Austenitic SS 317L

Austenitic SS 317L

Alloy 317L Stainless steel or UNS S31703 is molybdenum containing  low carbon content   corrosion-resistant austenitic stainless steel with increased addition of chromium, nickel, and molybdenum. 317L grade stainless steel is a low carbon version of the stainless steel grade 317. Both are recommended popularly by 317L stainless steel suppliers as they offer good strength and corrosion resistance. 

317L stainless steel chemical composition

As 317L v 316L properties, 317L Stainless steel is an enhanced grade of 316L stainless steel (SS316L) with a higher content of molybdenum (Mo). This increase in the Mo content enhances the pitting corrosion resistance abilities and makes It stronger. 317L Stainless Steel (SS317L) has lower carbon content than SS317 with more corrosion resistance capabilities when compared to 316L stainless steel (SS316L).

Grade NI CR MO C MN P S Fe
SS 317L MIN % 11 18 3 BALANCE
MAX % 15 20 4 0.03 2 0.045 0.03
MAX % 13 19 3.5 0.08 2 0.045 0.03

An alloy of 317L stainless steel has higher creep, stress-to-rupture, and tensile strength at extreme temperatures relative to conventional stainless steel. SS317L is low carbon or ‘L’ grade alloy which has sensitization resistance during welding and other thermal processes. In the annealed conditions, it is non-magnetic and cannot be hardened using heat treatment. However, the material will harden while cold working and may become slightly magnetic after welding. 

AISI 317 Stainless steel alloy offers better resistance compared to 316L in extremely corrosive environments with sulfurous media, chlorides, and other halides. The low carbon content allows welding and processing without intergranular corrosion by standard shop fabrication practices.

Applications recommended by 317L stainless steel suppliers

Alloy 317L Stainless steel with its higher molybdenum content makes it superior in general and localized corrosion resistance. It also improves its ability to resist pitting and crevice corrosion when it gets in contact with chlorides and other halides. It’s resistant to sulfuric acid attacks and other chemicals like acidic chlorine and phosphoric acid which makes it an ideal alloy for handling hot organic and fatty acids commonly found in food and pharmaceutical processing applications.

317L stainless steel properties and ideal working conditions

Due to the 317L composition, it is popularly recommended in typical hot working process temperatures. For SS317L, the ideal temperatures range from 1652 – 2102°F (900 – 1150°C). It is not recommended below 1742°F (950°C). A solution anneal of 1976 – 2156°F (1080 – 1180°C) is required when the final forming temperatures tend to fall below the previously mentioned threshold.

Grade Density
Elastic Modulus
Mean Co-eff of Thermal
Expansion (μm/m/°C)
Conductivity (W/m.K)
SS 317/ 317L 8 193 0-100°C at 100°C
16 16.3

The corrosion resistance of SS317 and SS317L Stainless should remain the same in any given environment. The one exception is where the alloy will be exposed to temperatures in the chromium carbide precipitation range of 800 – 1500°F (427 – 816°C). 

Popularly, both SS317 and SS317L are used in industries like chemical processing, pulp & papermaking, textile, and petrochemical piping.