AISI 304

The Definitive Guide for Professionals

AISI 304 stainless steel is one of the most widespread and versatile materials in the professional foodservice equipment and food industry sectors. Also known as 18/10 stainless steel or X5CrNi18-10 according to European nomenclature, this austenitic stainless steel has earned an excellent reputation thanks to its extraordinary corrosion resistance, hygienic properties, and durability.

In the HORECA world (HOtel, REstaurant, CAtering), AISI 304 is practically the reference standard for all elements that come into contact with food. If you're evaluating professional equipment for your business, understanding the characteristics of this material will allow you to make more informed purchasing decisions that comply with industry regulations.

Technical Characteristics of AISI 304 Stainless Steel

AISI 304 is an austenitic stainless steel characterized by a specific chemical composition that determines its exceptional properties. Its formula includes:

• Chromium (Cr): 18-20%
• Nickel (Ni): 8-10.5%
• Carbon (C): ≤0.08%
• Manganese (Mn): ≤2%
• Silicon (Si): ≤1%
• Phosphorus (P): ≤0.045%
• Sulfur (S): ≤0.03%

This composition gives AISI 304 excellent oxidation and corrosion resistance, especially thanks to its high chromium content, which forms an invisible passivating film of chromium oxide (Cr₂O₃) on the surface. This protective layer has the characteristic of self-regenerating if damaged, ensuring long-lasting protection over time.

Physical and Mechanical Properties

Property	Value	Notes
Density	7.9 g/cm³	Higher than carbon steel
Melting point	1450°C	High thermal resistance
Thermal conductivity	16.2 W/m·K	Lower than carbon steels
Electrical resistivity	0.73 μΩ·m	Relatively high
Brinell hardness	123 HB	Good wear resistance
Tensile strength	515-620 MPa	Excellent mechanical resistance
Elongation at break	40%	Excellent ductility

AISI 304 vs AISI 316: Fundamental Differences

In the professional equipment sector, the question of choosing between AISI 304 and AISI 316 often arises. Here's a technical comparison to help you navigate this decision:

• Composition: AISI 316 contains molybdenum (2-3%), which further improves corrosion resistance, especially in environments with chlorides (e.g., salt water)
• Corrosion resistance: AISI 316 offers superior resistance to marine environments and chloride solutions
• Cost: AISI 304 is generally 20-30% less expensive than AISI 316, thanks to the absence of molybdenum
• F&B Applications: For most foodservice applications, AISI 304 is more than sufficient, while AISI 316 is preferable in cases of prolonged exposure to acidic or salty foods

AISI 304 vs AISI 201: An Essential Comparison

AISI 201 is a more economical alternative to AISI 304, characterized by a lower nickel content (3.5-5.5%) compensated by higher percentages of manganese (5.5-7.5%). This makes it more cost-effective, but with inferior performance in terms of corrosion resistance. In the HORECA sector, AISI 201 is sometimes used for non-critical components or entry-level equipment, but it has significant limitations: greater vulnerability to humid environments, lower resistance to aggressive detergents, and overall inferior durability. Additionally, it tends to lose its shine more easily over time. For professional applications where hygiene and durability are priorities, AISI 304 remains the optimal choice despite the premium price, guaranteeing a more advantageous Total Cost of Ownership (TCO) in the long run.

Practical Applications in the HORECA Sector

In the professional foodservice equipment sector, AISI 304 stainless steel is the predominant material, thanks to its properties that make it perfect for food use. Here's where you'll find it:

Professional Kitchens

• Work surfaces and tables: Hygienic surface resistant to aggressive detergents
• Sinks and basins: Resistance to water and detergents, ease of cleaning
• Wall cabinets and shelving: Durability and absence of harmful substance release

Cooking Equipment

• Pots and casseroles: Excellent heat distribution, resistance to high temperatures
• Professional fryers: Resistance to high-temperature oils
• Ovens and pasta cookers: Durability in conditions of high humidity and temperature

