1. Introduction and industry context

Stainless steel, also known as inox, is one of the most defining and indispensable base materials of modern industrial production, architecture and sectors where hygiene is critical. Due to its special physical, mechanical and chemical properties — above all its self-healing corrosion resistance, structural resistance to extreme temperatures, and ability to meet strict food industry and pharmaceutical hygiene requirements — it has become a cornerstone of global supply chains. In the current global economic and industrial environment, where infection control, sustainability requirements, especially carbon neutrality and the circular economy, and Industry 4.0 digitalisation efforts jointly shape the market, the importance of high value-added, custom-designed stainless steel products is growing continuously and dramatically.

In the Hungarian market, one of the defining players in this specific segment requiring high-level engineering knowledge is THERMOKOR Élelmiszeripari berendezést gyártó és Szolgáltató Korlátolt Felelősségű Társaság, operating in Törökbálint. Since its foundation on 7 October 1991, the company has spent more than three decades specialising in the development and manufacture of industrial doors and openings, cold-room high-speed doors, special technological doors, and hospital and cleanroom equipment. Its portfolio includes sectional and spiral doors, painted and stainless steel edge protectors, hospital mortuary refrigeration equipment, lead-lined radiation shielding X-ray doors, bedpan washers, and custom stainless steel tanks for wineries and distilleries.

The purpose of this report is to explore the historical, metallurgical, surface-chemical and industrial application dimensions of stainless steel in full depth. Through this extensive knowledge base, the research analyses the global technological, regulatory and market trends that may define the industry over the next decade, and along which THERMOKOR Kft. can optimise its future strategy, product development and market positioning.

2. Historical overview: From ancient experiments to modern space exploration

The industrial-scale mass production and deliberate alloying of stainless steel is a technological achievement of only the last century, but humanity’s relationship with corrosion-resistant metals goes back thousands of years. The analysis shows that metallurgical innovations have always developed in response first to military needs, and later to industrial and healthcare requirements.

The first proven human use of iron dates to around 4000 BCE, but the vulnerability and rapid oxidation of pure iron soon pushed early civilisations towards alloying experiments. Around 3000 BCE, the Chinese Qin dynasty was already experimenting with chromium-containing surface coatings to improve the edge retention and corrosion protection of weapons, making this one of the earliest precursors of today’s passivation technologies. Later, around 300 BCE, the Indian and Sri Lankan region developed the production technique for so-called Wootz steel. Through crucible melting, this process created a unique microstructure that became known in Europe from the 1100s as the base material of the legendary Damascus swords, giving weapons exceptional strength, flexibility and rust resistance. In European metalworking, the first steel cutlery appeared in Great Britain in the 1400s, although these items still required continuous maintenance and oiling to prevent rust.

Scientific metallurgy began to take shape in the 18th and 19th centuries. In 1740, Benjamin Huntsman developed the crucible casting process, enabling the first industrial-scale mass production of steel. The discovery of the most important alloying elements of stainless steel also belongs to this period: in 1751 Axel Fredrik Cronstedt isolated nickel, in 1778 Karl Wilhelm Scheele discovered molybdenum, and in 1797 Nicolas-Louis Vauquelin successfully identified chromium. During the 19th century, in 1821, Pierre Berthier was the first to publish studies on the corrosion resistance of chromium-iron alloys, or ferrochromium, but due to the lack of proper carbon control, these materials were still too brittle for industrial use. In 1871, John T. Woods and John Clark received a British patent for a weather-resistant alloy, recognising the commercial potential of chromium alloys.

The birth of modern stainless steel belongs to the first decades of the 20th century, an exceptionally intense research race taking place in parallel across several continents. Between 1904 and 1911, French researcher Léon Alexandre Guillet carried out extensive studies on iron-chromium-nickel alloys, creating the predecessors of today’s stainless steels, although he did not yet describe the mechanism of passive layer formation. In 1907, the first commercial electric arc furnace, EAF, was commissioned in the United States, a technology that remains fundamental to stainless steel production today. Between 1910 and 1911, German researchers Philipp Monnartz and William Borchers patented their discovery that at least 12% chromium content and strictly controlled carbon content are required to achieve stainlessness.

The industrial breakthrough came on 17 October 1912, when engineers Benno Strauss and Eduard Maurer of the German Krupp company patented the austenitic stainless steel called “Nirosta”. This alloy, containing 18% chromium and 8% nickel, later became known as 18/8 or AISI Type 304 and became the most widely used stainless steel in the world. Almost at the same time in the United States, Christian Dantsizen and Frederick Becket were working on industrialising ferritic steels. Meanwhile, in 1913, British metallurgist Harry Brearley, head of the Brown-Firth research laboratory in Sheffield, was searching for a solution to erosion problems in British Army gun barrels on the eve of the First World War. During his experiments, he accidentally discovered martensitic stainless steel. Brearley noticed that test pieces thrown into the scrap yard showed no signs of rust even months later. Although he originally called the material “rustless steel”, a local cutlery manager, Ernest Stuart, suggested the much better-sounding name “stainless steel”, which then spread worldwide. Sheffield soon became a global synonym for metalworking and stainless cutlery production. Later, in 1919, Elwood Haynes received a US patent for martensitic steel.

Between the two world wars, the application areas of stainless steel expanded rapidly. In 1925, it was first used for chemical tanks storing nitric acid, opening the way to petrochemical applications. In 1926, 18-8 austenitic steel was introduced into the surgical implant market, as it proved more resistant and more biocompatible than the previously used vanadium steel. In 1928, the brewing industry also recognised the hygiene benefits and the first stainless fermentation tanks were installed. In 1929, William J. Kroll discovered precipitation-hardening steels produced with the addition of titanium. The year 1930 was a turning point in material development: at the Avesta Ironworks in Sweden, the world’s first duplex stainless steel was produced, combining the advantages of ferrite and austenite.

From the 1930s onward, stainless steel conquered architecture and transport. In 1930, the iconic spire of the Chrysler Building in New York was clad with stainless panels that have retained their original shine to this day. In 1931, the Edward G. Budd Company in Philadelphia built the “Pioneer”, the world’s first aircraft made of stainless steel. In 1934, the ocean liner SS Queen Mary was launched, using massive amounts of stainless steel in its kitchens, swimming pools and turbines. By 1935, enamelled cast iron was being replaced by household stainless kitchen sinks, and in 1936 Ford Motor Company produced six Deluxe Sedan models with stainless steel bodies.

After the Second World War, the material became critical in modern engineering achievements. In 1954, the first underwater television camera housing was built, and in 1956 stainless components were used in England’s first large nuclear power station. In 1966, turbine blades for the world’s first tidal power station in France were made from this alloy. The pinnacle was space exploration: between 1967 and 1973, NASA extensively used stainless steel in Saturn V rockets, so during the Apollo 11 mission in 1969, stainless steel even reached the Moon. Its role in architectural protection is well illustrated by London’s Thames Barrier, where ten massive stainless gates were built in the 1980s to protect the city from tidal flooding. By 2010, global production had exceeded 31 million tonnes, and China had become the world’s largest producer. This rich historical heritage clearly shows that stainless steel has become dominant in every industry where durability, cleanliness and extreme load-bearing capacity are expected, forming the foundation of THERMOKOR Kft.’s target markets as well.

3. Metallurgical foundations and the physicochemistry of the passive layer

The most important distinguishing feature of stainless steel compared with conventional, unalloyed or low-alloy carbon steels is its ability to protect itself spontaneously against environmental corrosion. According to the metallurgical definition, stainless steel, often called inox from the French word “inoxydable”, is an iron alloy containing at least 10.5% chromium by mass. This critical chromium content is the basis of the physicochemical process that makes the material invaluable from an industrial perspective.

Conventional unprotected steel undergoes rapid oxidation when exposed to atmospheric oxygen and moisture, resulting in iron oxide, commonly known as rust. The destructive nature of the process lies in the fact that the resulting iron oxide molecules have a significantly larger volume than the original iron atoms. This volume increase generates enormous internal stress on the metal surface, causing the oxide layer to crack, flake off and continuously expose new unprotected metal surfaces to environmental effects. This reaction continues until the material is destroyed across its full cross-section.

In stainless steel, when the chromium content reaches the required level, a completely different chemical mechanism occurs on the surface. Chromium on the metal surface immediately reacts with oxygen in the air and forms an extremely thin, invisible chromium oxide layer, Cr₂O₃, only a few nanometres thick, corresponding to only a few molecular layers at atomic scale. This process is described by the following redox equation: 4Cr + 3O₂ → 2Cr₂O₃.

The structural physics of the resulting chromium oxide layer is key to the material’s behaviour. The ionic sizes of chromium and the oxide formed from it are highly similar. As a result, the crystal structure of the film fits perfectly to the lattice structure of the base metal, making it dense, continuous and tightly adherent to the metal surface, preventing flaking caused by volume expansion. This is called the “passive” layer because it is chemically inert, non-reactive and creates a hermetic physical barrier against oxygen, moisture and other corrosive agents penetrating into the inner metal layers.

The material’s most special property is its self-healing capability. If the metal surface is damaged by thermal, chemical or mechanical action, such as cutting, scratching or grinding, the passive layer is disrupted and the clean iron-chromium alloy becomes exposed. In the presence of oxygen, however, the released chromium oxidises again in a fraction of a second, and the passive chromium oxide layer reforms immediately and spontaneously, sealing the wound.

