304 VS 316 Stainless Steel: How to Choose the Best Material for Your project

As a supplier of OEM precision CNC-machined parts, it’s important for quality and reliability that you choose the right stainless steel material for your projects. Two of the most popular stainless steel materials used in CNC machining are 304 and 316 stainless steel. It’s well to know the differences between these materials if you want to choose the best one for your project.

In this blog post, we’ll explore the composition and properties of 304 and 316 stainless steel, compare their advantages and disadvantages, and provide guidance on how to choose the best material for your CNC machining project.

I. Composition , Properties and disadvantage of 304 Stainless Steel

CNC machining is often done with 304 stainless steel because it is strong, doesn’t rust, and can be bent easily. It is an austenitic stainless steel, which means it has a face-centered cubic crystal structure and is non-magnetic.


The fact that 304 stainless steel is made up of 18% chromium and 8% nickel makes it very resistant to corrosion. Additionally, it contains small amounts of carbon, silicon, and manganese.

Element Composition (percentage by weight)
Carbon 0.08% max
Chromium 18%
Nickel 8%
Manganese 2% max
Silicon 1% max
Phosphorus 0.045% max
Sulfur 0.03% max
Nitrogen 0.10% max


In terms of properties, 304 stainless steel has good machinability and can be easily welded and formed. It has a maximum operating temperature of 870°C and a melting point of 1400-1450°C. It is also non-magnetic, making it ideal for applications where magnetic interference is a concern.

Property Value
Density 8 g/cm³
Melting point 1400-1450°C
Maximum operating temperature 870°C
Yield strength (annealed) 205 MPa
Ultimate tensile strength (annealed) 515 MPa
Modulus of elasticity 193 GPa
Poisson’s ratio 0.3
Electrical conductivity 3.05 × 10^6 S/m
Thermal conductivity 16.2 W/(m·K)
Coefficient of thermal expansion 17.2 × 10^-6 /°C


However, 304 stainless steel is not suitable for applications where exposure to highly corrosive environments, such as saltwater or acidic solutions, is expected. It also has lower strength compared to other stainless steel grades such as 316 stainless steel.

II. Composition, Properties and disadvantage of 316 Stainless Steel


316 stainless steel is a popular choice for CNC machining projects due to its unique composition and properties. It contains about 16-18% chromium, 10-14% nickel, 2-3% molybdenum, and small amounts of carbon, silicon, and manganese. This composition gives 316 stainless steel superior corrosion resistance compared to other grades, especially in chloride-rich environments.

The addition of molybdenum also makes 316 stainless steel more resistant to pitting and crevice corrosion, which can be a concern in some CNC machining applications. In addition to its corrosion resistance, 316 stainless steel is known for its high strength and excellent toughness at both high and low temperatures.

Element Composition (% by weight)
Carbon 0.08 max
Manganese 2.00 max
Nickel 10.00 – 14.00
Molybdenum 2.00 – 3.00
Silicon 0.75 max
Phosphorus 0.045 max
Sulfur 0.030 max
Nitrogen 0.10 max
Chromium 16.00 – 18.00
Iron Balance


When it comes to machinability, 316 stainless steel can be more challenging to work with compared to 304 stainless steel due to its higher hardness and strength. However, with the right tools and techniques, it can still be successfully machined.

Property Value
Density 8 g/cm³
Melting point 1370-1400 °C
Thermal conductivity 16.2 W/m·K
Electrical resistivity 740 nΩ·m
Modulus of elasticity 200 GPa
Poisson’s ratio 0.3
Specific heat capacity 500 J/kg·K
Thermal expansion coefficient 16.5 µm/m·K

Advantages and disadvantages

There are several advantages to using 316 stainless steel for CNC machining projects. Its superior corrosion resistance makes it an excellent choice for components that will be exposed to harsh environments, such as those used in the marine, chemical, and pharmaceutical industries. Its high strength and toughness also make it suitable for applications where durability and reliability are essential.

However, there are also some disadvantages to using 316 stainless steel. It can be more expensive compared to other grades, which may not be feasible for some projects. Additionally, its higher hardness and strength can make it more challenging to machine, requiring more time and effort during the manufacturing process.

Overall, the decision to use 316 stainless steel for CNC machining projects will depend on the specific requirements of the application. It is important to consider factors such as corrosion resistance, strength, machinability, and cost when making this decision.

