What is stainless steel 316L?
2025-01-03
1. What is stainless steel 316L?
316L stainless steel is an alloy steel. "316L" is the grade of this stainless steel, where "L" stands for low carbon. It is obtained by further reducing the carbon content on the basis of 316 stainless steel. Its main alloying elements include chromium (Cr), nickel (Ni) and molybdenum (Mo). In general, the chromium content of 316L stainless steel is about 16-18%, the nickel content is about 10-14%, and the molybdenum content is about 2-3%.
2. What is the meaning of L in stainless steel 316L?
In stainless steel 316L, "L" stands for "low carbon". The carbon content of 316 stainless steel is generally less than 0.08%, while the carbon content of 316L stainless steel is limited to less than 0.03%. This low carbon content is an important feature of 316L stainless steel.
3. Chemical composition of stainless steel 316L
Major alloying element
Chromium (Cr) : The content is about 16.0%-18.0%. It can react with oxygen in the air to form a dense oxide film, which effectively prevents further oxidation of the metal surface. Compounds such as Cr₂₃C₆ and Cr₂₃ ₆ can be formed to continue to protect the metal surface, thus significantly improving the corrosion resistance and high temperature resistance of stainless steel.
Nickel (Ni) : The content is generally 10.0%-14.0%, which can enhance the toughness, plasticity and corrosion resistance of stainless steel, especially the resistance to chloride corrosion, but also improve the mechanical properties and low temperature toughness of stainless steel, reduce its hardness, and improve the processing performance.
Molybdenum (Mo) : The content is about 2.0%-3.0%, which can significantly improve the corrosion resistance of stainless steel, especially in harsh environments such as seawater and chloride, and can also enhance the resistance to pitting and crevice corrosion of stainless steel.
Other elements
Carbon (C) : The content is very low, the maximum is not more than 0.03%, low carbon content can reduce the risk of intergranular corrosion in the welding process, improve the resistance of stainless steel to intergranular corrosion.
Silicon (Si) : The maximum content is 1.00%, which is used to stabilize and increase the performance of steel.
Manganese (Mn) : The content is up to 2.00%, which can improve the strength and hardness of the material, while also helping to resist corrosion.
Phosphorus (P) : The maximum content is 0.045%, phosphorus is a harmful element, the content should be controlled at a low level, so as not to affect the plasticity and toughness of the material.
Sulfur (S) : The maximum content is 0.030%, sulfur is also a harmful element, and its content needs to be controlled to avoid adverse effects on the performance of the material.
4. Corrosion resistance of stainless steel 316L
316L stainless steel has excellent corrosion resistance. It has a good tolerance to many chemicals, especially in environments containing aggressive media such as chloride. For example, in the Marine environment, sea water contains a lot of salt (mainly sodium chloride and other chlorides), 316L stainless steel made of ship parts, seaside building decoration materials, compared with ordinary steel, can effectively resist the corrosion of sea water, reduce the risk of rust and structural damage.
It can also withstand the corrosion of organic acids and inorganic acids (such as sulfuric acid, nitric acid, etc.), and is widely used in some chemical equipment, such as containers for storage and transportation of chemical reagents.
5. Weldability of stainless steel 316L
316L stainless steel has good weldability. Due to its low carbon content, it is not easy to produce intergranular corrosion in the welding process. This makes it easy to perform various welding operations, such as arc welding, laser welding, etc., for the manufacture of complex structural parts. For example, in the manufacture of food processing equipment and pharmaceutical equipment, the 316L stainless steel equipment after welding can ensure the structural integrity and tightness, and will not reduce corrosion resistance due to welding.
6. Mechanical properties of stainless steel 316L
316L stainless steel has good strength and toughness. Its yield strength is generally more than 200MPa, and its tensile strength is between 480-620MPa. This allows it to withstand a certain amount of external forces without easily deforming or breaking. For example, when making medical instruments such as surgical instruments, it can maintain its shape during frequent use and will not be damaged when subjected to certain external forces such as bending and twisting.