It is important to note, however, that despite the common name, stainless steel is not completely invulnerable. A necessary condition for passivation and for maintaining the passive layer is sufficient oxygen supply. If stainless steel remains for a long time in oxygen-poor, poorly ventilated environments, for example on muddy seabeds, in tightly fitting crevices with stagnant water, or in media with extremely high chloride and salt content, the passive layer cannot reform, and local corrosion begins, typically in the form of pitting or crevice corrosion. Precise knowledge of these limitations is essential for THERMOKOR Kft.’s engineers when designing the material and structural configuration of food industry or healthcare equipment, for example rounded edges that help avoid stagnant water.

4. Microstructural classification of steel alloys and their industrial applications

In addition to chromium as the base alloying element, many other alloying elements, including nickel, molybdenum, manganese, carbon, titanium and nitrogen, are added to stainless steels to modify the crystal structure of the metal, improve mechanical properties or increase resistance to specific chemicals. Based on their crystal lattice structure, stainless steels are classified into four main metallurgical categories.

4.1. Austenitic stainless steels: the 200 and 300 series

Austenitic steels account for around 70% of global stainless steel production and have a face-centred cubic crystal structure. This structure is stabilised by nickel or, in the more cost-efficient 200 series, by manganese alloying elements, from cryogenic temperatures all the way to the melting point of the material. Austenitic steels are characterised by high corrosion resistance, excellent formability, resistance to brittleness in cold environments and, unlike the other types, are practically non-magnetic. Most of THERMOKOR Kft.’s products are made from this category.

Within the 300 series, two alloys dominate the market:

• 304 (18/8 or 18/10): The most widely used stainless steel in the world, containing at least 18% chromium and 8-10% nickel, with no more than 0.08% carbon. It provides excellent general corrosion resistance and is easy to form and weld. It is widely used for kitchen equipment, sinks, heat exchangers, industrial doors, fasteners and general cladding. It is an ideal base material for THERMOKOR Kft.’s painted or stainless steel edge protectors, water-guiding elements and standard industrial high-speed doors where protection against mechanical impact and general humidity is the main requirement.
• 316 and 316L: The standard material of the pharmaceutical industry and aggressive chemical applications. Compared with 304, the 316 alloy contains slightly higher nickel, 10-14%, and most importantly 2-3% molybdenum. Molybdenum drastically increases the alloy’s resistance to chloride-ion-induced pitting corrosion and chemicals. In addition, the 316 alloy tolerates extreme temperature fluctuations, repeated freezing and sterilisation cycles much better without losing strength. The “L” mark stands for Low Carbon. While standard 316 has a maximum carbon content of 0.08%, for 316L this value is reduced below 0.03%. This microscopic difference provides a major technological advantage during welding. In higher-carbon steels, chromium and carbon may combine in the heat-affected zone, HAZ, forming chromium carbides, which withdraws chromium from the passive layer and causes intergranular corrosion along welds. The low carbon content of 316L prevents this precipitation, so after welding complex structures there is no need for expensive and time-consuming post-weld annealing to restore corrosion resistance. In THERMOKOR Kft.’s healthcare division, the use of 316L is indispensable in the manufacture of mortuary refrigerators, radiation shielding X-ray doors and especially bedpan washers. In bedpan washers, biological exposure followed by high-temperature, aggressive, often chlorine-containing chemical disinfection creates a load that 304 steel would not withstand in the long term without damage.

4.2. Ferritic stainless steels

Ferritic alloys, with body-centred cubic lattice structure, typically contain between 10.5% and 27% chromium, while their nickel content is negligible, often zero. Thanks to this alloy profile, ferritic steels are significantly cheaper to produce than austenitic grades. They are magnetic and have a lower thermal expansion coefficient. Although their processability, especially formability in some cases, may be better, their lower chromium and nickel ratio means their corrosion resistance falls short of the 300 series. Certain types may also contain molybdenum, aluminium or titanium, for example 18Cr-2Mo and 29Cr-4Mo. The best-known type is the 430 alloy, historically used for wires in sound recording machines and today primarily applied in washing machine drums, automotive exhaust systems and interior decorative elements.

4.3. Martensitic stainless steels

Martensitic steels are characterised by higher carbon content, 0.1-1%, and moderate chromium content, 12-14%, with a maximum of 2% nickel. This composition provides weaker rust resistance, but enables the material to be hardened and tempered to extremely high hardness and strength through heat treatment. Higher carbon content increases hardness, but also makes the material more brittle. These steels are highly machinable and magnetic. Typical uses include cutting tools, professional kitchen knives, razor blades, surgical scalpels and special bearings. A special subgroup is precipitation-hardened martensite, such as the 17-4PH alloy containing around 17% chromium and 4% nickel, which combines the corrosion resistance of austenite with the extreme load-bearing capacity of martensite, making it a preferred material in aerospace and nuclear industries.

