Ternecoated And Leadclad Steel

Lead and terne, an alloy of lead (80-90%) and tin (20-10%), are used as finishes to steel and stainless steel for cladding and roofing units. Terne can be applied to sheet stainless steel as a 20 micron layer by immersion in the molten alloy. Terne-coated stainless steel does not suffer from bimetallic corrosion and can normally be used in contact with lead, copper, aluminium or zinc. Thermal movement is similar to stainless steel, allowing for units up to 9 m in length to be used for roofing and cladding. The composite material, lead-clad steel, is produced by cold-roll bonding 0.75 mm lead to 1.0 mm terne-plated steel or to 0.8 mm terne-plated stainless steel. Lead-clad steel is suitable for cladding and roofing systems and has the appearance and corrosion resistance of milled lead. Because of the support afforded by the steel substrate, lead-clad steel or stainless steel can be used for self-supported fasciae, soffits, gutters and curved sections. Joints can be lead burned and soldered as traditional lead. Cut ends should be protected by soldering in the case of lead-clad steel, although the stainless steel version requires no protective treatment. Unlike traditional lead, the material is virtually theft-proof and does not suffer significantly from creep. Patination oil should be applied to the lead surface after installation to prevent staining effects.

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