Stainless Steel Grade 317L-UNS S31703

Stainless steel grade 317L is a molybdenum-bearing, low-carbon version of grade 317 stainless steel. It shares the high strength and corrosion resistance of 317 steel, but due to its low carbon content, it can produce stronger welds. The following datasheet offers an overview of stainless steel grade 317L.

Stainless Steel Grade 317L-UNS S31703

Corrosion Resistance

317L stainless steel offers excellent corrosion resistance in various chemicals, especially in acidic chloride environments. Compared to 316L stainless steel, it has increased chromium, nickel, and molybdenum levels, improving its resistance to chloride pitting and general corrosion. 317L is also resistant to sulfuric acid concentrations up to 5% at temperatures as high as 49°C. In processes involving the condensation of sulfur-bearing gases, 317L is much more corrosion-resistant than conventional alloy 316. Service tests are recommended to assess its performance under specific operating conditions.

Chemical Composition

The chemical composition of 317L stainless steel is detailed in the table below:

ElementCrNiMoMnNSiPCSFe
Content (%)18.0 – 20.011.0 – 15.03.0 – 4.02.0 Max0.1 Max.75 Max0.045 Max0.03 Max0.03 MaxBalance

Mechanical Properties

The mechanical properties of 317L stainless steel are summarized in the table below.

PropertiesImperialMetric
Yield strength37700 psi260 MPa
Tensile strength86300 psi595 MPa
Modulus of elasticity29000 ksi200 GPa
Poisson’s ratio0.27-0.300.27-0.30
Hardness, Rockwell B8585
Elongation at break (in 50 mm)55%55%

Fabrication Characteristics

Alloy 317L offers easy weldability and processing using standard shop fabrication practices.

Machining

The work hardening rate of Alloy 317L is higher, making it less machinable than 410 stainless steel.

Forming

The alloy is highly ductile and easy to form. Using molybdenum and nitrogen in the alloy means that more robust processing equipment may be needed compared to the standard 304/304L grades. It’s recommended to work at temperatures between 1652 – 2102°F (900 – 1150°C) for hot working processes. Do not work this alloy below 1742°F (950°C). If the final forming temperature is below this threshold, it’s necessary to do a solution anneal at 1976 – 2156°F (1080 – 1180°C), followed by rapid quenching.

Welding

Alloy 317L is easily weldable using most standard processes, and there is no need for a post-weld heat treatment.

Other Designations

Below are the equivalent materials to grade 317L stainless steel:

ASTM A167, ASTM A240, ASTM A182, ASTM A213,ASTM A249, ASTM A778, ASTM A312, AISI 317L, ASTM A774, ASTM A813,ASTM A814, DIN 1.4438, QQ S763, SAE 30317L, ASME SA240

Manufacturing Process

When machining stainless steel grade 317L, it’s essential to use low speeds and constant feeds to reduce the tendency for the material to work harden. Grade 317L is tougher than grade 304 stainless steel and produces long, stringy chips, so it’s recommended to use chip breakers. Most conventional fusion and resistance methods can be used for welding, but oxyacetylene welding should be avoided. It’s best to use AWS E/ER 317L filler metal for welding.

Conventional hot working processes are suitable for this material. It should be heated to 1149-1260°C (2100-2300°F), keeping it above 927°C (1700°F). A post-work annealing is recommended for optimal corrosion resistance.

Grade 317L stainless steel allows shearing, stamping, heading, and drawing. Post-work annealing is advised to eliminate internal stresses. Annealing is conducted at 1010-1121°C (1850-2050°F) and should be followed by rapid cooling.

Grade 317L stainless steel doesn’t respond to heat treatment.

Forms of 317L Stainless Steel

  • Bar
  • Plate
  • Sheet
  • Tube & Pipe
  • Band
  • Rod

Applications

Grade 317L stainless steel is extensively utilized in the following applications: