SS 317L — Stainless Steel (SS) Grade Specification, Properties & Equivalents
SS 317L is a low-carbon (with a maximum carbon content of 0.03%) austenitic stainless steel, widely recognised in India for its enhanced corrosion resistance, particularly against chloride stress corrosion cracking and general corrosion. As an L-grade, SS 317L offers improved wel
SS 317L is a low-carbon (with a maximum carbon content of 0.03%) austenitic stainless steel, widely recognised in India for its enhanced corrosion resistance, particularly against chloride stress corrosion cracking and general corrosion. As an L-grade, SS 317L offers improved weldability compared to its standard counterpart, making it a preferred choice for complex fabrications. Its higher molybdenum content (2-3%) significantly boosts its resistance to pitting and crevice corrosion, making SS 317L indispensable in aggressive environments. Industries in India, including chemical processing, pharmaceuticals, textiles, and marine engineering, rely on SS 317L for critical equipment like heat exchangers, tanks, piping systems, and valves where longevity and integrity are paramount. The availability of SS 317L from major Indian producers ensures a reliable supply chain for these demanding applications.
Chemical Composition of SS 317L
SS 317L Chemical Composition
| Element | Weight % |
| Carbon (C) | 0.03 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulfur (S) | 0.030 max |
| Silicon (Si) | 0.75 max |
| Chromium (Cr) | 18 - 20 |
| Nickel (Ni) | 11 - 14 |
| Molybdenum (Mo) | 3.0 - 4.0 |
| Nitrogen (N) | 0.10 max |
| Iron (Fe) | Balance |
Mechanical Properties of SS 317L
SS 317L Mechanical Properties
| Property | Value |
| Ultimate Tensile Strength (UTS) | 520 MPa min |
| Yield Strength (YS) at 0.2% offset | 240 MPa min |
| Elongation at Break (2 inch / 50mm) | 35% min |
| Hardness (Brinell) | 200 HB max |
| Density | 8.0 g/cm³ |
| Modulus of Elasticity | 193 GPa |
SS 317L Available Forms in India
| Shape | Typical Sizes | Indian Standard/Availability |
| Plate | 1.5 mm to 25 mm Thickness | IS 2062 Hot Rolled, ASTM A240 |
| Sheet | 0.5 mm to 3.0 mm Thickness | ASTM A240, EN 10088 |
| Coil | 0.5 mm to 3.0 mm Thickness | ASTM A240 |
| Bar | Round: 10 mm to 100 mm Dia | ASTM A479 / A276 |
| Pipe & Tube | Seamless & Welded (Sch 10, 40, 80) | ASTM A312, A358 |
| Pipe Fittings | Elbows, Tees, Reducers | ASTM A403 |
SS 317L Real-world Applications
- Chemical Processing: Tanks, reactors, and piping for handling corrosive chemicals and acidic solutions.
- Pharmaceuticals: Equipment and vessels for sterile processing and drug manufacturing where high purity is crucial.
- Pulp & Paper: Digesters, bleach tanks, and processing equipment resistant to sulfurous compounds.
- Textile Industry: Dyeing equipment and processing vats needing resistance to bleaching agents.
- Marine Engineering: Components exposed to saltwater environments, offering superior chloride resistance.
- Heat Exchangers: Tubes and shells requiring robust protection against corrosive fluids.
- Pollution Control: Flue gas desulfurization (FGD) systems operating in acidic conditions.
- Food Processing: Equipment demanding high hygiene standards and resistance to various food acids.
