A182 F317 is the molybdenum-alloyed austenitic stainless steel forging grade with enhanced corrosion resistance, and F317L is the low-carbon version suitable for welding and preventing intergranular corrosion.
What is A182 Gr. F317 / F317L?
A182 Gr. F317 and F317L are forged stainless steel grades within the 317 series, used for manufacturing flanges, fittings, valve bodies, pressure-vessel components, and other parts that operate under high-temperature or high-corrosion conditions. Both belong to the ASTM A182 standard.
The primary difference between them is carbon content, which affects weldability and resistance to intergranular corrosion.
A182 Gr. F317 / F317L — Equivalent Materials
| Grade (ASTM A182) | F317 | F317L |
| UNS Number | S31700 | S31703 |
| EN / DIN | 1.4438 | 1.4438 (Low C) |
| EN Name | X6CrNiMo17-12-2 | X2CrNiMo17-12-2 |
| JIS | SUS317 | SUS317L |
| GB (China) | 0Cr17Ni12Mo2 | 0Cr17Ni12Mo2 (Low C) |
| Typical ASTM Plate/Pipe | A240 317 / A312 TP317 | A240 317L / A312 TP317L |
| Notes | Standard 317 stainless steel | Low-carbon 317L for welding and intergranular corrosion resistance |
Chemical Composition
(Typical ranges, for reference — exact values depend on ASTM A182)
| Identification Symbol | UNS | C | Mn | P | S | Si | Ni | Cr | Mo | N |
| F317 | S31700 | 0.08 | 2 | 0.045 | 0.03 | 1 | 11–14 | 16–18 | 3–4 | ≤0.10 |
| F317L | S31703 | 0.03 | 2 | 0.045 | 0.03 | 1 | 11–14 | 16–18 | 3–4 | 0.10–0.16 |
Mechanical Properties
(General reference for forged condition)
| Grade Symbol | Tensile Strength, min. | Yield Strength, min. | Elongation min. % | Reduction of Area min. % | Brinell Hardness HBW |
| F317 | 75 ksi (515 MPa) | 30 ksi (205 MPa) | 30 | 50 | … |
| F317L | 70 ksi (485 MPa) | 25 ksi (170 MPa) | 30 | 50 | … |
Applications of A182 Gr. F317 / F317L
A182 F317 — General Purpose (Standard 317)
Suitable for high-corrosion environments, including:
- Flanges (WNRF / SORF / BLRF)
- Piping systems, fittings, valve components
- Chemical plants with moderate to strong corrosion (chlorides, acids)
- Food and pharmaceutical processing equipment
- Heat exchanger shells, pump bodies, mechanical structures
Feature:
Enhanced corrosion resistance due to molybdenum addition, suitable for more aggressive environments than 316.
A182 F317L — Low Carbon, Welding-Optimized
Ideal for welded systems and environments requiring resistance to intergranular corrosion:
- Pressure vessel welded systems
- Welded pipelines and welded flanges
- Chemical plants with chloride exposure
- Pharmaceutical & food equipment with welding
- Low-temperature and normal-temperature pipelines
Feature:
Low carbon content prevents intergranular corrosion after welding, ensuring long-term reliability in harsh environments.
Conclusion
A182 F317 and F317L belong to the same 317 stainless steel family, yet each grade serves specific performance needs:
- F317 for high-corrosion resistance in general forged components
- F317L for welded components and environments requiring intergranular corrosion resistance
By understanding their differences in carbon content and corrosion behavior, engineers and buyers can select the most suitable material for their applications.
