304, 304L, and 304H are different grades of the same base material, stainless steel, and the differentiating factor among these grades is the carbon content.
- 304 Stainless Steel: This is the most versatile and widely used stainless steel. It has excellent forming and welding characteristics. The balanced austenitic structure of Grade 304 enables it to be severely deep drawn without intermediate annealing, making this the stainless steel grade of choice in the manufacturing of sinks, hollow-ware, and saucepans. It has excellent corrosion resistance in a wide range of atmospheric environments and many corrosive media.
- 304L Stainless Steel: The “L” in 304L stands for “Low carbon.” This variant has a lower carbon content compared to 304 stainless steel, typically around 0.03%. The lower carbon content means that 304L is generally more weldable and offers more corrosion resistance after welding, making it a good choice for applications requiring extensive welding.
- 304H Stainless Steel: The “H” in 304H stands for “High carbon.” It is a high-carbon variant of 304 stainless steel, with a carbon content typically between 0.04% and 0.10%. This makes 304H more suitable for high temperature applications, because the higher carbon content improves the steel’s high-temperature strength.