Terne metal roofing is made from steel sheets hot dipped in an alloy of which two metals?

Terne metal roofing is indeed made from steel sheets that are hot dipped in an alloy of lead and tin. This specific alloy provides several advantages that are particularly beneficial for roofing applications.

Lead and tin create a protective layer that is resistant to corrosion and offers durability against harsh weather conditions. The combination of these metals enhances the roofing material's longevity and helps to prevent rusting, which is critical for maintaining the integrity of a building over time. Additionally, the lead-tin alloy can be easily worked and formed during installation, making it a practical choice for roofing applications.

The other alloys mentioned in the options, while used in different applications, do not provide the same properties that make lead and tin particularly effective for roofing. For instance, zinc is sometimes used with other materials, but it does not have the same characteristics as lead and tin in terms of corrosion resistance and durability when used as an alloying component for roofing sheets.