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{{Short description|Alloy of lead and tin}}
{{Refimprove|date=August 2020}}

'''Terne''' plate is a form of [[tinplate]]: a thin [[steel]] sheet coated with an alloy of [[lead]] and [[tin]]. The terne alloy was in the ratio of 10-20% tin and the remainder lead. The low tin content made it cheaper than other tinplates.

Terne plate was used for [[tinsmith]]ed sheet metal goods, such as storage vessels, jugs and [[funnel]]s, particularly for industrial use with flammable liquids. Unlike tinplate, it was not used for long-term storage or around food items, owing to the high lead content.  Terne plate has also been used for roofing, as a cheaper alternative to zinc or lead.

Until 2012 [[lead]] had been replaced with the metal [[zinc]] and was used in the ratio of 50% tin and 50% zinc. This alloy had a low melting point of approximately {{cvt|360|F|C}} but is no longer available.<ref>{{cite web |title=Follansbee Steel to Close |url=https://www.statejournal.com/story/16510860/follansbee-steel-to-close/ |website=StateJournal |access-date=29 January 2025}}</ref><ref>{{cite web |title=Follansbee Steel Forced to Shut the Doors of its 110 Years Old Plant |url=https://www.steelorbis.com/steel-news/latest-news/follansbee-steel-forced-to-shut-the-doors-of-its-110-year-old-plant-654306.htm#:~:text=West%20Virginia%2Dbased%20Follansbee%20Steel,closure%20on%20poor%20market%20conditions. |access-date=29 January 2025}}</ref> Today terne-coated metal is coated with 99.9% tin, instead of hot-dipping, a more consistent galvanic deposition process is applied. Additionally the substrate has been changed from steel to stainless steel, benefitting from the corrosion resistance of stainless steel alloys. The pure tin alloy makes soldering easier, as the melting point is homogenised and doesn't need to match the melting point of two metals with different melting temperatures.

==Use==

Terne was historically used to coat sheet [[steel]] to inhibit [[corrosion]]. It was one of the cheapest alloys suitable for this, and the tin content was kept at a minimum while still adhering to a hot-dipped iron sheet, to minimize the cost.{{Citation needed|date=November 2009}}

Historical terne metal must be painted. Terne metal can last 90 years or more if the paint is maintained. Terne-coated [[stainless steel]] (TCS II or [https://www.roofinox.com/ Roofinox]), or [[copper]] is commonly used to replace terne metal roofs as either material will outlast terne metal. Terne-coated stainless steel roofing can last 100 years or more unpainted; copper roofing can last 50 years or more unpainted.<ref>{{cite web |title=Follansbee TCS |url=https://cms.esi.info/Media/documents/Matth_TCS_ML.pdf |website=ESI.info |access-date=29 January 2025}}</ref><ref>{{cite web |title=Terne Roofing |url=https://www.roofingcontractor.com/articles/83767-terne-roofing |website=Roofing Contractor |access-date=29 January 2025}}</ref>

Terne II used [[zinc]] in place of lead for environmental reasons.<ref>{{cite web |title=Terne Over New Roof |url=https://trainmuseum.blogspot.com/2012/06/terne-over-new-roof.html |website=Northwest Railway Museum |access-date=29 January 2025}}</ref> Today's aesthetic behavior is the main reason and benefit of the tin coating. Tin develops a natural matte grey patina when exposed to the elements. The result of the weathering process depends on the environment and climate conditions present. Depending on the environment and atmospheric conditions different substrate alloys are used. The stainless steel alloy 439 is [[Allotropes of iron|ferritic]] and is used for normal environments; for coastal applications, the [[Austenite|austenitic]] stainless steel alloy 316L is used providing an increased corrosion resistance to chlorides.

==Terminology==
The term "terne" is derived from the French word for "dull" and was probably in reference to its dull appearance in comparison to the shiny surface of [[tinplate]].<ref>{{cite book |last1=Simpson |first1=Pamela H. |title=Cheap, Quick, & Easy: Imitative Architectural Materials 1870-1930 |date=1999 |publisher=University of Tennessee Press |location=Knoxville |isbn=978-1-62190-157-0 |page=33 |url=https://www.bibliovault.org/BV.book.epl?ISBN=9781572330375}}</ref>

Terne-coated steel is also known as terne-metal and often referred to as "tin" (see the ''Slate Roof Bible''). Traditional terne-coated steel cannot be purchased anymore; it has been replaced by a terne-coated stainless steel product (Roofinox tin-plated (Terne)), available at most roofing supply stores.<ref>{{cite web |title=Roofinox Stainless Steel Chosen to Fill Market Void Left by Follansbee |url=https://www.facilitiesnet.com/site/pressreleases/Roofinox-Companyaposs-Stainless-Steel-Chosen-to-Fill-Market-Void-Left-by-Follansbee--36595 |website=FacilitiesNet |access-date=29 January 2025}}</ref>

==See also==
*[[International Tin Council]]
*[[Tinning]]
*[[Cassiterides]]
*[[Tin pest]]

==References==
{{reflist}}

==External links==
{{Wiktionary|terne|terneplate}}

*[https://web.archive.org/web/20080611121212/http://howardhallfarm.com/ternetin.html Places to learn Terne Tin]
*[https://historicengland.org.uk/images-books/publications/church-roof-replacement-terne-coated-stainless-steel/ Historic England: Church Roof Replacement Using Terne-coated Stainless Steel]
*[https://historicengland.org.uk/images-books/publications/theft-metal-church-roofs-replacement-materials/heag305-theft-metal-church-roofs-replacement-materials/ Historic England: Theft of Metal from Church Roofs: Replacement Materials]
*[https://www.roofinox.com/en-us/products/design-surfaces/tin-terne/ Current example of terne coated stainless steel product]

[[Category:Building materials]]
[[Category:Tin alloys]]