When are 3 mm thick stainless steel sheets the right choice?

What are 3 mm thick stainless steel sheets?

Stainless steel sheets with a nominal thickness of 3.0 mm are produced from stainless steel by either cold or hot rolling. At a thickness of 3 mm, the material offers an ideal balance between weight and rigidity. We often regard these sheets as a borderline case, as they combine the precision of thinner sheet metal with the robustness of heavy plate. At mirrorINOX, these sheets form the basis for complex façade elements or heavy-duty machine enclosures. The material thickness ensures a flat surface, which is crucial for distortion-free reflections, particularly with mirror-polished finishes.

Terms and Synonyms for Stainless Steel Sheet

The terminology used for 3 mm stainless steel sheets varies depending on the application, standards system and regional conventions. To avoid technical misunderstandings, mirrorINOX uses precise material grade numbers and international standards.

V2A and V4A (Traditional German designations)

The terms V2A and V4A originate from the historical development of stainless steel alloys. Today, V2A (Versuchsschmelze 2 Austenit) generally corresponds to grade 1.4301. It is the standard grade for general indoor and outdoor applications. V4A, generally defined as 1.4404, also contains molybdenum. We recommend V4A for projects near the coast or in industrial environments with increased chloride exposure to ensure long-term resistance to pitting corrosion.

AISI Designations (American Standard)

In international trade and specifications for global projects, we frequently encounter the designations of the American Iron and Steel Institute. We supply stainless steel sheet grade 1.4301 under the designation AISI 304. The molybdenum-containing grade 1.4404 is designated as AISI 316L. These designations are particularly relevant in shipbuilding and international architectural projects, ensuring that material properties can be compared across national borders.

DIN EN 10088-2 and ISO Standards

DIN EN 10088-2 provides the technical basis for our production in Cleebronn. This standard defines the delivery conditions for sheet and strip made of corrosion-resistant steels. It specifies tolerances for thickness, width and flatness. For a 3 mm stainless steel sheet, this means exact dimensional accuracy, which we continuously monitor and document through our ISO 9001-certified processes.

Chemical Composition

The chemical composition determines the physical properties and corrosion resistance of the 3 mm stainless steel sheets. The proportions of the elements vary depending on the alloy type to meet specific requirements for weldability or acid resistance.

• Iron (Fe): Main constituent and base material of the alloy.
• Chromium (Cr): At levels of 17.5% to 19.5% (in 1.4301), it is responsible for forming the passive layer.
• Nickel (Ni): Stabilizes the austenitic structure and improves toughness (approx. 8% to 10.5%).
• Molybdenum (Mo): Increases resistance to pitting corrosion in V4A grades (1.4404) (approx. 2% to 2.5%).
• Carbon (C): Low levels (below 0.07%) ensure weldability and prevent intergranular corrosion.
• Manganese (Mn): Improves strength and formability during the rolling process.

Properties of 3 mm Stainless Steel Sheets

3 mm stainless steel sheets have a specific set of properties that distinguishes them from thinner foils or thicker plates. We continuously analyse these parameters to ensure their suitability for our finishing processes.

Mechanical properties

A 3 mm stainless steel sheet has a tensile strength of approximately 500 to 700 N/mm². The yield strength is typically at least 190 to 230 N/mm². Thanks to their 3.0 mm thickness, these sheets offer high inherent rigidity, allowing large-format panels to be used without excessive substructures. An elongation at break of approximately 40 to 45% also permits complex cold forming and tight bending radii without damaging the surface or material structure.

Physical Properties

The density of stainless steel sheet is approximately 7.9 to 8.0 kg/dm³. One square metre of 3 mm thick sheet therefore weighs around 24 kg. Its thermal conductivity is comparatively low at approximately 15 W/(m·K), which must be taken into account during welding. When manufacturing façade cassettes, we precisely factor in the coefficient of thermal expansion to prevent stresses caused by outdoor temperature fluctuations.

Corrosion resistance

The corrosion resistance results from the formation of a chromium oxide layer only a few nanometres thick. At a thickness of 3 mm, the material is resistant to mechanical surface damage, as the passive layer regenerates immediately upon contact with oxygen. We utilise this effect in our mechanical grinding and polishing processes. By selecting the appropriate grade (e.g. 1.4404 for marine environments), we ensure that the sheets remain maintenance-free for decades.

Magnetism

Austenitic stainless steel sheets such as 1.4301 or 1.4404 are non-magnetic in the solution-annealed condition. However, cold rolling to a thickness of 3 mm can produce a small proportion of strain-induced martensite, resulting in slight paramagnetism. If your application requires completely non-magnetic material (e.g. in medical technology), we offer suitable special grades. For most architectural and mechanical engineering applications, however, this minimal magnetism is negligible.

Applications and Industries

The applications for 3 mm stainless steel sheet are extremely diverse thanks to its mechanical strength and aesthetic versatility. We supply customers in global markets with custom finishes.

• Architecture and façade construction: We manufacture large-format façade panels whose 3 mm thickness ensures excellent flatness and reliable resistance to wind loads.
• Elevator construction: Our sheets are used for cabin walls and portals where resistance to mechanical stress and a sophisticated appearance (e.g. VIBES or BEADS) are required.
• Food industry: We supply sheet metal for work surfaces and containers that, thanks to its thickness, resists thermal deformation during cleaning.
• Shipbuilding and yacht construction: Grade 1.4404 with the Marine Mirror No. 9 finish is used here in particular for railing systems and decorative elements.
• Mechanical engineering: We finish 3 mm stainless steel sheets for housings and protective covers that must withstand vibrations and be easy to clean.
• Shopfitting and exhibition stand construction: High-gloss polished sheets serve as durable mirror surfaces or striking design elements in retail spaces.

Overview of international standard designations

For global sourcing and technical specifications, we provide an overview of the common designations for the stainless steel sheets we process in 3 mm thickness:

• 1.4301: X5CrNi18-10 (DE/EU), AISI 304 (USA), SUS 304 (JP), Z7CN18-09 (FR).
• 1.4404: X2CrNiMo17-12-2 (DE/EU), AISI 316L (USA), SUS 316L (JP), Z3CND17-11-02 (FR).
• 1.4571: X6CrNiMoTi17-12-2 (DE/EU), AISI 316Ti (USA) – titanium-stabilized for high temperatures.
• 1.4462: X2CrNiMoN22-5-3 (duplex stainless steel) – for maximum strength and corrosion resistance.
• 1.4016: X6Cr17 (ferritic stainless steel) – magnetic, for cost-conscious interior applications.

Finishing 3 mm stainless steel sheets – expertise from mirrorINOX

Since 2016, we have been finishing stainless steel sheets to the highest technical standards at our production facility in Cleebronn. We use state-of-the-art equipment to transform standard sheets into unique design products. Our production is certified to ISO 9001, ensuring complete reproducibility of every batch. A key focus is the processing of 3 mm material, as it provides the stability required for our intensive polishing and coating processes.

We use our proprietary brands selectively to create functional added value. With nanoINOX®, we apply a sol-gel coating that gives 3 mm stainless steel sheets anti-fingerprint (AFP) and easy-to-clean (ETC) properties. For projects with the most demanding reflection requirements, we produce Perfect Mirror No. 10®. This mirror-polished finish achieves values that far exceed conventional industry standards. We also offer PVD/TiN coatings, which give surfaces metallic colours such as gold, champagne, bronze or black without losing the tactile texture of the stainless steel. Our processes, such as vibration finishing (VIBES) or bead blasting (BEADS), create diffuse reflections that are particularly valued in modern lighting architecture.