Teknomek is the leading manufacturer of stainless steel furniture and equipment for hygiene-critical environments. With over 30 years of experience, Teknomek provides high-quality products that are designed to meet the strictest hygiene standards.
From stainless steel tables and workbenches to trolleys and shelving units, Teknomek offers a wide range of products to suit every need. All products are made from high-grade stainless steel, making them durable, easy to clean, and resistant to corrosion.
Whether you work in a food processing facility, pharmaceutical laboratory, or cleanroom environment, Teknomek has the furniture and equipment you need to maintain a clean and hygienic workspace. Trust Teknomek for all your stainless steel furniture and equipment needs.
Steel Composition
Steel is a combination of iron and carbon, offering enhanced strength and resistance to breakage, characterized by the carbon content. Additional elements like manganese, nickel, and chromium can be included to alter its properties.
Stainless Steel Properties
Stainless steel consists mainly of iron with a minimum of 10.5% chromium. The protective layer of chromium oxide that forms on its surface helps prevent rust, making stainless steel exceptionally resistant to corrosion.
Corrosion Resistance
When exposed to high levels of moisture and salt, iron in steel oxidizes to create iron oxide, leading to corrosion and potential structural damage. Stainless steel enriched with chromium forms a protective barrier of chromium oxide, halting further oxidation.
In addition to chromium, molybdenum and nickel are often added to stainless steel to further enhance its corrosion resistance. The presence of these alloying elements helps stainless steel withstand harsh environmental conditions, making it an ideal choice for applications requiring long-term performance and durability.
Stainless Steel Alloys Classification
Stainless steel is categorized into families and grades, with families indicating specific properties and metal compositions, while grades aid in identifying the type of alloy. There are four distinct families of stainless steel, each offering unique characteristics. Refer to the table below for more information.
| Types of Stainless Steel | Resistance to Rust | Durable and Tough | Magnetism |
|---|---|---|---|
| Austenitic | Outstanding | Strong and not capable of hardening | Negative |
| Ferritic | Moderate | Limited hardenability | Yes |
| Duplex Steel (combination of austenitic and ferritic) | Excellent | Superior tensile strength | Variable, influenced by the alloy makeup |
Classifications of Stainless Steel
There are several classifications of stainless steel, each uniquely suited for different applications. Below are explanations of the classifications, along with examples of where they are commonly used and reasons for their suitability.
| Types of Stainless Steel | Classification | Characteristics | Applications | Reasons for Use |
|---|---|---|---|---|
| 200 series | Austenitic | Chromium-nickel-manganese alloy | Ideal for indoor use in appliances, white goods, and interior automotive components. | Suitable for applications where exceptional corrosion resistance is not a priority. |
| 300 series | Austenitic | Chromium-nickel alloy | Commonly used in food processing equipment, kitchen utensils, and chemical containers. | Provides good corrosion resistance and high ductility. |
| 400 series | Martensitic | Chromium alloy | Used for knives, scissors, surgical instruments, and industrial equipment. | Offers high strength, hardness, and wear resistance. |
Different Stainless Steel Grades
Among the many grades in the 300 series of stainless steel, 304 and 316 are known for their unique properties and wide range of applications.
304 stainless steel is a versatile grade that is commonly used for kitchen appliances, food processing equipment, and architectural trim. It is known for its excellent corrosion resistance, easy fabrication, and aesthetic appeal.
316 stainless steel, on the other hand, is often used in more corrosive environments such as marine applications and pharmaceutical equipment. It has higher corrosion resistance than 304 and also offers excellent strength and heat resistance.
304 Stainless Steel
304-grade stainless steel, with 18-20% chromium and 8-10.5% nickel, provides strength and excellent resistance to corrosion. It is well-suited for use in industries involving food, chemicals, and water.
316 Stainless Steel
Similar to 304, 316 stainless steel contains added molybdenum for increased corrosion resistance. It is particularly useful in environments with high salt content, such as food processing.
Low Carbon Stainless Steel
These variations in stainless steel minimize carbide precipitation during welding, enhancing weld strength. They are ideal for use in hygienic furniture for food and pharmaceutical sectors.
Low carbon stainless steel is known for its high corrosion resistance and strength, making it suitable for a wide range of applications. It is often used in industries where cleanliness and durability are a priority, such as in food processing equipment, medical devices, and chemical processing plants.
Additionally, low carbon stainless steel is easy to clean and maintain, making it a popular choice for hygienic furniture in the food and pharmaceutical sectors. Its ability to withstand high temperatures and harsh chemicals also makes it a reliable option for these industries.
Electropolishing
Electropolishing is a process that removes a microscopic layer from stainless steel surfaces, improving smoothness, cleanliness, and resistance to bacteria. It simplifies the cleaning and disinfection procedures.
For more information on specific grades and processes, take a look at our article on the benefits of stainless steel.
While 304 and 316 stainless steel grades may appear similar, they have distinct differences that can lead to cost savings based on the intended applications.
All stainless steels contain a combination of iron and chromium, but the specific proportions and additional elements differentiate the grades.
Popular 304 stainless steel contains 18% chromium and 8% nickel, while 316 stainless steel has lower chromium, higher nickel, and molybdenum content.
Typical alloys contain 10% nickel and 2-3% molybdenum, but specialized alloys can have up to 9% molybdenum.
It is important to choose the right grade of stainless steel based on the specific requirements of your application to ensure optimal performance and cost-effectiveness.
While Grade 304 is commonly used in industries such as food processing, brewing, and chemical engineering, Grade 316 is preferred in marine and coastal environments due to its superior resistance to pitting and crevice corrosion. Additionally, Grade 316 is often chosen for architectural applications where aesthetics are important, as it has a higher resistance to staining and corrosion.
It is important to consider the specific requirements of your project when choosing between Grade 304 and Grade 316 stainless steel. While Grade 304 is more cost-effective and suitable for many applications, Grade 316 provides added durability and resistance in harsher environments.
Benefits of 316 Stainless Steel
If you’re curious about why 304 remains a popular choice, consider the typical applications for both grades:
Common Uses for Grade 304:
- Water pipelines
- Storage tanks
- Indoor electrical enclosures
- Automotive trim
- Kitchen equipment
Common Uses for Grade 316:
- Chemical pipelines
- Pharmaceutical equipment
- Medical equipment
- Commercial kitchen surfaces
Ultimately, the choice between 304 and 316 depends on cost and corrosion resistance requirements. 304 offers similar performance and durability at a lower cost, while 316 provides enhanced resistance and longevity benefits.
By selecting the appropriate stainless steel grade for your specific usage and environment, you can maximize the financial and functional advantages of your investment.
For more insights on stainless steel characteristics and performance considerations, consult Unified Alloys for their extensive range and expertise.
Check out our collection of stainless steel data sheets here.
Stainless steel, an alloy resistant to corrosion and rust, is heavier than aluminum and comprises materials like chrome and nickel for specialized needs.
Rust-Resistant Stainless Steel
Stainless steel with over 10.5% chromium forms a protective passive layer that enhances its durability.
Comparatively, stainless steel is on par with anodized aluminum, both susceptible to surface damage.
Applications of Stainless Steel
Stainless steel sees extensive use in automotive, transportation, medical, construction, and aviation sectors due to its strength and resistance properties. It is particularly favored in the food industry for its cleanliness, corrosion resistance, and ease of maintenance.
Common Stainless Steel Grades:
304 / 1.4301 – Good corrosion resistance, non-magnetic.
316 / 1.4401 – Excellent corrosion resistance, non-magnetic.
430 / 1.4016 – Low cost, magnetic.
409 / 1.4512 – Suitable for high-temperature applications, magnetic.
304L / 1.4307 – Good corrosion resistance, non-magnetic.
Strengths of Stainless Steel
Stainless steel maintains strength at extreme temperatures, making it ideal for demanding applications like aviation. Its hygienic properties suit medical and catering use with easy cleaning, sterilization, and bacteria resistance. The sleek appearance and functionality of stainless steel make it a popular choice in modern architecture.
With its resistance to corrosion, stainless steel can fend off rust and water stains. The addition of chromium to the metal creates a protective film when exposed to oxygen. Most stainless steel is crafted from recycled steel, retaining its properties even after recycling.
