Lead

Dense, soft and cheap, which is a rare combination and why it survives in shielding and ballast despite its toxicity. At 11,340 kg/m³ it is 44% denser than steel, so a lead brick the size of a house brick weighs about 25 kg. It creeps at room temperature — a lead sheet left vertical will slowly flow downwards over decades, which is why lead roofing is fixed in short bays rather than long runs.

Properties

Density

11,340 kg/m³ — 11.34 g/cm³

Melting point

327.5 °C

Tensile strength

12–18 MPa

Young's modulus

16 GPa

Thermal conductivity

35.3 W/(m·K)

Thermal expansion

28.9 µm/(m·K)

Floats in water

No

Magnetic

No

What it is used for

• Radiation shielding in X-ray and nuclear work
• Lead-acid battery plates
• Roof flashing and valley gutters
• Diving weights, ballast and wheel weights

How it compares

Does it rust?

Lead does not rust — rust is iron oxide specifically — but it does corrode, forming its own oxide or salts over time.

Is it magnetic?

Lead is not ferromagnetic. It is often assumed to be because it is a metal, but most metals are not — only iron, nickel, cobalt and a few alloys are attracted to an ordinary magnet.