What is the difference between SUS304L and SUS304?

​​SUS304 stainless steel is a typical material of stainless steel, which can be found everywhere in the market and is often seen in our daily life. Due to its excellent corrosion resistance, heat resistance and strength, it is not only used in daily life, but also in a wide range of industries.

The "L" of SUS304L stainless steel stands for "Low Carbon", and its carbon content is usually less than 0.03%. The carbon content of SUS304 stainless steel is generally around 0.08%. The low carbon property makes SUS304L less prone to intergranular corrosion during welding, so SUS304L is a better choice in occasions where welding is required. In addition, the low carbon content can also improve its oxidation resistance at high temperatures.

 

Secondly, due to the low carbon content, the strength and hardness of SUS304L are usually lower than SUS304, so SUS304 may be more suitable in applications that are subjected to high pressure or impact. In environments with higher requirements for corrosion resistance, SUS304L shows greater advantages, such as chemical industry, food processing and other industries.

 

SUS304L has the advantage of avoiding sensitization, but it is not always necessary to choose SUS304L when selecting stainless steel. Compared with SUS304, it is a material with improved intergranular corrosion resistance by reducing the carbon content to suppress the occurrence of sensitization. Sensitization is a phenomenon in which carbon and chromium combine when stainless steel is heated to about 550-900℃, reducing corrosion resistance.

 

			Hardness
Type Symbol	Yield Strength (MPa, N/mm²)	Tensile Strength (MPa, N/mm²)	HBW	HRB (or HRW)	HV
SUS304	205	520	187 or less	90 or less	200 or less
SUS304L	175	480	187 or less	90 or less	200 or less