III. Choosing the Best Material for Your Project:

When it comes to choosing between 304 and 316 stainless steel for your project, it’s important to understand the differences between these two grades of stainless steel. Here are some factors to consider:

1. Chemical Composition Difference: 304 stainless steel contains 18% chromium and 8% nickel, while 316 stainless steel contains 16% chromium, 10% nickel, and 2% molybdenum. This small addition of molybdenum in 316 stainless steel enhances its corrosion resistance, especially in chloride environments.

2. Mechanical Properties Difference: Both 304 and 316 stainless steel have excellent mechanical properties, but 316 stainless steel is slightly stronger and more ductile than 304 stainless steel.

3. Corrosion Resistance Difference: 316 stainless steel has better corrosion resistance than 304 stainless steel, especially in marine environments and other highly corrosive environments where chloride exposure is present.

4. Temperature Resistance Difference: Both 304 and 316 stainless steel can withstand high temperatures, but 316 stainless steel has better resistance to high temperatures than 304 stainless steel due to its higher nickel content.

5. Lasting Durability: 316 stainless steel has a longer lifespan than 304 stainless steel due to its higher corrosion resistance and durability.

6. Weldability and Formability: Both 304 and 316 stainless steel are highly weldable and formable, but 316 stainless steel requires more heat input during welding due to its higher thermal conductivity.

7. Price Difference: 316 stainless steel is generally more expensive than 304 stainless steel due to its higher molybdenum content and better corrosion resistance.

8. Application difference: Stainless 304 and 316 are versatile materials with a wide range of applications across industries. Here are some of the most common uses for each type:

Stainless Steel 304:

  • Kitchen equipment and appliances
  • Food processing and handling
  • Chemical containers and tanks
  • Automotive parts and trim
  • Architectural and structural applications
  • Industrial equipment and machinery

Stainless Steel 316:

  • Marine and coastal equipment
  • Pharmaceutical and medical devices
  • Chemical processing equipment
  • Heat exchangers and boilers
  • Oil and gas industry components
  • Aerospace and aviation components

While both types of stainless steel have similar applications in certain industries, the corrosion resistance and strength of 316 make it a better choice for more demanding environments such as marine or chemical processing applications. On the other hand, 304 is a cost-effective solution for less demanding applications where corrosion resistance is not as critical.

Consider these factors when choosing between 304 and 316 stainless steel for your project. If corrosion resistance is a top priority, 316 stainless steel is the way to go. However, if cost is a concern, 304 stainless steel may be the better choice.

IV. Conclusion

In conclusion, selecting the right type of stainless steel for your project depends on several factors, including your specific application requirements, budget, and production constraints. While both 304 and 316 stainless steel offer excellent properties, they have distinct differences in their chemical composition, mechanical properties, corrosion resistance, temperature resistance, and weldability.

For general-purpose applications, 304 stainless steel is a great option due to its good corrosion resistance, moderate strength, and affordability. On the other hand, 316 stainless steel is a more premium option that offers superior corrosion resistance, higher strength, and greater durability in harsh environments, but comes at a higher cost.

When selecting between SS304 and SS316, it is essential to evaluate the specific requirements of your project to determine which one is the most suitable. By taking into account the factors mentioned above, you can make an informed decision that will ensure optimal performance and longevity for your CNC machining project.

Worthy Hardware is very strong in making all kinds of stainless steel materials with CNC machining, prototypes and sheet metal fabrication parts. If you have the trouble in such materials, contact us for quote by today.


Is 304 better than 316 in water?

It depends on the specific application and the type of water. Generally, both 304 and 316 stainless steel are highly resistant to corrosion in water. However, 316 stainless steel has better corrosion resistance in saline and chloride environments, making it more suitable for marine and coastal applications.

Why is 316 more expensive than 304?

The main reason why 316 stainless steel is more expensive than 304 is due to its higher nickel and molybdenum content. These alloying elements enhance its corrosion resistance, strength, and durability, but also increase its production cost.

Which is better 304 or 316 stainless steel?

It depends on the specific requirements of the application. Generally, 304 stainless steel is more cost-effective and suitable for applications that require good corrosion resistance in non-saline and non-chloride environments. On the other hand, 316 stainless steel has better corrosion resistance in saline and chloride environments, making it more suitable for marine, coastal, and chemical processing applications that involve exposure to corrosive fluids or gases.

Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.