What is the Difference Between 304, 304L, and 316L Stainless Steel?

Corrosion Resistance:
All three grades offer good corrosion resistance in many environments. However, 316L stainless steel exhibits superior resistance to corrosion, especially in chloride-rich environments, due to its higher molybdenum content. If the application involves exposure to saltwater, chemicals, or acidic environments, 316L stainless steel is often preferred over 304 and 304L stainless steel.

Mechanical Properties:
304, 304L, and 316L stainless steel grades have similar mechanical properties. They possess high tensile strength, good impact resistance, and excellent toughness. However, due to its higher molybdenum content, 316L stainless steel offers slightly better overall mechanical properties, especially in terms of creep and stress rupture strength.

Weldability:
All three grades are readily weldable using common welding methods. However, 304L stainless steel, with its lower carbon content, is more resistant to sensitization and subsequent corrosion in the heat-affected zone after welding. It does not require post-welding annealing to restore its corrosion resistance, making it a preferred choice for welded components.

Cost:
In general, 304 stainless steel is more cost-effective compared to 316L stainless steel. The addition of molybdenum in 316L stainless steel increases its cost. Therefore, for applications that do not require the enhanced corrosion resistance of 316L, 304 stainless steel is a more economical option.