What Is The 316L Stainless Steel ?

316L is a stainless steel material grade. Every country has slightly different standards for the chemical composition of 316L. AISI 316L is the corresponding American label, and sus 316L is the corresponding Japanese label. my country's unified digital code is S31603, the standard grade is 022Cr17Ni12Mo2 (new standard), and the old grade is 00Cr17Ni14Mo2, which means it mainly contains Cr, Ni, and Mo, and the numbers indicate the approximate percentage. The national standard is GB/T 20878-2007 (current version). Apart from differences in production processes and technologies, the performance of stainless steel is mainly affected by the content of chemical element.

Corrosion Resistance Of Stainless Steel 316L

316L is widely used in the chemical industry because of its excellent corrosion resistance. 316L is also a derivative of 18-8 austenitic stainless steel, with 2 to 3% Mo added. On the basis of 316L, many steel types are derived. For example, 316Ti is derived by adding a small amount of Ti, 316N is derived by adding a small amount of N, and 317L is derived by increasing the Ni and Mo content.

Most of the 316L currently on the market is produced in accordance with American standards. For cost considerations, steel mills generally limit the Ni content of products as low as possible. The American standard stipulates that the Ni content of 316L is 10 to 14%, and the Japanese standard stipulates that the Ni content of 316L is 12 to 15%. According to the minimum standard, there is a 2% difference in Ni content between the American standard and the Japanese standard, which is still quite huge in terms of price. Therefore, customers still need to see clearly when purchasing 316L products whether the product refers to ASTM or JIS standards.

The Mo content of 316L makes this steel type have excellent corrosion resistance and can be safely used in environments containing halogen ions such as Cl-. Since 316L is mainly used for its chemical properties, steel mills have slightly lower surface inspection requirements for 316L (compared to 304). Customers with higher surface requirements should strengthen surface inspection.