316L stainless steel (SUS 316L, SS316L) is a type of stainless steel with excellent corrosion resistance and good mechanical properties. It is widely used in industries such as chemicals, healthcare, and marine applications.
As a low-carbon version of 316 stainless steel, 316L has better resistance to intergranular corrosion and performs exceptionally well in high-temperature and highly corrosive environments.
This article will explore the composition, properties, main applications, and market outlook of 316L stainless steel to provide a comprehensive understanding of this important material.
Composition of 316L Stainless Steel
316L stainless steel is an austenitic stainless steel, composed mainly of iron, chromium, nickel, and molybdenum. Below is a table of the main components of 316L.
| Element | Percentage Range (%) |
| Iron (Fe) | Balance (approx. 65-70%) |
| Chromium (Cr) | 16.0 – 18.0 |
| Nickel (Ni) | 10.0 – 14.0 |
| Molybdenum (Mo) | 2.0 – 3.0 |
| Manganese (Mn) | 2.0 – 2.5 |
| Silicon (Si) | 0.75 – 1.0 |
| Carbon (C) | ≤ 0.03 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.03 |
| Nitrogen (N) | ≤ 0.10 |
316L Stainless Steel Physical Properties
| Property | Value |
| Density | 7.98 g/cm³ |
| Thermal Conductivity | 16.2 W/m·K |
| Specific Heat | 500 J/kg·K (at 20°C) |
| Electrical Resistivity | 0.072 μΩ·m |
| Melting Point | 1371 – 1399°C |
| Coefficient of Thermal Expansion | 16.0 × 10⁻⁶ /°C (20-100°C) |
| Thermal Expansion | 16.0 × 10⁻⁶ /°C (20 – 100°C |
316L Stainless Steel Mechanical Properties
| Property | Value |
| Tensile Strength | 485 – 620 MPa |
| Yield Strength | 170 – 290 MPa |
| Elongation | ≥ 40% |
| Hardness | 80 HRB (approx.) |
| Modulus of Elasticity | 193 – 200 GPa |
| Poisson’s Ratio | 0.30 – 0.31 |
| Shear Strength | ~ 200 MPa |
| Fatigue Strength | ~ 250 MPa |
Advantages of 316L Stainless Steel
Corrosion Resistance
The greatest advantage of 316L stainless steel is its outstanding corrosion resistance.
Due to the addition of molybdenum, 316L can maintain excellent resistance to corrosion in environments with high chloride content (e.g., seawater and chemical solutions). This makes 316L the material of choice for many extreme environments, such as marine and chemical equipment.
High Temperature Resistance
316L stainless steel has strong high-temperature performance, maintaining stability even in high-temperature environments.
The typical working temperature range of 316L can reach up to 870°C, and it still maintains good strength and corrosion resistance even at higher temperatures. This makes 316L suitable for use in high-temperature and high-pressure industrial environments.
Mechanical Properties
316L stainless steel not only has excellent corrosion resistance and high-temperature resistance but also has good mechanical properties.
316L has high tensile strength and yield strength, maintaining good toughness and ductility in low-temperature environments, offering strong impact resistance and fatigue resistance.
Additionally, 316L has good weldability and machinability, making it easy to fabricate complex parts.
Processing Performance
316L stainless steel has excellent processing performance, especially in welding and forming processes. Due to its low carbon content, it exhibits higher resistance to intergranular corrosion. Therefore, after welding, it is less likely to suffer from corrosion issues, maintaining the material’s superior properties.
Applications of 316L Stainless Steel
Due to its excellent corrosion resistance, high-temperature resistance, and good mechanical properties, 316L stainless steel is widely used across many industries. Here are some key examples of its applications:
Chemical and Petrochemical Industry
316L stainless steel is widely used in the chemical and petrochemical industries because it resists strong acids, alkalis, and various chemical solvents. Typical applications include:
Chemical Reactors: These reactors may be exposed to strong acids, alkalis, and corrosive gases during production, and 316L can endure these harsh conditions for extended periods.
Storage Tanks and Pipelines: Used for storing and transporting corrosive chemicals (e.g., sulfuric acid, chlorides) in tanks, reactors, and pipelines.
