316L is a grade of stainless steel material, AISI 316L is the corresponding American label, and sus 316L is the corresponding Japanese label. The unified digital code in my country is S31603, the standard brand is 022Cr17Ni12Mo2 (new standard), and the old brand is 00Cr17Ni12Mo2, which means that it mainly contains Cr, Ni, and Mo, and the number indicates the approximate percentage. The national standard is GB/T 20878-2007 (current edition).
316L is widely used in the chemical industry due to its excellent corrosion resistance. 316L is also a derivative steel of 18-8 type austenitic stainless steel, with 2 to 3% Mo element added. On the basis of 316L, many steel grades are also derived. For example, 316Ti is derived from adding a small amount of Ti, 316N is derived from adding a small amount of N, and 317L is derived from increasing the content of Ni and Mo.
Most of the existing 316L on the market is produced in accordance with American standards. For cost considerations, steel mills generally keep the Ni content of their products as low as possible. The American standard stipulates that the Ni content of 316L is 10-14%, and the Japanese standard stipulates that the Ni content of 316L is 12-15%. According to the minimum standard, there is a 2% difference in Ni content between the American standard and the Japanese standard. This is reflected in the huge price. Therefore, when purchasing 316L products, customers still need to see clearly whether the product is based on ASTM or JIS standards.
The Mo content of 316L makes the steel have excellent pitting resistance and can be safely used in environments containing halogen ions such as Cl-. Because 316L is mainly used for its chemical properties, steel mills have slightly lower requirements for surface inspection of 316L (relative to 304). Customers with higher surface requirements should strengthen the surface inspection.