen here

Weld Comparison Bend Test• In order to see the relative strength of a Thermite weld, we compared it to three other types of traditional welds; shielded metal arc weld (SMAW), metal inert gas (MIG), and tungsten inert gas (TIG).

• All of our welds were done with ¼ in. thick mild steel (<.29% Carbon), and the welds are approximately 3 in. wide.

• After the welds were completed, we tested them in a bend/flexural strength test, where we recorded force and deflection distance.

• Stress, strain, and the flexural modulus were calculated with the following equations:

Raw data has been omitted due to its extensive size.

(Results)Weld Comparison Bend Test

Weld Comparison Bend Test

MIG SMAW TIG

Thermite

Sources• eHow: http://www.ehow.com/how_2081916_make-thermite.html• University of Illinois: http://fcp.mechse.illinois.edu/media/pdfs/Lawrence

%20presentation.pdf• Wikipedia:

– Thermite: http://en.wikipedia.org/wiki/Thermite– Carbon Steel: http://en.wikipedia.org/wiki/Carbon_steel