Heat Exchangers: 316L is commonly used in heat exchangers, cooling towers, and other equipment that frequently come into contact with chemical media.
Healthcare Industry
Due to its excellent biocompatibility and corrosion resistance, 316L stainless steel is widely used in medical devices and instruments. Specific applications include:
Surgical Instruments: Items such as surgical knives, scissors, and forceps benefit from 316L’s corrosion resistance and antibacterial properties, ensuring their safety and hygiene.
Medical Implants: Such as joint prostheses, dental implants, and stents, where 316L remains stable inside the human body without causing allergic reactions.
Medical Equipment Casings: 316L is used for casings of medical instruments, particularly those that require frequent cleaning and sterilization, like ultrasonic cleaners and hospital beds.
Marine and Seawater Treatment
The saltwater and chloride in the marine environment can corrode materials, but 316L stainless steel, due to its outstanding corrosion resistance, is the material of choice in marine engineering. Common applications include:
Ships: 316L is used in ship hulls, pipelines, valves, and offshore platforms, withstanding seawater corrosion and high-salt environments.
Seawater Cooling Systems: In power plants and industrial equipment, 316L is used in pipes and heat exchangers to ensure long-term, stable operation.
Offshore Oil Platforms: 316L is used for structural parts, drilling equipment, and subsea pipelines in offshore oil platforms, where its corrosion resistance and high-temperature performance are crucial.
Food and Beverage Industry
Due to its excellent hygiene, corrosion resistance, and high-temperature tolerance, 316L stainless steel is widely used in the food and beverage industry. Specific applications include:
Food Processing Equipment: Items such as mixers, conveyors, and cutting tools, which require frequent contact with food materials and cleaning agents, are made from 316L due to its resistance to contamination and ease of cleaning.
Dairy and Beer Production: 316L is used in the pipes, storage tanks, and fermentation tanks in dairy and beer production, preventing chemical reactions and food contamination.
Bottling and Packaging Equipment: Including bottling machines, filling systems, and cans, 316L can withstand frequent sterilization and high-temperature processing, ensuring the safety of food and beverages.
Aerospace and Energy Industry
In aerospace and energy industries, 316L stainless steel is widely used for its excellent corrosion resistance and high-temperature performance. Applications include:
Aircraft Parts: 316L is used in parts of aircraft engines, airframe components, and fasteners, capable of withstanding high temperatures and pressures, ensuring the safety of aircraft in extreme conditions.
Nuclear Energy Equipment: 316L is used in cooling systems, radiation shielding materials, and pressure vessels in nuclear reactors, providing high-temperature and corrosion resistance.
Wind Turbine Components: 316L is commonly used in wind turbine towers, support structures, and other corrosion-resistant parts, especially in coastal areas where salt mist corrosion is a concern.
Construction and Decorative Industry
Due to its aesthetic appearance and excellent corrosion resistance, 316L stainless steel is also widely used in the construction and decorative industry. Typical applications include:
Building Facades: 316L stainless steel is often used for modern building facades, curtain walls, and window frames, not only for aesthetic appeal but also for resistance to wind, rain, and acid rain corrosion.
Outdoor Decorations: Such as public art sculptures, city landscape installations, and bridge structures, where 316L maintains its stability and appearance in harsh outdoor environments.
Indoor Decoration: Including flooring, wall cladding, stair railings, and door handles, offering enhanced decor, while also being resistant to dirt, corrosion, and easy to clean.
Automotive and Transportation Industry
In the automotive and transportation industries, 316L stainless steel is used in several areas:
Exhaust Systems: 316L is commonly used for exhaust pipes, catalytic converters, and other components, as it can withstand the high temperatures and chemical corrosion found in exhaust systems.
Automobile Body Parts: Parts such as doors, window frames, and roof structures benefit from 316L’s strength and corrosion resistance, extending the lifespan of vehicles.
Railway and Highway Equipment: 316L is also used for railway facilities, road signs, and barriers, ensuring that these components don’t rust under prolonged exposure to outdoor conditions.
