Editing Thermite (section)

== Civilian uses ==
[[Image:Velp-thermitewelding-1.jpg|thumb|Thermite reaction proceeding for a railway welding. Shortly afterwards, the liquid iron flows into the mould around the rail gap.]]
[[Image:Thermite residues (railway welding).JPG|thumb|Remains of ceramic moulds used for thermite welding like the ones pictured here, left by railway workers near Årstafältet tramway station in Stockholm, Sweden, can sometimes be found along tracks.]]

Thermite reactions have many uses. It is not an explosive; instead, it operates by exposing a very small area to extremely high temperatures. Intense heat focused on a small spot can be used to cut through metal or weld metal components together both by melting metal from the components, and by injecting molten metal from the thermite reaction itself. {{citation needed|date=June 2021}}

Thermite may be used for repair by the welding in-place of thick steel sections such as [[locomotive]] [[axle]]-frames where the repair can take place without removing the part from its installed location.<ref>{{cite book|last1=Jeffus|first1=Larry|title=Welding principles and applications|date=2012|publisher=Delmar Cengage Learning|location=Clifton Park, N.Y.|isbn=978-1111039172|pages=744|edition=7th|url=https://books.google.com/books?id=uU0gBN2aYSgC&q=thermite+welding&pg=PA744|language=en}}</ref>

Thermite can be used for quickly cutting or welding steel such as [[rail tracks]], without requiring complex or heavy equipment.<ref>{{cite web|url=http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=TS19061115.2.43 |title=Papers Past — Star — 15 November 1906 — NEW WELDING PROCESS |publisher=Paperspast.natlib.govt.nz |date=15 November 1906 |access-date=12 October 2011}}</ref><ref>{{cite news|url=https://news.google.com/newspapers?id=wHw1AAAAIBAJ&pg=6875,1950492 |title=How Many Ways to Weld Metal? |newspaper=Eugene Register-Guard |date=8 December 1987 |access-date=12 October 2011}}</ref> However, defects such as slag inclusions and voids (holes) are often present in such welded junctions, so great care is needed to operate the process successfully. The numerical analysis of thermite welding of rails has been approached similar to casting cooling analysis. Both this [[finite element analysis]] and experimental analysis of thermite rail welds has shown that weld gap is the most influential parameter affecting defect formation.<ref>{{cite journal|last1=Chen|first1=Y|last2=Lawrence|first2=F V|last3=Barkan|first3=C P L|last4=Dantzig|first4=J A|title=Heat transfer modelling of rail thermite welding|journal=Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit|date=24 October 2006|volume=220|issue=3|pages=207–217|doi=10.1243/09544097F01505|citeseerx=10.1.1.540.9423|s2cid=17438646}}</ref> Increasing weld gap has been shown to reduce shrinkage cavity formation and cold lap [[welding defect]]s, and increasing preheat and thermite temperature further reduces these defects. However, reducing these defects promotes a second form of defect: microporosity.<ref>{{cite journal|last1=Chen|first1=Y|last2=Lawrence|first2=F V|last3=Barkan|first3=C P L|last4=Dantzig|first4=J A|title=Weld defect formation in rail thermite welds|journal=Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit|date=14 December 2006|volume=220|issue=4|pages=373–384|doi=10.1243/0954409JRRT44|citeseerx=10.1.1.501.2867|s2cid=16624977}}</ref> Care must also be taken to ensure that the rails remain straight, without resulting in dipped joints, which can cause wear on high speed and heavy axle load lines.<ref>{{cite web|url=http://goliath.ecnext.com/coms2/gi_0199-2063863/Strengthening-the-track-structure-for.html |title=Strengthening the track structure for heavy axle loads: strengthening track infrastructure provides another method of dealing with ever-increasing car capacities. (TTCI R&D). |publisher=Goliath Business News|date=1 September 2002 |access-date=12 October 2011}}</ref> Studies to make the hardness of thermite welds to repair tracks have made improvements to the hardness to compare more to the original tracks while keeping its portable nature.<ref name=":02">{{Cite journal |last1=Oo |first1=Hein Zaw |last2=Muangjunburee |first2=Prapas |date=March 2023 |title=Improving microstructure and hardness of softening area at HAZ of thermite welding on rail running surface |url=https://linkinghub.elsevier.com/retrieve/pii/S2352492823001757 |journal=Materials Today Communications |language=en |volume=34 |pages=105485 |doi=10.1016/j.mtcomm.2023.105485}}</ref>

