AISI 316 and AISI 316L Steel at Room Temperature
Introduction
The stainless steel grades AISI 316 and AISI 316L are most often used in the form of austenitic stainless steels. These steels contain both chromium and nickel and are commonly employed all over the world in many different applications. There is a broad usage of these two alloys in the industrial, chemical, and food sectors. Apart from these applications, AISI 316 and AISI 316L are widely used in the production of medical instruments and equipment. Therefore, it is necessary for those who work with these steels, to understand their properties and performances. The writing that follows, examines the material properties and mechanical properties at room temperature of AISI 316 and AISI 316L.
Material Properties of AISI 316 and AISI 316L
AISI 316 and AISI 316L are austenitic stainless steels containing 16 and 18% chromium, 11 and 14% nickel, and 2% molybdenum respectively. The addition of molybdenum in AISI 316L steel increases the corrosion resistance of this alloy over the unalloyed AISI 316 steel. The elemental composition of both AISI 316 and AISI 316L steels is presented in Table 1. The post-chloride corrosion resistance of AISI 316 and AISI 316L steels are similar when the chloride concentrations are high. AISI 316L has higher carbon content, which makes it more prone to intergranular corrosion than AISI 316 when it is exposed to temperatures above 400°C for a long time.
Table 1: Elemental Composition of AISI 316 and AISI 316L Steels (weight percentage)
Element AISI 316 AISI 316L C% ≤ 0.08 ≤ 0.035 Si% ≤ 1.00 ≤ 1.00 Mn% ≤ 2.00 ≤ 2.00 Cr% 16.0 - 18.0 16.0 - 18.0 Ni% 11.0 - 14.0 10.0 - 14.0 Mo% 2.00 - 3.00 2.00 - 3.00 P% ≤ 0.045 ≤ 0.045 S% ≤ 0.03 ≤ 0.03
Mechanical Properties of AISI 316 and AISI 316L at Room Temperature
The mechanical properties of AISI 316 and AISI 316L at room temperature are of great importance in the manufacture and design of components and equipment containing this alloy. Table 2 shows typical mechanical properties at room temperature for AISI 316 and AISI 316L in the form of hot-rolled sheet.
Table 2: Typical mechanical properties at room temperature for AISI 316 and AISI 316L in the form of hot-rolled sheet
Property AISI 316 AISI 316L Tensile strength (Ultimate) (ksi) 75 75 Yield strength (0.2% offset) (ksi) 30 25 Elongation (%) 40-60 50 Hardness range (Brinell) 95-215 90-150
Corrosion Resistance at Room Temperature
AISI 316 and AISI 316L steels provide good resistance to general corrosion and to pitting or crevice corrosion in polluted environments. They are relatively resistant to localized corrosion especially in chemically acid atmospheres. Tests have shown that the corrosion resistance of AISI 316L increases in solutions containing chlorides.
Conclusion
In conclusion, AISI 316 and AISI 316L are austenitic stainless steels containing 16 and 18% chromium, 11 and 14% nickel, and 2% molybdenum respectively. The room temperature mechanical properties for AISI 316L and AISI 316 are presented in table 2. They both provide good general corrosion and pitting or crevice corrosion resistance in polluted environments. The corrosion resistance of AISI 316L increases in solutions containing chlorides.
