What does stainless steel mean, and which properties define this material?

The term “stainless steel” is used as a collective term for corrosion-resistant steels to which specific alloying elements are added during melting to enhance corrosion resistance. Unlike unalloyed steels, these materials form a protective passive layer when exposed to air. In addition to technical performance, visual and tactile characteristics play a key role in industrial applications. We primarily process corrosion-resistant grades known for their durability in aggressive environments and optimise them through targeted mechanical and chemical surface treatments for use in architecture and mechanical engineering.

Designations and synonyms

Stainless steel is identified using various standards systems and trade names, which vary depending on the region and application. Below, we explain the most common terms to help you select the right material for your specifications.

V2A and V4A

The abbreviations V2A and V4A originate from the historical development of these steels (“experimental melt 2 austenite”). Today, V2A generally refers to the standard grade 1.4301, while V4A, such as grade 1.4404, offers increased resistance to chlorides due to the addition of molybdenum.

AISI and International Standards

In international communications, we frequently use the AISI designations of the American Iron and Steel Institute. Grade 1.4301 corresponds to AISI 304, while material grade 1.4404 is classified as AISI 316L. This standardisation ensures that material properties can be compared worldwide.

Inox and Nirosta

“Inox” is derived from the French “inoxydable” and is the internationally recognised abbreviation for stainless steel. “Nirosta”, by contrast, is a trade name that has become synonymous with “stainless steel” in German-speaking countries, much like VA steel is used as a generic term for corrosion-resistant alloys.

Chemical composition

The chemical composition largely determines the material’s potential applications. Below, we list the composition of the materials most relevant to our finishing processes:

• Chromium (Cr): The principal element responsible for corrosion resistance, accounting for 12% to 20% in ferritic and austenitic steels.
• Nickel (Ni): Present in austenitic steels at a content of 8 % or more, nickel stabilizes the microstructure and improves chemical resistance.
• Molybdenum (Mo): Added at a minimum of 2 % to grades such as 1.4404 (V4A) to increase resistance to pitting and salt water.
• Grade 1.4301 (X5CrNi18-10): Contains at least 17.5% chromium and 8% nickel for good general corrosion resistance.
• Grade 1.4404 (X2CrNiMo17-12-2): A low-carbon alloy containing nickel (min. 10 %) and molybdenum (min. 2 %) for extreme loads.
• Grade 1.4016 (X6Cr17): A ferritic chromium-iron stainless steel with no nickel content, which has limited suitability for oxidative environments.
• Material 1.4310 (X10CrNi18-8): An alloy with optimized spring hardness due to its chromium and nickel content.
• Grade 1.4306 (X2CrNi19-11): Particularly low in carbon, improving weldability and resistance to intergranular corrosion.

Properties

The physical and mechanical properties of stainless steel form the basis of the processing methods used at mirrorINOX. We take these parameters into account for every order in Cleebronn to deliver precise results.

Mechanical Properties

Stainless steels are characterised by high toughness and good formability. Austenitic grades such as 1.4301 in particular offer excellent cold formability, making them ideal for deep-drawing applications and complex façade elements. Tensile strength varies depending on the alloy and degree of work hardening, while our targeted surface finishing processes preserve the material’s mechanical integrity.

Physical Properties

The thermal conductivity of stainless steel is lower than that of unalloyed steel, while its coefficient of thermal expansion is higher. These factors are essential in welded structures and large-scale façade cladding. We manufacture our products with these thermal dynamics in mind to prevent distortion and stresses in the finished product.

Corrosion Resistance

Resistance to rust results from the spontaneous formation of a chromium oxide layer. While 1.4301 (V2A) offers good resistance in moderate environments, the molybdenum content of 1.4404 (V4A) provides excellent protection against chlorides and acids. We also finish special alloys such as duplex stainless steel (1.4462) for marine applications with the most demanding corrosion conditions.

Magnetism

Austenitic stainless steels such as 1.4301 or 1.4404 are generally non-magnetic in the solution-annealed condition. However, cold working can produce a small proportion of strain-induced martensite, resulting in slight magnetism. Ferritic grades such as 1.4016, by contrast, are inherently magnetic, which must be taken into account when selecting materials for electronic components.

Applications and Industries

The versatility of stainless steel makes it suitable for use in virtually all technologically demanding sectors. We supply companies in the following industries with finished surfaces:

• Architecture and façade construction: Large-format panels for durable, prestigious building envelopes.
• Yacht and shipbuilding: Use of highly corrosion-resistant 1.4404 for deck fittings and interiors exposed to salt-laden air.
• Pharmaceutical and medical technology: Polished finishes are used to meet the strictest hygiene requirements and sterilization processes.
• Food industry: Used in commercial kitchens and processing plants due to its acid resistance and ease of cleaning.
• Elevator and shopfitting: Enhanced visual appeal through decorative finishes such as VIBES or BEADS for high-traffic areas.
• Vessel and equipment fabrication: Manufacture of components for the chemical industry that require high acid resistance.

Overview of international standard designations

To ensure error-free material procurement, we precisely cross-reference national and international standards. Here is an overview of the most common material numbers and their equivalents:

• 1.4301: Equivalent to AISI 304 / X5CrNi18-10 – standard grade for general applications.
• 1.4404: Equivalent to AISI 316L / X2CrNiMo17-12-2 – Enhanced resistance for chemical applications and coastal regions.
• 1.4307: Equivalent to AISI 304L / X2CrNi18-9 – Low-carbon variant of 1.4301 for improved weldability.
• 1.4571: Equivalent to AISI 316Ti / X6CrNiMoTi17-12-2 – titanium-stabilized steel for high temperatures.
• 1.4016: Equivalent to AISI 430 / X6Cr17 – ferritic chromium stainless steel for household appliances and decorative applications.
• 1.4462: Duplex stainless steel with high strength and exceptional corrosion resistance for offshore applications.

Stainless steel finishing – precision by mirrorINOX

At mirrorINOX, we transform standard stainless steel into functional design materials. At our Cleebronn facility, we operate state-of-the-art surface finishing equipment that ensures precise reproducibility for every batch. Our portfolio includes polishing and mirror polishing up to the quality grade Perfect Mirror No. 10®, which offers the highest levels of reflectivity for optical applications.

Using the PVD/TiN process, we coat stainless steel with hard material layers that not only add colour accents but also increase surface hardness. Our proprietary brand nanoINOX® also offers a sol-gel-based coating with anti-fingerprint properties and enhanced chemical resistance. For tactile textures, we use processes such as vibratory finishing (VIBES) or bead blasting (BEADS) to create matt, non-directional surfaces. Every project is individually documented in accordance with ISO 9001, providing B2B customers in industry with maximum process reliability.