The main differences between stainless steel 316L and 316 are chemical composition, corrosion resistance, strength, welding treatment, high temperature resistance, and **. Here's the breakdown:
1. Different chemical compositionsThe carbon content of 316L stainless steel is lower than that of 316 stainless steel, and in fact, the "L" in the model number means ultra-low carbon. 316 stainless steel contains approximately 17-20% chromium, 11-14% nickel, and 2-3% molybdenum, with a carbon content of 008% or so. 316L stainless steel also contains 16-18% chromium, 10-14% nickel and 2-3% molybdenum, but is distinguished by a lower carbon content, usually controlled at 003% or less.
2. Corrosion resistance:Due to the ultra-low carbon content of 316L, it has better resistance to grain boundary corrosion. This means that in harsh environments, especially in the presence of chloride, 316L will perform better.
3. Strength:316 stainless steel has stronger mechanical properties and higher tensile strength than 316L stainless steel. Generally speaking, the tensile strength of 316 stainless steel is required to be greater than 520MPa, while the tensile strength of 316L stainless steel is only required to be greater than 480MPa. This is due to the fact that carbon is a strong austenite forming element that can significantly increase the strength of steel. The strength of 316L is slightly lower than that of 316, which makes 316L easier to machine and shape. In some applications, this difference in strength may affect the choice of material.
4. Welding treatment: 316 stainless steel usually needs to be annealed after welding to restore its corrosion resistance. On the other hand, 316L stainless steel usually does not need to be annealed due to its ultra-low carbon content and low risk of grain boundary corrosion after welding.
5. High temperature resistance:In a high-temperature environment, 316L stainless steel has better carbide precipitation resistance than 316 stainless steel, so it can be used continuously in the range of 800 1575 degrees. Outside of this range, when 316 stainless steel is used continuously, the material still has good heat resistance.
Due to the low carbon content of 316L stainless steel and the ease of welding, it is usually slightly higher than 316 stainless steel, but the difference between the two is not significant.
In summary, 316L stainless steel has excellent corrosion resistance due to its ultra-low carbon content, especially in terms of grain boundary corrosion. In applications where higher strength is required, 316 may be a better choice. In practice, the choice between 316 and 316L should be based on the specific use environment and requirements.