Commercial Refrigeration

• Refrigerators and blast chillers: Ease of cleaning, moisture resistance
• Refrigerated counters: Compliance with HACCP regulations
• Cold rooms: Resistance to humidity and low temperatures

Sanitization and Washing

• Industrial dishwashers: Resistance to aggressive chemical products
• Sterilizers: Tolerance to high temperatures for sterilization
• Filtration systems: Compatibility with water and other food liquids

Advantages and Disadvantages of AISI 304

Advantages

• Supreme hygiene: Non-porous surface that prevents bacterial proliferation
• Ease of cleaning: Resistance to detergents and aggressive chemical agents
• Durability: Excellent resistance to wear and corrosion
• Aesthetics: Professional, modern appearance that easily integrates into any environment
• Food compatibility: Absence of harmful substance release into food
• Eco-sustainability: 100% recyclable, reduces environmental impact

Disadvantages

• Initial cost: Higher price compared to other alternatives such as galvanized steel
• Sensitivity to chlorides: Not ideal for environments with high salt concentration (AISI 316 is preferable for these cases)
• Specific maintenance: Need to avoid abrasive products that can damage the passivating film
• Magnetism: Generally non-magnetic, which can be a limitation in some applications

Maintenance and Care of AISI 304 Stainless Steel

To ensure the longevity of your AISI 304 equipment, you should follow some maintenance best practices:

1. Daily cleaning with non-abrasive, pH-neutral detergents
2. Complete rinsing after cleaning to remove detergent residues
3. Thorough drying to prevent water spots
4. Avoid prolonged contact with saline solutions or concentrated acids
5. Use specific products for stainless steel in case of stubborn stains
6. Periodic passivation (chemical process that restores the protective layer) in particularly aggressive environments

Recommended Products for Maintenance

• Professional detergents: Citric acid-based solutions for limescale removal
• Protective oils: To maintain a glossy appearance and protect the surface
• Passivation kits: For professional treatment after welding or repair interventions

Compliance and Certifications

In the food service sector, AISI 304 equipment must comply with various regulations and certifications:

• EU Regulation 1935/2004: Relating to materials intended to come into contact with food
• ISO 9001: Standard for quality of production processes
• NSF International: Certification for food use suitability
• HACCP compliance: Compatibility with food safety protocols

Frequently Asked Questions (FAQ)

Q: Is AISI 304 stainless steel the same as 18/10 stainless steel? A: Yes, they are the same thing. The "18/10" designation indicates the chromium (18%) and nickel (10%) content that characterizes the composition of AISI 304.

Q: How long does AISI 304 equipment last? A: With proper maintenance, AISI 304 equipment can last 15-20 years or more. Longevity depends on use, environment, and maintenance quality.

Q: Is AISI 304 suitable for all foods? A: AISI 304 is compatible with most foods, but for particularly acidic or salty foods exposed for long periods, AISI 316 might be more suitable.

Q: How can I verify if equipment is truly made of AISI 304? A: You can verify it with a magnetic test (AISI 304 is not magnetic), by checking the manufacturer's certifications, or through spectrographic analysis for critical applications.

Q: Is AISI 304 stainless steel resistant to high temperatures? A: Yes, AISI 304 maintains good mechanical properties up to approximately 870°C, making it ideal for cooking equipment.

Purchasing Guide for AISI 304 Equipment

When purchasing professional equipment made of AISI 304, pay attention to:

1. Material thickness: An indicator of quality and durability
2. Weld quality: Welds should be continuous and well-finished
3. Surface finish: Satin or scotch-brite finishes are preferable for work surfaces
4. Certifications: Verify the presence of certifications such as EU 1935/2004
5. Construction details: Rounded corners and absence of sharp edges facilitate cleaning
6. Manufacturer's warranty: An indicator of the manufacturer's confidence in product quality

On our e-commerce site bianchipro.it, you'll find a wide range of high-quality AISI 304 equipment, all selected according to rigorous standards of excellence and regulatory compliance.

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