4.4. Duplex stainless steels

The microstructure of duplex steels, as their name suggests, is dual: the crystal lattice contains roughly 50-50%, or in common commercial grades 40-60%, austenitic and ferritic phases. Their composition is characterised by exceptionally high chromium content, 19-32%, molybdenum content of up to 5%, and lower nickel content than austenitic steels. This hybrid structure produces brilliant engineering properties: the yield strength and tensile strength of duplex steels are approximately twice those of austenitic steels, while they show exceptional resistance to local corrosion, pitting and chloride-induced stress corrosion cracking. Their use is dominant mainly in offshore oil rigs, desalination plants and high-pressure chemical pipelines.

5. Surface roughness (Ra), hygiene and food safety regulations

In food processing, hospital care and pharmaceutical manufacturing, the chemical quality of steel, meaning its alloy grade, represents only half of the requirements. The hygienic suitability of equipment, whether a stainless steel food industry high-speed door installed by THERMOKOR, a winery tank or a cleanroom device, is fundamentally determined by the macroscopic and microscopic topography of the metal surface, in other words the quality of the surface finish. Stainless steel is inherently non-porous, resists moisture absorption, mould and bacterial adhesion, making it one of the best tools for preventing cross-contamination. On smooth surfaces, cleaning and sterilisation procedures, including CIP, Clean-In-Place, and SIP, Sterilization-In-Place, are orders of magnitude more effective, which is essential for compliance with HACCP, Hazard Analysis and Critical Control Points, and GMP, Good Manufacturing Practice standards in food and pharmaceutical safety.

5.1. Measuring surface roughness and global standards

To measure surface fineness and porosity, global industry uses the Roughness Average, Ra. It is measured with a profilometer, whose tiny stylus travels along the metal surface and records the height of microscopic “peaks and valleys”. The Ra value is the arithmetic average of the absolute values of these profile height deviations relative to the centre line, expressed in micrometres, µm, or microinches, µin. The lower the Ra value, the smoother the surface, reducing the chance that biological residues, proteins or pathogens become trapped in valleys and survive the washing cycle. Although older technical drawings sometimes use RMS, Root Mean Square, which is more sensitive to outlying peaks, Ra is today’s accepted industry standard.

Different industries require different Ra values, achieved through physical grinding, rolling or electropolishing:

• Food industry and general hygiene: According to industry regulations, such as those of the American Meat Institute or EU hygiene directives, safe food-contact surfaces typically have Ra values between 0.5 µm and 0.8 µm, or 20-32 µin. The standard brushed “No. 4 Finish” has roughness of approximately 0.8 µm, suitable for general food processing plants. Due to the higher requirements of lactic acid and cheese production, the finer “No. 4 Dairy/Sanitary” surface has an Ra value between 0.3 and 0.4 µm. In addition, there is the “2B Mill Finish”, created by cold rolling, which produces a mirror-like surface of 0.3-1.0 µm depending on material thickness, and is used for bakery equipment and tanks. The sheet metal cladding of THERMOKOR Kft.’s food industry doors and the internal walls of winery storage tanks are manufactured according to these standards.
• Pharmaceutical industry and biotechnology: In cleanrooms and during the manufacture of pharmaceutical active ingredients and biopharmaceutical products, such as injectable and optical solutions, requirements become extremely strict, because even the smallest bacterial biofilm may cause the rejection of an entire production batch. According to the ASME BPE, American Society of Mechanical Engineers – Bioprocessing Equipment, standard system, high-purity systems with Surface Designation SF4 require a maximum Ra of 0.38 µm, or 15 µin, achievable only by mechanical polishing followed by electropolishing. For dry powders and aspirin-type tablets, the SF1 standard, 0.5 µm, may be sufficient and does not require electropolishing. Among the industry’s most modern achievements are dry electropolishing processes, such as DLyte technology, which remove surface unevenness through ion exchange using solid particles instead of liquid. With this process, microscopically perfect mirror surfaces with astonishingly low Ra values below 0.02 µm can be produced for pharmaceutical mixers or tablet presses.

5.2. European Union and national regulatory frameworks (FCM, ÉMI)

In addition to surface design, stainless steel products must comply with strict legal and quality assurance frameworks. In the European Union market, every food contact material, FCM, must comply with Framework Regulation (EC) No 1935/2004. In the interest of protecting human health, this regulation states that equipment and packaging materials, under normal and foreseeable conditions of use, must not release, or migrate, constituents from the metal into food in quantities that endanger consumer health, unacceptably alter the composition of the food or modify its taste and odour.

This is complemented by Regulation (EC) No 2023/2006 on GMP, which requires manufacturers to follow Good Manufacturing Practice. The cornerstone of the administration is the Declaration of Compliance, DoC, through which the manufacturer, including THERMOKOR Kft., must prove raw material traceability and compliance with the rules. While detailed EU directives exist for plastics, such as EU 10/2011, the legal framework for steels and metals is less complete, so manufacturers often need to adapt to member-state national requirements during export.

In France, for example, strict national regulation requires stainless steel used as an FCM to contain at least 13% chromium, while Italy maintains its own positive list of authorised metal compositions. Deep knowledge of this asymmetric regulatory environment is essential for expansion into foreign markets.

As for construction and industrial doors and openings, one of THERMOKOR Kft.’s main profiles, in Hungary the condition for placing products on the market is certification issued by ÉMI, Építésügyi Minőségellenőrző Innovációs Kft., and the existence of a National Technical Assessment, NMÉ, or European Technical Assessment, ETA. The design, safety and mechanical requirements, and thermal insulation tests of industrial, commercial and garage doors are regulated by MSZ EN 12604:2001 and MSZ EN 12605:2001, as well as the installation-related 12635:2002 standard. The manufacturer must guarantee the stability of doors over defined operating cycles, proving the long-term consistency of insulation, air tightness and water tightness through a Certificate of Constancy of Performance.

6. Maintenance, chemical passivation and lifetime maximisation

Although stainless steel has a self-healing passive layer, in heavy industrial, food industry and pharmaceutical daily use this mechanism is often inhibited. For this reason, the planned lifetime of equipment can only be maintained through strict maintenance and chemical passivation protocols.

When stainless steel equipment is installed, the surface may suffer physical and chemical damage during installation processes such as welding, grinding, sanding and bending. These procedures thin the chromium oxide layer and, even more dangerously, microscopic iron particles from tools can adhere to the surface. In addition, continuous expansion and contraction caused by temperature fluctuations also weakens the integrity of the layer. If damage occurs faster than the surface can naturally absorb oxygen from the air for regeneration, or if oils, manufacturing greases or strong food industry cleaning agents cover the surface and prevent oxygen from reaching the metal, the passive layer cannot rebuild and the “free iron” begins to oxidise, resulting in orange or red rust stains.

The zero step of prevention is strict processing discipline. The most important industrial rule is this: stainless steel must never be brought into contact with carbon steel or iron-containing material. Shared tools must not be used, such as steel wool or iron-containing grinding discs, and carbon steel must not be welded, cut or ground near stainless materials, because airborne iron dust embedded in the surface creates immediate local corrosion points, or galvanic corrosion.

The highest-level industrial method for surface restoration and long-term protection is chemical passivation. This is a controlled chemical post-treatment, governed by ASTM A967 or AMS 2700 standards, with a dual purpose: first, it removes foreign iron embedded in the surface; second, through acidic oxidising agents, it artificially forces the formation of a thick, uniform chromium oxide layer, improving the chromium-to-iron ratio in the surface atomic layers. The ideal chromium-to-iron ratio is 1.5:1 or higher.

The chemical passivation process consists of three strict steps:

1. Degreasing and alkaline cleaning: Freshly manufactured or maintained surfaces must be cleaned of all organic grease, machine oil and mineral silicone, since a greasy film prevents the acid from contacting the metal. This is typically carried out using a 5% by mass sodium hydroxide alkaline solution at a high temperature of 71-82°C for 30 minutes. In industry, effectiveness is often checked with the extremely sensitive camphor test.
2. Acid treatment: removal of iron and forced oxidation:
   • Nitric acid process: This is the oldest and most aggressive, so-called dual-action method. Nitric acid, as a strong mineral acid, dissolves free iron, while also being an extremely strong oxidising agent, forcing chromium oxidation in the same step. It is generally used at 20-50% by volume concentration, at temperatures up to 80°C, for 3-4 hours. Its disadvantage is that nitric acid is toxic, creates hazardous waste and may damage rubber seals in equipment, which often need to be replaced after treatment.
   • Citric acid process: An increasingly popular environmentally friendly alternative. Citric acid is biodegradable, food-safe and excellent at removing iron through chelation. However, since it is not an oxidising agent, the actual formation of the passive layer is left to natural oxygen in the air at the end of the process. This method is typically used in a 12% by mass solution at ambient or moderately heated temperatures. Sometimes dichromate is added to accelerate oxidation, but due to its toxicity environmental regulations aim to phase it out.
3. Rinsing, neutralisation and drying: After the acid phase, the surface is rinsed with hot demineralised water, then, if necessary, fully neutralised with another alkaline NaOH wash to remove acid residues. Finally, the surface is dried perfectly with a clean cloth or compressed air, allowing the passive layer to solidify.

The maintenance schedule depends on the application. While a normal food industry cladding may be inspected annually, processing facilities dealing with high-chloride, acidic foods such as tomato juice or salsa, or pharmaceutical ultra-pure water, UPW, systems may require passivation as often as quarterly to preserve perfect sterility and freedom from corrosion. Maintenance of stainless steel is therefore not merely an aesthetic issue, but a guarantee of operational safety.

7. Technological requirements of industrial doors and openings: energy efficiency

One of THERMOKOR Kft.’s most important market segments is the manufacture of industrial high-speed doors, spiral doors and sectional doors used to separate climate-controlled environments such as cold stores, cleanrooms and pharmaceutical warehouses. In these applications, the stainless steel frame and skin system alone is not enough; the value of the product is provided by the insulation core integrated between steel panels and the thermodynamic performance of the door.

