What is the difference between SUS304 and SUS304L ?

Among stainless steel materials, 304 stainless steel plate and 304L stainless steel plate are two widely used alloy types. Although their main components are similar, there are obvious differences in carbon content, corrosion resistance, mechanical properties and application areas. This article will compare the characteristics of these two stainless steel plates in detail to help buyers make the most appropriate decision when choosing.

The main difference between SUS304 and SUS304L is the carbon content.
The "L" in SUS304L stainless steel plate stands for "Low Carbon", and its carbon content is usually less than 0.03%. The carbon content of SUS304 is generally around 0.08%. The low carbon property makes SUS304L stainless steel cold rolled plate less prone to intergranular corrosion during welding, so SUS304L is a better choice in situations where welding is required. ‌

Corrosion resistance comparison

304L stainless steel alloy plate is generally superior to 304 stainless steel plate in terms of corrosion resistance due to its low carbon content. Especially in high temperature or highly corrosive environments, 304L hot-rolled stainless steel plates show stronger oxidation resistance and can effectively avoid intergranular corrosion (sensitization).
Sensitization refers to the fact that when stainless steel is heated to 550-900°C, carbon and chromium combine to form non-corrosion-resistant substances, reducing its corrosion resistance. 304L effectively inhibits the occurrence of sensitization by reducing the carbon content, further improving its corrosion resistance.

‌Strength and hardness‌:
Due to the low carbon content, the strength and hardness of SUS304L are generally lower than SUS304. Therefore, in applications subject to high pressure or impact, SUS304 may be more suitable‌.

Application field comparison
304 stainless steel plate has excellent performance in hot processing, can be made into various shapes through stamping, bending and other processing methods, and will not produce magnetism after heat treatment. It is suitable for environments with temperatures ranging from -196°C to 800°C.
304L stainless steel plate has outstanding resistance to intergranular corrosion and can work stably under harsh conditions. The operating temperature range of 304L is also from -196°C to 800°C.