316L stainless steel pipe is certified as pure grade, and the carbon content must be up to 0.03% to obtain double certification. 316L stainless steel tubes can be used seamlessly for pressure applications or welded for structural applications. 316L SS seamless pipe contains more molybdenum and nickel than 304 stainless steel, thereby improving the corrosion resistance of the metal. 316L stainless steel pipe is used in a more corrosive environment than 304 pipe. http://www.kntubes.com/stainle....ss-steel-pipe/stainl