What is the density of stainless steel, and what does it mean in practice?

Density describes the ratio of a material’s mass to its volume. For stainless steel, this value is usually expressed in kilograms per cubic decimetre (kg/dm3) or grams per cubic centimetre (g/cm3). As stainless steel is an alloy of iron and various alloying elements such as chromium, nickel or molybdenum, there is no single fixed value. Instead, it falls within a range that varies depending on the microstructure and chemical composition. At mirrorINOX, we use precise values to accurately calculate the theoretical weight of sheets before mechanically polishing or coating them.

As a general rule, the following applies to practical calculations:

• A volume of 1 dm3 of stainless steel weighs approximately 8 kg on average.
• For a 1.0 mm thick sheet, we calculate a weight of approx. 8 kg per square metre.
• The exact density depends largely on the alloying elements (e.g. molybdenum increases the density, while aluminium would reduce it).
• We distinguish between austenitic, ferritic and duplex stainless steels, each of which has a specific density.

Designations and synonyms

Stainless steel is identified using various standards systems that are often used synonymously but have different origins. The exact material number is crucial for determining the density of stainless steel.

V2A and V4A

These designations have their origins in the historical development process ("Experimental Melt 2 Austenite") and are now commonly used to refer to grades 1.4301 (V2A) and 1.4404 (V4A). V2A typically has a density of 7.9 kg/dm3, while V4A is calculated at 8.0 kg/dm3 due to the addition of molybdenum.

AISI designations

The US system of the American Iron and Steel Institute (AISI) uses three-digit numbers. AISI 304 is largely equivalent to material grade 1.4301. AISI 316L is the equivalent of 1.4404. These designations are particularly relevant to mirrorINOX’s international project business and yacht building.

DIN and EN Standards

The European standard (EN 10088) uses five-digit material numbers. These numbers enable us to clearly identify the physical properties during production in Cleebronn. This allows us to determine precisely whether a material is suitable for the PVD coating process (nanoINOX®).

Chemical composition

The density of stainless steel is directly determined by the atomic mass of its alloying elements. Since iron forms the base, the overall value is always close to the density of iron at 7.87 kg/dm3, but is modified by the following constituents:

• Chromium (Cr): The most important element for corrosion resistance, with a density of approx. 7.19 kg/dm3.
• Nickel (Ni): Stabilizes the austenitic microstructure and has a higher density of approx. 8.90 kg/dm3.
• Molybdenum (Mo): Increases resistance to pitting corrosion and significantly increases the overall density (individual density approx. 10.20 kg/dm3).
• Manganese (Mn): Used for deoxidation and to increase strength, with a density of approx. 7.43 kg/dm3.
• Titanium (Ti): Used for stabilization against intergranular corrosion and slightly reduces density (approx. 4.50 kg/dm3).
• Carbon (C): Present in small amounts, but has little effect on the macroscopic density.

Properties

The physical and mechanical properties of stainless steel are closely linked to its density and microstructure. We select the base materials for our finishing processes specifically according to these parameters.

Mechanical Properties

Density indirectly affects the strength-to-weight ratio. Austenitic steels offer excellent toughness and formability. This enables us to carry out complex cold forming operations after polishing. A higher molybdenum content, which increases density, often also improves the material’s high-temperature strength.

Physical Properties

In addition to density, thermal expansion and electrical conductivity are key factors. Stainless steel expands more when heated than unalloyed structural steel. When manufacturing façade panels in Cleebronn, we take these physical constants into account to ensure a precise fit under the influence of temperature.

Corrosion Resistance

Density often correlates with the content of heavy elements such as molybdenum. Grades with a density of 8.0 kg/dm3 (e.g. 1.4404) are generally more resistant to chloride-containing media than lighter grades such as 1.4016 (7.7 kg/dm3). mirrorINOX always recommends the denser V4A grades for marine environments.

Magnetism

Density does not directly indicate magnetic properties, but the microstructure does. Ferritic steels (lower density, approx. 7.7 kg/dm3) are magnetic. Austenitic steels (higher density, approx. 7.9–8.0 kg/dm3) are non-magnetic in the solution-annealed condition, which is crucial for sensitive electronic applications.

Applications and Industries

Thanks to its specific density and resulting durability, stainless steel is used in numerous high-performance applications. mirrorINOX provides the appropriate surface solutions.

• Architecture and façade construction: Use of large-format panels where the weight (based on density) determines the structural subframe.
• Yacht and shipbuilding: Preferred use of 1.4404/1.4435 (V4A) due to its corrosion resistance and mechanical stability at high density.
• Food industry: Use of 1.4301 (V2A) for containers and work surfaces, as its density ensures a non-porous, hygienic surface.
• Pharmaceutical industry: Use of high-density grades such as 1.4435, which we polish to achieve extremely low surface roughness values (Perfect Mirror No. 10®).
• Elevator construction: Here, we manufacture finished sheets for which weight calculation is essential in determining the load capacity of the elevator cars.

Overview of international standard designations

To ensure that stainless steel density can be compared worldwide, we use the following

• Material number 1.4016: Equivalent to AISI 430, ferritic, density approx. 7.7 kg/dm3.
• Material number 1.4301: Corresponds to AISI 304, austenitic, density approx. 7.9 kg/dm3.
• Material number 1.4404: Corresponds to AISI 316L, austenitic, density approx. 8.0 kg/dm3.
• Material number 1.4462: Corresponds to AISI 318LN, duplex stainless steel, density approx. 7.85 kg/dm3.
• Material number 1.4571: Corresponds to AISI 316Ti, titanium-stabilized, density approx. 8.0 kg/dm3.

Stainless Steel Finishing – Precision at mirrorINOX

At our production facility in Cleebronn, we finish stainless steel sheets using state-of-the-art processes. The density of the base material is a fixed parameter to which we tailor our mechanical and chemical processes. We produce mirror finishes such as Perfect Mirror No. 10®, which lead the market in reflectivity and flatness. Our nanoINOX® sol-gel coatings and PVD processes give stainless steel functional colours and additional protective layers without compromising the benefits of its high material density.

Our processes, such as VIBES and BEADS, create unique textures that we deliver with the highest level of reproducibility. Since 2016, customers worldwide have relied on our expertise because we not only design surfaces, but also understand the materials science behind every stainless steel grade. Every batch is rigorously inspected to ensure that its physical parameters meet your requirements.