Views: 6 Author: Monica Publish Time: 2025-09-03 Origin: Site
18/8 stainless steel is also known as 304 stainless steel. The AISI standard designates 304 as 18/8. It is one of the most common and widely used grades of stainless steel.
18 8 stainless steel international names and standards:
Country | Standards | 18/8 steel equal names |
US | ASTM | A240, A240M |
EU | EN-1008801 | X5CrNi18-10 |
ISO | ISO15510 | X5CrNi-18-10, X2CrNi19-11 |
Japan | JIS | SUS304 |
China | GB/T20878 | 0Cr18Ni9 |
18/8 stainless steel is composed of 18% chromium and 8% nickel. This combination of elements provides optimal corrosion resistance, durability, and strength.
18/8 stainless steel is austenitic structure, with a high concentration of chromium and nickel in its chemical composition. The chromium oxide layer that forms on the surface protects against rust and corrosion. Nickel enhances the strength, formability, and durability of 18/8 stainless steel. Furthermore, 18/8 stainless steel is non-magnetic and offers excellent weldability, heat treatability, and food safety.
To understand 18 8 stainless steel, you must know its chemical composition.
Iron (Fe): 72% to 78%
Iron forms the backbone of 18-grade stainless steel. It imparts strength and durability, ensuring safe and reliable applications. This dominant element lays the foundation upon which other components enhance the steel's performance.
Chromium (Cr): 18% (minimum)
Chromium is the secret weapon against corrosion. Chromium ensures the material's corrosion resistance and prevents rust. This property allows stainless steel to be used in harsh environments without requiring frequent maintenance.
Nickel (Ni): 8% (minimum)
Nickel provides the strength and flexibility you need for demanding applications. It also maintains the metal's properties under stress, preventing deformation in stainless steel structures. This element makes the material versatile and adaptable to meet industrial or aesthetic needs.
Carbon (C): 0.08% (maximum)
Adding carbon increases the material's hardness and strength, resulting in a higher-quality material. Small amounts of carbon can effectively improve the material's wear resistance.
Manganese (Mn): 2% (maximum)
Manganese enhances the material's weldability, making it easier to machine. It also increases strength by eliminating impurities.
Silicon (Si): 1% (maximum)
Silicon enhances thermal stability, which is crucial for high-temperature applications. It also improves the material's resistance to oxidation under harsh conditions. When your project demands more from the material, silicon can enhance your reliability.
Phosphorus (P): 0.045% (maximum)
Phosphorus enhances the machinability of stainless steel, making it easier to work. While small amounts of phosphorus are beneficial, large amounts can be detrimental, causing embrittlement.
Sulfur (S): 0.03% (maximum)
Sulfur enhances the machinability of stainless steel, making it easier to machine. Limited use of sulfur allows you to create intricate patterns or components while maintaining the necessary toughness.
Understanding the mechanical properties of 18-8 stainless steel allows you to assess the material's strength, durability, and suitability for your project.
Tensile Strength
18 8 stainless steel has a tensile strength of at least 515 MPa (75,000 psi). It will not break under high tensile forces.
Yield Strength
18 8 stainless steel has a yield strength of at least 205 MPa (30,000 psi), making it resistant to deformation under moderate pressure. You can be sure it will retain its shape under stress, which is crucial for structures where stability is paramount.
Elongation
This material can stretch up to 40% in a 50 mm sample before breaking. This is crucial for avoiding crack formation under stress.
Hardness
Its hardness ranges from 70 to 85 HRB (201 HB). This ensures the material will not abrade component surfaces, extending the life of the component.
Understanding the physical 18 8 stainless steel properties can help you determine if it is suitable for your application and requirements.
Density
18 8 stainless steel density is 8.0 g/cm³, making it both strong and lightweight. This material can withstand heavy loads while adding virtually no weight. Its low weight makes it ideal for projects requiring strength without adding bulk.
Melting Point
The melting point ranges from 1400°C to 1450°C (2550°F to 2650°F). This steel can be used in high-temperature applications without worrying about material deformation. Its heat resistance ensures reliability in critical applications.
Thermal Conductivity
18 8 stainless steel has a thermal conductivity of 16.2 W/m·K. This allows you to tailor heat transfer to your needs for optimal results. Whether you're cooling or heating, this property offers advantages.
Resistivity
The resistivity is approximately 720 nΩ·m at 20°C. This property helps manage electrical insulation when low conductivity is required. You will benefit greatly from its stable performance in electronic and industrial applications.