As the reaction of thermite is oxidation-reduction and environmentally friendly, it has started to be adapted into use for sealing oil wells instead of using concrete. Though thermite is usually in a powder-state, a diluted mixture can reduce damage to the surroundings during the process, though too much alumina can risk hurting the integrity of the seal.<ref>{{Cite journal |last1=De Souza |first1=Kesiany M. |last2=de Lemos |first2=Marcelo J.S. |date=May 2023 |title=Advanced one-dimensional modeling of thermite reaction for thermal plug and abandonment of oil wells |url=https://linkinghub.elsevier.com/retrieve/pii/S0017931023000686 |journal=International Journal of Heat and Mass Transfer |language=en |volume=205 |pages=123913 |doi=10.1016/j.ijheatmasstransfer.2023.123913|bibcode=2023IJHMT.20523913D }}</ref><ref>{{Cite journal |last1=De Souza |first1=Kesiany M. |last2=de Lemos |first2=Marcelo J.S. |last3=Ribeiro |first3=Roberta dos R. |last4=Marin |first4=Ana M.G. |last5=Martins |first5=Paulo G.C. |last6=Gouvêa |first6=Leonardo H. |date=March 2024 |title=Experimental investigation of Al-Fe2O3 thermite reactions for thermal plug and abandonment of oil wells |url=https://linkinghub.elsevier.com/retrieve/pii/S2949891023012071 |journal=Geoenergy Science and Engineering |language=en |volume=234 |pages=212620 |doi=10.1016/j.geoen.2023.212620}}</ref> A higher concentration of mixture was needed to melt the plastic of a model tube, making it a favorable mixture.<ref>{{Cite journal |last1=Pena |first1=Fabrício J.C. |last2=de Souza |first2=Kesiany M. |last3=de Lemos |first3=Marcelo J.S. |date=December 2023 |title=Thermal behavior of aluminothermic thermite reaction for application in thermal sealing of oil wells |url=https://linkinghub.elsevier.com/retrieve/pii/S073519332300502X |journal=International Communications in Heat and Mass Transfer |language=en |volume=149 |pages=107113 |doi=10.1016/j.icheatmasstransfer.2023.107113|bibcode=2023ICHMT.14907113P }}</ref> Other experiments have been done to simulate the heat flux of the well sealing to predict the temperature on the surface of the seal over time.<ref>{{Cite journal |last1=Dourado da Silva |first1=Rodrigo G. |last2=Magalhães |first2=Elisan S. |last3=Pires |first3=Luis Carlos M. |date=November 2023 |title=Estimation of thermal input in thermite reaction for innovative wellbore plugging & abandonment techniques |url=https://linkinghub.elsevier.com/retrieve/pii/S0735193323004608 |journal=International Communications in Heat and Mass Transfer |language=en |volume=148 |pages=107071 |doi=10.1016/j.icheatmasstransfer.2023.107071|bibcode=2023ICHMT.14807071D }}</ref>

A thermite reaction, when used to purify the [[ore]]s of some metals, is called the {{vanchor|thermite process}}, or aluminothermic reaction. An adaptation of the reaction, used to obtain pure [[uranium]], was developed as part of the [[Manhattan Project]] at [[Ames Laboratory]] under the direction of [[Frank Spedding]]. It is sometimes called the [[Ames process]].<ref>{{cite patent | country = US | number = 2830894 | status = patent | title = Production of Uranium | gdate = 1958 | fdate = 1947 | invent1 = Spedding, Frank H. | invent2 = Wilhelm, Harley A. | invent3 = Keller, Wayne H. | assign1 = [[United States Atomic Energy Commission]]}}</ref>

Copper thermite is used for welding together thick copper wires for the purpose of electrical connections. It is used extensively by the electrical utilities and telecommunications industries ([[exothermic welded connection]]s).