Processing and Maintenance of 316L Stainless Steel
Processing Techniques
316L stainless steel performs well during processing. Its excellent weldability makes it easy to join and repair, and it is suitable for the production of complex parts. Common processing methods include investment casting, CNC machining, welding, cutting, stamping, and bending.
Surface Treatment
The surface treatment techniques for 316L stainless steel usually include polishing, pickling, and passivation. Polishing improves the surface finish, reduces dirt buildup, and enhances its appearance. Pickling and passivation help remove surface oxides and contaminants, further improving its corrosion resistance.
Maintenance and Care
Although 316L stainless steel is highly resistant to corrosion, regular checks and cleaning are still necessary in certain environments to ensure optimal performance. For example, in seawater environments, periodic removal of salt buildup is needed. In high-temperature environments, it’s important to inspect weld joints and surfaces for cracks or corrosion.
Difference Between 316L and 316 Stainless Steel
316L and 316 stainless steel are very similar materials, both of which belong to the austenitic stainless steel family and have excellent corrosion resistance and high-temperature performance. However, there are some key differences between the two, primarily in carbon content, corrosion resistance, welding performance, and strength.
Below is a comparison of these two alloys to help you choose the most suitable one for your application.
Property | 316L Stainless Steel | 316 Stainless Steel |
Carbon Content | ≤ 0.03% | 0.08% or higher |
Corrosion Resistance | Higher | High, but more prone to localized corrosion in high-temperature environments |
Welding Performance | Excellent, reduces the risk of intergranular corrosion | May suffer from intergranular corrosion if welding precautions are not taken |
Strength | Slightly lower, but sufficient for most industrial applications | Higher, better for strength-critical applications |
Applications | Ideal for environments that require low carbon content and better welding and corrosion resistance | More suited for applications requiring higher strength |
Carbon Content Difference
316L has very low carbon content, typically less than 0.03%. This gives it better resistance to intergranular corrosion. The low carbon content prevents carbide precipitation during welding, reducing the risk of intergranular corrosion.
316 has a carbon content of around 0.08%, and although it still has good corrosion resistance, the higher carbon content may cause carbide precipitation in high-temperature environments, especially in the weld areas, leading to localized corrosion.
Corrosion Resistance
316L offers better corrosion resistance than 316, especially in applications where low carbon content and resistance to intergranular corrosion are required.
316 also has good corrosion resistance, but due to its carbon content, it is more susceptible to localized corrosion in welded areas when exposed to high-temperature and corrosive environments.
Welding Performance
316L’s low carbon content gives it superior weldability, reducing the risk of carbide formation and intergranular corrosion. This makes it ideal for high-strength welding applications.
316 needs special care during welding, as its higher carbon content can lead to intergranular corrosion in the welded joints if not properly treated.
Strength Difference
316L’s strength is slightly lower than 316, but it is still strong enough for most industrial applications, particularly where superior corrosion resistance and welding performance are critical.
316, with its higher carbon content, has better strength, especially in applications where strength is a priority and corrosion resistance is not as critical.
Application Areas
316L is typically used in areas that require low carbon content, high corrosion resistance, and excellent weldability, such as:
- Medical instruments (implants, surgical tools)
- Marine engineering (seawater pumps, heat exchangers)
- Chemical equipment (reactors, storage tanks)
- High-end food processing equipment (dairy and beer production,
316 is suitable for applications where strength is more important than corrosion resistance, such as:
- General industrial equipment (pumps, valves, heat exchangers)
- Aerospace, automotive parts
- Food processing (equipment and storage tanks)
Choosing between 316L and 316 depends on the specific requirements of your application, especially the need for welding performance and corrosion resistance. If welding and long-term corrosion resistance are crucial, 316L is often the better choice. If strength and performance are more critical, and localized corrosion in welded areas is not a concern, 316 may be more suitable.
At Manek Casting, we provide the production of 316L and 316 stainless steel parts. Our production processes include investment casting, sand casting, CNC machining and surface treatment.
For more information about 316L, please contact our business and technical staff. If you need to customize stainless steel products, you can contact our sales team directly.
