AISI 317 steel and AISI 317L steel are austenitic stainless steels. The main difference between them is the lower carbon content in AISI 317L, which minimizes carbide precipitation and improves weldability. They also have good corrosion resistance and elevated temperature strength.
AISI 317 and AISI 317L are grade designations defined by the American Iron and Steel Institute (AISI). AISI 317 steel is defined as an austenitic stainless steel on the basis of its composition and mechanical properties. AISI 317L is an additional low-carbon version of AISI 317, with only 0.03% of its composition containing carbon.
AISI 317 and AISI 317L have a composition that consists of iron, 16-18% chromium, and 11-14% nickel. In addition, AISI 317 contains 2-3% molybdenum, and AISI 317L contains only 1.0-2.0% molybdenum.
AISI 317 and AISI 317L are high-alloy, austenitic stainless steels with excellent corrosion resistance in acidic and high-temperature environments. When compared to 304 and 316 stainless steel, AISI 317 and AISI 317L provide better performance under high temperatures and chloride environments. Additionally, AISI 317 and AISI 317L offer higher creep, stress-rupture, and tensile strength than other austenitic stainless steels.
AISI 317 and AISI 317L both have a desirable combination of mechanical properties. In the annealed condition, both grades yield strength of 45 ksi and elongation of 45%. At a temperature of 1500°F, they have tensile strength of around 65 ksi and yield strength of 25 ksi. They also have a hardness of 79-95 HRC and a modulus of elasticity (Young’s modulus) of 29.0 x 10^3 ksi.
AISI 317 and AISI 317L are suitable for applications in many industries. They are commonly used in chemical processing, pharmaceuticals industry, oil and gas industry, food processing, and electrical and power industry. They are naturally non-magnetic and can be welded using common process like electric arc and resistance welding.
In addition to excellent resistance to chemical attacks, AISI 317 and AISI 317L also offer good thermal fatigue and stress-rupture properties. This makes them well-suited for parts that require frequent cycling between high and low temperatures. These steels are also used for cryogenic and low-temperature applications due to their low-temperature strength and durability.
AISI 317L has a maximum operating temperature of 800°F (427°C) while AISI 317 can be used at higher temperatures due to higher chromium and molybdenum content which provides greater resistance to oxidation and corrosion.
Overall, AISI 317 and AISI 317L provide good performance in terms of corrosion resistance, thermal fatigue, and stress-rupture properties. But the low-carbon version, AISI 317L, is the steadier of the two grades and offers better weldability over AISI 317.
