317L / 317 Stainless Steel Plate – High-Performance Corrosion-Resistant Alloy
Sandmeyer Steel Company has the heaviest and largest inventory of Alloy 317L stainless steel plate in thicknesses from 3/16″ through 4″.
Available thicknesses for 317 / 317L:
| 4.8mm | 6.3mm | 7.9mm | 9.5mm | 12.7mm | 15.9mm | 19mm | 22.2mm | 25.4mm | 28.6mm |
| 1 1/4" | 1 1/2" | 1 3/4" | 2" | 2 1/4" | 2 1/2" | 2 3/4" | 3" | 3 1/2" | 4" |
| 31.8mm | 38.1mm | 44.5mm | 50.8mm | 57.2mm | 63.5mm | 69.9mm | 76.2mm | 88.9mm | 101.6mm |
Alloy 317L (UNS S31703) is a molybdenum-bearing austenitic stainless steel with greatly increased resistance to chemical attack as compared to the conventional chromium-nickel austenitic stainless steels such as Alloy 304. In addition, Alloy 317L offers higher creep, stress-to-rupture, and tensile strength at elevated temperatures than conventional stainless steels. It is a low carbon or “L” grade which provides resistance to sensitization during welding and other thermal processes.
Specification Sheet Overview
for Alloy 317L (UNS S31703)
W. Nr. 1.4438:
General Properties
Alloy 317L (UNS S31703) is a low carbon corrosion resistant austenitic chromium-nickel-molybdenum stainless steel. The high levels of these elements assure the alloy has superior chloride pitting and general corrosion resistance to the conventional 304/304L and 316/316L grades. The alloy provides improved resistance relative to 316L in strongly corrosive environments containing sulfurous media, chlorides, and other halides.
The low carbon content of Alloy 317L enables it to be welded without intergranular corrosion resulting from chromium carbide precipitation enabling it to be used in the as-welded condition. With the addition of nitrogen as a strengthening agent, the alloy can be dual certified as Alloy 317 (UNS S31700).
Alloy 317L is non-magnetic in the annealed condition. It cannot be hardened by heat treatment, however the material will harden due to cold working. Alloy 317L can be easily welded and processed by standard shop fabrication practices.
Corrosion Resistance
The higher molybdenum content of Alloy 317L assures superior general and localized corrosion resistance in most media when compared with 304/304L and 316/316L stainless steels. Environments that don’t attack 304/304L stainless steel will normally not corrode 317L. One exception, however, are strongly oxidizing acids such as nitric acid. Alloys that contain molybdenum generally do not perform as well in these environments.
Alloy 317L has excellent corrosion resistance to a wide range of chemicals. It resists attack in sulfuric acid, acidic chlorine and phosphoric acid. It is used in handling hot organic and fatty acids often present in food and pharmaceutical processing applications.
The corrosion resistance of 317 and 317L should be 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). Because of its low carbon content, 317L is the preferred material in this service to guard against intergranular corrosion.
In general, austenitic stainless steels are subject to chloride stress corrosion cracking in halide service. Although 317L is somewhat more resistant to stress corrosion cracking than 304/304L stainless steels, because of its higher molybdenum content, it is still susceptible.
The higher chromium, molybdenum and nitrogen content of 317L enhance its ability to resist pitting and crevice corrosion in the presence of chlorides and other halides. The Pitting Resistance Equivalent including Nitrogen number (PREN) is a relative measure of pitting resistance. The following chart offers a comparison Alloy 317L and other austenitic stainless steels.
| Cr | Mo | N | ||
| 304 Stainless Steel | 18.0 | — | 0.06 | 19.0 |
| 316 Stainless Steel | 16.5 | 2.1 | 0.05 | 24.2 |
| 317L Stainless Steel | 18.5 | 3.1 | 0.06 | 29.7 |
| SSC-6MO | 20.5 | 6.2 | 0.22 | 44.5 |
1Pitting Resistance Equivalent, including Nitrogen, PREN = Cr + 3.3Mo + 16N
Chemical Analysis
Weight % (all values are maximum unless a range is otherwise indicated)
| Nickel | 11.0 min.-15.0 max. | Sulfur | 0.030 |
| Molybdenum | 3.0 min. - 4.0 max. | Silicon | 0.75 |
| Carbon | 0.030 | Nitrogen | 0.10 |
| Manganese | 2.00 | Iron | Balance |
Density
0.285 lbs/in3
7.89 g/cm3
Specific Heat
0.12 BTU/lb-°F (32 – 212°F)
502 J/kg-°K (0 – 100°C)
Modulus of Elasticity
29.0 x 106 psi
200 GPa
Thermal Conductivity 68°F (20°C)
8.1 BTU/(hr x ft x °F)
14 W/(m x K)
Melting Range
2540 – 2630°F
1390 – 1440°C
Electrical Resistivity
33.5 Microhm-in at 68°C
85.1 Microhm-cm at 20°C
Mean Coefficient of Thermal Expansion
| °F | °C | in/in °F | cm/cm °C |
| 68-212 | 20-100 | 8.9 x 10-6 | 16.2 x 10-6 |
Mechanical Properties
Values at 68°F (20°C) (minimum values, unless specified)
0.2% Offset | Strength | in 2 in. | |||
|---|---|---|---|---|---|
| psi (min.) | (MPa) | psi (min.) | (MPa) | % (min.) | (max.) |
| 30,000 | 205 | 75,000 | 515 | 40 | 95 Rockwell B |
Fabrication Data
Alloy 317L can be easily welded and processed by standard shop fabrication practices.
Cold Forming
The alloy is quite ductile and forms easily. The addition of molybdenum and nitrogen implies more powerful processing equipment may be necessary when compared with the standard 304/304L grades.
