Terne plate is a form of

tinplate Tinplate consists of sheets of steel coated with a thin layer of tin to impede rusting. Before the advent of cheap milled steel, the backing metal was wrought iron. While once more widely used, the primary use of tinplate now is the manufacture of ...

: a thin

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

sheet coated with an alloy of

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

and

tin Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...

. 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 A tinsmith is a person who makes and repairs things made of tin or other light metals. The profession may sometimes also be known as a tinner, tinker, tinman, or tinplate worker; whitesmith may also refer to this profession, though the same w ...

ed sheet metal goods, such as storage vessels, jugs and

funnel A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening. Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its construct ...

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

had been replaced with the metal

zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

and was used in the ratio of 50% tin and 50% zinc. This alloy had a low melting point of approximately 360 degrees Fahrenheit but is no longer available. 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

to inhibit

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

. 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. Historical terne metal must be painted. If the paint is maintained, terne metal can last 90 years or more. Terne coated

stainless steel Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...

(TCS II or Roofinox) or

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

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. Terne II used

in place of lead for environmental reasons. Today's main reason and benefit of the tin coating is its aesthetic behavior. 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

ferritic A ferrite is a ceramic material made by mixing and firing large proportions of iron(III) oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as strontium, barium, manganese, nickel, and zinc. Th ...

and is used for normal environments; for coastal applications, the

austenitic Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 ...

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

. 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 had been replaced by a terne coated stainless steel product (Roofinox tin-plated (Terne)), available at most roofing supply stores.

References

External links

{{Wiktionary, terne, terneplate
Places to learn Terne Tin
Building materials Tin alloys

Use

Terminology

See also

References

External links