SS 317/L

 Difference between SS317 and SS317L

Stainless Steel 317 was designed to be a higher-strength alternative to the 316 grades. Composed of larger amounts of chromium, nickel and molybdenum, SS 317 also is more corrosion resistant compared to 316, and tougher than Type 304. This is due to the high percentage of iron in its composition, which is much higher than many stainless steels. This combination of iron with the chromium-nickel-molybdenum content yields a strong, hardy alloy. In terms of working capability, all common welding, hot working and cold working practices can be applied. 317 demonstrates good versatility. It will only work harden under cold working, which will also increase its strength. When heat treating this metal, temperatures should not drop below 1700°F as this is the threshold for response. Stainless steel 317 is commonly found in the textile industry, where its strength and corrosion resistance can be utilized. Other applications include the manufacturing of chemical equipment and the machines used in pulping paper.

Stainless Steel 317L is the low-carbon derivative of SS 317. The metal maintains its high strength and strong corrosion resistance; however, the carbon content does have several effects. 317L has greater strength under welding; its products are stronger. Like 317, stainless steel 317L does not respond or harden from heat treatments. When hot working, the metal should be heated ideally within the range of 2100-2300°F. Dropping below 1700°F will cause the metal to be unresponsive. For these reasons, 317L is effective in high-temperature areas that experience high rates of chemical corrosion, creep, and stress-to-rupture. 317L is commonly utilized in chemical environments. It has shown itself to be effective in conditions where acids are present, such as acidic chloride. The metal is resistant to corrosion from such substances. As such, it is common to find 317L in equipment used in pulp and paper mills. The acidic environment requires a strength, corrosion-resistant metal. It is possible for grades 317 and 317L to become dually certified

Specification

Types 316 (UNS S31600), 316L(S31603), 317 (S31700), and 317L (S31703) are molybdenum-bearing austenitic stainless steels which are more resistant to general corrosion and pitting/crevice corrosion than the conventional chromium-nickel austenitic stainless steels such as Type 304. These alloys also offer higher creep, stress-to-rupture and tensile strength at elevated temperatures. In addition to excellent corrosion resistance and strength properties, the Types 316, 316L, 317, and 317L Cr-Ni-Mo alloys also provide excellent fabricability and formability which are typical of the austenitic stainless steels.

• ASTM: A167, A182, A193. A194, A213, A240, A249, A269, A270, A271, A276, A312, A313, A314, A320, A336, A358, A368, A376, A403, A409, A430, A473, A478, A479, A492, A493, A511, A554, A580, A632, A666, A688, A771, A813, A814, A826, F138
• UNS: S31600
• AMS: 5524, 5573, 5648, 5690, 5696

Chemical Composition, %

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Applications of Stainless Steel 317

• Oil & petroleum refining equipment
• Food processing equipment
• Pulp and paper processing equipment
• Soap and photographic handling equipment
• Textile Industry Equipment
• Architectural
• Pharmaceutical processing equipment

Physical Properties 

• Density: 0.29 lb/in³ (8.03 g/cm³)
• Melting Point: 2540-2630°F (1390-1440°C)
• Modulus of Elasticity in Tension: 29 x 106 psi (200 GPa)
• Electrical Resistivity: Electrical Resistivity 33.5 Mic - 85.1 Microhm-cm at 20°C
• Thermal Conductivity: 4.6 W/m.K
• Thermal Expansion: 17.2 x 10⁶/K
• Modulus of Shear: 11.9 x 10⁶ psi (82 GPa)

 For more details click the PDF here with all regulations here

Linear Coefficient of Thermal Expansion

 Thermal Conductivity 212°F (100°C)

• 113 BTU in/hr.ft².°F
• 16.3 W/mK

Electrical Resistivity, microhm-in, (microhm-cm)

• 68°F (20°C): 29.4 (74.0

Specific Heat, BTU/lb/°F (kJ/kg•K)

• 32-212°F (0-100°C): 0.12 (0.50)

Heat Resistance of Stainless Steel 317

• All chromium-nickel-molybdenum steels all have excellent resistance to oxidation
• Demonstrates a low scaling rate in ordinary atmospheres at temperatures up to 1600-1650°F (871-899°C).

Hot Working of Stainless Steel 317

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

Cold Work Stainless Steel 317

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

Heat Treatment of Stainless Steel 317

Alloy 317 is non-hardenable by heat treatment

Fabrication of Stainless Steel 317

Alloy 317L can be easily welded and processed by standard shop fabrication practices.

Mechanical Properties

 For more details click the PDF SS 317L here with all regulations here

Corrosion Resistance of Stainless Steel 317

• Demonstrates superior corrosion resistance in difficult environments including a wide range of chemicals, especially in acidic chloride environments
• Excellent resistance in applications where contamination is desired to be kept to a minimum
• Low carbon content allows 317L to be highly resistant to intergranular corrosion
• Combats the tendency to pit when in contact with phosphorus acids, chlorides, bromides, and iodides

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.

Machinability

The cold work hardening rate of Alloy 317L makes it less machinable than 410 stainless steel. The table below provides relevant machining data.

Welding of Stainless Steel 317

317L is readily welded by a full range of conventional welding procedures (except oxyacetylene). AWS E317L/ER317L filler metal or austenitic, low carbon filler metals with molybdenum content higher than that of 317L, or a nickel-base filler metal with sufficient chromium and molybdenum content to exceed the corrosion resistance of 317L should be used to weld 317L steel.