In modern manufacturing industries, 317L stainless steel is one of the most preferred alloys. There is a reason everyone turns to 317L stainless steel; it is corrosion-resistant. And its durability in harsh environments? Simply superb.
What else makes the 317L stainless steel outstanding?
Well, you’ll find out.
What Is 317L Stainless Steel?
You should know this first; the L in 317L stainless steel stands for low carbon.
317L stainless steel is different from 317 stainless steel. 317L stainless steel is, in fact, the version of 317 stainless steel with a lower carbon grade. So, it is more corrosion-resistant.
The lower carbon content in the 317L stainless steel makes it more weldable. This is the result of lesser carbide precipitation—a phenomenon which is common when welding metals with higher carbon content.
317L stainless steel belongs to the austenitic family of stainless steels. It is designated by UNS S31703. This code helps you identify the 317L and its properties in an industrial setting.
(Stainless steels in the austenitic family of steel have a face-centered cubic crystalline structure. They are also non-magnetic.)
Although the 317L stainless steel is austenitic steel, it is slightly different. It contains more molybdenum and nickel than your average austenitic stainless steel.
Hence, it has a higher resistance than other steels in this family to chemical attacks. It also withstands chloride-induced corrosion and reduces acid environments better.
Regardless of its recognized designated code, manufacturers make 317L stainless steel under different recognized standards.
These standards are coined based on the presentation of the 317L stainless steel.
Thus, you may find the metal as sheets designated ASTM A240; pipes designated as ASTM A312; fittings designated as ASTM A403; flanges designated as ASTM A182; tubes designated as ASTM A213, or other equivalents in your region.
Chemical Elements That Make up 317L Stainless Steel
317L stainless steel properties and its functions and applications are a function of the chemical elements that compose the metal. For a stainless-steel metal to pass as 317L stainless steel, it should comprise the following in these proportions:
| Chemical Element | Average Composition Content Range in Percent (%) |
| Chromium (Cr) | 17.5 – 20 |
| Nickel | 12 – 15 |
| Molybdenum | 3.5 |
| Carbon | ≤0.025 |
| Manganese | ≤2 |
| Silicon | ≤0.9 |
| Nitrogen | ≤0.10 |
| Phosphorus | ≤0.04 |
| Sulphur | ≤0.025 |
| Iron | Balance |
Of all the elements that you put into make up the 317L stainless steel, molybdenum and nickel stand out. Molybdenum and nickel improve the properties of 317L stainless steel above other stainless steels in its category.
Both elements enhance the pitting resistance, crevice corrosion resistance, and stability in harsh chemical situations.
Physical and Mechanical Properties of 317L Stainless Steel
After processing and annealing via heat, the mechanical properties of 317L stainless steel are deduced to be:
- Density: ≈7.9gm/cm³
- Electrical resistance: 84.9 – 85.2 microohm/cm at 20°C
- Tensile strength: 500 – 600 MPa (≈75 ksi)
- Yield strength: 200 – 250 MPa (≈30 ksi)
- Elongation yield: Within 30 and 40%
- Hardness (Rockwell): Approximately 80 –90 HRB
- Elasticity modulus: 190 – 210 GPa
- Melting range: 1365 – 1405 °C
This data shows why the 317L stainless steel is super weldable and excellently ductile.
The mechanical strength of 317L stainless steel and other properties make the metal a trustworthy material; your 317L alloy can withstand continuous stress, thermal cycling, and remains stable in high temperatures.
Distinguishing Features and Advantages of 317L Stainless Steel
Due to its unique composition, 317L stainless steel has its unique features and advantages. Some of these features include:
Long-lasting and durable
317L stainless steel is resistant to most forms of corrosion, chemical attacks, and cracks from stress unlike other steel types.
The nickel content in the stainless steel reduces this risk as you use the alloy. So for the equipment you make with the 317L stainless steel, they have a longer lifespan. In addition, the metal is for handlers.
When you get 3187L stainless steel equipment, you will rarely experience downtime or spend much on maintaining the equipment.
High Performance in High Temperature Environments
317L stainless steel happens to maintain its chemical composition in every kind of environment. The alloy maintains its oxidation resistance which often compromises its quality.
This quality gives your 317L metal its strength in moderate to high temperature applications. This feature makes the metal an ideal fit for making heaters, evaporators, chemical plants, and other equipment that should function under high thermal stress.
Superior Corrosion Resistance
The outstanding corrosion resistance of 317L stainless steel is the primary reason many manufacturers go for the material. And to state facts from testimonies about the metal, you should join the train too.
Because of 317L stainless steel’s unique composition, the metal is resistant to forms of corrosion common to the average steel. Common examples of these corrosive instances that you are familiar with are chloride-induced pitting, and different acids. 317L stainless steel can withstand acids like sulfuric, acetic, phosphoric, and organic acids, salt water, and so on.
Since the metal withstands tough chemical environments, you can use it for chemical processors, coastal installations, and fertilizer production.
It also works for petrochemical refining and saltwater-based systems. 317L stainless steel’s ability to function in chloride and salt water environments is due to its high PREN (Pitting Resistance Equivalent Number).
Low-Carbon Structure
317L stainless steel has one of the lowest amounts of carbon a stainless steel may contain.
Hence, it is more weldable; low levels of carbon prevent precipitation of the content during any heating procedure. For metals, lower carbon content means you retain the quality and quality of the metal in welded sections.
Excellent Weldability and Moldability
As 317L stainless steel is easy to weld, you can weld it using conventional processes such as GTAW, GMAW, and SMAW without causing intragranular corrosion. In addition, it is relatively simpler to mould and form the metal as it is bendable.
