317 317L 1.4449 1.4438 Stainless Steel
317 317L 1.4449 1.4438 Stainless Steel
317 is an austenitic chromium-nickel stainless steel that possesses excellent corrosion resistance. Of all the 300 series stainless steels, alloy 317 is the most corrosion resistant and has the highest tensile and creep strength properties at elevated temperatures. The high molybdenum content the alloy’s superior pitting resistance.
317L is a molybdenum containing, low carbon austenitic stainless steel with increased additions of chromium, nickel, and molybdenum for better corrosion resistance and increased resistance to chemical attack for sulfurous, acetic, formic, citric, and tartaric acids. Due to its low carbon content, 317L also provides resistance to sensitization when welded and higher creep, stress to rupture, and tensile strength at elevated temperatures. It is non-magnetic in the annealed condition but may become slightly magnetic after welding.
APPLICATIONS
317/317L is commonly used to handle sulfur, pulp liquor, acid dyestuffs, acetylating and nitrating mixtures, bleaching solutions, severe coal and oil, and many chemical compounds. Some other applications that use alloy 317L include:
- Paper and pulp handling equipment
- Chemical and petrochemical processing equipment
- Condensers in fossil and nuclear fueled power generation stations
- Food processing equipment
- Textile equipment
Equivalent
| ASTM | UNS | EN | DIN | JIS |
| 317 | S31700 | 1.4449 | X3CrNiMo18-12-3 | SUS317 |
| 317L | S31703 | 1.4438 | X2CrNiMo18-15-4 | SUS317L |
Chemical Properties:
| % | Cr | Ni | C | Si | Mn | P | S | Mo | Fe |
| 317 | min: 18.0 max:20.0 | min: 11.0 max: 15.0 | 0.080 max | 0.75 max | 2.0 max | 0.04 max | 0.03 max | min: 3 max: 4 | balance |
| 317L | min: 18.0 max:20.0 | min: 11.0 max: 15.0 | 0.035 max | 0.75 max | 2.0 max | 0.04 max | 0.03 max | min: 3 max: 4 | balance |
Smelting Option
1 EAF: Electric Arc Furnace
2 EAF+LF+VD: Refined-smelting and vacuum degassing
3 EAF+ESR: Electro Slag Remelting
4 EAF+PESR: protective atmosphere Electro Slag Remelting
5 VIM+PESR: Vacuum induction melting
Forming Option
1 Hot rolling process
2 Hot Forging: Electro-hydraulic; High-speed-hydraulic; Oil-hydraulic; Precision-forging
Heat-treatment Option
1 +A: Annealed (full/soft/spheroidizing)
2 +N: Normalized
3 +NT: Normalized and tempered
4 +QT: Quenched and tempered (water/oil)
5 +AT: Solution annealed
6 +P: Precipitation hardened
Suface Option
1 Black Surface
2 Grounded: Bright but rough ; Not precision
3 Machining for plate: Bright and precision; Little turning scar
4 Peeled/Turned: Bright and precision; Little turning scar
5 Polished: Very Bright and precision size; Not turning scar
Other Services
1 Cutting: Small pieces
2 CNC Machine: Produce as your drawing
3 Package: Bare/Nylon/Canvas/Wooden
4 Payment:T/T, L/C, O/A(request credit)
5 Transport:FOB/CFR/CIF/DDU/DDP (train/ship/Air)
Mechanical Properties:
| Grade | Tensile Strength ksi (min.) | Yield Strength 0.2% Offset ksi (min.) | Elongation – % in 50 mm (min.) | Hardness (Brinell) MAX | Hardness (Rockwell B) MAX |
| 317 | 75 | 30 | 35 | 217 | 95 |
| 317L | 75 | 30 | 40 | 217 | 95 |
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.
Machinability
Grade 317 stainless steel is tougher than 304 stainless steel. It is recommended to use chip breakers. Hardenability of this alloy will be reduced if constant feeds and low speeds are used.
Welding
Grade 317 stainless steel can be welded using fusion and resistance methods. Oxyacetylene welding method is not preferred for this alloy. AWS E/ER317 or 317L filler metal can be used to obtain good result.
Hot Working
Grade 317 stainless steel can be hot worked using all common hot working procedures. It is heated at 1149-1260°C (2100-2300°F). It should not be heated below 927°C (1700°F). Post-work annealing can be done to retain the corrosion resistance property.
Cold Working
Stamping, shearing, drawing, and heading can be done successfully. Post-work annealing is performed in order to reduce internal stress.
Annealing
Grade 317 stainless steel is annealed at 1010-1121°C (1850-2050°F) followed by cooling.
