What is the Density of Stainless Steel?

The density of stainless steel is an important consideration, having much relevance to the application it is going to be used for. In the simplest terms, density is defined as 'mass per unit volume' and is expressed in the algebraic formula p=m/V ('p' represents density, 'm' represents mass and 'v' represents volume). Thus, density is calculated as mass divided by volume. 

Scientifically, density is expressed as grams per centimetre cubed (g/cm³) but, as stainless steel is usually used in much larger amounts, its density is most often expressed as kilograms per metre cubed (kg/m³). The density of stainless steel varies between 7,600 kg/m³ and 8,000 kg/m³ depending on its grade and composition.   

Austenitic 
Austenitic stainless steels like those of the popular 316 and 304 grades have the highest densities at around 7,980 kg/m³ and 7,930 kg/m³ respectively. This high density enhances their resistance to corrosion and their non-magnetic properties.  

Ferritic
Ferritic stainless steels like grades 430 and 446 have a lower density, averaging around 7,700 kg/m³. This makes ferritic steel both more cost-effective and easier to use in certain applications.  

Martensitic
440, 420 and 410 are some of the most common martensitic stainless steel grades. Though their density is similar to ferritic at between 7,600 kg/m³ and 7,700 kg/m³, they have a high content of carbon that allows them to be hardened through heat treatment.

Many factors can affect the density of stainless steel, including:

• Composition of the alloy. The density of alloying elements can change the overall density of the finished stainless steel. Chromium has a density of around 7,190 kg/m³ so it can lower overall density while nickel has a density of around 8,900 kg/m³, raising overall density. Molybdenum has an extremely high density of 10,280 kg/m³ so stainless steels that include this element can be of significantly higher density than those that do not. 
• Temperature. A rise in temperature causes thermal expansion of stainless steel and this expansion results in decreased density. As a general rule, each increase of 100°C in temperature can cause a drop in density of as much as 0.4%. 
• Porosity. Some manufacturing processes can have an effect on the porosity of stainless steel: the greater the amount of pores, the lower the density. 

Density is just one of the many considerations that need to be made when choosing the right type and grade of stainless steel for any given application. Our technical team can give expert advice on this matter so please do not hesitate to give us a call.