---
title: "Monel 400 — density, melting point and properties"
description: "Monel 400 has a density of 8,800 kg/m³. Melting point, strength, conductivity, what it is used for, and whether it floats, rusts or is magnetic."
url: https://atoneplace.net/material/monel-400/
site: "At One Place"
---

# Monel 400

**Density of Monel 400: 8,800 kg/m³**

8.80 g/cm³ · 549.4 lb/ft³

Roughly two thirds nickel and one third copper, one of very few alloys that resists flowing seawater indefinitely, including in the crevices where 316 stainless eventually pits. It is the standard material for hydrofluoric acid, which attacks glass and most steels. Being nickel-rich it is tough and gummy to machine, and it is expensive enough that it appears only where a cheaper material has already been tried and failed.

## Properties

- **Density:** 8,800 kg/m³ — 8.80 g/cm³
- **Melting range:** 1300–1350 °C
- **Tensile strength:** 480–620 MPa
- **Young's modulus:** 179 GPa
- **Thermal conductivity:** 21.8 W/(m·K)
- **Thermal expansion:** 13.9 µm/(m·K)
- **Floats in water:** No
- **Magnetic:** No

## What it is used for

- Seawater pumps, valves and piping
- Marine propeller shafts
- Hydrofluoric acid plant
- Musical instrument strings

## 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
- Monel 400: 8,800 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× |
| Monel 400 ← | 8,800 kg/m³ | 8.80× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |

## Does it rust?

Monel 400 does not rust — rust is iron oxide specifically — but it does corrode, forming its own oxide or salts over time.

## Is it magnetic?

Monel 400 is not ferromagnetic. Most metals are not.

## Common questions

### What is the density of Monel 400?

8,800 kg/m³, or 8.80 g/cm³.

### Does Monel 400 float?

No. At 8,800 kg/m³ it is denser than water.

### Is Monel 400 magnetic?

Monel 400 is not ferromagnetic. Most metals are not.

## Related pages

- [Does Monel 400 float?](https://atoneplace.net/does-it-float/monel-400/)
- [Mild steel](https://atoneplace.net/material/mild-steel/)
- [Stainless steel 304](https://atoneplace.net/material/stainless-304/)
- [Brass](https://atoneplace.net/material/brass/)
- [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/)

## Sources

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