Ultra 317L
EN 1.4438, ASTM TYPE 317 / UNS S31700, TYPE 317L / UNS S31703

General characteristics

Mo alloyed austenitic grade with higher corrosion resistance than “316L”, e.g. used in the chemical processing industry.

Typical applications

  • Chemical tankers
  • Pulp and Paper equipment
  • Condenser tubes and heat exchanger tubes
  • Equipment for the petrochemical industry
  • Flue-gas desulfurization equipment


Product forms, available sizes and finishes


Product typeFinishesThicknessWidth
Cold rolled coil and sheet2E1,51-6,50≤ 2000
Hot rolled coil and plateHot rolled white5,00-10,00≤ 2000
Quarto plateHot rolled white5,00-50,00≤ 3200
Chemical composition

The chemical composition may vary slightly between different product standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by weight.

TypicalUltra 317L0.0218.211.63.1
ASTM A240/A240MTYPE 317 / UNS S31700<0.08<218.0-20.011.0-15.03.0-4.0<0.10Si:<0.75 P:<0.045 S:<0.030
ASTM A240/A240MTYPE 317L / UNS S31703<0.030<218.0-20.011.0-15.03.0-4.0<0.10Si:<0.75 P:<0.045 S:<0.030
EN 10088-21.4438<0.030<217.5-19.513.0-16.03.0-4.0<0.10Si:<1 P:<0.045 S:<0.015
Mechanical properties

The mechanical properties of the available products are given in the table below.


StandardGradeRp0.2Rp1.0RmElongationImpact strengthRockwellHBHV
Product type: Hot rolled quarto plate
Typical (thickness 15 mm)Ultra 317L30034061050

1)Elongation according to EN standard:
A80 for thickness below 3 mm.
A for thickness = 3 mm.
Elongation according to ASTM standard A2” or A50.

Corrosion resistance

For more information, see Outokumpu Corrosion Handbook.

Pitting corrosion resistanceCrevice corrosion resistance

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
CPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).
CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F



Physical properties

Data according to EN 10088, EN 10095 or typical values.


DensityModulus of elasticityThermal exp. at 100 °CThermal conductivityThermal capacityElectrical resistanceMagnetizable

*) Austenitic stainless steel grades may be magnetizable to a certain degree after cold deformation, e.g. in temper rolled condition.


Cold forming

Ultra 317L can be readily formed and fabricated by a full range of cold working operations. It can be used in heading, drawing and bending. Any cold working operations will increase the strength and hardness of the material and may leave it slightly magnetic. Work hardening is aaccentuated by the partial transformation of the austenite phase of the material to hard martensite. For more information contact Avesta Research Centre.


Ultra 317L can be readily welded by a full range of conventional welding methods such as:
Shielded metal arc welding (SMAW)
Gas tungsten arc welding, TIG (GTAW)
Gas metal arc welding, MIG (GMAW)
Flux-cored arc welding (FCAW)
Plasma arc welding (PAW)
Submerged arc welding (SAW)

Subsequent passes may cause precipitates of secondary phases in the weld metal. For this reason a low heat input and a maximum interpass temperature of 100ºC should be used.


Standards & approvals

The most commonly used international product standards are given in the table below.


ASTM A240/A240MTYPE 317 / UNS S31700; TYPE 317L / UNS S31703
EN 10088-21.4438