The main metric of the energy efficiency of cold-room and industrial doors is the heat transfer coefficient, U-value or U-factor, which indicates how much heat energy flows through a given surface unit, usually expressed in W/(m²K), due to the temperature difference between the internal and external space. While the R-value, which is the reciprocal of the U-value, R = 1 / U, indicates the material’s resistance to heat flow, the higher the better, the construction industry prefers the U-value for evaluating the complete structure, including door, frame and seals, where the lower value is more favourable.

A professional insulated industrial roller or sectional door is built so that an insulating core, usually high-density polyurethane foam, is located between the internal and external stainless steel skins. Since steel is an excellent conductor of heat, thermal bridge-free construction, or thermal break design, is extremely important. The external and internal steel sheets must not touch directly; they must be separated by non-metal parts such as plastic inserts and rubber seals, thereby “breaking” the path of heat transfer. Energy-saving industrial doors reduce overloading of heating and cooling systems, drastically reduce operating costs and guarantee product protection in sensitive food industry and pharmaceutical warehouses. In the United States, DASMA, the Door & Access Systems Manufacturers Association, operates a strict independent verification programme, TPVP, for validating these U-values. These standards also provide guidance for energy-saving benchmarks in European, and therefore Hungarian ÉMI-certified, door manufacturing.

8. THERMOKOR Kft.’s market position and strategic opportunities in light of the numbers

THERMOKOR Kft.’s multi-decade presence in Hungary and its custom, “tailor-made” manufacturing model provide a serious competitive advantage against international competitors optimised for mass production. Statistical data reveal the economic dynamics of the company’s environment. According to the January 2026 second estimate of the Hungarian Central Statistical Office, KSH, the volume of Hungarian industrial production fell by 2.5% compared with the same period of the previous year, although it showed a 1.5% month-on-month correction. The general slowdown in manufacturing and pressure caused by energy prices particularly affect the classic steel and metal industries.

At the same time, a deeper analysis of the data shows that certain sectors are specifically resilient in terms of exports and added value. Although vehicle manufacturing and electronics dominate, the pharmaceutical industry shows outstanding stability: in Budapest and Pest County, where THERMOKOR Kft. also operates, pharmaceutical added value is 2.14 times the national average. In addition, the food industry and special infrastructure investments, such as hospitals and cleanrooms, are less exposed to business cycles.

THERMOKOR Kft.’s operation is specifically built to serve technically demanding, crisis-resistant industrial segments such as healthcare, pharmaceuticals, quality food and wine industries, and cold-room logistics, where custom design, reliable operation and durable stainless technological solutions are considered basic requirements. The manufacture of custom 304 edge protectors, 316L bedpan washers and precision mortuary refrigerators requires the flexibility that large-scale steel processors cannot provide. The key to future growth, however, is not necessarily capacity expansion, but the integration of new disruptive technologies entering the industry. The following chapters outline the defining trends of the stainless steel industry between 2025 and 2030, whose adaptation can further strengthen THERMOKOR’s leading market position in technological metal processing.

9. Future outlook I: Additive manufacturing, 3D printing and micro-nanostructures in the steel industry

One of the most revolutionary changes of the coming decade in metal processing will be additive manufacturing, AM, commonly known as metal 3D printing. In the industrial-standard Laser Powder Bed Fusion, LPBF, process, a high-power laser melts metal powder layer by layer, enabling the production in a single piece of steel components with complex geometries, internal cooling channels or honeycomb structures that would be impossible with conventional machining or casting. Through drastic reduction of material use and design freedom, this technology revolutionises manufacturing and reduces ecological footprint. Life-cycle analyses indicate that AM can reduce global warming potential, GWP, by up to 15% for certain parts compared with traditional casting.

The microstructure of printed steels, however, differs fundamentally from conventional wrought or rolled materials, creating new engineering challenges. The latest research by the Argonne National Laboratory in the United States, which examined 316H and advanced A709 stainless steels for the nuclear industry, produced remarkable results. In-situ X-ray diffraction and electron microscopy studies revealed that 3D printed steels contain much higher numbers of dislocations, microscopic defects in the regular crystal lattice structure. Although these dislocations increase hardness and tensile strength, they also increase internal stress, which may make the material more prone to brittle fracture.

The most important discovery, however, was the presence of nano-oxides inevitably formed during the printing process within the structure of 316H steel. It turned out that during solution annealing these nanoscale defects function as physical barriers: they prevent dislocations from moving and block the growth of new stress-free crystal grains, or recrystallisation. As a result, printed samples begin recrystallising only at temperatures several hundred degrees higher than conventional steels. In contrast, in the A709 alloy, the increased dislocation count had a specifically beneficial effect: it promoted the formation of strengthening micro-precipitates during heat treatment, enabling printed A709 to show higher tensile strength both at room temperature and at 550°C, or 1022°F, than its wrought counterpart.