By A. K. Vaish, Ritesh Patel*, B. J. Chauhan, S. D. Kahar, Ankit Bhojani, K.M.Bhaisaheb and Keshva Narayana.* Department of Metallurgical and Materials Engineering, The M.S.University of Baroda, India;
*Larsen and Toubro Ltd., Hazira.
Welding is the process of heating, melting, and combining metals to create a joint, resulting in a stronger weld with filler material compared to the base metal. Weldability of stainless steel depends on its alloy components.
Versatile stainless steel
Stainless steel can be classified into five main groups:
- Ferritic stainless steel: Body-centered cubic grain structure, not hardened by heat but slightly by cold rolling.
- Martensitic stainless steel: Transforms to martensite upon cooling, can be quenched in oil or air.
- Austenitic stainless steel: Single-phase FCC material, strengthened by cold working.
- Duplex stainless steel: Combination of ferrite and austenite.
- Precipitation–hardening stainless steel: Iron-nickel-chromium alloy with special elements for hardening.
Mechanism of welding of stainless steel
Understanding the welding mechanism of stainless steel is crucial, considering factors like carbon content, alloy components, and filler types. The welding mechanism changes as the composition of stainless steel shifts across categories.
Ferritic stainless steel
Ferritic stainless steel is generally non-hardenable and easily fusion welded. Poor weldability may occur due to rapid grain growth at high temperatures.
Martensitic stainless steel
Martensitic stainless steel, whether low-carbon or high-carbon types, is susceptible to cold cracking. Precautions are taken to prevent cracking in the heat-affected zone, especially in thicker sections.
Austenitic stainless steel
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Austenitic stainless steel offers high weldability, ductility, toughness, and formability, requiring no pre- or post-weld treatment. It can be easily welded using various arc welding processes.
Duplex (austenitic+ ferritic) stainless steel
Duplex stainless steel blends austenite’s toughness with ferrite’s strength. It boasts better weldability and formability than other stainless steel types.
Precipitation hardening stainless steel
PH stainless steel exhibits good weldability without the need for preheating, but post-weld treatment is essential. Careful heat treatment helps achieve optimal mechanical properties in both the weld and parent material.
The welding mechanisms of different stainless steel categories are illustrated in Figure 2.
Welding stainless steel to other metals
Often, stainless steel components are welded to parts made of other metals. The considerable difference in melting points poses challenges in joining these materials.
Plain carbon steel – Austenitic stainless steels, such as 304 or 316, are usually welded to plain carbon steel using MIG and TIG welding. Filler materials are preferred in MIG welding, and resistance welding can be employed if the carbon steel is preheated.
Low carbon plain steel (mild steel) – Carbon content typically ranges from 0.05% to 0.25% by weight. MIG welding is an effective method for welding stainless steel to low carbon steel, with proper selection of wire being crucial. 309 is the recommended filler metal.
Medium carbon plain steel – Medium carbon steel has a carbon range of 0.30-0.60% and manganese content of 0.60-1.65%, making it stronger but more challenging to weld.
High carbon plain steel – High carbon steel contains 0.60-1.0% carbon and 0.30-0.90% manganese, known for its extreme hardness and strength. Arc welding requires preheating and post-heating.
Galvanized steel – Stainless steel welds well to galvanized steel, but the zinc coating must be removed before welding.
Aluminum – Stainless steel can be welded to aluminum using special techniques that isolate the metals during the welding process.
- The first method involves bimetallic transitions.
- In the second method, stainless steel is coated with aluminum.
Welding Materials for Stainless Steel
Connecting Copper and Stainless Steel – Welding copper to stainless steel can be a challenging task, but it is achievable with the use of electron beam welding (EBW), which is the recommended method for achieving a strong bond.
Utilizing Tungsten – Tungsten is a highly suitable material for welding stainless steel because of its excellent properties such as high melting point and strength. For high amperage welding, thoriated tungsten electrodes are particularly effective. To prevent weld contamination, tungsten is typically welded in an environment of inert gas or vacuum to avoid the presence of interstitials.