With the metal, you can fabricate tanks, pipes, or complex and custom machine parts and components.
Machinability
Like other members of the austenitic stainless-steel family, the 317L stainless steel hardens quickly. This may make machining with the metal a bit tedious.
To improve its machinability, you have to use sharp tools and slow cutting speeds. To further boost the machinability, ensure that you lubricate the metal well.
Poor Magnetism
Since most metals are sensitive to magnets, 317L stainless steel is a break from the norm. You can exploit the non-magnetic property of this metal to make transport pipes and bio-implants.
Limitations of the 317L Stainless Steel
- Compared to other forms of food-safe stainless steel, like 18/8, 304, 306, and 316, 317L is quite pricey. It is understandable as more concentrations of expensive nickel and molybdenum are added to make the metal.
- 317L stainless steel, although it can withstand several kinds of acids, does not do well with some acids, like nitric acid. The metal reacts with strong oxidizing acids generally.
- It is scarce compared to some forms of steel
- It is weightier than some metals with similar applications
Different Forms and Products of 317L Stainless Steel
317L stainless steel comes in a wide range of forms and products as it has a high demand. In general, the metal may be made into:
- Welded and seamless pipes
- Plates and corrugated sheets
- Metal coils
- Round metal bars and rods
- Forgings and billets
- Fittings
- Machine flanges
- Welding wires and electrodes
- Complex machine parts and geometries for industrial use, and so on
Applications of 317L Stainless Steel in Industries
For its several advantages, the 317L stainless steel is used in different industries. Some of the most common applications include:
Petrochemical and Refinery Systems
In refineries and petrochemical processing industries, highly corrosive chemicals are often used. Refiners and manufacturers perform production processes at higher temperatures too.
Because the metal is resistant to corrosion and heat, you may use them for making heat exchangers, distillation systems, and lasting refinery oil pipes.
Sea Water Structures and Desalination Equipment
Salt water is aggressive and highly corrosive, yet 317L stainless steel can withstand the fluid to a large extent. Your 317L properties make it a great fit for seawater pipes, osmotic systems, evaporators, and other equipment used in salt manufacturing industries.
Environmental and Pollution Control Systems
Manufacturers use the 317L stainless steel to make pollution control devices. Some of these devices include scrubbers, exhaust systems, gas handling equipment, sewage and waste management pipes, etc. These devices rely on the ability of your 317L alloy to withstand corrosive gases and fluids.
Chemical Processing Equipment
Manufacturers also use the 317L stainless steel to produce steady machine parts that can undergo chemical processes without a reaction. You can use the metal for making chemical reactors, tanks, agitators, and pipes used in chemical industries.
Paper Manufacturing
Paper manufacturing industries use some corrosive chemicals in their production process. Components like digesters, bleaching equipment, and processing tanks also benefit from the corrosion resistance attribute of your 317L stainless steel.
Food Industries
317L stainless steel is safe for some food applications too. So for equipment exposed to concentrated salts, acids, or sanitizing chemicals, the alloy works.
Pharmaceutical and Biotech Industries
Pharmaceutical and biotech equipment go through a series of sterilisations to ensure precise production of drugs and bio-safe substances. 317L cleaning ease and corrosion resistance make it ideal for making storage vessels, high-purity pipes, and sterile industrial parts.
Power Industries
317L stainless steel is also used to make industrial parts that can withstand the high temperature of that environment. The parts you can produce with the metal is the heat exchanger. Nevertheless, manufacturers also make condensers with the equipment.
Other industries where the 317L stainless steel is used include:
- Aerospace for making airplane components
- Automotive industries for making car engines
- Medical devices and implant production like braces, surgical pins, and surgical tools
- Water supply systems and pipes
- Fertilizer production companies
- Architectural and aesthetic uses such as for making decorative screens and sculptures, jewellery, and other accessories
- Structural engineering manufacturing industries
Maintaining and Cleaning 317L Stainless Steel
Luckily, the 317L stainless steel is low-maintenance because it is inherently resistant to many forms of corrosion. Nevertheless, to further enhance its lifespan, you should:
- Clean the stainless steel with non-chlorine detergents
- Regularly check welded and joined parts for signs of stress and weakening
- Avoid exposing the metal to stagnant chloride-rich environments
- When you expose the metal to highly corrosive solutions and substances in process plants, rinse out with a mild and acceptable solvent. That way, you’d prolong its lifespan.
Conclusion
317L stainless steel stands out for several applications and corrosive environments. At JiejaCNC, we are keen on delivering stainless steel grade metals with excellent mechanical strength and stability.
Do you have a metal or CNC machine need? Book us today!
FAQs
Does 317L stainless steel require post-weld heat treatment?
Not really. The 317L stainless steel metal already has a lower proportion of carbon, hence, carbide precipitation is minimal (if it occurs).
What is the recommended machining speed for 317L stainless steel?
317L stainless steel is work-hardening. And due to its work-hardening nature, machining speeds between 50 and 100 surface feet per minute are fine.
Nevertheless, for better results, you should pair this speed rate with sharp tooling and aggressive feed rates. You will also need sufficient cooling systems to maintain the surface finish after you work on the stainless steel.
Is 317L stainless steel hardenable by heat treatment?
No, 317L stainless steel is not very hardenable by heat treatment as the process does not yield desired results. You can improve the strength of the metal through cold working though.
How thick can 317L stainless steel be welded without preheating?
You can weld 317L stainless steel up to 1.2cm or half an inch thick without preheating it. You can attribute this strength to the good weldability of the metal and its low carbon content.
While half an inch is acceptable, you can weld thicker sections. However, controlling the heat you put in is vital.
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