Food and Beverage Industry
As mentioned above, 18-8 stainless steel has hygienic properties and easily resists food acids. This material is very common in food and kitchen accessory manufacturing plants. Common examples include sinks, cookware, storage tanks, and food service equipment.
Medical and Pharmaceutical Industry
Sterile components are crucial in the medical field. Therefore, CNC machining companies use 18-8 stainless steel to manufacture surgical components. Examples include sterilization trays, scissors, trocars and cannulas, and vascular clamps. These components are remarkably resistant to the sterilization process.
Household Appliances
Household appliances remain vulnerable to daily use. For example, dishwashers, ovens, and refrigerators are often affected by moisture and oxidation. Therefore, most of these appliances are made of 18-8 stainless steel.
Building and Construction
Today, people are increasingly installing fancy decorations, exterior walls, and roofs. Weather changes can affect these installations, so 18/8 stainless steel is used to manufacture these components to ensure long-term performance.
Industrial Equipment
In manufacturing companies, large machine units must be high-quality and wear-resistant. These components are expensive and cannot be replaced frequently. Therefore, 18 8 stainless steel is a good choice for manufacturing these components. Some common examples of these components are heat exchangers, tanks and vessels, compressors, and conveying systems.
18 8 stainless steel vs 304
18 8 stainless steel and 304 stainless steel are actually the same thing. The numbers "18 8" tell you what is inside the metal. It means the steel has about 18% Chromium and 8% Nickel. Chromium is the key element that makes stainless steel resist rust and stains. Nickel helps make the steel strong and easy to shape.
"304" is just the official scientific name for this same type of steel. When you see "304", it is the same metal as "18 8". It is the most common stainless steel used in everyday things. You find it in kitchen sinks, pots, pans, cutlery, and appliances. It works well for these things because it handles normal wear, water, and food acids without rusting easily. If a product says "18 8" or "304", you know it is this popular, reliable, general-purpose stainless steel.
18/8 vs 18/10 steel
18/8 and 18/10 stainless steel are very close relatives. Both have the same amount of Chromium, which is about 18%. Chromium is the most important part for fighting rust. The difference is in the amount of Nickel. 18/8 has about 8% Nickel, while 18/10 has about 10% Nickel.
That extra Nickel in 18/10 makes a small difference. It can make the steel look slightly shinier and more mirror-like. It might also make the steel feel a tiny bit heavier or more solid. Because of the extra Nickel, 18/10 is often used for higher-quality forks, knives, and spoons. The extra Nickel can make the metal a little less likely to bend slightly under stress.
However, the most important thing, rust resistance, is almost the same for both because they have the same Chromium level. 18/10 is usually more expensive than 18/8 because Nickel costs more.
18-8 stainless steel vs 316
18-8 stainless steel (also known as 304) is great for many things, but 316 stainless steel is better for tougher jobs. Both have Chromium and Nickel to resist rust. The main difference is that 316 has an extra element called Molybdenum.
Adding Molybdenum is a big upgrade. Molybdenum gives 316 steel much stronger resistance to corrosion, especially in harsh environments. This means 316 is much better at fighting rust caused by salt. If something will be near ocean saltwater, swimming pools, or road salt in winter, 316 is the better choice. It also handles strong chemicals better than 18-8. Because of this, 316 is called "marine-grade stainless steel". You find it on boats, ship fittings, chemical tanks, and medical equipment.
However, 316 costs more than 18-8. For everyday things like kitchen items or indoor fixtures where salt or harsh chemicals aren't a big problem, the less expensive 18-8 is usually perfect. The molybdenum makes 316 the champion for tough, salty, or chemical-heavy situations.
Is 18-8 stainless steel of good quality?
Yes, it is, due to its high corrosion resistance, mechanical properties, and flexibility.
What are the disadvantages of 18-8 stainless steel?
It is susceptible to chloride attack, making it unsuitable for use in areas with high salt concentrations.
Which is stronger, 18-8 or 18-10 stainless steel?
18-10 is stronger than 18-8.
What is the yield strength of 18-8 stainless steel?
The yield strength is at least 205 MPa, making the material very strong.
Is there an equivalent material to 18-8 stainless steel?
Yes, grades like 304 are available.
What is the price of 18-8 stainless steel?
Prices vary depending on market factors and the quantity you require.
