Terne

[turn]

Terne is an alloy coating of lead and tin used to cover steel, in the ratio of 20% tin and 80% lead. Terne is used to coat sheet steel to inhibit corrosion. It is the one of the cheapest alloys suitable for this, and the tin content is kept at a minimum while still adhering to a hot-dipped iron sheet, to minimize the cost.

The term "nonterne" is frequently used to refer to substances or materials that do not contain terne or have not had terne used in their creation, as in the expression, "nonterne-plated oil filters."

Terne-coated steel is also known as terne-metal and often referred to as "tin" (see the Slate Roof Bible). You can still buy terne-coated steel at any roofing supply store.

Terne metal must be painted. If the paint is maintained, terne metal can last 90 years or more. Terne coated STAINLESS steel (TCS) or copper is commonly used to replace terne metal roofs as either material will outlast terne metal. TCS or copper roofing can last 50 years or more unpainted.

Terne II uses zinc in place of lead for environmental reasons. The new terne coated stainless is called TCSII.

The main element used in the production of Terne coils is steel.