What is the difference between 303 and 304 stainless steel?

Grade 303 Stainless Steel is similar to Grade 304 Stainless Steel but has added sulfur to help improve machinability while maintaining the corrosion resistance and mechanical elements associated with stainless steel. The added sulfur reduces the corrosion resistance of Grade 303 compared to Grade 304, but for some applications, it is worth the tradeoff for machinability.

Grade 304 stainless steel is one of the most popular alloys due to its incredible corrosion resistance. Its low carbon content makes it ideal for common welding operations such as those in the construction industry. Type 304 stainless steel is austenitic and non-magnetic, which means it also has low thermal and electrical conductivity.

The decision to use 303 or 304 stainless steel generally depends on the application. Several factors come into play when choosing the type of stainless steel to use.