Hot Forming
Working temperatures of 1652 – 2102°F (900 – 1150°C) are recommended for hot working processes. Do not work this alloy below 1742°F (950°C). If the final forming temperature falls below this threshold, a solution anneal of 1976 – 2156°F (1080 – 1180°C) is necessary. Rapid quenching is required.
Machining
The cold work hardening rate of Alloy 317L makes it less machinable than 410 stainless steel. The table below provides relevant machining data.
| Operation | Tool | Lubrication | ||||||
|---|---|---|---|---|---|---|---|---|
| Depth-mm | Depth-in | Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||
| Turning | High Speed Steel | Cutting Oil | 6 | .23 | 0.5 | .019 | 11-16 | 36-52 |
| Turning | High Speed Steel | Cutting Oil | 3 | .11 | 0.4 | .016 | 18-23 | 59-75 |
| Turning | High Speed Steel | Cutting Oil | 1 | .04 | 0.2 | .008 | 25-30 | 82-98 |
| Turning | Carbide | Dry or Cutting Oil | 6 | .23 | 0.5 | .019 | 70-80 | 230-262 |
| Turning | Carbide | Dry or Cutting Oil | 3 | .11 | 0.4 | .016 | 85-95 | 279-313 |
| Turning | Carbide | Dry or Cutting Oil | 1 | .04 | 0.2 | .008 | 100-110 | 328-361 |
| Depth of cut-mm | Depth of cut-in | Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||
| Cutting | High Speed Steel | Cutting Oil | 1.5 | .06 | 0.03-0.05 | .0012-.0020 | 16-21 | 52-69 |
| Cutting | High Speed Steel | Cutting Oil | 3 | .11 | 0.04-0.06 | .0016-.0024 | 17-22 | 56-72 |
| Cutting | High Speed Steel | Cutting Oil | 6 | .23 | 0.05-0.07 | .0020-.0027 | 18-23 | 59-75 |
| Drill ø mm | Drill ø in | Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||
| Drilling | High Speed Steel | Cutting Oil | 1.5 | .06 | 0.02-0.03 | .0007-.0012 | 10-14 | 33-46 |
| Drilling | High Speed Steel | Cutting Oil | 3 | .11 | 0.05-0.06 | .0020-.0024 | 12-16 | 39-52 |
| Drilling | High Speed Steel | Cutting Oil | 6 | .23 | 0.08-0.09 | .0031-.0035 | 12-16 | 39-52 |
| Drilling | High Speed Steel | Cutting Oil | 12 | .48 | 0.09-0.10 | .0035-.0039 | 12-16 | 39-52 |
| Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||||
| Milling Profiling | High Speed Steel | Cutting Oil | 0.05-0.10 | .002-.004 | 10-20 | 33-66 | ||
Welding
Alloy 317L can be readily welded by most standard processes. A post weld heat treatment is not necessary.
Alloy 317/317L Stainless Steel – Frequently Asked Questions
1. What is Alloy 317/317L stainless steel, and how does it differ from other stainless steels?
Alloy 317 and 317L (UNS S31700 / UNS S31703) are molybdenum-bearing austenitic stainless steels with higher levels of chromium, nickel, and molybdenum compared to conventional 304 and 316 grades. These enhanced compositions provide superior corrosion resistance, particularly in environments containing chlorides, sulfurous media, and other halides. The “L” in 317L denotes a low carbon content, which offers improved weldability and resistance to intergranular corrosion after welding.
2. What are the primary applications of Alloy 317/317L stainless steel?
Due to its excellent corrosion resistance and mechanical properties, Alloy 317/317L is commonly used in:
• Air pollution control systems, such as flue gas desulfurization units
• Chemical and petrochemical processing equipment
• Food and beverage processing facilities
• Pulp and paper industry components
• Power generation condensers
• Petroleum Refining
These applications benefit from the alloy’s resistance to aggressive chemical environments and its ability to maintain structural integrity at elevated temperatures.
3. How does Alloy 317/317L perform in corrosive environments?
Alloy 317/317L exhibits superior resistance to general and localized corrosion, especially in environments containing chlorides, sulfuric acid, acidic chlorine, and phosphoric acid. Its higher molybdenum content enhances pitting and crevice corrosion resistance, making it suitable for handling hot organic and fatty acids often present in food and pharmaceutical processing applications.
4. Can Alloy 317/317L be welded, and what are the considerations?
Yes, Alloy 317/317L can be welded using standard shop fabrication practices. The low carbon content in 317L minimizes the risk of chromium carbide precipitation during welding, reducing the likelihood of intergranular corrosion. Post-weld annealing is generally not required.
5. What are the mechanical properties of Alloy 317L stainless steel?
Typical mechanical properties of Alloy 317L include:
• Tensile Strength: 515 MPa (75,000 psi)
• Yield Strength: 205 MPa (30,000 psi)
• Elongation at Break: 40%
• Hardness: 95 Rockwell B
These properties indicate that Alloy 317L maintains excellent strength and ductility, making it suitable for various industrial applications.
6. What standards and specifications apply to Alloy 317/317L stainless steel?
Alloy 317/317L stainless steel conforms to several industry standards, including:
• ASTM A 240
• ASME SA 240
These standards ensure the material meets specific requirements for chemical composition, mechanical properties, and other critical factors.
7. What are the available thicknesses for Alloy 317/317L plates at Sandmeyer Steel?
Sandmeyer Steel offers Alloy 317/317L stainless steel plates in a wide range of thicknesses, from 3/16″ (4.8 mm) through 4″ (101.6 mm), accommodating various application needs.