When choosing the best stainless steel for a project that requires endurance in a corrosive environment, the best selection is often austenitic stainless steel. Austenitic stainless steel is also known to possess excellent mechanical attributes. At the same time, the high amount of nickel and chromium in this type of steel makes it more resistant to corrosion. Additionally, these kinds of steel are easily weldable and formable. The most used grades of austenitic stainless steel are 304 and 316 stainless steel. If you are looking for the right grade for your projects, then you should know the differences between 304 and 316 stainless steel. This article will help you make an informed choice.
304 vs 316 stainless steel differences
The easiest way of differentiating 304 and 316 stainless steel is by looking at 304 vs 316 stainless steel material properties and other attributes like 304 vs 316 stainless steel chemical composition and 304 vs 316 stainless steel cost, among others.
304 Stainless Steel
The grade 304 stainless steel is the most popular austenitic stainless steel. This grade contains between 8% and 10.5% of nickel by weight. Additionally, it has a high amount of chromium between 18% and 20% by weight. Other 304 stainless steel alloying elements are silicon, manganese, and carbon. The remaining chemical composition is mainly iron.
High amounts of nickel and chromium in 304 stainless steel make is more resistant to corrosion.
304 Stainless steel applications
The common applications of 304 stainless steel include;
- Making home appliances like refrigerators and dishwashers.
- Making commercial food processing units.
- Used as fasteners
- Used in piping
- Used in heat exchangers
- Applied in structures in a corrosive environment where standard carbon steel cannot be used
316 Stainless Steel
One thing about the chemical composition of 304 and 316 stainless steel is that they both have high amounts of chromium and nickel. At the same time, 316 stainless steel also contains manganese, silicon, and carbon, while a higher percentage is made of iron. A major difference in 304 and 316 stainless steel chemical composition is that 316 stainless steel has a higher amount of molybdenum, while 304 stainless steel only has traces of the same. This difference makes 316 stainless steel more resistant to corrosion compared to 304 stainless steel.
316 Stainless steel applications
Accordingly, 316 stainless steel is mostly preferred in marine applications due to its high resistance to a corrosive environment. Other common uses include the following:
- Used in chemical processing units and storage equipment
- Used in making refinery equipment
- Applied in medical tools
- Used in a marine environment where there is plenty of chlorides
304 vs 316 stainless steel: which one to choose
If you are still undecided on which grade to choose for your projects, here are some of the situations that may require the use of 304 stainless steel.
- If the project requires great formability: grade 316 stainless steel has a higher molybdenum content, which harms its formability. Grade 304 stainless steel is, therefore, the preferred choice in such applications.
- If you are running on a tight budget: grade 304 stainless steel is more affordable compared to 316 stainless steel.
On the other hand, you may have to use 316 stainless steel if your project requires the following:
- If the environment is highly corrosive: 316 stainless steel is more resistant to corrosion than 304 stainless steel.
- If the environment is wet: 316 stainless steel has a better performance in a waterlogged environment than 304 stainless steel.
- If strength and hardness are required: 316 stainless steel is more robust and harder than 304 stainless steel and is, therefore, the preferred choice in such conditions.
304 vs 316 stainless steel: other comparisons
As said before, both 304 and 316 stainless steel have high nickel and chromium content. The chemical composition of 304 and 316 stainless steel has the following impact:
- Chromium: the chromium content increases the tensile strength, hardness, and corrosion resistance.
- Nickel: As much as nickel increases strength and hardness, it does not compromise flexibility like chromium.
- Molybdenum: This alloying element increases strength, hardenability, creep resistance, and strength at extreme temperatures.
304 vs. 316 stainless steel cost
The price of stainless steel depends significantly on the alloying elements used to make it. The basic requirements for stainless steel are 10.5% chromium and largely iron. All these elements have an impact on the material characteristic and the cost of the final product.
316 stainless steel has a higher percentage of molybdenum than 304stainess steel. This chemical content makes 316 more expensive.
304 vs 316 stainless steel magnetism
Both 304 and 316 stainless steel are austenitic grades. This implies that they do not possess magnetic properties. However, this can be changed through processes like cold working. For instance, there is a slight increase in the magnetic property of stainless steel when it is formed or cut. The magnetism is, however, very negligible.
304 vs. 316 stainless steel corrosion resistance
Stainless steel is mostly a very corrosion resistant family of metal. The addition of molybdenum in 316 stainless steel makes it more resistant to corrosion than any other stainless steel grade. This feature makes 316 stainless steel be referred to as the marine grade because it is ideal for applications in environments with harsh and aggressive conditions. It is, however, advisable to clean the metal regularly to increase its lifespan.
In a nutshell
304 stainless steel is the widely used grade of austenitic stainless steel. The grade is mostly applied in industrial appliances and home equipment. 304 stainless steel is highly resistant to heat and has excellent formability, which makes it easy to weld. Additionally, 304L stainless steel has low carbon content, which prevents the creation of toxic carbide precipitation during welding.
On the other hand, 316 stainless steel has better corrosion resistance that can withstand chlorides. Additionally, this grade can withstand extreme temperatures due to the addition of molybdenum. Such features make 316 stainless steel more suitable for applications like marine, chemical, and textile equipment. 316L stainless steel has low carbon contents like 340L stainless steel and prevents the creation of harmful carbide precipitation.