The difference between stainless steel SUS304 and SUS316

Did you know that SUS304 and SUS316 are the most popular stainless steels and are widely used around the world? It is extremely difficult to tell the difference between these two grades of stainless steel from our naked eye. The appearance of both stainless steels is almost identical and the differences between the two can easily be missed. So, what is the difference between SUS304 and SUS316?

We will answer this question and discuss the different applications where the grades of stainless steel are used below.

What is the difference between SUS304 and SUS316 stainless steel?

The most basic difference between SUS304 and SUS316 stainless steels is that SUS316 tends to have more nickel and molybdenum in the mix than SUS304. The general mechanical properties of the two metals are mostly comparable.

The increased nickel content and the addition of molybdenum give SUS316 stainless steel better chemical resistance compared to SUS304 stainless steel. Its resistance to acids and chlorides, including salts, makes SUS316 stainless steel ideal for chemical processing and marine applications.

The addition of nickel and molybdenum alloys will make SUS316 stainless steel more expensive compared to SUS304 stainless steel.

SUS304 stainless steel will have a slightly higher melting point than SUS316 stainless steel. SUS316 melts in the range of 2500°F to 2550°F (1371°C to 1399°C), approximately 50 to 100°F lower than the melting point of SUS304 stainless steel.

Compared to SUS304 stainless steel, SUS316 stainless steel has better resistance to chemicals and chlorinated substances such as salt. When it comes to applications involving chloride solutions or exposure to salt, SUS316 stainless steel would be considered superior.

Three benefits of using SUS316 stainless steel

Corrosion resistance

SUS316 stainless steel is more resistant to corrosion than SUS304 stainless steel due to the addition of molybdenum. This reduces pitting in chemical environments and allows SUS316 stainless steel to be used in highly acidic and corrosive environments that would otherwise eat away at the metal. For example, SUS316 stainless steel can withstand aggressive solutions and corrosive applications such as steam degreasing or many other parts cleaning processes.

These properties also make SUS316 stainless steel ideal for pharmaceutical and medical applications. As sterilisation processes in these industries combine both powerful disinfectants and or with high temperatures to prevent contamination, a corrosion resistant alloy like SUS316 is the ideal choice.

Marine applications

Seawater and salty air can cause damage to metals. In addition to the harsh environment of the ocean and marine applications, chlorides, such as salt, can erode even the world's hardest metals. Salt can even destroy the protective oxide layer of SUS304 stainless steel, leading to rusting. For marine applications, or processes involving chlorides, SUS316 stainless steel is ideal.

SUS316 offers better resistance to salt and chloride pitting. Pitting corrosion can occur when stainless steel alloys, such as SUS304 stainless steel, come into contact with salt-rich sea air and seawater. Chloride resistant metals, such as SUS316 stainless steel, are essential for naval applications or anything involving chlorides.

Long-lasting durability

SUS316 stainless steel is both tough and versatile, which makes it ideal for custom wire baskets that will last for years. This grade of stainless steel can be used to create durable baskets that are designed to withstand even repeated exposure to high impact processes.