These deep materials science findings will be critical for future industrial applications. For THERMOKOR Kft., 3D printing may in the future enable the in-house, immediate, waste-free manufacture of low-volume custom components exposed to extreme loads, such as precision mechanical parts of high-speed spiral doors, hinges or special tank valves, provided that the heat treatment, or annealing, protocols of printed profiles are adapted to the new microstructural conditions.

10. Future outlook II: Green Steel and the circular economy

The sustainability transformation of heavy industry, decarbonisation, is fundamentally redrawing stainless steel supply chains. The global steel industry has traditionally been an extremely energy- and emissions-intensive sector, responsible for approximately 7% of the world’s greenhouse gas emissions and more than 11% of CO₂ emissions. The European Union’s objective, aligned with the 2050 Paris Climate Agreement and requiring a 55% reduction in industry emissions by 2030, is forcing the introduction of a completely new production paradigm: Green Steel.

The core of this technological paradigm shift is the replacement of traditional fossil-carbon-based metallurgy, BF-BOF, Blast Furnace-Basic Oxygen Furnace, with H2-DRI-EAF technology, Hydrogen Direct Reduced Iron - Electric Arc Furnace. In this new process, green hydrogen produced by electrolysis using renewable electricity, wind and solar, is used instead of coal and coke to reduce iron ore. Hydrogen reacts with the oxygen content of iron ore to reduce the metal, and instead of gigantic clouds of carbon dioxide, the process produces only harmless water vapour, H₂O, as a by-product. Although global low-emission hydrogen production was still in its infancy in 2024, with the technology moving towards only 4 GW of electrolysis capacity in 2025 instead of the promised 190 GW, the market dynamics are formidable. Sweden’s H2 Green Steel, in cooperation with Midrex technology, plans to launch the world’s first large-scale steel mill operating on 100% green hydrogen in 2025-2026. According to Grand View Research market analysis, the global green steel market, starting from USD 572 billion in 2024, will reach USD 766.76 billion by 2030 with a 6.0% compound annual growth rate, CAGR.

Another pillar of reducing energy intensity is the complete, 100% recyclability of metals. Stainless steel is the “greenest” material of the modern economy, because it can be remelted indefinitely without losing its mechanical properties or quality. Remelting steel scrap in EAF furnaces results in roughly 60-75% energy savings compared with primary production from iron ore, while in the case of aluminium this can be as high as 95%. Industry leaders such as Finland’s Outokumpu now use more than 90% recycled content in production, achieving a carbon footprint 75% lower than the global average.

At the same time, there are serious structural contradictions in the European Union’s raw material supply. In 2024, only 12.2% of materials used in the EU came from recycling, the Circular Material Use Rate. Within this, there is enormous contrast between member states: while the Netherlands stood at 32.7%, Hungary’s broader region is behind, with Romania for example producing only 1.3%. The metal market currently suffers from a “scrap paradox”: the European Union is a net importer of high value-added finished products, such as stainless steel sheets and coils, while being the world’s largest exporter of iron and steel scrap, shipping around 20% of collected metal outside the continent instead of using it for domestic remelting and value creation. This sharply contrasts with the petrochemical industry and the chemical recycling sector, which are making major commitments to increase recycling. In Hungary, the centralisation of the waste management system through the MOHU concession and the new deposit return systems, DRS, will hopefully improve the domestic circularity of raw materials and reduce landfill pressure in the 2025-2027 period.

In THERMOKOR Kft.’s future positioning, the use of Green Steel and verified recycled content will not merely be a marketing tool. Due to increasingly strict ESG, Environmental, Social, Governance, reporting obligations, such as the CSRD directive, multinational pharmaceutical companies and major food chains will soon purchase only from suppliers who work transparently, with a low Scope 3 carbon footprint and “green” raw materials.

11. Future outlook III: Industry 4.0, IoT integration and intelligent door control

The fusion of mechanical engineering and software development is radically transforming the market for industrial doors, openings and stainless equipment. As demonstrated by the enormous attendance of 55,000 people at the SPS, Smart Production Solutions, exhibition in Nuremberg in November 2025, and by the dominance of IT and AI technologies, traditional hardware alone is no longer sufficient. Equipment must integrate into the Industry 4.0 IoT, Internet of Things, ecosystem.

Modern smart automatic industrial doors and stainless devices are now equipped with sensors, embedded microcontrollers and network communication modules. Their greatest practical benefit is predictive maintenance. IoT sensors in doors and equipment collect telemetry data in real time: they measure the number of opening and closing cycles, motor current draw, vibration frequencies of steel hinges and rail systems, and the temperature of components. Software supported by artificial intelligence can use this data to predict the fatigue failure of a component, such as a bearing or spring, before it actually occurs. The system automatically sends a service alert to maintenance staff.

