Editing Invar (section)

== Applications ==
Invar is used where high dimensional stability is required, such as precision instruments, clocks, seismic creep gauges, color-television tubes' [[Shadow mask|shadow-mask]] frames,<ref>{{cite web |title=Nickel & Its Uses |publisher=Nickel Institute |work=Nickel Magazine |date=3 May 2005 |url=http://www.nickelinstitute.org/index.cfm/ci_id/12313.htm |access-date=20 March 2011 |url-status=dead |archive-url=https://web.archive.org/web/20101219005643/http://www.nickelinstitute.org/index.cfm/ci_id/12313.htm |archive-date=19 December 2010 }}</ref> valves in engines and large aerostructure molds.<ref>{{Citation |title=Boeing 787 Fuselage (MIE-375) | date=30 October 2018 |url=https://www.youtube.com/watch?v=VyWFiUnoT5E |access-date=2023-06-29 |language=en}}</ref>

One of its first applications was in watch [[balance wheel]]s and [[pendulum]] rods for precision [[regulator clock]]s.  At the time it was invented, the [[pendulum clock]] was the world's most precise timekeeper, and the limit to timekeeping accuracy was due to thermal variations in length of clock pendulums.  The [[Riefler regulator clock]] developed in 1898 by Clemens Riefler, the first clock to use an Invar pendulum, had an accuracy of 10 milliseconds per day, and served as the primary time standard in [[naval observatory|naval observatories]] and for national time services until the 1930s.

In [[Surveying|land surveying]], when first-order (high-precision) elevation [[leveling]] is to be performed, the [[level staff]] (leveling rod) used is made of Invar, instead of wood, fiberglass, or other metals.<ref>{{Cite book |last1=Baričević |first1=Sergej |last2=Barković |first2=Đuro |last3=Zrinjski |first3=Mladen |last4=Staroveški |first4=Tomislav |chapter=Development of Levelling Staff Scale Calibration Method by Integrating a CCD Camera |date=2022 |editor-last=Ademović |editor-first=Naida |editor2-last=Mujčić |editor2-first=Edin |editor3-last=Akšamija |editor3-first=Zlatan |editor4-last=Kevrić |editor4-first=Jasmin |editor5-last=Avdaković |editor5-first=Samir |editor6-last=Volić |editor6-first=Ismar |title=Advanced Technologies, Systems, and Applications VI |chapter-url=https://link.springer.com/chapter/10.1007/978-3-030-90055-7_40 |series=Lecture Notes in Networks and Systems |volume=316 |language=en |location=Cham |publisher=Springer International Publishing |pages=514–521 |doi=10.1007/978-3-030-90055-7_40 |isbn=978-3-030-90055-7}}</ref><ref>{{Cite web |title=ISO 12858-1:2014 Optics and optical instruments — Ancillary devices for geodetic instruments — Part 1: Invar levelling staffs |url=https://www.iso.org/standard/57606.html |access-date=2023-09-02 |website=ISO |language=en}}</ref> Invar struts were used in some pistons to limit their thermal expansion inside their cylinders.<ref>{{cite book|title=Internal combustion engines illustrated|year=1947|publisher=Odhams Press Limited|location=Long Acre, London|page=85}}</ref> In the manufacture of large [[composite material]] structures for [[aerospace]] [[Carbon fiber reinforced polymer|carbon fibre]] [[layup mold]]s, Invar is used to facilitate the manufacture of parts to extremely tight tolerances.<ref>[https://www.aero-mag.com/tooling-mould-die/ Tooling to mould and die for!] {{Webarchive|url=https://web.archive.org/web/20180410202335/https://www.aero-mag.com/tooling-mould-die/ |date=10 April 2018 }}, Mike Richardson, Aerospace Manufacturing, 6 April 2018, accessed 10 April 2018.</ref><ref>{{Cite book|first1=Hiromichi T.|last1=Fujii|first2=Haruyasu|last2=Ohno|first3=Naoki|last3=Sakaguchi|first4=Shingo|last4=Matsumura|first5=Kotaro|last5=Ona|first6=Junichi|last6=Go|first7=Umito|last7=Yoshioka|title=Camx Proceedings |chapter=Revolutionizing molding precision for aviation and urban air mobility: The power of low thermal expansion tooling in CFRTP press forming |year=2024|chapter-url=https://www.nasampe.org/store/viewproduct.aspx?id=24547917|volume=TP24|pages=237|doi=10.33599/nasampe/c.24.0237 }}</ref>

In the astronomical field, Invar is used as the structural components that support dimension-sensitive optics of astronomical telescopes.<ref>{{Cite book|first1=Hiromichi T.|last1=Fujii|first2=Naoki|last2=Sakaguchi|first3=Kotaro|last3=Ona|first4=Yutaka|last4=Hayano|first5=Fumihiro|last5=Uraguchi|title=Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV |chapter=Precise control of negative thermal expansion in stainless invar type alloy for astronomical telescopes |editor-first1=Roland |editor-first2=Ramón |editor-last1=Geyl |editor-last2=Navarro |year=2020|chapter-url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11451/2561193/Precise-control-of-negative-thermal-expansion-in-stainless-invar-type/10.1117/12.2561193.short|volume=11451|pages=1145118|doi=10.1117/12.2561193 |bibcode=2020SPIE11451E..18F |isbn=9781510636897 |s2cid=230575165 |accessdate=2021-05-08}}</ref> Superior dimensional stability of Invar allows the astronomical telescopes to significantly improve the observation precision and accuracy.