SS 317L Machinability & Weldability
SS 317L, like other austenitic stainless steels, machines well but requires careful attention due to its work-hardening characteristics. For optimal machinability of SS 317L, utilise slower speeds and higher feed rates compared to carbon steels. Use sharp, robust tools made of high-speed steel or carbide, with ample cutting fluid for lubrication and cooling. Flood lubrication is highly recommended to manage the heat generated. The work-hardening rate of SS 317L means that repeated machining in the same area can increase cutting forces; hence, maintaining a continuous cut is beneficial. When welding SS 317L, its low carbon content significantly reduces the risk of sensitization and subsequent intergranular corrosion, particularly when welded using the gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) processes. Due to the higher molybdenum and chromium content of SS 317L, preheating is generally not required for sections under 12mm thick, but for thicker sections or specific service conditions, a low-temperature preheat (around 100-150°C) may be beneficial. It is crucial to use matching filler metals, typically 317L or 308L types, to maintain the corrosion resistance of the weld joint. Post-weld heat treatment (PWHT) for SS 317L is usually not necessary for maintaining corrosion resistance, as the low carbon content prevents carbide precipitation. However, if PWHT is performed for stress relief, it should be done at temperatures between 850-1050°C followed by rapid cooling, though this can affect mechanical properties.SS 317L Heat Treatment & Processing
The heat treatment of SS 317L is primarily focused on optimising its corrosion resistance and mechanical properties. The most common condition for SS 317L is the solution annealed state, typically achieved by heating the material to temperatures between 1040°C and 1120°C, followed by rapid cooling (quenching) in water. This process dissolves any carbides or intermetallic phases, ensuring maximum corrosion resistance and ductility for SS 317L. Annealing at lower temperatures or slower cooling rates can lead to the precipitation of detrimental phases, reducing the grade's performance, especially in corrosive environments. SS 317L is not hardenable by heat treatment; its mechanical strength is achieved through solid solution strengthening from alloying elements like molybdenum and nickel, and cold working. Cold working SS 317L, such as through rolling or drawing, will increase its tensile and yield strength but will also decrease its ductility. If significant cold working is performed, a subsequent solution annealing treatment may be necessary to restore ductility and corrosion resistance. Normalizing is not a standard heat treatment for SS 317L. Tempering is also not applicable as SS 317L is not hardened by heat treatment in the way martensitic steels are. In summary, the critical processing step for SS 317L is solution annealing to achieve optimal performance.Sourcing SS 317L in India
SS 317L is readily available across India from major domestic producers like Jindal Stainless, SAIL (through their distributors), and POSCO-Korea, alongside several well-established Indian stockists and importers. Key procurement hubs, particularly for SS 317L plates, sheets, and coils, include Mumbai, Pune, and Chennai, offering good availability for standard product forms. Minimum Order Quantities (MOQs) for SS 317L typically range from 500 kg to 1000 kg for standard size stock items, though project-specific orders for larger quantities or non-standard sizes can be negotiated directly with manufacturers. Pricing for SS 317L in India is subject to fluctuations in nickel and molybdenum prices and global demand; expect price bands for common forms like plates and sheets to be approximately INR 450/kg to INR 650/kg, dependent on thickness, finish, and order volume. Mill Test Certificates (MTC) conforming to EN 10204 3.1 are a standard requirement and are always supplied with shipments of SS 317L. Positive Material Identification (PMI) is also commonly requested by end-users to verify the alloy composition, especially for critical applications in the chemical and pharmaceutical sectors.SS 317L International Equivalents
| IS | ASTM | EN | JIS | DIN | GOST |
| NA | UNS S31703 | X2CrNiMo18-15-3 | SUS 317L | 1.4438 | 12Х18Н10ТЛ* |
| NA | ASTM A240 / A479 | 1.4438 | NA | NA | NA |
*Note: GOST 12Х18Н10ТЛ is functionally similar but may have slight variations. SS 317L is the most direct UNS equivalent.
FAQs about SS 317L
What makes SS 317L superior to SS 304L for corrosion resistance in India?
SS 317L contains higher levels of molybdenum (3-4%) and chromium (18-20%) compared to SS 304L. This increased alloy content in SS 317L provides significantly enhanced resistance to pitting, crevice corrosion, and chloride stress corrosion cracking, making it ideal for aggressive industrial environments prevalent in India, such as coastal regions or chemical plants, where SS 304L may falter.
Can SS 317L be used in high-temperature applications in India?
While SS 317L possesses good resistance to oxidation, its high-temperature strength is limited, similar to other austenitic stainless steels. For continuous service above approximately 800°C, SS 317L might not be the optimal choice due to potential issues with creep and scaling. However, for intermittent service or temperatures below this range, SS 317L offers reliable performance, especially when corrosion resistance at elevated temperatures is also required.
What are the typical lead times for procuring SS 317L in bulk from Indian suppliers?
Lead times for SS 317L can vary based on product form and current market demand. Standard items like sheets and plates from major stockists in Mumbai or Pune might be available for dispatch within 1-2 weeks. For larger project requirements or specific dimensions like pipes or bars manufactured to order, lead times can extend to 6-10 weeks. Mill deliveries for SS 317L are subject to production schedules.
Is SS 317L magnetic?
No, SS 317L is a non-magnetic grade in its annealed condition, characteristic of austenitic stainless steels like SS 304L and SS 316L. While cold working can induce slight magnetism in SS 317L, it typically remains essentially non-magnetic, which is advantageous for applications where magnetic interference must be avoided.
What is the difference between SS 317L and SS 317?
The primary difference between SS 317 and SS 317L lies in their carbon content. SS 317L has a maximum carbon content of 0.03%, designated by the 'L' for low carbon. SS 317 has a higher maximum carbon content, typically 0.08%. This lower carbon level in SS 317L significantly reduces the risk of sensitization and subsequent intergranular corrosion after welding or heat treatment, making SS 317L the preferred choice for welded applications.
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