This predictive capability is vital in a pharmaceutical cleanroom, a segment also served by THERMOKOR Kft. If a door unexpectedly fails and remains open, cleanroom overpressure immediately disappears, which can cause biological or particulate contamination and damage pharmaceutical batches worth millions. IoT integration eliminates the risk of unplanned downtime. In addition, through improving interoperability, APIs, Application Programming Interfaces, and open industrial communication protocols, these smart doors can be seamlessly integrated into complex Building Management Systems, BMS, optimising climate control, minimising energy loss and increasing safety through access control. THERMOKOR’s future development direction also lies in combining its already excellent passive stainless steel structures with intelligent sensor technology.

12. Future outlook IV: Nanocoatings — antimicrobial and anti-fingerprint (AFP) surfaces

12.1. Anti-Fingerprint (AFP) coatings

While the traditional passive chromium oxide layer of stainless steel protects only against corrosion, 21st-century nanotechnology has created active surface-treatment processes that give the metal new functions: aesthetic durability and bactericidal capability. Two technologies are especially important in THERMOKOR Kft.’s segments.

One of the biggest aesthetic and maintenance problems of stainless steel, especially brushed surfaces such as hairline, satin and No. 4 finishes, is that the oily, acidic secretion of human skin, fingerprints, easily adheres in the microscopic grooves of the metal. In industrial kitchens, lift panels or elegant office doors and openings, this requires continuous labour-intensive cleaning. AFP technology was created to solve this problem.

During the AFP process, an extremely thin, transparent nanocoating preserving the texture of the metal is applied to the steel surface. The coating may be a dense crystalline layer based on PVD, Physical Vapor Deposition, a fluorocarbon coating or a layer made with the most modern ALD, Atomic Layer Deposition, technology. This coating drastically reduces the surface tension of the metal, giving it oleophobic, oil-repellent, and hydrophobic, water-repellent, properties. The polymer or ceramic nano-network fills the micropores of the metal, so fingerprints and oil stains cannot become mechanically embedded in the structure. An oil drop from a fingertip does not spread across the surface, but remains as a small, easily wipeable spot. Market-leading products such as CernoTex AFP remain on the surface even during bending, up to 180 degrees, or laser cutting, without cracking or delamination, providing an ideal raw material for THERMOKOR’s exclusive claddings and doors.

12.2. Silver nanoparticle (AgNP) antibacterial surfaces

As explained earlier, stainless steel is an inert material: by itself it does not kill bacteria, it merely makes the surface easy to sterilise if the Ra value is appropriate. In hospital environments, however, such as THERMOKOR’s bedpan washers or operating-room X-ray doors, there is growing demand for active self-disinfecting, antimicrobial surfaces. The biocidal effect of silver and copper, the oligodynamic effect, has long been known, but due to the negative environmental impact of copper, attention has turned towards nanotechnology.

The solution is the physical embedding, surface grafting or electroplating of silver nanoparticles, AgNPs, onto the stainless surface. Silver nanoparticles launch a triple attack against pathogens: they continuously release active silver ions, Ag+, generate reactive oxygen species, ROS, that cause oxidative stress, and physically damage bacterial cell membranes, interfering with DNA and intracellular metabolic pathways. The technology destroys both Gram-positive bacteria, such as Staphylococcus aureus, and Gram-negative bacteria, such as Escherichia coli, with astonishing effectiveness, including multidrug-resistant, MDR, superbugs. Although coatings may wear over time, the most advanced binders can ensure outstanding infection control for hospital and food industry equipment, including THERMOKOR products, for many years on industrial surfaces, especially direct contact points and handles.

13. Strategic synthesis

The science and industrial use of stainless steel, as shown by the analysis, has developed over the last century from simple forging to the integration of quantum-physical, nano-oxide, dislocation and passivation-dynamics processes and digitalisation. Without high-chromium iron alloys protected by a passive layer, modern healthcare, large-scale safe food processing and space exploration would simply be unimaginable.

With its stable financial background, highly trained engineering base and specialised “tailor-made” production experience, THERMOKOR Kft. is in an excellent position to benefit from the outlined industry trends. The analysis shows that for the company, future exponential growth and higher profit content will not lie in increasing the volume of traditional mass products made from 304 steel, such as standard industrial doors, but in knowledge-based innovation.

The strategic advantage lies in the precise application of premium materials, such as heat-treatment-free 316L or surfaces complying with strict FCM and ASME BPE hygienic Ra standards, possibly electropolished, and in radically extending the functions of steel. Integrating intelligent doors equipped with predictive IoT sensors, low-carbon-footprint ESG-compliant sheets reduced with green hydrogen, and microbiologically active silver nanoparticle and anti-fingerprint AFP coatings into hospital and cleanroom equipment will not only open new market segments, but also provide an exclusive premium-priced position in both domestic and international supply chains. The future of stainless steel is an ecosystem of networked, sustainable and microbiologically active surfaces, where conscious materials knowledge is the key to long-term industrial success.