---
title: "Brass — density, melting point and properties"
description: "Brass has a density of 8,500 kg/m³ (8,400–8,730). Melting point, strength, conductivity, what it is used for, and whether it floats, rusts or is magnetic."
url: https://atoneplace.net/material/brass/
site: "At One Place"
---

# Brass

**Density of brass: 8,500 kg/m³ (8,400–8,730)**

8.50 g/cm³ · 530.6 lb/ft³

Copper and zinc, with the ratio setting both the colour and the behaviour: 70/30 cartridge brass draws deeply without splitting, 60/40 is stronger and cheaper, and free-machining brass adds a little lead so it cuts like chalk. It is the standard against which machinability is measured, which is why small turned parts default to it. Brass in contact with ammonia or with residual forming stresses can crack spontaneously — season cracking — which is why drawn cases are stress-relieved.

## Properties

- **Density:** 8,500 kg/m³ (8,400–8,730) — 8.50 g/cm³
- **Melting range:** 900–955 °C
- **Tensile strength:** 300–550 MPa
- **Young's modulus:** 110 GPa
- **Thermal conductivity:** 120 W/(m·K)
- **Thermal expansion:** 20 µm/(m·K)
- **Floats in water:** No
- **Magnetic:** No

## What it is used for

- Plumbing fittings and valves
- Door handles, locks and hinges
- Cartridge cases and musical instruments
- Machined electrical terminals

## How it compares

*Water is 1,000 kg/m³. Anything with a shorter bar than water floats in it.*

- air: 1.2 kg/m³
- expanded polystyrene foam: 20 kg/m³
- rigid polyurethane foam: 40 kg/m³
- Water — the float line: 1,000 kg/m³
- brass: 8,500 kg/m³
- tungsten: 19,250 kg/m³
- gold: 19,300 kg/m³
- platinum: 21,450 kg/m³

*Water is 1,000 kg/m³. Anything below that floats.*

| Material | Density | Relative to water |
| --- | --- | --- |
| rigid polyurethane foam | 40 kg/m³ | 0.04× |
| expanded polystyrene foam | 20 kg/m³ | 0.02× |
| air | 1.2 kg/m³ | 0.00× |
| brass ← | 8,500 kg/m³ | 8.50× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |

## Does it rust?

No. Copper and its alloys cannot rust, since rust is iron oxide. They form a patina instead — copper oxide first, turning to the familiar green carbonate over decades — and that layer is adherent and protective, which is why copper roofs last centuries.

## Is it magnetic?

Brass 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.

## Common questions

### What is the density of brass?

8,500 kg/m³ (8,400–8,730), or 8.50 g/cm³.

### Does brass float?

No. At 8,500 kg/m³ it is denser than water.

### Is brass magnetic?

Brass 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.

## Related pages

- [Does brass float?](https://atoneplace.net/does-it-float/brass/)
- [Mild steel](https://atoneplace.net/material/mild-steel/)
- [Stainless steel 304](https://atoneplace.net/material/stainless-304/)
- [Gray cast iron](https://atoneplace.net/material/cast-iron/)
- [High-carbon steel](https://atoneplace.net/material/carbon-steel/)
- [Stainless steel 316](https://atoneplace.net/material/stainless-316/)
- [Aluminum 6061](https://atoneplace.net/material/aluminum-6061/)
- [Bronze](https://atoneplace.net/material/bronze/)
- [Aluminum 7075](https://atoneplace.net/material/aluminum-7075/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)